MINERALS - ANUBIH - Naslovna · Herzegovina”, Book IV “Magmatism and Metalogenia” (1978). The Geological – Institute was awarded Veselin Masleša Prize for this book. As a

Fabijan Trubelja, PhDProfessor emeritus, University of Sarajevo

Ljudevit Barić, PhDProfessor emeritus, University of Zagreb

MINERALSof Bosnia and Herzegovina

Part 1 – Silicates

ANUBiHAHYБиХ

Sarajevo, 2011

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SILICATES

Fabijan Trubelja and Ljudevit BarićMinerals of Bosnia and HerzegovinaPart 1 – Silicates

Original title: Minerali Bosne i Hercegovine. Knjiga I – Silikati.Translated by Prof. Goran Kniewald,*1 PhD

Publisher: Academy of Sciences and Arts of Bosnia and Herzegovina, Sarajevo

Editor: Acad. Enver Mandžić, PhD

Technical revision: Prof. Goran Kniewald, PhD, Acad. Enver Mandžić, PhD

DTP: Štamparija „Fojnica“, Fojnica

Printed in Fojnica, Bosnia and Herzegovina, by “Štamparija Fojnica“ D.D. Fojnica, 2011

Circulation: 300

CIP - Katalogizacija u publikacijiNacionalna i univerzitetska bibliotekaBosne i Hercegovine, Sarajevo

549.6(497.6)

TRUBELJA, Fabijan Minerals of Bosnia and Herzegovina. ½Pt. ½1, Silicates / Fabijan Trubelja, Ljudevit Barić ; [translated by Goran Kniewald]. - Sarajevo : Academy of Sciences and Arts of Bosnia and Herzegovina, 2011. - 356 str. : graf. prikazi ; 24 cm

Prijevod djela: Minerali Bosne i Hercegovine. - Fabijan Trubelja, Ljudevit Barić: str. 6-7. - Bibliografija: str. 424-448.

ISBN 978-9958-501-65-41. Barić, LjudevitCOBISS.BH-ID 19153670

* Goran Kniewald (1955, Zagreb), Senior scientist and and Head of Laboratory for Physical Trace Chemistry, Department of Marine and Environmental Research, Rudjer Boskovic Institute, Zagreb, Croatia and Professor at the University of Zagreb, Faculty of Science, Department of Geology; visiting professor or scientist at Université de Toulon-Sud-Var, France; Institute of Chemistry and Dynamics of the Geosphere, Research Center Juelich, Germany; Scripps Institution of Oceanography, University of California, USA; Max Planck Institute of Chemistry, Biogeochemistry department, Germany; Institute of Applied Physical Chemistry, Nuclear Research Center Juelich, Germany; member of American Geophysical Union, European Union of Geosciences, Geochemical Society, International Symposia on Environmental Biogeochemistry and permanent court interpreter of English, German and Serbian language.

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MINERALS of Bosnia and Herzegovina

CONTENTS

Page

Preface ........................................................................................................... 9 Historical overview of the production, use and exploration of mineral resources of Bosnia and Hercegovina ............................................ 11I The period of production and use of mineral resources ......................... 11II The period of scientific exploration and research .................................. 20Olivine ........................................................................................................ 30Garnets ......................................................................................................... 39Hibschite ...................................................................................................... 48Zircon .......................................................................................................... 48Thorite ......................................................................................................... 53Andalusite .................................................................................................... 55Kyanite ........................................................................................................ 57Staurolite ..................................................................................................... 59Braunite ....................................................................................................... 60Titanite ........................................................................................................ 63Chloritoide, Ottrelite ................................................................................... 68Datolite ........................................................................................................ 69Hemimorphite .............................................................................................. 71Suolunite ..................................................................................................... 72Clinozoisite – Epidote ................................................................................. 75Clinozoisite ................................................................................................. 75Epidote ........................................................................................................ 78Allanite ........................................................................................................ 85Zoisite ......................................................................................................... 87Pumpellyite ................................................................................................. 90Vesuvianite .................................................................................................. 90Axinite ......................................................................................................... 90Beryl ............................................................................................................ 91Cordierite .................................................................................................. 100Tourmaline ................................................................................................ 101Pigeonite .................................................................................................... 111Diopside and Diallag ................................................................................. 111Augite ........................................................................................................ 111Omphacite ................................................................................................. 127Enstatite, Bronzite, Hypersthene ............................................................... 128Tremolite, Actinolite ................................................................................. 136

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Hornblende ................................................................................................ 142Glaucophane .............................................................................................. 155Crocidolite ................................................................................................. 155Wollastonite ............................................................................................... 157Tobermorite ............................................................................................... 158Xonotlite .................................................................................................... 159Rhodonite .................................................................................................. 164Pyrophyllite ............................................................................................... 165Talc ............................................................................................................ 166Muscovite .................................................................................................. 172Glauconite ................................................................................................. 179Phlogopite ................................................................................................. 182Biotite ........................................................................................................ 183Illite ........................................................................................................... 191Hydromuscovite ........................................................................................ 196Hydrobiotite .............................................................................................. 197Stilpnomelane ........................................................................................... 198Montmorillonite ........................................................................................ 198Beidellite ................................................................................................... 202Nontronite ................................................................................................. 204Saponite ..................................................................................................... 206Vermiculite ................................................................................................ 206Chlorite group ............................................................................................ 206Kaolinite .................................................................................................... 217Dickite ....................................................................................................... 224Nacrite ....................................................................................................... 224Chrysocolla ............................................................................................... 224Serpentine group ....................................................................................... 225Meta-Halloysite ......................................................................................... 237Sepiolite .................................................................................................... 238Prehnite ..................................................................................................... 242Searlesite ................................................................................................... 250Nepheline .................................................................................................. 254Analcite ..................................................................................................... 254Sanidine ..................................................................................................... 256Orthoclase ................................................................................................. 258Microcline ................................................................................................. 261Anorthoclase ............................................................................................. 262Hyalophane ............................................................................................... 264

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Plagioclase group ...................................................................................... 274Albite ......................................................................................................... 274Oligoclase ................................................................................................. 286Andesine ................................................................................................... 289Labradorite ................................................................................................ 295Bytownite .................................................................................................. 301Anorthite ................................................................................................... 306Lazurite ..................................................................................................... 308Scapolite .................................................................................................... 308Natrolite .................................................................................................... 309Scolecite .................................................................................................... 311Mesolite ..................................................................................................... 313Thomsonite ............................................................................................... 313Laumontite ................................................................................................ 316Stilbite ....................................................................................................... 317Chabazite ................................................................................................... 319References ................................................................................................. 326Index ......................................................................................................... 352

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FABIJAN TRUBELJA

(Ključ near Varaždin 1927 – Split 2007)

Fabijan Trubelja was born and educated in Ključ near Varaždin. In 1953, he graduated from the Faculty of Science, Department of Geology, University in Zagreb. As of 1953, he worked as an assistant lecturer for courses in mineralogy and petrology at the Faculty of Arts, University in Sarajevo. After having specialised in mineralogical and petrological research in Zagreb, he returned to Sarajevo and worked on his doctoral thesis “Petrology and Petrogenesis of the Magmatic Rocks of the Višegrad

Area in Eastern Bosnia”. After having successfully defended his doctoral thesis, he was elected senior lecturer in 1959, associate professor in 1968 and full professor in 1972 at the Faculty of Science, University in Sarajevo. In 1981, he was elected corresponding member, and in 1987 full member of the Bosnia and Herzegovina Academy of Sciences and Arts.

As a research worker, from the very beginning, Fabijan Trubelja started a mineralogical-petrological research of the problems of Triassic and Jurassic ultrabasic, magmatic rocks, and of the mineralogical features, genesis and classification of bauxite in Bosnia and Herzegovina, using the results of the specialist studies he had attended in Zagreb, Moscow and Leningrad. One of his most important theory contributions in mineralogy is a research into the weathering crust of the Jablanica gabbro and the emergence of bauxite matter in Herzegovina. By means of synthesising his theory knowledge and personal investigations in more than one hundred published papers, he has made a great contribution to the investigation of the geological evolution of the Dinarides.

Investigations of rare minerals in Bosnia and Herzegovina served him and Ljudevit Barić as the basis for writing a major work, “Minerals of Bosnia and Herzegovina – Silicates” in 1979, which was followed by “Minerals of Bosnia and Herzegovina – Non-Silicates” in 1984. In the capacity of an associate of the Geological Institute of Bosnia and Herzegovina, he was in charge of the project “Geology of Bosnia and Herzegovina”, Book IV – “Magmatism and Metalogenia” (1978). The Geological Institute was awarded Veselin Masleša Prize for this book. As a professor at the Faculty of Science in Sarajevo and the Faculty of Mining and Geology in Tuzla, he taught mineralogy, petrography, crystallography and other courses. He also wrote university textbooks for these courses.

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LJUDEVIT BARIĆ (Zagreb 1902 – Zagreb 1984).

Born and educated in Zagreb, Ljudevit Barić graduated from the University of Zagreb in 1927, receiving degrees in chemistry, physics and mathematics. These disciplines are fundamental to the study of mineralogy, the science for which he developed an enthusiasm already as a student. In the period 1929-1932 he went to Germany to study goniometric-methods and crystallometry with professor Victor Goldschmidt at Heidelberg where he aquired skills which he subsequently developed to utmost proficiency. Ljudevit Barić

also took courses in petrological methods (with prof. Erdmannsdörfer), X-ray crystallography and structure determination methods (prof. Schiebold, Leipzig) and rotating-stage methods in microscopy (prof. Nikitin, Ljubljana, Slovenia). In 1932 he was appointed as curator of the Museum of Mineralogy and Petrology in Zagreb. He received his PhD degree at the University of Zagreb in 1935, with a thesis on kyanite from Prilepac at Mt. Selečka in Macedonia.

His thesis was published in extenso by the Zeitschrift für Kristallographie in 1936, and his data were cited in all significant reference handbooks on optical mineralogy (Winchell, Tröger and others). He was appointed as assistant professor (1937) and associate professor (1941) at the University of Zagreb. After the II World War Ljudevit Barić was commissioned as director of the Museum of Mineralogy and Petrology in Zagreb (1954), where he worked until his retirement in 1973. As an adjunct professor of the Faculty of Science in Zagreb, he taught various courses in the field of mineralogy, and was well-known among his students as an excellent teacher.

He authored more than 150 scientific and professional publications, and several books, including the two-volume treatise on the minerals of Bosnia and Hercegovina (together with Fabijan Trubelja). In 1975, a new mineral – barićite – was named after him, in honour of his significant contributions to the science of mineralogy.

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Preface

This book is a translation of the first part of the two-volume treatise on the “Minerals of Bosnia and Herzegovina”. Book 1 of this set, dealing with silicate minerals, was originally published in Serbo-Croatian/Bosnian language in 1979. Book 2, on nonsilicate minerals, was published in 1984. When published, this set was the most comprehensive treatise on the minerals found in Bosnia and Hercegovina – as it is today.

In 2005 the Academy of Sciences and Arts of Bosnia and Herzegovina decided to translate the two volumes into English and thus make this valuable encyclopaedic compilation accessible to a much wider audience of mineralogists and earth scientists. This was initiated by one of the authors-Fabijan Trubelja, professor emeritus at Sarajevo University. Sadly enough, Fabijan Trubelja passed away in 2007 and would thus, unfortunately, not see the completion of his project. The task of editorial supervision of the translation was taken over by Enver Mandžić, professor at Tuzla University and full member of the Academy of Sciences and Arts of Bosnia and Herzegovina.

The style in which the two-volume set has been written reflects the foundations of the subject of mineralogy which lie in the systematic, taxonomic description of the compositions and structures of minerals and mineral groups. Even though this approach may today seem somewhat outdated, the translation follows the original text and only minor modifications have been made in cases where clarity or modern usage required this. The order in which the minerals are described follows the classic crystallochemical approach by Hugo Strunz (1966) and the formulae have also been written following his system. Even the one or two odd minerals which were subsequently rejected by the Commission on New Minerals and Mineral Names (CNMMN) of the International Mineralogical Association (IMA) have not been omitted in this translation. In the section on literature references, all titles of publications have been translated into English, except for those originally published in German or French. No new references have been added, except the one on the new mineral tuzlaite (in volume 2 – nonsilicate minerals), identified in the rock-salt deposits at Tuzla. This is the first and – up to now – only new mineral which has been found in Bosnia and Herzegovina. A recently published geological map of Bosnia has been added to the translation, and most diagrams and drawings were revised and reproduced using modern graphic tools. Several figures of thermal analysis spectra were omitted in the translation as they did not provide substantial information, or the data was duplicated in tables or otherwise.

The editors wish to express their sincere gratitude to Ms. Amra Avdagić from the Academy of Sciences and Arts of Bosnia and Herzegovina who supervised the translation project on behalf of the Academy and was instrumental in the keeping

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of the time plan. Asim Abdurahmanović edited all graphic material and produced new figures and drawings where required.

The editors – Enver Mandžić and Goran Kniewald

Original title and reference of the two-volume set:

1. Fabijan Trubelja i Ljudevit Barić (1979): Minerali Bosne i Hercegovine. Knjiga I – silikati. Zemaljski muzej Bosne i Hercegovine, Sarajevo, 452 pp.

2. Ljudevit Barić i Fabijan Trubelja (1984): Minerali Bosne i Hercegovine. Knjiga II – nesilikati.

Svjetlost, Sarajevo, 571 pp.

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Historical overview of the production, use and exploration of mineral resources of Bosnia and Hercegovina

Research into the history of mining and associated use of the mineral resources of Bosnia and Hercegovina, from the early times-based upon oldest available data – has shown that mining has during all those historical periods been an important activity for the economies of the people and ethnic groups living in the area. The rich mineral resources of Bosnia and Hercegovina have also attracted conquerors and others insurgents, but has also been of utmost importance in establishing frameworks of small scale economies and living conditions of the local, autochtonous population.

The following sections provide a historical overview of the exploration and use of the mineral resources of Bosnia and Hercegovina, from ancient times until the middle of the 19th century. The period of scientific research of our minerals and rocks will also give an overview of people who have contributed to this research.

I The early period of ore production and use of mineral resources1

1. Paleolithic to Roman era

There are only very few written documents or archaeological findings about the early period of mining in Bosnia and Hercegovina. Neither Roman nor Greek authors have provided any descriptions of these activities. Even more recent literature dealing with early mining activities in Bosnia and Hercegovina is based rather on assumptions than on more solid proof. Nevertheless, various archaelogical artefacts including relicts of mining activities and tools belonging to similar age groups, provide an indication of the geographical distribution, scale and methods of mining activities in this area during the early period.

There are three areas of importance in Bosnia and Hercegovina where more or less extensive and continuous mining activities have been taking place during ancient times, but also during the Illyrian and subsequent periods of various rulers, Roman through Austrian. Most important of these is the so called area of “central Bosnian mountains” located between the rivers Vrbas, Lašva, Neretva, Rama and their tributaries. The second one is the area of western Bosnia, bordered by the Vrbas and Una rivers, with its main orebearing formations found in the river-valleys of Sana and Japra, and their tributaries. The third area is eastern Bosnia, around the river Drina between the towns of Foča and Zvornik, the principal mining activity centered around Srebrenica.1

1 This section was written by Dr Ratimir Gašparović, professor at the Faculty of Natural Sciences and Mathematics in Sarajevo. His contribution is gratefully acknowledged.

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Ores of various metals, including iron, are found in these areas and exploitation has been going on for more than 5000 years – from the period of prehistoric human settlers, thorugh Illyrian, Roman, Slavic, Turkish and Austrian rulers, into the present. Various metals were extracted from these ores, including antimony, nickel, arsenic, manganese, chromium, copper, zinc, lead, bismuth, tin, cadmium, mercury, gold, silver and iron. But man, especially the prehistoric man, used these ores but also other minerals like quartz which was of importance for his daily life. It was found that the choice of temporary settlements of palaeolithic man was influenced by sources of quartz material – the palaeolithic settlements in the valleys of the rivers Ukrina and Bosna were close to these sources (Benac 1964, p. 17).

The mountains of central Bosnia are the most important area in Bosnia and Hercegovina where mining activities took place during the prehistoric and Illyrian periods. There are numerous remnants of mining and smeltering activity, including slag heaps, remnants of smelters, and washing sites. The most significant areas where mining took place are Mt. Vranica, the area around the township of Gornji Vakuf with tributaries of the rivers Vrbas, Bistrica and Krupa, the Lašva river valley and areas around Kreševo, Fojnica, Busovača and Vareš (Čurčić 1908, p. 86-89).

Already the oldest evidence of mining during the Illyrian period shows that substantial amounts of gold were produced from the alluvial deposits of the Vrbas and Lašva rivers and their numerous tributaries. Some Illyrian tribes probably lived in the “gold areas” of central Bosnia and were engaged in gold production. Thus the Ardianes living in the Lašva river valley fought the Antariates tribe, living around Fojnica and the Vrbas, Rama and Neretvica watershed, because of the gold. The Antariates were the most powerful Illyrian tribe, and they were neither agricultural nor artisanal people. Their wealth and power was rather based on gold (Rücker 1896, p. 18). According to some more recent authors, the Illyrians were knowledgable not only about the production of gold, but also of silver, lead, iron, copper and zinc (Pašalić 1975, p. 278).

The oldest iron production centers in Bosnia appeared during the Iron Age (8th – 1st century BC). Mining and iron working in this area was already taking place during the Bronze Age, evidence of which is provided by occurences of iron ores and production of charcoal used for smeltering. The locations of some slag heaps in mountainous areas around Fojnica and Kreševo indicate that mining was taking place here already in the pre-Roman i.e. Illyrian period, since it is well known that these tribes had their smelting camps located in well fortified and inaccessisble places. Several slag heaps, indicating the presence of smelting camps were thus found at the mountains of Vranica, Inč, Zahor, Lisina near Konjic, Karaula above Gornji Vakuf, Vilenica and Komar near Travnik, Konjuh near Olovo, Stožer west of Olovo and elsewhere (Pašalić 1975, p. 156).

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Contemporary development of mining and ironworking occured in northwestern Bosnia around the Sana river and its tributaries. A number of artefacts (slag, moulds, tools etc.) found close to prehistoric settlements around Sanski Most indicate that extensive iron working was taking place in this area (Fiala 1899, p. 62-128). Particularly large slag heaps were found at Blagaj in the Japra river valley, and around Čela (Radimsky 1891, p. 443-444). The amount of weathered slag together with the absence of other smelting constructions in a surrounding of dense oaktrees imply a very primitive iron working process, probably one of the first such activities in Bosnia. A similar Illyrian settlement where iron working was done is located in the Gradina and Majdan area near Jajce (group of authors 1966, p. 161-163; Radimsky 1893, p. 180-183).

During the Bronze Age, copper mining and copper working was taking place around the settlements of Mračaj and Mačkara, southeast of Gornji Vakuf. Remnants of smetling activities were found at Mt. Gradina near the village of Varvare close to the source of the Rama river. According to several researchers of prehistoric Bosnia and Hercegovina, extensive copper working was done in the area of the Rama river (Katzer 1907, p. 23; Čurčić 1908, p. 86-89). Metalurgical activity also existed at Debelo Brdo, located on the western flanks of Mt. Trebević, where one of the major Bronze Age settlements existed around Zlatište – Soukbunar (Čurčić 1908, p. 85).

2. The Roman Period (1st – 4th Century)

When the Roman Empire became a significant military and political factor during the 3rd century BC, its influence spread to the eastern Adriatic coast and its extensive hinterland, all the way north to the Danube. This area was inhabited by numerous Illyrian tribes, whose political and military organization was not particularly well founded. The Romans were very much aware of the geostrategic and economic potential of this region, and by conquering the area they secured their presence in the Adriatic, including important lines of communication between Italy, the Danubian basin and further on to the Middle East. The Illyrian region also had extensive resources in metal ores, timber and arable land. Immediately after their final conquest of the Illyrian lands in year 9 AD, the Romans partitioned the area into two major provinces: Dalmatia and Panonia. Most of the territory of Bosnia and Hercegovina became part of Dalmatia, while only the northernmost part, north of the line Bosanski Novi – Banja Luka – Doboj – Zvornik – Bijeljina were included into the province of Panonia.

Mining activities had an important role for the economy of the Roman province of Dalmatia, since Bosnia had the most significant resources of metal ores of the entire province. Some information about mining and metal working in this part of the Roman Empire can be found in writings of several authors (Anonymous

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1879; Plinius 1873), but most of the evidence is to be found in the field – remnants of mining and smeltering activity as well as administrative documents pertaining to mining. The first three hundred years after the Roman conquest in 9 AD were a period of peaceful economic and social development for local populations, including extensive mining activities. There is, therefore, evidence of mining and metal working from the first decades of Roman rule in Bosnia until its decline in the 4th century. Mining and smelting of gold started immediately, this being a continuation of earlier practice, from prehistoric times, over the Illyrian period to the Roman rule. The most productive gold mines during the Roman era were those around the upper part of the river Vrbas. There is ample evidence that the diluvial deposits of Mt. Vranica were mined for gold at the following localities: Rosinje, Radovine, Devetak, Crvena Zemlja, Uložnica, Zlatno Guvno etc. The alluvial sediments of the Bistrica and Krupa brooks, tributaries of the Vrbas river close to Gornji Vakuf, have been panned for gold and large amounts of washed-out gravel and sand was found in the area. Structures containing objects related to gold mining were located nearby (Jireček 1951, p. 69; Conrad 1871, p. 220; Rücker 1896, p. 20)2.

Extensive gold washing sites during the Roman period were located in the Lašva river valley at Vrela, Čosići, Đelilovci, where large piles of washed gravel can still be seen. Along the tributaries of Lašva river – Kaurski brook, Grovica, Večeriska, Dubravica, Dolovski brook, Krčevina brook, Panovac, Vraniska brook etc. similar larger or smaller gravel piles are located (Simić 1951, p. 117; Rückner 1896, p. 18-60).

The largest Roman gold washing sites were located in the Fojnička Rijeka river valley and Željeznica, tributary to the former. The washed-out material on these sites is around 15-20 meters thick, i.e. west of Gomionica (Foullon 1893, p. 46).

Due to the military character of the Roman Empire, and the numerous conquests and military missions it has undertaken, the need for iron mining and working became especially great during their rule in Bosnia and Hercegovina (Pašalić 1975, p. 46). During the Roman rule, mining activities increased substantially as compared to the Illyrian period – especially pertaining to iron production. Iron ore mined in Bosnia was transported to large state smeltering facilities at Sisak, Mitrovica and to Italy, due to the fact that transportation of ore from Bosnia was easier and cheaper than transport from other Roman provinces, or beyond those (Mikolji 1969, p. 18-19). Important sites of Roman iron ore mining and workings were at Bugojno, Donji and Gornji Vakuf, between Busovača and Kiseljak, at Fojnica, Kreševo, Vareš and Breza. Large amounts of iron slag originating from Roman and pre-Roman

2 Plinius the elder who lived during the reign of Emperor Nero in the 1st century AD notes that in the Gornji Vakuf area gold could be found on the ground, and sometimes as much as 50 pounds could be gathered in a single day

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activities was found in the vicinity of these sites. Substantial mining was done also in the western-Bosnian ore province, encompassing the watersheds of the rivers Sana, Una and Japra. Mines were located at Ljubija, Sanski Most, Blagaj, Bosanski Novi and elsewhere. Large amounts of slag was found at Ljubija (Adamuša). The local mining administration was located at Briševo near Ljubija (Pašalić 1975, p. 269; Mandić 1931, p. 35; Radimsky 1891, p. 431 and 437).

Extensive iron mining was also done around Majdan and Sinjakovo, near Jajce. There are indications that copper was also mined and worked in this area during the Roman period. Today, the impact of mining during the Austro-Hungarian rule prevails in the area.

Remnants of smelters can be seen in the vicinity of Mrkonjić-Grad, as well as in the town itself. This area was at a crossroads of Roman lines of communication, and it may be inferred that also here mining was important during the Roman period (Patsch 1898, p. 493).

The third region important for mining activities during the Roman rule is in eastern Bosnia, the most important sites around the Jadro river valley, at Ljubovija and Srebrenica. Close to Srebrenica was the Roman township of Domavia where lead ore was being mined and smeltered. The ead ore was also the source of silver, which alongside with gold and iron was the main mining product of Bosnia at the time. Some remnants indicate possible Roman mining activities around Foča (Pašalić 1975, p. 264; Pogatschnik 1890, p. 125).

Mercury production from cinnabar, tetrahedrite or their decomposition products probably took place already during the Roman period in Bosnia, although precise information is lacking. Since mercury is important in collecting small gold particles, it may be expected that some mercury production was going on since the requisite ore minerals were available. This was probably done at Čemernica, north of Fojnica and at Vranak close to Kreševo (Simić 1951, p. 130).

The decline of the Roman Empire in the 4th century AD saw also a decline in mining activities in Bosnia, especially with respect to iron production. Frequent hostile insurgencies into Roman provinces by Huns, Vandals, Markomans, Alans and Goths occured during the 5th century AD and looting was common. This also happened in Bosnia and Hercegovina, and the 300-year long rule of the Romans was terminated in the year 480 AD when the Gothic ruler Odoacar occupied Bosnia west of the Drina river.

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3. The Middle Ages (Early Slavic period – The State of Bosniain the Middle Ages, 7th Century – 1463)3

The prehistoric and Roman mining activities becan to decline in Bosnia and Hercegovina when the major movements of peoples commenced. Most of the mines in Bosnia and Hercegovina ceased their operations by the end of the 6th century, coinciding with the insurgencies of Slavic and Avar tribesmen into the region of the Balkans, and particularly Bosnia and Hercegovina. A revival of mining in the region took place only the latter part of the Middle Ages. In the late 12th and early 13th centuries Bosnia was ruled by Ban Kulin, during whose reign Bosnia experienced a significant rise in terms of political issues, economy and culture. Trade between Bosnia and Dubrovnik began in this period. Businessmen from Dubrovnik were granted mining concessions in Bosnia, and their colonies and townships became important in and around mining areas – at Duboštica, Kamenica, Olovo, Srebrenica, Fojnica, Ostružica etc. During the 13th and early 14th centuries Bosnia was ruled by Bans (a local ruler or viceroy) among which Stjepan Kotromanić II was the most important one. Bosnia flourished during his reign, with territories between the Sava river and the Adriatic coast, and the Cetina and drina rivers. A revival of mining activities takes place during this time, which coincides with a decline of mining activities in the rest of Europe. New mines were opened in numerous locations and they flourished until the end of the middle-age Bosnian state during the 15th century. The most important mining area of those days was the central-Bosnian ore province with eight active mines producing silver, lead, copper and iron, while information on gold production is inconsistent.

Silver was the most important metal produced in most of the mines in central Bosnia. Apart from the mine at Busovača which produced iron and Olovo producing lead, all other mines produced silver – the most productive ones at Fojnica, Kreševo, Dusina and Deževica (Jireček 1951, p. 69; Kovačević 1961).

Gold production during the Middle Ages in Bosnia cannot be compared with Roman times, when production was considerably larger. The old gold washings were worked by Saxon miners which were invited from Erdelj and Banat by the Bans of Bosnia during the 13th century. They re-washed those parts of the deposits which were considered to be nonfeasible for production during the Roman rule. This was the case with gold-washings at Vranica, and along the rivers Bistrica, Krupa, Vrbas, Lašva, Fojnička Rijeka and Lepenica, as well as their tributaries.

Concerning iron, it can be said that middle-age Bosnia was the only state in the Balkans which was not only selfsustaining in the production of iron but also was

3 The symposium ‘Mining and metallurgy in Bosnia and Hercegovina from prehistoric times to the 20th century’ was held in October 1973 in Zenica. Professor M. Vego presented a lecture on ‘The sources of information on mining in Bosnia and Hercegovina in the Middle Ages – 7th to 15th century’, p. 1-21, which we have cited here.

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able to export this commodity, mainly to Venice and the Middle East. The beginning of the 14th century saw steady exports of iron to Dubrovnik, the Venetian republic and to southern Italy. The Bans and Kings of Bosnia maintained in their possession the mining areas around Skoplje on Vrbas, and the areas around Fojnica, Olovo and Vareš. The main production and export centers were at Visoko and Konjic (Mikolji 1969).

Lead was, next to silver, the most important metal in terms of production quantities. The main production centres were at Deževica and Olovo, famous for its lead mines operated in the 14th and 15th centuries.

The Saxon miners were especially active in producing mercury from cinnabar, and the Čemernica mine – north of Fojnica – was considered as one of the most important bosnian mercury mines (Simić 1951, p. 124).

After the death of King Tvrtko at the end of the 14th century Bosnia was involved in numerous battles for the throne, fought by a number of bosnian feudal landlords whose might arose from political, economic and military power. After a period of internal turmoil, which resulted in a steady decline of its territory, Bosnia was finally occupied by the Turks in 1463 which had started their raids and conquests already during the late 14th century.

4. Period of Ottoman rule (1463 – early geological investigations in the mid-19th Century)4

The mining and production of metals in Bosnia, and elsewhere in the Balkan region, was revived with the advent of Ottoman rule. Production was continued using the technologies and manpower already available locally. The Saxon miners, which had been so important for maining practices in Bosnia during the Middle Age, had the most expertise. The businesspeople of Dubrovnik retained most of the mining claims. Nevertheless, there was a short period during which mining seems to have been interrupted, at the beginning of Ottoman rule. To mediate the problem, new mining regulations were introduced, including new contracts and mining concessions (Škarić 1935 and 1939; Spaho 1913, p. 133-194; Truhelka 1936).

4 Most of the information about this period can be found in the following publications: A. Handžić – 1. ‘Oldest turkish sources of information on mines in Bosnia’. Lecture presented at the Symposium on Balkanology in Istanbul, 15-21.9.1973. – 2. ‘Mining and mining areas in Bosnia in the second half of the 15th century’ and the publication by R. Skender ‘Mining in Bosnia during the 16th and 17th centuries based on turkish information sources’ – presented at the Symposium ‘Mining and metallurgy in Bosnia and Hercegovina from prehistoric times to early 20th century’, held in Zenica in October 1973.

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The first reliable information on mining in Bosnia and Hercegovina at the beginning of the Ottoman rule are derived from several regulations (canons) issued by Mehmed II the Conqueror (1451–1481) and Bayazid II (1481–1512) dealing with the mines at Srebrenica, Sasa, Crnča, Kreševo, Fojnica, Deževica, Dusina and Ostružnica. Information is provided about the exploitation of metal ores conatining silver, lead, copper and iron. During later period of Ottoman rule in Bosnia, several travellers write about mining in Bosnia, especially gold washing. First such data is given in the travelogues of Jeronim Zlatarić dated 1599, where gold washing on the Lašva river is mentioned. Grgičević (1626) and A. Đorđić (1626) mention gold washing and production around Fojnica. Both authors mention a decline in gold production, due to difficulties in exploitation and sale.

Production of mercury, gold, silver and iron in Bosnia is also mentioned in the 1771 travelogue of V. Brkić, while the frenchman Chaumette de Fosse in passing through Bosnia during 1807/1808 notes its rich mineral resources, particularly gold along the rivers Bosna, Vrbas, Lašva and Drina. The mining engineer A. Conrad (1871, p. 221) mentions that people from Dubrovnik were washing gold on the river Vrbas and its tributaries as late as the 1860-ies.

Based on written accounts and various administrative documents pertaining to the early period of Ottoman rule, as well as from various travel reports and similar sources, it can be seen that there were three important mining regions in Bosnia in those days: central Bosnia, eastern Bosnia and the river Drina region, and western Bosnia and the river Una region. Of some significance was alse the secondary region of the Krivaja river, northeast of central Bosnia.

The principal mines which operated in central Bosnia during early Ottoman rule were the following: Fojnica – settlement and silver/mercury mine and commercial centre for silver trade; Ostružnica – iron mine, mentioned in 1349 also as a silver mine, leased to Dubrovnik merchants; Kreševo – the second largest silver mine in Bosnia, generating ca. 30% less income than the Fojnica silver mine; the somewhat smaller silver mines at Deževica and Dusina, both in the Kreševo mining area; Mt. Inač, a very important occurence of cinnabar close to Deževica, from which mercury production by means of distillation was until the Austro-Hungarian occupation of Bosnia. The mercury from Kreševo was exported to Dubrovnik. Mercury production also took place in the Kostajnica valley, southwest of Kreševo (Rimska Jama). The Oberska Rupa locality was considered to be among the most productive mercury mining areas in Bosnia during the Ottoman rule. The Rimska Jama near Vranak, some 2.5 km west of Kreševo was an important mercury mine during the Roman period (Jurković 1956a, p. 5-20), and it is probable that production continued into the Turkish times.

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In the northeastern part of the central Bosnian ore province the folowing mines were active: Borovica – an iron and silver mine; Vareš – iron; Dahštansko, southeast of Vareš – silver; Busovača and Pržići – iron. The town of Visoko was also in the Middle Ages known to be an important mining and trade center.

The important Olovo lead mine in the Krivaja river valley was both a mine and trade center. Three smaller mines operated in the vicinity – Čičal, a lead mine which operated also during the Middle Ages (Cecegel 1382), and the Kruševo–Donje Podgrađe mine. The iron mine at Varci (today called Vruci) was first mentioned in the 16th century. The eastern Bosnian region encompasses the Srebrenica and Zvornik area. The Srebrenica mine (and the adjacent Sasa mine), known to have produced lead and silver from ancient times, was the main source of lead and silver in this area during the Ottoman rule. Silver was the main product, along with some lead and iron. Some of these mines were leased to Dubrovnik merchants. The Srebrenica mine generated a substantial income even at the beginning of the 16th century, althugh production agains starts to decline and the Sasa mine ceases all operation by the end of the 16th and early 17th century.

Other mines in this area, on the left bank of the Drina river were the following: Đevanje, Mratinci and Hlapovići, Đevanje being the most important one. In early 16th century it was known as a silver and lead mine, but in 1533 the locality is only mentioned as a township and not as a mine. A production decline was also seen at Mratinci, west of Bratunci, and the mine is mentioned no more in later documents. In the Srebrenica area, the Daljegošće mine produced iron, but likewise terminated operations at the beginning of the 16th century.

Further to the south of the Srebrenica region was the area of Višegrad and Čajniče, producing iron. In the Prača river valley the following mines operated: Hladilo (Vrhprača), Čelopek, Grabovica and Busovac (Buševac). During the Ottoman rule Čajniče is mentioned in 1468 and during the 16th century as an iron mining and trading center with some blacksmith shops and iron ore smeltering huts, although this area is not mentioned in earlier accounts to be of importance. Four mines operated also in the Goražde area: Križevo, Mrković, Kluščić and Bučje. Goražde was an important mining and trading center during early turkish rule, like Borač and Prača which both had strong links with Dubrovnik.

In the region of western Bosnia, iron production was the most important one. During the 16th and 17th centuries the Kamengrad iron mine near Bihać was of importance. According to a turkish document from the 16th century, there was an iron mine in this area between the forts of Ključa and Kamengrad. Another document from the early 18th century mentions a copper mine at the village of Bušavić, close to Kamengrad.

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There is not much information available about mining activities during the 17th and 18th centuries (and early 19th century). However, it is generally known that there was a steady decline in mining activities, compared to the beginning of the Ottoman rule in Bosnia and Hercegovina, or to the pre-Ottoman conditions during the Middle Ages. According to information, the silver mines in Bosnia and Hercegovina ceased production by mid-17th century. From the late 17th century onwards there is a steady decline in the military and economic power of the Ottoman Empire, and the decline in mining activities followed suit. However, mining and metal working never completely ceased in Bosnia and Hercegovina, as can be seen from travel reports of Hadži Kalfa, Evlija Ćelebija and A. Conrad. The devolution of mining activities in the Ottoman countries, hence also in Bosnia and Hercegovina correlates with a general degeneration of turkish economy and military power, leading to the termination of Ottoman rule in Bosnia in 1878.

II The period of scientific exploration and research5

1. The end of Ottoman rule in Bosnia and Hercegovina (1840–1878)

Until the middle of the 19th century Turkey was quite enclosed within its borders and influence from the western countries hardly existed. Then however, Turkey initiates a process of opening up – especially towards Austria and France. With permission of the turkish authorities many professional people start coming to Bosnia and Hercegovina – geologists, mining engineers, biologists, archaeologists, diplomats and military experts, initiating for the first time scientifically based investigations in the country. This approach has also included investigations of minerals and rocks in Bosnia and Hercegovina, its ores in particular.

Even though ores and minerals have been exploited in Bosnia and Hercegovina for ages, it was only then that systematic scientific studies were initiated. It is interesting to note that in that period geological sciences were rather well developed, both in western Europe as well as in Russia.

One of the first geologists who came to Bosnia and Hercegovina was Ami Boué. His travels in the Balkans (1836–1838) mark the advent of geological and mineralogical investigations in our latitudes. The first information on the geology of Bosnia and Hercegovina are the notes of A. Boué published in 1828 in ‘Leonhards Zeitschrift’, but most of his observations are contained in two publications: ‘Esquisse géologique de la Turquie d’Europe’ (1840) and ‘La Turquie d’Europe’ (1840a). Both of these publications contain significant scientific information and are the first account of rocks and minerals in Bosnia and Hercegovina. Ami Boué is thus rightly considered to be the founder of geological sciences in our area.

5 This section is authored by F. Trubelja

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The arrival of A. Boué and other professionals, diplomats and military experts in what was then Turkey, influenced also some changes in its social and political environments and in 1878 the territory of Bosnia and Hercegovina was occupied by the Austro-Hungarian Monarchy. This state of affairs can be deduced from reports which all these named professionals brought back to Vienna. Some of these reports were also published.

Other authors which have provided information on our minerals include D. Wolf, O. Sendtner (a botanist), J. Roskiewicz, M. Hantken, A. Conrad, O. Blau, K. M. Paul and others. These professionals may be regarded as forerunners to those eminent geologists from Vienna who arrived immediately before the occupation or shortly after 1878. It is interesting to note that J. Roskiewicz was a military officer, while O. Blau arrived as the Prussian consul. In his 1847 publication D. Wolf mentions the iron ores at Fojnica and mercury from Kreševo, correlating this occurence with the one at Idrija. He also described the galena from Vareš and rock salt from Tuzla.

M. Hantken (1867) first described the occurence of sepiolite (sea-foam) at the Branešci locality near Prnjavor, which was already quarried and used for making pipes. In spite of Hantkens publication, scientific authorities in Vienna were reluctant to accept our sepiolite, a rare mineral species, as a separate mineral. Twenty years later B. Walter (1887) mentions the occurence in Bosnia of magnesite which is macroscopically similar to sepiolite. Our petrologist M. Kišpatić (1893, p. 99) noted with some flippancy that following Walters paper, they were ready to dismiss our sea-foam from the list of Bosnian ores.

An interesting but overoptimistic account of Bosnian minerals and their economic importance can be found in several publications of A. Conrad (1866, 1870 and 1871). Data from his papers was used for an evaluation of the economic potential of some of our ore-bearing regions (such as the schist mountains of central Bosnia). The mining engineer from Saxony A. Conrad worked in Bosnia during 1866–1867 on behalf of the Turkish authorities. The information he collected concerned primarily the mercury-antimony-silver containg tetrahedrites, baryte, goldbearing quartz veins and goldbearing sulfides from which gold is released due to surface weathering processes of ore bodies in central Bosnia. In these papers Conrad explains that Bosnia has a nice future, because of its rich metal ores and extensive forests.

H. Sterneck (1877) published the first petrological map of Bosnia and Hercegovina and some adjacent areas.

An account of this early period of investigations and reporting on the geology of Bosnia and Hercegovina is given by L. Marić (1974). He writes that “these reports were written between 1846 and 1872 with an obvious goal to provide a good account

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of Bosnia and Hercegovina assets in ores and forests, and the economy in general. The reports also include information on communication lines such as rivers and roads – information which was shown to be of vital importance at the Congress of Berlin held in 1878. At the Congress of Berlin the Austro-Hungarian Empire was empowered to occupy Bosnia and Hercegovina, and this was done during the same year. The military occupation of Bosnia and Hercegovina also provided access to its natural resources which were needed by the Monarchy, especially the mineral and ore resources required for the industrialization of the Empire”.

2. Period of Austro-Hungarian Empire (1878–1918)

Immediately following the occupation of Bosnia and Hercegovina, a whole wave of geologists and petrologists started to arrive in the Balkans – mainly from Vienna, and to a lesser extent from Budapest. The geoelogists E. Mojsisovics, A. Bittner, E. Tietze. K. M. Paul, F. Hauer and others publish significant geological publications – some of them monographs – as early as 1879 and 1880. Even today we can find in them important information about our minerals. The most extensive and most important monograph of that time was written by Mojsisovics, Tietze and Bittner (1880) entitled “Grundlinien der Geologie von Bosnien-Herzegovina (Outline of the geology of Bosnia and Herzegovina)’’. This publication covers mostly geological issues, but contains also various mineralogical and petrological information. However, most important for mineralogy is the appendix to the volume written by C. John (1880) entitled “Über krystallinische Gesteine Bosnien’s und der Hercegovina (On the crystalline rocks of Bosnia and Hercegovina)’’. In this publication the author provides data on extensive microscopic investigations (also some chemical investigations) of mostly igneous and some metamorphic rocks and minerals contained in them. As noted by the author in the introduction, most of the samples were collected by the above named authors as well as some other geologists working in the area, on behalf of the Vienna Geological Survey.

John determined numerous rock-forming minerals in the muscovite-containing granite of Mt. Motajica, in the diabase porphyres from the river Vrbas valley between Donji Vakuf and Jajce, and from the Rama river valley close to Prozor. John paid considerable attention also to the rocks and minerals of the Bosnian serpentine zone (named as such by M. Kišpatić in 1897). He thus investigated diabases, diorites, olivine gabbros, serpentinites and other rocks from this area. Detailed microscopical data is provided for effusive rocks from Maglaj, from Mt.Vranica, and from the areas around Srebrenica, Ljubovija and Zvornik. The following minerals were found in these rocks: muscovite, orthoclase, quartz, hornblende, magnetite, calcite, epidote, augite, chlorite, ilmenite, diallag, biotite, olivine, garnet, oligoclase, labradorite, anorthite, sanidine, serpentine, picotite, apatite, halite, zoisite, actinolite. For some of these minerals John gave detailed microphysiographic data.

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Based on the above, John may be regarded as the founder of microscopic mineralogy and mineral chemistry in our area.

Several less detailed publications appeared during this time, but they were also of great value for knowing our minerals and rocks. Papers were published by F. Schafarzik (1879), A. Rzehak (1879), H. Rittler (1878), R. Potier (1879) and K.M. Paul (1872, 1879 and 1879a). Schafarzik (1879) identified andesine in the diabase on which the Doboj fortress was erected. More recently Lj. Barić found this andesine to have high-temperature optics. K.M. Paul (1879) also identified andesine in this rock.

Towards the end of the 19th century a local geologist (mineralogist and petrologist) started working in Bosnia and Hercegovina. This was Gj. Pilar, a professor of geology at the University of Zagreb. In fact, he joind the team of the austrian geologists Mojsisovics, Tietze and Bittner. It is important to note that Pilar published results of his investigations in a rather extensive paper published by the Yugoslav Academy of Sciences and Arts in Zagreb in 1882. Pilar identified various minerals in igneous and metamorphic rocks around Jajce – some of this minerals were not mentioned in earlier papers: chrysotile from Kozara, fluorite from Jajce, gypsum from Bosanski Novi. On pages 64-68 Pilar gives an account of ‘’Bosnian ores’’ known to him mentioning pyrite, baryte, arsenopyrite, chalcopyrite, cinnabar, realgar, orpiment, antimonite, tetrahedrite, tennantite, cuprite, hematite, quartz, chalcedony, picotite, chromite, magnetite, limonite, psilomelane, fluorite, calcite, dolomit, ankerite, siderite, malachite, gypsum, garnet, sepiolite and chrysotile. This list of minerals and descriptions of their parageneses was Pilar’s real contribution to topographic mineralogy.

In the period between 1878 and the end of the century, the following authors provided information on our minerals: G. Primics (1881), F. Hauer (1884), A. Götting (1886), B. Walter (1887), K. Vrba (1885 and 1889), H.B. Foullon (1893, 1893a and 1895), A. Rücker (1893 and 1897), F. Poech (1888 and 1900), W. Radimsky (1889), J. Grimmer (1897 and 1899) and L. Pogatschnig (1890).

During this period, and later, our mineralogist and crystallographer M. Kišpatić (1893, 1897, 1900, 1902, 1904, 1904a, 1904b, 1909, 1910, 1912, 1915 and 1917) also worked in Bosnia and Hercegovina. He published extensively, but his most important contribution is the monography on the rocks and minerals of the Bosnian serpentine zone (1897) which was also translated into German (1900).

Kišpatić authored the monography entitled “The crystalline rocks of the serpentine zone in Bosnia’’ which is of great significance for Bosnia and Hercegovina. Here he argues on genetic issues based on microscopic investigations of ‘Bosnian serpentines’ and associated basic rocks which he termed diabase and crystalline

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schists. His microscopic data are still valid today and have not been revised to any major extent. Based on qualitative and quantitative chemical and microscopic investigations, Kišpatić was able to identify many more minerals than found earlier by various investigators, mainly C. John. Thanks to the efforts of this tireless researcher, many minerals from this zone of igneous and metamorphic rocks in the inner Dinaride range of Bosnia were also chemically analysed (diopside, sepiolite, magnezite, broncite).

Kišpatić also investigated the Tertiary-age effusive rocks from Srebrenica and from the Bosna river valley where he was able to identify numerous rock-forming minerals (1904 and 1904a).

At the beginning of the 20th century Kišpatić authored an important mineralogical and petrological investigation, with numerous goniometric measurements of realgar, cerrusite, anglesite, pyrite, siderite, kalcite, quartz, heulandite and beryl and he was able to identify several crystal forms on several of these minerals.

Among the several publications by Kišpatić given above, we should point out the one published in 1912 where he gives data on minerals in bauxites from Duvno (Županjac) in Hercegovina. A student and coworker of Kišpatić, F. Tućan identified several minerals in the terra-rossa from the same area (1912).

Next to Kišpatić, other mineralogists and petrographers working in Bosnia and Hercegovina which need to be mentioned were F. Koch (1897, 1899, 1899a, 1902 and 1908) and M. Čutura (1918).

Several of the earlier mentioned foreign researchers gave important contributions to the knowledge of the minerals in Bosnia. The extensive publication by B. Walter (1897) entitled “Beitrag zur Kentniss der Erzlagerstätten Bosniens (Contribution to the knowledge of Bosnian ore deposits)’’ can be regarded as our first practical mineralogy text featuring detailed descriptions of ore deposits of iron, gold-bearing pyrite, chalcopyrite, manganese, gold, silver ores of Srebrenica, antimony, mercury and chrome ores. The parageneses are decribed in detail as well as their genetic implications.

Several years prior to the publication of Walters text, a publication authored by the famous viennese geologist (paleontologist) and director of the Vienna Geological Survey, F. Hauer (1884) appeared. This publication, entitled “Erze und Mineralien aus Bosnien (Ores and minerals of Bosnia)’’ is based on samples of minerals amd ores which were donated to the museum in Vienna by B. Walter (samples from Čemernica, Sinjakovo, Hrmza, Vareš, Pogorelica, Srebrenica, Čevljanovići, Vranjkovci, Duboštica). Hauer was able to identify the

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following minerals, based on physiographic characteristics and partly their chemical composition: realgar, orpiment, antimonite, galena, sphalerite, pyrite, arsenopyrite, tetrahedrite, chalcopyrite, cinnabar, boulangerite, berthierite, cuprite, hematite, limonite, psilomelane, pyrolusite, chromite, Ni-serpentine, cerrusite, baryte, ankerite, malachite and azurite. It is interesting to note that Hauer also described the graphite schists from the iron ore deposit Smreka (Vareš). Some chemical analyses of sulfide ores from Srebrenica are also given in the paper.

F. Boullon (1893) published an extensive paper on the mineral composition of schists from the central Bosnian mountains, describing some 30 mineral species.

K. Vrba (1885 and 1889) has undertaken crystallographic investigations of realgar from Hrmza in the Kreševo area. He was able to identify numerous crystal forms. J. Krenner (1884) has also published some data on the realgar and orpiment from the same location. These two researchers should be regarded as the founders of our crystallography since they were the first ones to undertake such investigations.

B. Baumgärtel (1904) and J. Schiller (1905) have also contributed to the knowledge of Bosnian minerals and rocks.

F. Katzer has a special place in the history of mineralogical research in Bosnia and Hercegovina. His contribution is most relevant and substantial. Katzer started his investigations into the geology and mineralogy of Bosnia immediately upon his arrival in occupied Bosnia and Hercegovina in 1898. When the Geological survey in Sarajevo was established in 1912, he became its first director and he headed this institution until his death in 1925. Katzer spent most of his career in Bosnia and Hercegovina, although he spent some time in Czechia and in Brasil. Based on this fact, and his major contributions to the geological investigations in our area, he can be referred to as a Bosnian-Hercegovinian geologist (mineralogist).

An evaluation of Katzers earlier publication shows that he was a most dilligent and productive researcher. However, the sheer volume of his investigations in Bosnia and Hercegovina causes a feeling of profound admiration towards his person. Among his publications on the mineralogy and ore-deposits of our areas, the following warrant mentioning: on iron ores from Vareš (1900 and 1910); gold-bearing alluvial deposits of the Pavlovac creek (1901); the Glauber-salt deposit in the Jahorina tunnel (1904); pyrite and chalcopyrite deposits (1905); deposits of tetrahedrite and mercury ore (1907); manganese ores from Čevljanovići (1906); ores from Sinjakovo and Jezero (1908); Bosnian sepiolite (1909 and 1912a); arsenic ores (1912); the bauxite deposit of Domanovići in Hercegovina (1917) etc. The largest amount of data on minerals are contained in his most significant publication – Geology of Bosnia and Hercegovina (1924, 1925 and 1926).

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An interesting feature of Katzer’s mineralogical investigations lies in the fact that he usually mentioned the combination of crystal forms he was able to identify, but seldom provided goniometric data. Due to the lack of such information, it is impossible to verify his results. The data on minerals usually included information on their hardness and density, but seldom optical information obtained by a polarizing microscope or other appropriate instrument. He gave considerable importance to quantitative chemical analysis. He describes in detail the paragenetic relationships in the investigated ore-deposits, and provides ample location sketches, profile and geological maps. Based on field observations and laboratory work, Katzer derives his conclusions on the genesis of specific mineral assemblages. His conclusions were mainly focused on the possibilities of ore and mineral exploitation, but never neglected fundamental scientific issues.

Some of Katzer’s conclusions were not completely correct, when they were based only on quantitative chemical analyses of minerals. This can be clearly seen from the example of the allegedly new mineral poechite, which he “discovered” in the iron ore bodies of Droškovac and Smrika near Vareš (1911 and 1921). The relative coherence of chemical data for poechite, which Katzer mentioned several times and which made him believe that it was a new mineral, can be easily explained. It is well known that in many major ore deposits a geologist or mining engineer can, based upon his knowledge of the ore body and its characteristics, recognize those ores whose chemical composition is practically constant. In such a case the reason for this is the aggregate of several major minerals, and not neccessarily a new mineral. Further investigations concerning poechite showed this to be a mixture of goethite, hematite and quartz (and sometimes rhodochrosite). The poechite from Vareš today is a discredited mineral species (Barić and Trubelja, 1975a).

Katzer (1917) made some significant conclusions regarding the genesis of the bauxites from Hercegovina, based on his research of this material from Domanovići. Katzer suggested that the material from which bauxite formed was transported from distant sources in the form of clayey silicate mud, subsequently litified into bauxite. However, he did not provide sufficient explanation for the process of bauxitization of these coastal muds. Katzer’s views on bauxite formation seem to have disagreed with current theories of bauxite formation of that time, advanced by M. Kišpatić and F. Tućan which postulate that bauxite has been formed from “red soil” (terra rossa) – this being an insoluble residue of the weathering of carbonate rocks in the karst of the Dinarides.

Katzer intended to produce a systematic description of all mineral occurences in Bosnia and Hercegovina. However, due to his numerous other commitments on the geological mapping of the area, he managed only to begin this work and provided data for graphite, sulphur, gold, mercury, copper and iron only (Katzer

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1920). His idea was to provide a “Topographic and practical mineralogy of Bosnia and Hercegovina”. Unfortunately, this task remained unfinished, much like his other significant project on the geology of Bosnia and Hercegovina in which he wanted to compile his great expertise on the geological relationships of the country, based upon twentyfive years of intensive research.

There is one more “document” of Katzer’s mineralogical research – the collection of minerals located in the State Museum in Sarajevo (Zemaljski muzej) containing all important mineral species from Bosnia and Hercegovina, and elsewhere, which Katzer obtained through direct exploration or through his international contacts and exchange. Even today this collection is frequently visited and studied by pupils, students and researchers, and is a part of Bosnia and Hercegovina’s cultural heritage.

It can be said without exaggeration that, due to Katzer’s research and activities, Sarajevo was in the first quarter of the last century a significant center of geological and mineralogical research in Europe.

3. Period between the two World Wars (1918–1945)

Very little mineralogical research was done in Bosnia and Hercegovina during the period between the two World Wars. Katzer’s Geology, discussed in the previous chapter, was established in this period. Although this was a period of decline of geological and mineralogical research in Yugoslavia, some investigations did take place nevertheless.

R. Koechlin (1922) published data on several rare minerals in the Ljubija ore deposit, and found nowhere else in Bosnia and Hercegovina – leadhillite and beudantite. These minerals are secondary products of galena weathering, and Koechlin performed crystallographic measurements on them.

In the Ljubija deposit there are also occurences of rhodochrosite, investigated in detail by Lj. Barić and F. Tućan (1925). The crystallographic features of sphalerite from the same locality were investigated by M. Tajder (1936).

The aforementioned book Geology authored by Katzer was translated by T. Jakšić and M. Milojković, two geologists from Bosnia and Hercegovina. At that time, this was an important contribution in the sense that information on minerals was made available to a broader public audience. Jakšić published several papers on the bauxites from Hercegovina (1927, 1934), rock salt in Tuzla (1929), arsenic minerals from Hrmza (1930, 1937) and manganese ores from Mt. Kozara near Banja Luka (1938). Another important paper on the geology and minerals of Bosnia and Hercegovina was written by M. Milojković (1929).

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A. Polić wrote two short papers – one on magnesite from Dubnica close to Višegrad (1938) and another, dealing with manganese ores from Mt. Ozren near Sarajevo (1940).

L. Marić (1927) authored an important petrological and mineralogical description of the gabbro complex of Jablanica in Hercegovina. Marić was able to identify numerous minerals in various differentiates of the gabbro, using a polarising microscope. Of particular value are the extinction angle measurement and other optical data obtained on feldspar, pyroxene, amphibole and other minerals. This data was used to obtain information on the chemical composition of these minerals. In addition to the above, Marić paid special attention to vein minerals like tourmaline, stilbite, calcite, pennine, quartz, titanite, prehnite, epidote etc. It is interesting to note that until the end of the second World War this was the only identification of prehnite (in the Jablanica gabbro) in Bosnia and Hercegovina.

Important contributions to the identification of several rock-forming minerals from around Višegrad in eastern Bosnia were made by S. Pavlović (1937), in his paper on ultrabasic, basic and metamorphic rocks of Mt. Zlatibor.

This short account of mineralogical and petrological research in Bosnia and Hercegovina between the two World Wars could not cover all work of all authors who were active in the area, but we hope to have given information on most important achievements. The appended reference list provides complementary information.

No organized research took place in Bosnia and Hercegovina during the 2nd World War.

4. Mineralogical research in Yugoslavia

In the previous chapter we have shown that in the period between the two World Wars there was no specialized institution for mineralogical and petrological research in Bosnia and Hercegovina, and that educated mineralogists were also very few. After the end of the 2nd World War, young geologists – educated in our universities in Zagreb, Belgrade and Ljubljana – started coming to Bosnia and Hercegovina and soon become very active with their research. In those early days these researchers worked at the Geological Survey (Geološki zavod, today called the Institute of Geology) and at the University of Sarajevo. Later on, a Department of Geology was established at the State Museum in Sarajevo, where fundamental research in geology, palaentology, mineralogy and petrology took place.

The University of Sarajevo was established in 1950 and two centers for research in the field of geology were set up. One of these centers was located in

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the Technical faculty (today called the Civil Engineering faculty), the other one in the Faculty for Philosophy (today called the Faculty of Natural Sciences and Mathematics). Courses in mineralogy, petrology and related disciplines started to be held at the Technical faculty, as well as research required by the engineering sector. Today, a well organised Laboratory for Mineralogy and Petrology is part of the Faculty of Natural Sciences and Mathematics, where research has been going on for the past twentyfive years.

These centers were being equipped with modern instrumentation, however with rather limited funds. Some major and costly equipment has been acquired only recently. Even though mineralogical and petrological research is quite important for many geological fields as well as the economic sector, the limited number of researchers was not always able to respond to all requirements. An important step forward was the establishment of the Faculty of Mining in Tuzla, later reorganised into the Faculty of Mining and Geology with its independent Department of Mineralogy, Petrology and Ore Deposits.

Today, organised high-level research is being done at the Geological institute in Sarajevo (Ilidža), the Faculty of Natural Sciences and Mathematics in Sarajevo and at the Faculty of Mining and Geology in Tuzla – comprising both fundamental research as well as applied investigations for the requirements of the industry and other customers. Chemical analyses, optical crystallography measurements, X-ray diffraction, IR-spectroscopy and other modern techniques form the core of these investigations.

The community of geologists, mineralogists and petrologists of Bosnia and Hercegovina is comparatively small but is involved in significant research leading to important scientific results. Research is published in the Journal of the Geological institute in Sarajevo (Geološki glasnik) and in the Journal of the State Museum in Sarajevo (Glasnik Zemaljskog muzeja), as well as in other local and international journals. Much of this research has been done in collaboration with colleagues from other research centers and groups.

In the period after the 2nd World War, the mineralogists and petrologists working in Bosnia and Hercegovina have been to numerous to be mentioned individually. It would be even harder to make a lists of all their results and achievements. To this end, we would like to invite the reader to make use of the rather extensive list of references, appended to this book.

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SILICATES

OLIVINE(Mg,Fe)2[SiO4]

Crystal system and class: Orthorhombic, Rhombic-dipyramidal;Lattice ratio: a : b : c = 0.467 : 1 : 0.586 (for Mg2SiO4)Unit cell parameters: a = 4.76, b = 10.20, c = 5.98, Z = 4 (Mg2SiO4); ao = 4.82Å, bo = 10.48Å, co = 6.11Å (fayalite Fe2SiO4). Properties: colour usually olivegreen (hence the name), also (Mg2SiO4); white (forsterite) and brown to black (fayalite). Cleavage weak and present only in Fe-rich members of the group. Hardness is 7-6.5, specific gravity 3.22 (Mg2SiO4) to 4.37 (Fe2SiO4), common olivine 3.3-3.4. Streak is white to gray. Vitreous lustre. Refractive indices are high: Nx = 1.635-1.827 Ny = 1.651-1.869 Nz = 1.670-1.879. Birefringence is high at 0.035-0.052.

X-ray diffraction data: forsterite d 2.77 (100), 2.51 (100), 2.46 (80), ASTM-card 7-19; fayalite d 2.83 (100), 2.50 (70), 2.57 (50), ASTM-card 7-164.

IR spectrum: 428 473 512 545 612 840 890 958 995 cm-1 (forsterite, Mt. Vesuvius, Italy); 418 475 516 612 848 898 950 1002 cm-1 (olivine, Teplice, Czech Republic).

OLIVINE IN BOSNIA AND HERCEGOVINA

A u t h o r s: Baumgärtel (1904), Đorđević (1969a), Đurić (1963), Golub (1961), Hauer (1879), Hiessleitner (1951/52), John (1879, 1880, 1888), Karamata and Pamić (1960), Kišpatić (1897, 1900, 1904b, 1910), Majer (1962), Majer and Jurković (1957, 1958), Marić (1927, 1953), Marković and Takač (1958), Pamić (1960a, 1964, 1969a, 1970, 1971, 1972, 1972c, 1972d, 1973 and 1974), Pamić and Antić (1964), Pamić, Šćavničar and Međimorec (1973), Pamić and Trubelja (1962), Paul (1879), Pavlovich (1937), Pilar (1882), Primics (1881), Ristić, Pamić, Mudrinić and Likić (1967), Schiller (1905), Sijarić and Šćavničar (1972), Sunarić and Olujić (1968), Trubelja (1957, 1960, 1961), Trubelja and Pamić (1957, 1965), Tscherne (1892), Varićak (1966).

Olivine is one of the most common and ubiquitous rock-forming minerals in Bosnia and Hercegovina. Numerous mountain ranges or parts thereof in the inner Dinarides range in Bosnia (Kozara, Borja, Skatovica, Ljubić, Ozren, Konjuh) are built of olivine rocks. These mountains spread from the northewest (Bosanski Novi area) towards southeast, close to the town of Višegrad. This area has been named “the Bosnian serpentine zone” by M. Kišpatić (1897, 1900) – here olivine is an

31


important constituent of ultrabasic and occasionally basic igneous rocks. Olivine is a constituent of peridotites and serpentinized peridotites, dunites, gabbro-peridotites, olivine-gabbros and troctolites (Figure 1).

Figure 1. Map of Bosnia and Hercegovina showing the location of the “Bosnian serpentine zone”

Outside the “Bosnian serpentine zone” olivine occurs in specific products of triassic magmatism (basic intrusive and dyke rocks), in the area of central-bosnian schist mountains, as well as near Jablanica and Kalinovik.

Data on olivine can be found in many petrological publications and monographs, implying that the results of optical microscopy and theodolitic measurements for olivine are rather numerous and detailed.

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SILICATES

1. Olivine in rocks of the Bosnian serpentine zone

Mt. Kozara. First information on olivine in igneous rocks of Mt. Kozara were published in 1882 by Gj. Pilar. According to him, olivine is an important constituent of olivine gabbro. Olivine is partially or completely transformed into serpentine.

The monograph by M. Kišpatić on the igneous rocks of the “Bosnian serpentine zone” provides substantial data on olivine and other rock-forming minerals (Kišpatić’s data-set on minerals of the “Bosnian serpentine zone” is quite extensive and largely composed of qualitative measurements). According to Kišpatić (1897, 1900) olivine is an essential constituent of lherzolite, troctolite and olivine gabbro. Kišpatić mentions or describes olivine in olivine gabbro of Kozaračka Rijeka, from Kotlovac stream and in the areas of Jankovića mill, Lake Benkovac, Kozarac, Omarska stream and the Bistrica river valley. In addition to olivine gabbro, Kišpatić describes olivine containing troctolites from Kotlovac stream. In gabbros from the Elkina spur, olivine is of subordinate significance. Kišpatić also describes the transition of olivine into amphibole.

Olivine is the most important constituent of lherzolite rocks of Mt. Kozara. Kišpatić provides optical microscopic investigations and descriptions of olivine in lherzolites from Kozarac, from the Benkovac and Elkina spur, Mimići and from Ljučica stream. In all these rocks olivine is more or less transformed into serpentine.

Detailed microscopic investigations on olivine in lherzolites, troctolites and olivine gabbros from various locations on Mt. Kozara are given in more recent investigations by Lj. Golub (1961). His data are given in Table 1.

Olivine in lherzolites from Jovača stream is in the form of “eyes” in a serpentine matrix. Troctolites from Jovača stream show olivine serpentinization and exsolution of magnetite. Most of the olivine crystals are rounded due to magmatic resorption. Some of the partially preserved olivine crystals are surrounded by a single or double layer of acicular amphiboles of the tremolite-actinolite isomorphous series. The amphibole layers around olivine have formed at the contact with plagioclase. The olivine content of olivine gabbro from Jovača stream is 17.9 vol %.

Rocks between the rivers Bosna and Vrbas. Numerous mountains (Prisjeka, Skatovica, Uzlomac, Borja, Čavka, Ljubić) or parts thereof located in the area between the rivers Bosna and Vrbas are composed of olivine rocks (mainly peridotites). Most of the microscopic data on olivine and other minerals comes from the already mentioned research by M. Kišpatić (1897, 1900). Olivine in rocks of this area is also mentioned in publications by other cited authors, but no detailed information is given. It is interesting to note that olivine in the olivine gabbros of Barakovac from the valley of the river Vrbanja was already determined in 1880 by John and in 1882

33


by Pilar. According to these authors, this olivine gabbro also contains labradorite and monoclinic pyroxene. This research provided first microscopic data on the olivines from the part of the serpentine zone.

Table 1. Optical axes angle and chemical composition of olivine

Locality and rock type Optical axes angle 2V Chemical composition

Jovača stream, lherzolite -2V = 88° (median value) 18% Fa

Vrela stream, lherzolite 2V = +88° to 2V = -88°(median value 2V = -89°)

16% Fa

Jovača stream, lherzolite -2V = 87° (median value) 21% Fa

Jovača stream, troctolite -2V = 80° to 87° (median value 84°) 28% Fa

Kozarački stream, olivine gabbro

-2V = 84°, 86°, 80°, 85°, 80° (median value -2V = 82°)

32% Fa

More recently, the olivine and other rocks of this area have been investigated by V. Majer (1962) and J. Pamić (1969a and 1972c). According to Pamić, olivine is the essential constituent of the ultrabasic complex of Mt. Skatovica. It occurs as hypidiomorphic and allotriomorphic fragments, with some crystals showing effects of pressure twinning. Chemically, they are enriched in forsterite (86-100%). The optic axes angle is in the range 2V = +86° to ±90°. The olivine is moderatly to significantly serpentinized, with occasional exsolution of substantial amounts of magnetite.

M. Tscherne (1892) needs to be mentioned as one of the early investigators mentioning olivine at Mt. Ljubić, occuring in association with the sepiolite formations in this area.

Mt. Ozren and the Bosna river valley. Mt. Ozren is located eastwards of the Maglaj-Doboj transverse and south of the Spreča river. It is built mainly out of ultrabasic olivine-pyroxene rocks which are partially serpentinized. Olivine is an essential constituent of these rocks.

Numerous authors have mentioned olivine in rocks of Mt. Ozren and in the Bosna river valley (Đorđević 1969a; Hauer 1879; Hiessleitner 1951/52; John 1879 and 1880; Kišpatić 1897 and 1900; Pamić 1973, Pamić and Trubelja 1962; Paul 1879; Trubelja and Pamić 1965). The original data by Kišpatić are also quite significant for the olivines of this area also. The author has microscopically determined olivine in troctolites of Vukovac stream, in troctolites and gabbros of Krušička Rijeka, troctolite from Rakovac, and lherzolites from Riječica, Mala Prenja, Krušička Rijeka and Vukovac stream. In thin sections prepared from the abovementioned rocks, olivine was fresh or somewhat serpentinized. Occasionally – mainly in troctolites – it transforms into colourless or pale green amphibole.

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SILICATES

More detailed microscopic investigations and theodolitic measurements of olivine and other minerals occuring at Mt. Ozren were performed recently by J. Pamić and F. Trubelja (1962) and F. Trubelja and J. Pamić (1965). Data on the optical axes angles are shown in Table 2.

Table 2. Data for olivine from Mt. OzrenLocality and rock type Optical axes angle 2VOstravica, dunite 2V = -89°, 89°, -86°, +86°, +87°Paklenica stream, feldspar-peridotite 2V = +89° to 2V = -85°Krivaja stream, serpentinized harzburgite 2V = +86°Malo Selište, serpentinized lherzolite no dataJadrina river, harzburgite 2V = +88°Pištala stream, lherzolite 2V = -84.5°Gostilj (774 m), lherzolite 2V = -85° to 2V = -88°V. Ostravica, harzburgite 2V = +81°, +86°, +88°

The dunite from Ostravica is largely a monomineralic olivine rock with very little secondary serpentine and accessory chromite. The olivine fragments are similar in size, fresh, always fractured and partly eliptically rounded.

Olivine and enstatite are the most important minerals forming the serpentinized harzburgites of the Krivaja stream. The fragments show fracturing along which the serpentinization process proceeds.

The olivine in the serpentinized lherzolites of Malo Selište is largely serpentinized so that only its relicts may be found in the matrix. These relicts display a high relief, lively interference colours and wavy extinction under the microscope.

Olivine in lherzolites of the Pištala stream and in harzburgites of V. Ostravica shows similar features as in other mentioned rocks. Some twinning of olivine crystals occurs.

Mt. Konjuh and the Krivaja river valley. Olivine is the essential constituent of ultrabasic and basic rocks of Mt. Konjuh and those of the Krivaja river valley (Baumgärtel 1904; Hiessleitner 1951/52, Karamata and Pamić 1960; Kišpatić 1897, 1900; Pamić 1970, 1974; Pamić and Antić 1964; Primics 1881; Ristić, Pamić, Mudrinić and Likić 1967; Sijarić and Šćavničar 1972; Sunarić and Olujić 1968; Trubelja 1961). Some of these authors provide information on olivine in the vicinity of the Duboštica chromite deposit.

More detailed microscopic investigations of olivine occuring in this part of the “Bosnian serpentine zone” can be found in publications by Kišpatić, Pamić, Ristić and coworkers, Šćavničar and Sijarić, and Trubelja. Results of theodolitic measurements of olivine from ultrabasic and basic rocks of the SE section of Mt. Konjuh are given in Table 3 (Trubelja 1961).

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Table 3. Data on olivine from the rocks of Mt. Konjuh

Locality, rock type Optic axes angle 2V Chemical composition

Lisac (970 m), lherzolite 2V = +88°, +89° 7-10% FaZečji vrat (1275 m), lherzolite 2V = +83°, +87°, +85.5° almost pure FoGrabovica stream, lherzolite 2V = +82°, +88°, +89°, +89.5° very little FaOlovo-Kladanj road, feldspar peridotite 2V = -87°, -87.5° 20% FaBlizanci stream, troctolite 2V = -85.5° 22.7% FaStupačnica stream, olivine gabbro 2V = -89.5° ---

Data presented in Table 3 show that the olivine in ultrabasic rocks is very depleted in the fayalite component. On the other hand, the olivine in feldspar-peridotites and gabbroid rocks contains ca. 20% fayalite which is consistent with the crystalisation and differentiation of peridotite magma from which the ultrabasic and basic rocks formed.

Olivine in the lherzolite from Lisac (970 m) amounts to ca. 60% of the total mineral content of the rock. It shows fracturing and some serpentinization, with secondary magnetite exsolution along the fractures.

Olivine in the lherzolite from Zečji Vrat (1275 m) shows extensive serpentinization, with exsolution of magnetite in the form of black dust in the serpentine matrix. Some olivine fragments are surrounded in a veil-like manner by enstatite.

Other lherzolite rocks in the area contain olivine which has undergone varying degrees of serpentinization. Olivine in the lherzolite from the source area of Grabovica stream shows a characteristic elliptically shaped magmatic resorption of almost all mineral fragments.

According to data by Ristić, Panić, Mudrinić and Likić (1967), olivine is an essential component of lherzolite and harzburgite from Mt. Konjuh, being of only secondary importance in gabbros. Some lherzolites contain almost 90% olivine. The fragments are fractured, serpentinized, with regular magnetite exsolution. The olivine is optically positive, with values of 2V = 82° to 89° which corresponds to ca. 14% of fayalite content.

The quantitative chemical analysis of olivine from Mt. Konjuh is given in Table 4.

36

SILICATES

Table 4. Chemical analysis of olivine from Mt. Konjuh1 2

SiO2 42.56 40.94Al2O3 1.04 0.69Fe2O3 0.47 0.68FeO 10.46 12.43MgO 45.44 44.24CaO 0.28 0.42TotalSpec. gravityComposition

100.253.43

88% Fo12% Fa

99.40 3.51

93% Fo 7% Fa

1 – olivine, Bebrave stream; 2 – olivine, nameless stream flowing into Lašva river

Ristić and coworkers provide x-ray diffraction data for olivine from Dinkovac – d 3.74 (1) 2.85 (4) 2.50 (1) 2.455 (3) 1.74 (1).

As mentioned previously, olivine is also the most common constituent of the investigated harzburgites. Serpentinization of olivine is quite extensive. The 2V values are 84°, 88°, 89° these values being almost the same for the optically positive olivine from lherzolite rocks. The olivines from gabbros have similar 2V values.

According to J. Pamić (1970), olivine in ultrabasic rocks from the Duboštica chromite deposit area is commonly allotriomorphic, often corroded and showing rounded edges. Its contains around 8% fayalite, and is almost always serpentinized to some degree, showing a wavy extinction in thin section. Pressure twinning is also present.

Based on diffraction data of the serpentine minerals associated with occurences of magnesite at Miljevci near Kladanj, Šćavničar and Sijarić (1972) identified olivine in the serpentine paragenesis.

The Višegrad area. Ultrabasic and basic olivine rocks are rather common also in the area of Višegrad in eastern Bosnia. Olivine is the dominant constituent of harzburgites and feldspar-peridotites, while of secondary importance in gabbros (Trubelja 1957, 1960).

In harzburgites from the Karaula spur near Dobrun, the olivine is present only in the form of “islets” in the serpentine matrix.

Olivine in harzburgites from Bosanska Jagodina in the Rzav river valley is also largely serpentinized. All fragments are elliptically corroded and sometimes completely embedded into enstatite. Some mineral fragments of olivine display distinct cleavage parallel to (010).

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The olivine in feldspar-peridotites from Bosanska Jagodina has several characteristic features. Its content in these rocks is around 50%. In thin section it is rather fresh and fractured, with magnetite in the fractures. The serpentinization process is still in its early stages. Most of the fragments are elliptically shaped and surrounded by amphibole of tremolite-actinolite composition, forming a distinct kelyphytic corona around the olivine – a textbook example of a kelyphytic reaction rim. This rim is best developed along the olivine-plagioclase contact.

Table 5. Data for olivine from the Višegrad area (Trubelja 1960)

Locality, rock type Optic axes angle 2V Chemical composition

Bosanska Jagodina, harzburgite 2V = +89°, +83°, +86°, +83° 0-10% FaKaraula spur (Dobrun), harzburgite 2V = +89.5° (median) 14% FaBosanska Jagodina, feldspar-peridotite 2V = -82° to 90° 13-17% FaGornji Dubovik, troctolite 2V = +87°, +86°, +84°, +89.5°, +86° 0-11% FaGornji Dubovik, troctolite 2V = 90°, 90°, +87°, +87.5° 13-20% FaMirilovići village, olivine gabbro 2V = +81°, 90°, +82°, +80° ---Rijeka (Velika Gostilja), olivine gabbro 2V = 90° (median) ---Banja stream (Lahci village), troctolite 2V = -85°, -86.5°, -87°, -88°, -89° 15-24% Fa

The elliptically shaped olivine fragments are commonly embedded in monoclinic or orthorhombic pyroxene, sometimes also in amphibole or plagioclase. The olivine shows a characteristic almost perfect cleavage parallel to (100). We feel the need to stress this finding since olivine is in the mineralogical literature usually described as having no pronounced cleavage.

Olivine is also the predominating constituent in troctolite from Gornji Dubovik. Almost all fragments are elliptically shaped and surrounded by plagioclase, Some fragments display a thin rim of augite. Primary magnetite is usually embedded in olivine fragments.

Data on olivine in basic and ultrabasic rocks of the Višegrad area can also be found in older petrological publications (John 1880, Schiller 1905, Pavlovitsch 1937). Research by M. Kišpatić must be mentioned since it made a significant contribution to our knowledge on olivine and other rock-forming minerals.

Marković and Takač (1958) have more recently investigated olivine in the olivine gabbros from Bosanska Jagodina. The olivine was optically positive, the 2V values = 88°, 88.5°, 86° corresponding to 18-21% of the fayalite component.

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SILICATES

2. Olivine in products of triassic magmatism

Outside of the “Bosnian serpentine zone” olivine occurs in the schist mountains of central Bosnia (Bijela Gromila), in products of triassic magmatism, as well as in more basic gabbro-type rocks at Jablanica.

Around Kalinovik, olivine is an important constituent of diabases and picrite-basalts occuring within the triassic volcanogenic-sedimentary series (Pamić 1960a). In the basalt-type rocks the olivine is substantially serpentinized and rich in forsterite.

First microscopic determinations of olivine in the schist mountains of central Bosnia were done by M. Kišpatić (1910). The olivine occurs as an accessory mineral in gabbro from a locality called Peredine Liske, close to the village of Kopilo.

Majer and Jurković (1957 and 1958) perfomed microscopic investigations of an olivine gabbro from Stajište-Margetići (Novi Travnik) where olivine is a principal mineral, together with hyperstene, plagioclase and some other minerals.

At Jablanica, olivine occurs as a constituent of the olivine gabbro series (John 1888; Kišpatić 1910; Marić 1927). Marić determined some optical constants characteristic of olivine. According to this author the maximum birefringence Nz – Nx = 0.035; the refractive indices measured by the immersion method are Nx > 1.645 < 1.646; Nz > 1.680 < 1.695.

3. Olivine in other rocks

According to scant data by Varićak (1966), olivine occcurs in amphibolites and amphibolite schists of Mt. Motajica, only in the porphyroblastic varieties. The grains are small and usually very fresh with some signs of magmatic corrosion. The optic axis angle 2V lies in the range between -82° and -86°, corresponding to chrysolite with ca. 20-30% of fayalite.

Uses

Olivine rock with a small content of iron, either fresh or partly serpentinized, are a valuable source material for the production of fireproof forsterite bricks. Olivine is also used as a metal casting sand, instead of quartz sand. This use is based on its high melting point -1890°C for forsterite and 1205°C for fayalite. The production of fireproof bricks requires a MgO : SiO2 ratio of around 2, meaning that the olivine should be depleted in iron. When this is not the case, the iron present in the olivine results in the formation of pyroxene which has inferior fireproof qualities. The quality of natural olivine material can be improved by the addition of magnesite.

The transparent, greenish-yellow variety of olivine (peridote) is also a popular gemstone.

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GARNETSThe Garnet Group

Almandine Fe3Al2 [SiO4]3 Pyrope Mg3Al2 [SiO4]3 Grossular Ca3Al2 [SiO4]3 Andradite Ca3Fe2 [SiO4]3 Uvarovite Fe3Cr2 [SiO4]3

Crystal system and class: Cubic, Hexaoctahedral class; Properties: garnets have no pronounced cleavage. Hardness = 6-7.5. Vitreous to resinous lustre. Colour depends on the mineral species i.e. chemical composition. Pyrope is dark red, pinkish-red, black. Almandine is red, dark red, black. Spessartine can be dark red, orange-red, brown. Grossular is yellow like honey, light green, brown, red. Andradite is yellow, greenish, dark red, black. Uvarovite has a characteristic emerald-green colour.

The refractive index, specific gravity and unit cell parameters vary:

n D ao (Å)Almandine 1.830 4.318 11.526Pyrope 1.714 3.582 11.459Grossular 1.734 3.594 11.851Andradite 1.887 3.859 12.048Uvarovite 1.86 3.90 12.00

Grossular, andradite and uvarovite sometimes display significant birefrigence.

X-ray diffraction data:d

Almandine 2.57 (100) 1.54 (50) 2.87 (40)Pyrope 2.58 (100) 1.54 (100) 1.07 (70)Grossular 2.65 (100) 1.58 (90) 2.96 (80)Andradite 2.70 (100) 3.02 (60) 1.61 (60)Uvarovite 2.68 (100) 3.00 (70) 1.60 (60)

IR-spectrum:cm-1

Almandine 455 480 527 570 638 872 902 970 1000 1090Pyrope 460 482 530 575 820 872 900 970 1000 1080Grossular 450 470 540 618 840 860 915 960 1080Andradite 428 482 512 592 820 840 895 930 1085Uvarovite 420 455 540 609 825 840 900 945 1000

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SILICATES

GARNETS IN BOSNIA AND HERCEGOVINA

A u t h o r s: Arsenijević (1967), Cissarz (1966), Čelebić (1967), Čutura (1918), Džepina (1970), Đorđević, Buzaljko and Mijatović (1968), Đurić and Kubat (1962), Foullon (1893), Gaković J. and Gaković M. (1973), Grafenauer (1975), Jurković (1957), Katzer (1924 and 1926), Kišapatić (1897, 1900 and 1912), Koch (1908), Kubat (1964), Magdalenić and Šćavničar (1973), Majer (1962), Marić (1965), Milenković (1966), Mojsisovicz, Tietze and Bittner (1880), Nöth (1956), Pamić (1960, 1969a, 1971, 1971a, 1972c and 1972d), Pamić and Kapeler (1970), Pamić and Maksimović (1968), Pamić, Šćavničar and Međimorec (1973), Pavlović and Ristić (1971), Pavlović, Ristić and Likić (1970), Pilar (1882), Primics (1881), Ristić, Likić and Stanišić (1968), Sijerčić (1972), Šćavničar and Jović (1961 and 1962), Šibenik-Studen, Sijarić and Trubelja (1976), Trubelja and Pamić (1957), Varićak (1966), Walter (1887).

Garnets belong to the group of fairly common and widely distributed rock-forming minerals in Bosnia and Hercegovina. They are most common in metamorphic rocks of the Bosnian serpentine zone, and have been studied in detail in these environments. Garnets are found both as principal and accessory minerals in igneous and metamorphic rocks of Mt. Motajica and the schist mountains of central Bosnia. Around Jablanica and Prozor the garnets occur as typical contact metamorphic minerals. In the triassic granits of Komar, garnet is incorporated in quartz grains. Being resistants and stable minerals, garnets frequently find their way into clastic sediments also.

1. Garnets in metamorphic rocks of the Bosnian serpentine zone

Early information on garnets in metamorphic rocks of the Bosnian serpentine zone can be found in the paper by C. von John (Mojsisovics, Tietze and Bittner 1880, p. 282). According to John, bright red garnet occurs in the Podbrđe eclogite. In thin section the garnet is colourless, surrounded by a chlorite layer formed from the garnet material. These garnets are also mentioned by Pilar (1882).

A substantial amount of information on the distribution of garnets in rocks of the Bosnian serpentine zone can be found in the monograph by M. Kišpatić (1897 and 1900). Through microscopic investigations of eclogites, eclogite amphibolites, amphibole eclogites, eclogite pyroxenites, amphibolites, pyroxene amphibolites, garnet pyroxenites and garnet phyllites, Kišpatić was able to determine garnets in the area of Mt. Pastirevo and Višegrad.

Thin sections of rocks where garnet occurs either as an accessory or principal mineral, garnet grains are seldom colourless and idiomorphic. They are mostly pinkish to reddish in colour. Grains are of irregular shape and fractured. Inclusions

41


in garnet are frequent and consist of omphacite, rutile, zircon – while feldspars are less common. Grains often have a kelyphytic corona, consisting of omphacite or amphibole. This summarizes the data provided by Kišpatić.

V. Majer (1962) mentions garnet as a constituent of garnet-gabbro and garnet-hornblendites in the area between the Vrbas and Bosna rivers. In these rocks the garnet is usually pink in colour. The amount of garnet varies within a broad range, and can sometimes comprise 90% of the total rock volume. Majer mentions a frequent kelyphytic rim around garnet grains in garnet gabbros, corroborating an earlier similar finding by M. Kišpatić. The kelyphytic rim is less common in the case of garnet hornblendites. According to Majer, the garnet gabbros and garnet hornblendites could be classified as igneous rocks, although their metamorphic origin cannot be completely excluded. To this end, no final opinion about the genesis of garnets – either as principal or accessory minerals – can be given.

Almandine garnet is a constituent of the garnet amphibolite og Mt. Čavka (Đurić and Kubat 1962; Kubat 1964).

According to Pamić and some other authors, garnet-containing metamorphic rocks are found in three independent parts of the Bosnian serpentine zone. The Mt. Skatovica area is located east of Banja Luka, where outcrops of amphibolite with garnet as the principal mineral occur. The second area is around Mt. Borja and Mt. Mahnjača, as already described by Kišpatić. Finally, garnet rocks at the southern flanks of the Mt. Krivaja – Mt. Konjuh metamorphic complex need mentioning. In this section of the Bosnian serpentine zone, garnet rock outcrops several kilometers in length can be found (garnet amphibolites, garnet-pyroxene amphibolite schists). In these rocks the garnet grains can be several centimeters in diameter, since they seem to be porphyroblasts with macroscopically visible rhombododecahedral and other crystal forms.

Some details on garnets extracted from amphibolites can be found in the papers by Pamić (1969a, 1971 and 1972c), and – particularly – Pamić, Šćavničar and Međimorec (1973). In the largely petrographic publication “Ultramafitic-amphibolitic rocks of Mt. Skatovica in the ophiolitic zone of the Dinarides”, Pamić (1969a and 1972c) provides the chemical analysis of the garnet fraction of these rock, and identifes it as a pyrope-type garnet (Table 6, column 4).

Pamić, Šćavničar and Međimorec (1973) have recalculated 5 chemical analyses of garnets in terms of their end-member chemistries – the data is given in Table 6. It can be seen that the chemical compositions of garnets in amphibolitic rocks can be quite different and variable, a fact which may be related to the variable chemistry of the host rocks. In other words, there seems to be a functional interdependence between the chemical composition of the garnets on one side, and that of amphibole and plagioclase on the other side.

42

SILICATES

Pyrope-type garnets (Table 6, columns 3 and 4) occur in rocks of andesine-labradorite and pargasite/edenite amphibole composition. Almandines (Table 6, columns 1 and 2) are rather associated with Na-andesine and chermakite-type amphiboles or “common hornblende”.

X-ray diffraction data of one garnet showed that the lattice parameter ao = 11.570 ± 0.003 Å, implying pyrope composition.

In a detailed description of rocks from the southern flanks of Mt. Borje, which have undergone regional metamorphism, D. Džepina (1970) provides data on refractive indices, unit cell parameters and composition of several garnets from various locatlities (Table 7). The garnet compositions have been derived from the Srimadas diagram, using refractive index values and cell parameters. The garnets occur as xenoblastic grains of different sizes ranging from large porphyroblasts to microscopically small grains. A kelyphytic reaction rim is a common feature of these garnets, inferring a reaction with other minerals derived from the rock (diopside, hornblende).

Table 6. Chemical composition of garnets from amphibolite rocksSample 1 2 3 4 5SiO2 38.5 39.3 38.94 38.46 39.0TiO2 0.09 0.07 --- 0.02 0.11Al2O3 21.4 21.7 18.61 21.70 21.4Cr2O3 nd nd 0.10 nd ndFe2O3 1.89 2.62FeO 24.7 22.5 16.96 13.99 24.2MnO 0.81 0.50 0.60 0.86 0.52MgO 6.4 7.3 13.75 12.75 6.0CaO 8.9 9.5 8.90 9.45 10.1Na2O nd nd --- 0.20 ndK2O nd nd --- 0.14 ndH2O+ nd nd --- --- ndH2O- nd nd --- --- ndP2O5 nd nd 0.09 0.05 nd

Total 100.80 100.87 99.84 100.25 101.33

Pyrope 27.6 24.5 45.8 45.9 22.6Almandine 45.7 49.5 31.7 28.3 48.6Spessartine 1.1 1.8 1.1 1.4 1.1Grossular 22.4 18.9 16.3 17.3 23.1Andradite 3.2 5.3 4.8 7.1 4.5Uvarovite --- --- 0.3 --- ---

Localities: 1, 2 and 4 – Mt. Skatovica; 3 – Mt. Konjuh; 5 – Mt. Čavka

43


S. Grafenauer (1975, p. 103) identified small uvarovite grains in the well known chromite deposit at Duboštica. Here, the chromite grains are very fractured. There is a zonal distribution of uvarovite with pyrrhotite and pentlandite, in the form of grains or veins. The veins can be rather long, but only about 1 μm thick.

Andradite occurs together with diopside, serpentine and chlorite at Mt. Ozren, near the village of Gornji Rakovac. The minerals were identified by X-ray diffraction (Šibenik-Studen, Sijarić and Trubelja 1976).

2. Garnets in rocks of Mt. Motajica

F. Koch (1908) was the first to describe the garnets in igneous and metamorphic rocks of Mt. Motajica. According to his microscopic determinations, the garnets occur mostly as accessory constituents of granite, muscovite-granite, biotite-granite/gneiss and micaschists. Granet is a principal mineral of the biotite-gneisses from Studena Voda and Kamen-potok near Korbaš. It occurs in the form of red nodules. In thin section the garnet grains are fresh and easily visible due to their rough surface. The smaller grains are usually birefringent. Metamorphic transformation into chlorite is common. Inclusions in garnet grains consist of magnetite, zircon, rutile and – sometimes – biotite. The garnets contained in biotite gneisses of Hercegov Dol and Bosanski Svinjar are strongly birefringent. The garnet is colourless and fresh, but fractured.

Table 7. Data on garnets from the Mt. Borje metamorphites

Locality Mineral assemblage N ao

Composition %Pyrope Almandine Grossular

Crni potok

hornblendediopsidegarnetplagioclase

1.767 11.64 23 37 40

Velika Usora

diopsideplagioclasehgornblendegarnet

1.772 11.57 33 46 21

Velika Usora

diopsidehornblendeplagioclasegarnet

1.767 11.57 36 43 21

Velika Usora garnethornblende

1.772 11.54 40 47 13

Borovnica

hornblendediopsidegarnetprehnite

1.768 11.57 35 44 21

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SILICATES

Velika usorahornblendegarnetplagioclase

1.772 11.59 26 48 26

Velika usora rodingitized garnet rock

1.752 11.56 46 29 25

F. Katzer (1924 and 1926) also mentions the garnets in rocks of Mt. Motajica. Results of more recent petrographic investigations of the Mt. Motajica garnets show that the garnets are common accessory minerals in granite, pegmatites, gneiss (amphibole and albite gneisses), cornites (biotite and pyroxene), gneissphyllites, amphibolites, amphibole schists and glaucophanites (Varićak 1966).

3. Garnets in rocks around Jablanica and Prozor

According to available literature data, garnets occur as products of contact metamorphism in the area south of Prozor, and in the magnetite body of Tovarnica near Jablanica (Nöth 1956; Cissarz 1956; Pamić 1960; Čelebić 1967).

Garnet has also been identified in the contact zone in the Crima creek – close to the village of Lug south of Prozor. It seems to be genetically associated with the albite diabase which protrudes through the Triassic limestones and upper horizons of the Werfen series. In addition to garnet, the paragenesis contains also epidote, clinozoisite, chlorite (probably pennine), hydromica, prehnite, sericite, albite, apatite, magnetite and pyrite (Pamić 1960). Relevant changes in the composition and grain size distribution of the material impacted by contact metamorphism are given in Table 8.

Table 8. Paragenesis of the contact metamorphism area south of Prozor (Pamić 1960)

Loca

lity

Dis

tanc

e fr

om ro

ck

(m)

Gra

in si

ze

(mm

)

Gar

net

Epid

ote

Clin

ozoi

site

Chl

orite

Hyd

rom

ica

Preh

nite

Seric

ite

Alb

ite

Apa

tite

Mag

netit

e

Pyrit

e

11 140-150 ca. 0.001

- - - - - - - - - - -

12 105-115 0.01 - - - - - - - - - - -13 ca. 10 0.05 - - - + + - - - - - +14 ca. 35 0.05-0.1 - - + - + - - - + - +15 0-10 0.1-0.6 + + - + - - - - + + -10 0-10 0.5 + - - + - - - + - + -17 ca. 45 0.05 - - + - + - - - - + -28 ca. 65 0.07 - - - - + - - - - - +29 0-10 0.05 + - - + - + + + - + -31 ca. 30 0.15 + + - + - - - - - + -

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In the western part of the contact zone (the Crima creek) the Triassic limestones have undergone alteration, while in the eastern part (Bare creek) mostly clayey schists of the Werfen series and marls with interlayers of limestone were affected.

Grossular is found in the immediate contact with albite diabase. In the rock the grossular appears to be yellowish and only sometimes green, however it is colourless in thin section. Some grains are idiomorphic in shape, and have a high relief. With crossed polarizers the grossular is completely isotropic (i.e. dark). Fracturing is common, with calcite filling the fractures.

The grossular was separated from the marble host rock by acetic acid, and analysed for chemical composition. The “end-member” compositions are shown in Table 9 (analysed by J. Pamić).

Table 9. Chemical analysis and the “molecular” composition of garnet from the Crima creekSiO2 39.30 Grossular 85.5%TiO2 0.22 Pyrope 6.4%Al2O3 20.95 Andradite 5.4%Fe2O3 1.93 Almandine 0.5%FeO 0.32 Spessartine 0.4%MnO 0.24

Locality: Crima creekMgO 1.72CaO 34.66Na2O 0.15CO2 0.52

The garnet crystals from the Crima creek locality show two crystal forms: the rhombic dodecahedron {110} and the icosatetrahedron {112}.

Another occurence of garnets formed by contact metamorphism is located near the rims of the gabbro body of Jablanica (Tovarnica), where the gabbro protrudes through Triassic limestones and schists forming an elongated and irregular metamorphism zone. The paragenesis of this zone was investigated in some detail by A. Cissarz (1956) – it consists of garnets, epidote, albite, calcite, magnetite and pyrite.

46

SILICATES

Figure 2. Exsolution sequence of minerals in the contact metamorphism zone of Tovarnica near Jablanica (Cissarz 1956)

A garnet of andradite-grossular composition is the oldest member of the paragenesis, alongside with calcite. Magnetite, together with minor amounts of pyrrhotite and chalcopyrite also formed in the initial phase. The Tovarnica locality is known for its potential as a magnetite ore body. The scarn mineral paragenesis of the Tovarnica region has been further described by Đ. Čelebić (1967) based on earlier microscopic investigations by S. Pavlović and coworkers.

J. Pamić and V. Maksimović (1968) have also identified a contact metamorphism paragenesis in sediments of Bijela, near Konjic, similar to the one in Crima creek. In addition to garnet, this paragenesis consists also of hydromica, clinozoisite, epidote and albite. The garnet grains are isometric, sometimes clearly idiomorphic, so that the crystal habit is usually observable. In thin section the garnet is colourless, has a high relief and frequently displays fracturing. It is isotropic under crossed polarizers.

4. Garnets in sedimentary rocks

Garnet is frequently found in sedimentary rocks, due to its mechanical stability and chemical inertness, and pertaining information can be found in numerous publications (Foullon 1893; Gaković, J. and Gaković, M. 1973; Magdalenić and

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Šćavničar 1973; Marić 1965; Pavlović and Ristić 1971; Pavlović, Ristić and Likić 1970; Ristić, Likić and Stanišić 1968; Sijerčić 1972; Šćavničar and Jović 1961 and 1962; Kišpatić 1912).

Foullon (1893) mentions an occurence of garnet in the alluvium of Zlatno Guvno and Bijela Gomila in the schist mountains of central Bosnia.

Small quantities of garnets can be retrieved from the insoluble residue of Triassic carbonates (clayey micrite, microsparite) around Glamoč, as well as in Triassic pelsparites, micrites and dolomites from Livno (Gaković and Gaković 1973).

The heavy mineral fraction of Pliocene sand from the Kreka coal basin also contains garnets (Šćavničar and Jović 1961 and 1962). The garnets from the “A” horizons are pinkish in colour, irregular and angular or subangular in shape. They are isotropic and display a high relief. Based on the refractive index of 1.81-1.83, determined by the immersion method, the garnet has almandine composition. Almandine can also be found in Miocene-age clastic sediments and Eocene sandstone.

Occurences of garnet in sands of the Tuzla basin are mentioned by Pavlović, Ristić and Likić (1970), Ristić, Likić and Stanišić (1968) and Sijerčić (1972).

Pavlović and Ristić (1971) describe an occurence of garnet in the quartz sand and gravels at Bijela Stijena near Zvornik. Magdalenić and Šćavničar (1973) have identified garnet in the heavy mineral fraction of Miocene-age sandy calcarenites from Lupina near Kulen Vakuf.

M. Kišpatić (1912) investigated garnets in bauxite from Studena Vrela (Duvno) – this research is also mentioned by L. Marić (1965).

Uses

Due to its hardness, absence of cleavage and irregular fracture, garnets are commonly used as abrasives. Garnets of almandine composition are most common abrasive agents, spessartine much less so. Best for this purpose are larger crystals which are ground into smaller grains and attached to paper or cloth. Such abrasive items are widely used for polishing various materials. According to literature data, about 90% of garnets produced are used as abrasives. The presence of lamellae is deleterious, since the grains are prone to split into platelike fragments under pressures attained in the abrasion process.

Transparent and attractively coloured garnets are frequently used as gemstones (almandine, pyrope, uvarovite).

48

SILICATES

HIBSCHITECa3Al2[(Si,H4)O4]3

Hibschite is apparently identical with plazolite (hydrogrossular). It crystalizes in the cubic system, with unit cell dimensions of ao = 12.02-12.16 Å. Part of the SiO4 tetrahedra are substituted with OH groups. It has a vitreous lustre, and is colourless to yellowish. Hardness = 6.5, specific gravity = 3.13.

X-ray diffraction data: d 2.68 (100), 3.00 (80), 1.61 (80)

In Bosnia and Hercegovina hibschite has been found within the Bosnian serpentine zone, at the confluence of the creeks Omrklica and Rakovac, at Mt. Ozren. It was identified by XRD and IR-spectroscopy (Šibenik-Studen, Sijarić and Trubelja 1976).

ZIRCONZr[SiO4]

Crystal system and class: Tetragonal, ditetragonal-dipyramidal class.Lattice ratio: a : c = 1 : 0.9054Unit cell parameters: ao = 6.604, co = 5.979, Z = 4.

Properties: cleavage weak along {110}. Hardness = 7.5, specific gravity = 4.6-4.7 (for crystalline varieties) decreasing to 3.9 for metamict varieties. Seldom colourless, mostly brown, redish-brown due to admixtures or inclusions. Streak is white, lustre vitreous to adamantine. Refractive indices and birefringence are high, depending on variations in chemical composition:NE = 1.96-2.02, NO = 1.92-1.96, NE – NO = 0.04-0.06

Zircon is optically positive, uniaxial.

X-ray diffraction data: d 3.30 (100), 4.43 (45), 2.52 (45), ASTM-card 6-0266.IR-spectrum: 438 455 618 895 1040 cm-1 (zircon, Haddan, CT, USA)

ZIRCON IN BOSNIA AND HERCEGOVINA

A u t h o r s: Barić (1966), Barić and Trubelja (1971), Čutura (1918), Džepina (1970), Đorđević (1969), Đorđević and Mijatović (1966), Đorđević and Stojanović (1964), Foullon (1893), Gaković and Gaković (1973), Jakšić (1927), Jovanović (1972), Jurković (1956, 1958, 1958a and 1961), Jurković and Majer (1954), Karamata (1953/54), Karamata and Pamić (1964), Katzer (1924 and 1926), Kišpatić (1897, 1900, 1904, 1904a, 1904b, 1909, 1912 and 1915), Koch (1908), Luković (1957), Magdalenić and Šćavničar (1973), Majer (1963), Majer and Jurković

49


(1958), Maksimović (1968), Marić (1965), Marić and Crnković (1961), Markov and Mihailović-Vlajić (1969), Mihailović-Vlajić (1967), Mudrinić and Janjić (1969), Pamić (1961, 1969a, 1970a, 1971a, and 1972c), Pamić and Kapeler (1970), Pamić and Olujić (1969), Pamić and Tojerkauf (1970), Pamić, Šćavničar and Međimorec (1973), Pavlović and Ristić (1971), Podubsky (1968 and 1970), Ristić, Likić and Stanišić (1968), Sijerčić (1972), Šćavničar and Jović (1961 and 1962), Šinkovec and Babić (1973), Tajder (1936, 1951/53 and 1953), Trubelja (1962a and 1963), Trubelja and Šibenik-Studen (1965), Varićak (1955, 1956 and 1966), Vasiljević (1969).

In Bosnia and Hercegovina zircon is a constituent of igneous, sedimentary and metamorphic rocks, mainly as an accessory mineral. It occurs mainly in granites, albitic granitoid rocks, quartzporphyres, gneisses and pegmatites. It is also commonly found in sedimentary rocks of the schist mountains of central Bosnia, as well as in eastern and western Bosnia. In these areas it is frequently associated with ore deposits. It also occurs as a accessory mineral in the metamorphic rocks (middle and high degree of metamorphism) of the Bosnian serpentine zone. Zircon is also found in the heavy mineral fraction of the carbonate rocks of the outer Dinaride complex. Because of its mechanical stability and chemical inertness zircon is frequently found in alluvial deposits and sands, as well as in other clastic sediments.

1. Zircon in the schist mountains of central Bosnia

In the schist mountains of central Bosnia zircon occurs in a variety of rocks, and has been described by numerous authors: Barić and Trubelja (1971), Čutura (1918), Foullon (1893), Jurković (1956, 1958, 1958a and 1961), Jurković and Majer (1954), Trubelja and Šibenik-Studen (1965). Earliest information on the occurence of zircon in alluvial deposits and sands of numerous rivers and creeks in the schist mountains of central Bosnia can be found in the paper by Foullon (1893). On pp. 32-33 of the cited paper, the author writes that zircon is associated with most minerals present in these deposits, with the exception of tetrahedrite (in the Mačkara forest), occuring sometimes in substantial quantities. It would be interesting to verify this data. Zircon is also an accessory mineral in quartzporphyres.

In his publication “Petrographic notes from Bosnia” M. Kišpatić (1904b) describes the occurence of small crystals of zircon in the chloritoid phyllites between Fojnica and Čemernica. This zircon is yellowish in colour and has strong birefringence.

In the schist mountains of central Bosnia, zircon is aloa associated with ore formations at Trošnik, Vrtlasce and Banjak, as a member of the high-temperature mineral series – together with rutile, tourmaline and apatite (according to I. Jurković).

50

SILICATES

Zircon has been described as an accessory constituent in granitoids, quartzporphyres and diorites of the schist mountains (Čutura 1918; Jurković and Majer 1954; Majer and Jurković 1958, Trubelja and Šibenik-Studen 1965).

Zircon can be rarely seen in thin sections of the altered rhyolites (hydromica-schists) found at Repovci village, west of Bradina. Occasional colourless zircon crystal sometimes have a bipyramidal shape, showing a high relief. The largest crystals were ca. 0.05 mm long and 0.017 mm thick (Barić and Trubelja 1971).

2. Motajica, Prosara, northwestern and eastern Bosnia

In northwestern Bosnia, within the Paleozoic-age series of rocks in the area of the rivers Una and Sana, zircon is sometimes found as an accessory mineral in sediments and metamorphic rocks, and in the parageneses of the Ljubija ore deposit (Kišpatić 1909, Marić and Crnković 1961, Podubsky 1968). Kišpatić was able to determine zircon in association with pyromorphite, limonite, cerrusite, anglesite, quartz and siderite (the Adamuša locality near Ljubija).

D. Varićak (1956) found zircon as an accessory constituent of the Mt. Prosara quartzporphyres. Most igneous and metamorphic rocks from Mt. Motajica contain zircon as an almost ubiquitous accessory mineral (Varićak 1966).

According to F. Koch (1908) zircon is a characteristic accessory constituent of the Mt. Motajica granite, gneiss and pegmatite. It is also found in micaschists and amphibolites. In the Vlaknica granite zircon occurs in the form of colourless egglike grains or crystals of prismatic or dipyramidal shape, and usually forms inclusions in feldspar, quartz and biotite. Koch mentions zircon in rocks from the Osovica creek near Šeferovac. In the biotite gneisses of Studena Voda, zircon occurs as numerous smaller and larger crstals of dipyramidal shape.

N. Mihailović-Vlajić (1967, pp. 194-195) gave a comparatively detailed account of zircon in various rocks of Mt. Motajica. Zircon occurs in the form of pinkish crystals 0.1-0.2 mm in size, in a combination of (100) and (111) crystal forms. Their length-to-width ratio is in the range from 1 : 2.5 to 1 : 3, in aplite-type rocks even 1 : 5. In other rock types (greisens) zircon shows (110) forms, and (311) forms (leucocratic rocks).

In muscovite-granites zircon occurs as opaque or almost black crystals 0.1 to 0.3 mm in size of characteristic dipyramidal shape. Sometimes the (110) crystal form in cobination with (111) can be observed. Colourless zircon is seldom present.

In aplitic biotite-granites the zircon is commonly colourless or yellowish, translucent and often showing signs of corrosion. Crystals are 0.1-0.4 mm in size.

51


Within the main granite body there is some zircon larger than 0.2 mm. The muscovitic, leucocratic and aplitic granites contain more of the corroded and colourless zircon, and these varieties usually amount to ca. 80% of the total zircon content. These crystals are always fractured, of lesser transparency and rounded edges. Crystals are sometimes malformed or torqued.

In all rock types of the Mt. Motajica granite, gasesous inclusions in zircon have been observed (mostly in muscovitic granite and greisens). Sometimes can a partial ‘overgrowth’ of zircon on metallic minerals be observed in biotitic granites. Zircon is a common accessory mineral of the Paleozoic-age sedimentary rocks and semimetamorphites of eastern and southeastern Bosnia (Podubsky 1970).

3. Zircon in rocks of the Bosnian serpentine zone

Zircon as an accessory constituent of rocks belonging to the Bosnian serpentine zone has been decribed by numerous authors: Džepina (1970), Đorđević and Mijatović (1966), Đorđević and Stojanović (1964), Karamata (1953/54), Karamata and Pamić (1964), Majer (1963), Pamić (1969a, 1970a, 1971a, and 1972c), Pamić and Kapeler (1970), Pamić and Olujić (1969), Pamić and Tojerkauf (1970), Pamić, Šćavničar and Međimorec (1973).

The occurences of zircon, mentioned by these authors, mainly pertain to igneous and metamorphic rocks in peripheral sections of the Bosnian serpentine zone (oligoclastites, albitic granites, albitic rhyolites, albitic syenites, amphibolites). It is most common in albite granitoid rocks.

4. Zircon in Tertiary-age effusive rocks and tuffs

Zircon as an accessory constituent of Tertiary-age effusives and associated tuffs occurs in various parts of Bosnia and Hercegovina (Barić 1966a, Đorđević 1969, Kišpatić 1904 and 1904a, Luković 1957, Tajder 1951/53 and 1953).

Microscopic investigations of tuffs from the Livno area showed that small quantities of zircon are present in these rocks. Crystals are very small, in the range of ca. 0.02-0.05 mm and have a high relief (Barić 1966a).

S. Luković (1957) identified zircon in the form of prismatic crystals in volcanic tuffs within Neogene-age sediments around Tuzla.

In the products of Tertiary magmatism (dacites) of the Srebrenica area and the river Bosna valley, zircon is only an infrequent accessory mineral (Kišpatić 1904

52

SILICATES

and 1904a). In dacites from Kneževac (around Srebrenica) zircon occurs in the form of beautiful, small crystals with prismatic and dipyramidal faces. It occurs both in the rock matrix as well as included in quartz or plagioclase.

Zircon occasionally occurs in tourmaline-quartz rocks around Srebrenica (Đorđević 1969).

5. Zircon in other rocks

Zircon is a fairly common constituent of the insoluble residues of Triassic carbonates from the outer Dinarides in Bosnia and Hercegovina (Gaković and Gaković 1973).

Due to its mechanical stability and chemical inertness, zircon often occurs in alluvial deposits and riverine sands, and in other clastic sediments. Jovanović (1972) found it in Pliocene-age sands of the Prijedor basin; Magdalenić and Šćavničar (1973) in clastic sediments of Lupina, Kulen-Vakuf; Pavlović and Ristić (1971) in the sands and gravels of Bijela Stijena near Zvornik; Ristić, Likić and Stanišić (1968) in the sands of the Tuzla basin; Sijerčić (1972) in the sands at Mt. Majevica; Šćavničar and Jović (1961 and 1962) in the sands and sandstones of the Kreka coal basin.

According to B. Šćavničar and P. Jović, zircon is a common constituent of the heavy mineral fraction of Pliocene sands of the so-called “A” horizons in the Kreka coal basins. It occurs as colourless or pinkish crystals, of short prismatic shape, more seldom elongated or needlelike. The authors believe that the zircon has undergone several events of resedimentation, and that it originates from acid igneous rocks, pegmatites and gneisses.

Trubelja (1962a and 1963) found zircon to be an accessory constituent of the quartzporphyres of Triassic age in the Lim river valley.

In the red granites of Mt. Maglaj, zircon occurs in the form of prismatic crystal 0.8 x 0.2 mm in size, with pronounced idiomorphism. They can be easily recognized under the microscope, due to its characteristic prismatic and dipyramidal shapes (Varićak 1955).

Zircon crystals have also been identified in some bauxites in Bosnia and Hercegovina (Kišpatić 1912 and 1915; Jakšić 1927; Maksimović 1968; Marić 1965; Mudrinić and Janjić 1969; Šinkovec and Babić 1973).

M. Kišpatić and T. Jakšić have both identified zircon in the bauxite from Široki Brijeg (Lištica) in Hercegovina. According to Kišpatić, zircon can also be

53


found in the bauxite from Studena Vrela (Duvno). Maksimović provides data on zircon from hercegovinian bauxites, while Mudrinić and Janjić found zircon in bauxite from Vlasenica in eastern Bosnia. Šinkovec and Babić identified detritic zircons in the bauxite from Grmeč (the Oštrelj deposit), with crystals 50 μm in size.

Uses

Zircon is a source of the elements zirconium and hafnium. It is also used in the production of ceramics and fireproof linings. Clean and transparent zircon is also used as a gem material (yellow-red hycinth, colourless, blue).

Zirconium oxide ZrO2 and metallic zirconium are widely used in nuclear reactor technology and for special alloys and glazings.

THORITETh[SiO4]

Crystal system and class: Tetragonal, ditetragonal-dipyramidal class.Lattice ratio: a : c = 1 : 0.627 (based on XRD data. The XRD and morphological orientation are different due to a 45° rotation around the vertical axis).Unit cell parameters: ao = 7.03, co = 6.25, Z = 4.Nomenclature and synonyms: In 1828 Prior M. Esmark found a dark coloured mineral in pegmatitic veins of the augite syenite at Brevik on Lövö island (Langesundfjord, southern Norway). Berzelius discovered a new element in this mineral, and in 1829 named it thorium, after the nordic god Thor. As a matter of fact, he used this name previously, in 1818, when he investigated some minerals from Falun in Sweden – but some years later realized that he was dealing with yttrium phosphate. The mineral was named accordingly thorite. In 1851 Krantz gave the name orangeite to the orange-yellow variety of thorite. The variety in which thorium is substituted with 8-20% UO3 has been named uranothorite. Ferrithorite may contain up to 13% Fe2O3, thorogummite contains water, calciothorite contains ca. 7% CaO. In auerlite (named after the Austrian chemist Auer von Welsbach) the SiO4 is partially substituted with PO4. In the case of macintoshite (named after the chemist J. B. Macintosh), it has been found that it is thorogummite with some uranium and cerium.

Properties: The crystal structure of thorite is usually metamict, because of its radioactivity. The usual consequences are a change of colour towards black, a decrease in specific gravity, hardness and refractive indices. In fresh (nonmetamict) thorite the refractive index is 1.84, specific gravity 6.7. Such thorite is clearly birefringent and optically uniaxial-positive. The dark variety is much more common – these are optically isotropic, the refractive index decreases to ca. 1.635, density is 4.1 and less, the hardness decreases from 4.5-5 down to ca. 2.5.

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SILICATES

X-ray diffraction data: d 4.68 (100), 3.55 (100), 2.65 (60), ASTM-card 11-72 (referenced after the Index to the X-ray powder data file, 1962, p. 364).

THORITE IN BOSNIA AND HERCEGOVINA

A u t h o r s: Markov and Mihailović-Vlajić (1969), Mihailović-Vlajić (1967), Mihailović-Vlajić and Markov (1967), Petrović (1957)

J. Petrović (1957) found thorite in riverine deposits of Mt. Motajica, and inferred that thorite must be an accessory constituent of the granites in this area. More detailed information was provided by Mihailović-Vlajić and Markov (1967) and Mihailović-Vlajić (1967).

The thorite from Mt. Motajica occurs as brightgreen grains, transparent and with a vitreous lustre. The surface and edges of the grains are sometimes overgrown with products of thorite hydration. These products have a darker, olivegreen colour, and have a lower transparency and lustre. In thin section, the edges of such grains appear darker and less transparent in transmitted light.

The thorite has been formed during the latter magmatic events, in the intergranular spaces between quartz and feldspar grains – in the aplitic sections of the Mt. Motajica granite. This finegrained granite contains up to 4.18% (vol.) thorite, as analysed by N. Kreminac. The biotite and biotite-muscovite granites contain only traces of thorite, while it is completely absent in the overlying gneisses and amphibole-biotite granites and pegmatites.

The grainsize of thorite varies in the range between 0.1-0.3 mm, seldom up to 0.4 mm. In the aplitic granite thorite occurs in grains of up tom 1 mm in size. Accord-ing to information provided by Mihailović-Vlajić and Markov (1967, p. 71), the thorite grains are xenomorphic, crystal faces can be observed only rarely. In a later report (Mihailović-Vlajić 1967, p. 198) the author mention that thorite occurs as crystallites or incompletely idiomorphic crystals, with a length-to-width ratio of 1 : 2.5. In the aplitic granite this ratio increases to 1 : 5. The faces {110} and {111} can be observed on some crystals. Prism faces are narrow or completely absent (Figure 3).

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Figure 3. – Thorite from the Mt. Motajica granite (Mihailović-Vlajić 1967)

In their investigations, the authors collected rock specimens of ca. 80-150 kg. These were crushed and the material was used to obtain a heavy concentrate on a vibrational table. This concentrate was then fractionated using heavy liquids (bromoform, methylene iodide and Clerici's solution) or using a magnet. The obtained fractions were investigated by binocular loupe and a polarising microscope. This procedure was used to identify and retrieve thorite grains that were subsequently analysed with spectrochemical methods.

According to Mihailović-Vlajić and Markov (1967, p. 76) the Mt. Motajica granite is a typical example of thorite enrichment and complementary uraninite depletion in the late magmatic phases (vein stages). There is a further brief reference to thorite in the Mt. Motajica granite by the same authors (Markov and Mihailović-Vlajić 1969, p. 257).

ANDALUSITEAl2[O|SiO4]

Crystal system and class: Orthorombic, rhombic-dipyramidal class.Lattice ratio: a : b : c = 0.982 : 1 : 0.703Unit cell parameters: ao = 7.78, bo = 7.92, co = 5.57, Z = 4.Properties: cleavage pronounced along {110}. Hardness = 7.5, specific gravity = 3.13. Occurs in different colours – colourless, white, gray, brown, pinkish-red, green. Streak is white, lustre vitreous to resinuous. Refractive indices are high, birefringence is low. X-ray diffraction data: d 5.54 (100), 4.53 (90), 2.77 (90).IR-spectrum: 415 440 455 480 520 558 600 685 735 775 855 895 938 1010 cm-1

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ANDALUSITE IN BOSNIA AND HERCEGOVINA

A u t h o r s: Katzer (1924 and 1926), Koch (1908), Majer and Pamić (1974), Ristić, Likić and Stanišić (1968), Šćavničar and Jović (1961 and 1962), Varićak (1966), Vasiljević (1969).

According to available literature data, andalusite is not a very common rock-forming mineral in Bosnia and Hercegovina. As a typical metamorphic mineral, andalusite has in a primary setting been identified only in the Mt. Motajica series, and in metamorphic shales of Mt. Borja within the Bosnian serpentine zone. As a resistant mineral, andalusite has been found in sands of the Tuzla basin and in quartzites from Podrašnica near Mrkonjić-Grad.

1. Mt. Motajica

Koch (1908) gave a description of two micaschists in which he was able to identify andalusite. He classified one of these rocks as a chiastolite containing micaschist, with outcrops around Vinogradac, close to Svinjar. The other rock was determined as an andalusite containing micaschist, with outcrops in the nearby Resavac creek.

Andalusite is a major constituent of the Resavac micaschist. Here it occurs in the form of large grains or short prismatic crystals. Sections are usually squarelike, with rounded corners. There are two cleavage systems, at right angles to each other. It shows parallel extinction under crossed polarizers. Interference colours are vivid. Andalusite is normally colourless, but some grains are pinkish-red or yellow in colour, showing strrong pleochroism. Pleochroitic colours are reddish and yellow, in thicker sections the colours are olive-green, yellow and brownish-red.

Andalusite normally contains numerous inclusions. Koch determined the minerals quartz, ilmenite, biotite, muscovite and a carbonaceous material as inclusions.

In his treatment of the Geology of Bosnia and Hercegovina, Katzer (1924 and 1926) mentions andalusite data compiled by F. Koch.

According to Varićak (1966), andalusite is an accessory constituent of some gneissphyllites and micaschists of Mt. Motajica. Thin sections of these rocks contain andalusite as colourless, sericitized grains with a well developed cleavage. Measured optic axial angles on a teodolite (rotating stage) microscope vary in the range 2V = -82° to -85°.

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2. Mt. Borja

In the northwestern part of the ultrabasic massif of Mt. Borja within the Bosnian serpentine zone, andalusite occurs in altered shales (Majer and Pamić 1974). Andalusite grains are prismatic, their sections are square shaped. They are fresh, or into a mixture of sericite and biotite. The authors provide no further data on the andalusite from this locality.

3. Andalusite in sedimentary rocks

B. Šćavničar and P. Jović (1961 and 1962) have determined andalusite in the heavy mineral fraction of the Pliocene-age sands of the Kreka coal basin. It occurs almost exclusively in the gray sands underlying the coalbeds. The andalusite variety of chiastolite has also been identified. A characteristic pink pleochoritic colour is observable under the microscope. Prismatic crystals display parallel extinction and posess a negative elongation character. The authors believe that this andalusites originates from rocks impacted by contact metamorphism.

In the sands of the Tuzla basin andalusite has also been determined in the heavy mineral fraction and amounts to 0.1-1.5 % (Ristić, Likić and Stanišić 1968).

According to R. Vasiljević (1969) andalusite occurs in sedimentary quartzites at Podrašnica near Mrkonjić-Grad (data by S. Pavlović and D. Nikolić).

Uses

Andalusite is primarily used in the production of high quality fireproof materials, used mainly for automobile spark plugs. When heated, andalusite, sillimanite and disthen are transformed into mullite (3Al2O3.2SiO2). This material has not only good fireproof properties but is also chemically unreactive in contact with acids, bases and HF. Minerals of the kynite (disthen) group are used in the fabrication of a SiAl alloy – silumine.

KYANITE / DISTHENEAl2[O|SiO4]

DISTHENE / KYANITE

Crystal system and class: Triclinic, pinacoidal class.Lattice ratio: a : b : c = 0.9066 : 1 : 0.7102, α = 89° 58.5’, β = 101° 08.5’, γ = 105° 57’Unit cell parameters: ao = 7.10, bo = 7.74, co = 5.57, Z = 4.Properties: cleavage perfect along {100}, very good along {010}. Parting along {010}. Hardness is variable (thus the name) = 4-7, specific gravity = 3.63. Usually

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SILICATES

blue in colour, occasionally patchy colouration; green, white or gray colour are also common. Refreactive indices are high, birefringence is low.X-ray diffraction data: d 3.18 (100), 1.38 (75), 3.35 (65). ASTM-card 11-46.IR-spectrum: 442 470 512 550 572 598 610 628 630 645 720 905 952 1010 1040 1640 cm-1

A u t h o r s: Jakšić (1927), Kišpatić (1912 and 1915), Marić (1965), Ristić, Likić and Stanišić (1968), Sijerčić (1972), Šćavničar and Jović (1962), Tućan (1912), Vasiljević (1969).

As a typical metamorphic mineral, up to now kyanite has not been found in primary rocks in Bosnia and Hercegovina. The cited authors have, however, noted its presence as an accessory constituent of clastic sediments, bauxite and terra rossa – where its presence is explained by its mechanical stability.

First information on kyanite in bauxite and terra rossa was simultaneously provided by M. Kišpatić and F. Tućan. According to Kišpatić (1912 and 1915) kyanite can frequently be found in the bauxites from Studena Vrela (Duvno) and Široki Brijeg (Lištica) in Hercegovina. In the Široki Brijeg bauxite, kyanite occurs in the form of small, colourless platelets. The extinction angle in the (100) section is 31-32°. Jakšić (1927) has identified kyanite at this same location.

F. Tućan (1912) identified kyanite in the terra rossa near Eminovo Selo (Duvno). The data on kyanite, provided by Kišpatić and Tućan, can be found in the publication on terra rossa in dinaric karst systems by L. Marić (1965).

Ristić, Likić and Stanišić (1968) have identified kyanite in the heavy mineral fraction of the sands from the Tuzla basin.

T. Sijerčić (1972) determined kyanite in the heavy mineral fraction isolated from the Eocene-age flysch deposits in the western part of Mt. Majevica.

According to B. Šćavničar and P. Jović (1962) kyanite occurs sporadically in the heavy mineral fraction of the Pliocene sands of the Kreka coal basin.

R. Vasiljević (1969) notes the occurence of kyanite in sedimentary quartzites of Podrašnica (Mrkonjić-Grad), based on microscopic determinations by S. Pavlović and D. Nikolić.

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STAUROLITE2FeO . AlOOH . 4Al2[O|SiO4]

Crystal system and class: Monoclinic (pseudo-orthorhombic), prismatic class.Lattice ratio: a : b : c = 0.471 : 1 : 0.340, β = 90°Unit cell parameters: ao = 7.83, bo = 16.62 co = 5.65, Z = 4.Properties: cleavage very good along {010}, very good along {010}. Hardness = 7, specific gravity = 3.7-3.8. Colour is brown, streak gray. Vitreous lustre, sometimes resinuous.X-ray diffraction data: d 1.387 (100), 2.38 (50), 1.96 (50).IR-spectrum: 435 485 595 650 695 785 802 855 910 1030 1090 1170 3420 cm-1 (staurolite, Scaer, Finisterre, France).

A u t h o r s: Đurić (1963a), Ristić, Likić and Stanišić (1968), Šćavničar and Jović (1962).

Staurolite is a comparatively rare and moderately investigated mineral in Bosnia and Hercegovina. It has been identified, together with magnetite, near Čajniče and in clastic sediments of the Tuzla basin.

According to S. Đurić (1963a), the occurence of staurolite at Stravnje njive near the village of Okosovići (ca. 6 km north of Čajniče in southeastern Bosnia) is associated with the magnetite deposit. This can be seen from the microphotographs in this publication.

In thin section, staurolite frequently shows the characteristic twinning in the form of a cross. It has a high relief. Measurements on a rotating-stage microscope gave an optic axial angle 2V = +88°. The vibration direction Z of the optical indicatrix is codirectional with the crystallographic axis [001]. Pleochroism: yellow for vibration direction X, almost red for direction Z. The edges of the “cross”-twins are mutually perpendicular.

Magnetite, occuring near the village of Okosovići, has formed on the contact of sercite phyllites and amphibole granites. Since the genesis of magnetite is probably associated with the pneumatolytic processes following the granitization phase, we believe that this could also explain staurolite formation.

Staurolite is commonly found in the Pliocene sands of the Kreka coal basin (Šćavničar and Jović 1962). Grains are irregularly shaped, of yellow or brown colour. They have a high relief, and a visible pleochroism in the range from colourless to yellow. The authors believe that the staurolite is associated with the highly metamorphic crystalline rock series. Staurolite was also determined in Miocene-age clastic sediments.

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SILICATES

Ristić, Likić and Stanišić (1968) determined staurolite in the sands of the Tuzla basin. The heavy mineral fractions contains 0.5-1.8 % staurolite.

Use

According to H. Kirsch (1968) staurolite can be used as an abrasive material, because of its hardness. Twins in the shape of a cross make popular jewelry items in some countries.

BRAUNITEMn2+Mn6

4+[O8|SiO4]

Crystal system and class: Tetragonal, ditetragonal-dipyramidal class.Lattice ratio: a : c = 1 : 1.9904Unit cell parameters: ao = 9.38, co = 18.67, Z = 3, Mn : Si = 7 : 1Properties: cleavage perfect along {112}. Hardness = 6-6.5, specific gravity = 4.72 -4.83. Colour and streak are darkbrown to black. Semimetallic lustre.X-ray diffraction data: d 2.69 (10), 1.65 (9), 1.415 (8) d 2.75 (10), 1.66 (10), 1.415 (8)IR-spectrum: 455 480 530 555 625 712 815 850 953 1015 1040 1112 cm-1

BRAUNITE IN BOSNIA AND HERCEGOVINA

A u t h o r s: Hauer (1884), Jeremić (1959), Jurković (1956), Katzer (1906), Kubat (1969), Pavlović (1890), Pavlović (1953), Poech (1888), Vujanović (1962), Walter (1887).

Within the occurences of manganese minerals in Bosnia and Hercegovina, braunite is probably one of the most common minerals – together with psilomelane and other manganese ore minerals. However, more detailed information on the occurence of barunite in different parageneses is available only for the Čevljanovići area.

1. Braunite in the area of Čevljanovići

The earliest and somewhat scanty data on braunite occurence at Čevljanovići can be found in the publications by F. Hauer (1884), B. Walter (1887) and F. Poech (1888).

In his general account on manganese ores in Bosnia, Walter (1887) maintains that braunite is of less importance in terms of quantity. However, braunite and

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pyrolusite are the principal components of the manganese ore at Vranjkovci. Large chunks of braunite, weighing between 1-350 kg have been found in the surrounding diluvial deposits. In a description of the Vranjkovci manganese deposit, Hauer writes that braunite was mistakenly regarded as hausmannite, but that braunite crystal were found in some geodelike formations. This was already noted by Foullon (see section on hausmannite).

Katzer (1906) found no evidence for the presence of braunite, manganite or hausmannite in the Čevljanovići deposit.

More recent research by S. Pavlović (1963) has identified braunite as a principal constituent of the manganese mineral parageneses found at Čevljanovići.

A detailed mineralogical investigation of the Čevljanovići ore deposit (Vujanović 1963) provides a better account on the importance of manganese minerals in this area. According to this investigation, braunite is the principal mineral of primary parageneses. It is also present in the so-called thermal (regenerated) parageneses at Čevljanovići, Draževići and Mt. Ozren.

Minerals belonging to the primary manganese paragenesis are the most important part of the ore which was mined here in earlier days. This ore is found in the form of veins of various thickness within the mid-Triassic volcanogenic-sedimentary series of rocks. Here, braunite is the main manganese mineral, followed in importance by cryptomelane, romanechite, hausmannite and manganite. Manganite is normally associated with these Mn minerals (Figure 4).

The minerals of the primary paragenesis have sustained alteration during subsequent hydrothermal events. Some of them have recrystallized within the primary deposit – forming “thermal” braunite and other minerals of this regenerated paragenesis (romanechite, hausmannite, manganite, Mn-calcite, rodochrosite, calcite, quartz etc.).

Vujanović determined the main properties of this braunite by optical microscopy and differential thermal analysis. The DTA curve shows a clear endothermic peak at 1125°C.

Braunite occurs here in the form of a finegrained mass, with a grain-size range between 1 and 30 μm, apparently forming from an initial gel.

The braunite posesses a weak bireflection, and a weak to clear anisotropy. Internal reflections are common, as determined by ore microscopy.

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Figure 4. The mineral paragenesis at Čevljanovići (Vujanović 1962)

Braunite is commonly associated with cherts, and more seldom with schists. When associated with cherts, braunite occurs as irregular intergrowths or dispersed. Intergrowths withg hematite are common.

According to Vujanović, braunite occurs at the following localities in the Čevljanovići area: Gornji and Donji Gojanovići, Gornji and Donji Vrgalj, Velike Šume and Grk.

The genesis of braunite in primary parageneses is the same as that of psilomelane (see section on psilomelane).

2. Occurence of braunite in northewestern Bosnia

M. Jeremić (1959) provided very general data on braunite occurences in northwestern Bosnia. Occurences of manganese ore minerals lie along the transect Bosanska Krupa – Bužim – Velika Kladuša, and braunite appears to be the main constituent of these ores. Pyrolusite frequently occurs together with braunite.

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According to Jeremić, the main occurence of braunite is in Bužim Polje. Other localities, also for pyrolusite, are Mačkovac, Kajtezovac, Varoška Rijeka, Cenić Glavica, Lubarda and Porić Selo.

3. Occurences of braunite in eastern Bosnia

In eastern Bosnia, braunite is a constituent of manganese and iron parageneses, which are genetically and spatially associated only with the Mesozoic-age formations in the Mioče – Strmica area, on the right banks of the Lim river. Braunite and other manganese minerals are to be found only in the Mioče area, at the localities Gornji i Donji Jelići and Jagline.

4. The schist mountains of central Bosnia

In the area of the schist mountains of central Bosnia, braunite occurs only in the region of Busovača, at Šuplje Bukve locality (Jurković, 1956).

Use

Braunite is one of the most important manganese ore minerals.

TITANITECaTi[O|SiO4]

SPHENE

Crystal system and class: Monoclinic, prismatic class.Lattice ratio: a : b : c = 0.753 : 1 : 0.854, β = 119° 43’,Unit cell parameters: ao = 6.55, bo = 8.70, co = 7.43, Z = 4.Properties: distinct cleavage along {110}. Hardness = 6, specific gravity = 3.5. Usually brown, yellow, green or grey colour. Streak is white, lustre adamantine.X-ray diffraction data: d 3.23 (100), 2.99 (90), 2.60 (90). ASTM-card 11-142.IR-spectrum: 415 440 500 570 865 960 cm-1 (titanite, Ontario, Canada).

TITANITE IN BOSNIA AND HERCEGOVINA

A u t h o r s: Arsenijević (1967), Barić (1966a and 1970a), Cissarz (1956), Čelebić (1967), Čutura (1918), Džepina (1970), Đorđević and Mojičević (1972), Đorđević and Stojanović (1964), Đurić and Kubat (1962), Foullon (1893), John (1888), Jovanović (1972), Jurković and Majer (1954), Karamata and Pamić (1964), Katzer (1924 and 1926), Kišpatić (1897, 1900, 1904b and 1910), Koch (1908), Magdalenić and Šćavničar (1973), Majer (1963), Majer and Jurković (1957 and

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1958), Marić (1927), Marić and Crnković (1961), Olujić, Vuletić and Pamić (1971), Pamić (1960a, 1961, 1961b, 1969a, 1971, 1971a and 1972c), Pamić and Maksimović (1968), Pamić and Papeš (1969), Pamić, Šćavničar and Međimorec (1973), Paul (1879), Pavlović and Ristić (1971), Podubsky (1968 and 1970), Ramović (1966 and 1968), Ristić, Likić and Stanišić (1968), Tajder (1953), Tućan (1912, 1922, 1930 and 1957).

Titanit is a very common accessory mineral in igneous, sedimentary and metamorphic rocks. It occurs in various rocks within the Bosnian serpentine zone, also in product of Triassic and Tertiary magmatism. It can be found in rocks of Mt. Motajica and in other formations of Paleozoic age. Because of its mechanical resilience, titanite is often found in alluvial deposits and sands, as well as in other clastic sediments.

1. The Bosnian serpentine zone

First data on titanite, obtained by microscopical investigation, were provided by M. Kišpatić (1897 and 1900). According to this author, titanite occurs mostly in metamorphic rocks and less frequently in diabases and crystalline limestones. It is a constituent of amphibolites, pyroxene amphibolites, eclogite amphibolites, actinolite schists – all along the Bosnian serpentine zone, from Mt. Kozara to Višegrad.

Titanite is a significant constituent of the pyroxene amphibolites of Ozren Manastir, near Bosansko Petrovo Selo. It comes as small or larger irregular grains, seldom pointed in shape. In thin section, this titanite is yellowish in colour with a rough surface. In other amphibolites titanite appears similar. Inclusions of rutile can sometimes be seen. In the pyroxene amphibolites of Reljevac on Mt. Ljubić, the titanite is included in amphibole grains. Its surface is again rough, with dark rims.

In the porphyric diabase of Benkovačko Jezero on Mt. Kozara, ilmenite is transformed into titanite (Kišpatić 1897 and 1900). This author asserts that titanite is an accessory constituent of crystaline limestones from around Zvornik. Grains are fairly small and have a rough surface, the shape is usually pointed at both ends. Grains appera to be lined up in certain directions. In these limestones, titanite occurs together with salite (malacolite). More recent investigations also describe titanite as an accessory mineral in rock from these areas (Džepina 1970; Đorđević and Mojičević 1972; Đorđević and Stojanović 1964; Đurić and Kubat 1962; Karamata and Pamić 1964; Majer 1963; Olujić, Vuletić and Pamić 1971; Pamić 1969a, 1971, 1971a and 1972c; Pamić, Šćavničar and Međimorec 1973).

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2. Titanite in products of Triassic and Tertiary magmatism

Occurences of titanite in products of Triassic magmatism in the area of Jablanica, Konjic and Prozor have been investigated by the folowing authors: Cissarz 1956; Čelebić 1967; John 1888; Marić 1927; Pamić 1961 and 1961b; Pamić and Maksimović 1968; Ramović 1966 and 1968; Tućan 1922, 1930 and 1957. Most of these authors refer to the titanite in the gabbro rocks of Jablanica.

The titanite in the Jablanica gabbros was studied in some detail by F. Tućan and L. Marić.

According to L. Marić, titanite can be observed in all thin sections of the Jablanica gabbro where it occurs as grains or irregular formations. Together with ilmenite, titanite crystallizes in the intergranular spaces of feldspar crystals. In the southern part of the Jablanica massif, titanite is common in anorthosite sequences.

Beautiful titanite crystals can be found in veins of the Jablanica gabbro. These have a platlike shape along (102), yellowish-brown in colour and have an adamantine lustre (Tućan 1922, 1930 and 1957). The following crystal forms have been determined on these crystals (following the Des Cloizeaux notation): c (001), d (113), n (111), m (110), x (102), g (-7.7.20), l (-112), t (-111). Specific gravity = 3.4988 at 24°C.

The chemical composition of the titanite is as follows: SiO2 = 28.61; TiO2 = 34.31; Al2O3 = 6.35; Fe2O3 = 2.34; CaO = 27.58.

Titanite crystals from the Jablanica gabbro are shown in Figure 5 (Tućan 1922).

Figure 5. Titanite in gabbro from Jablanica (Tućan 1922)

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SILICATES

Tućan explained the formation of titanite as a product of lateral secretion. However, we believe that the formation of titanite and other minerals (prehnite, zeolites) is associated with hydrothermal and postmagmatic processes which have imapcted the rocks at Jablanica. A similar theory has also been advanced by L. Marić (1927, p. 11).

Pamić (1961 and 1961b) determined titanite in granites from Mt. Prenj and in quartz keratophyres from Krstac. In this latter rock, titanite has a very high relief, yellow in colour and very weak pleochroism. It is optically positive and displays vivid interference colours.

Titanite in products of Triassic magmatism from around Kupres was studied by J. Pamić and J. Papeš (1969). Pamić (1960a) made a microscopic determination of titanite in similar rocks from the Kalinovik area. Accessory titanite in Triassic intrusives from the schist mountains of central Bosnia (area around Jajce, Kopilo and Bijela Gromila) was investigated by M. Čutura (1918), M. Kišpatić (1910), V. Majer and I. Jurković (1957 and 1958).

Little is known about accessory titanite in products of Tertiary magmatism, but some data was provide by Barić (1966a) and Tajder (1953). Barić investigated titanite in tuffs from Livno, while Tajder studied this mineral in the Srebrenica dacites.

3. Mt. Motajica and other areas with Paleozoic-age formations

Titanite is an accessory mineral in various rock formations of Mt. Motajica (Koch 1908; Katzer 1924 and 1926; Varićak 1966).

Koch determined titanite mainly in metamorphic rocks (biotite gneisses, micaschists, amphibolites) where it occurs after being tranformed from ilmenite. In the andalusite micaschists from Resavac creek near Svinjar, the titanite is of yellow colour, with strong pleochroism and birefringence. In thin section, both irregular and wedge shaped grains can be observed.

D. Varićak described titanite as a frequent accessory mineral in granite, granite porphyres, rhyolite, gneiss, amphibolite and other rocks. This author has not done further research concerning titanite, because of its minor importance as an accessory constituent.

M. Arsenijević (1967, p. 88 and 91) determined the content of tin (1340 g/ton) and niobium (1900 g/ton) in titanite contained in the Mt. Motajica granite. According to Kišpatić (1904b) titanite forms finegrained aggregates in the porphyric diabase from Sinjakovo (Mrkonjić-Grad).

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Jurković and Majer (1964) established that titanite occurs together with some other contact metamorphic minerals minerals at the contact of albite rhyolite and Paleozoic-age limestones at Alinovci, near Jezero (Jajce).

Titanite occurs rather infrequently in the keratophyres in the Trešanica gorge near Bradina in Hercegovina (Barić 1970a). This titanite has a high relief, and is often associated with leucoxene.

Accessory titanite occurs in Paleozoic sediments and altered sediments of northwestern and eastern Bosnia (Marić and Crnković 1961; Podubsky 1968 and 1970). According to Podubsky, titanite occurs much more frequently in rocks of northwestern Bosnia than in those of its eastern part.

4. Titanite in other rocks

According to F. Tućan (1912) titanite is a constituent of terra rossa from Eminovo Selo near Duvno, together with quartz, muscovite, epidote, zoisite, kyanite, tourmaline, rutile and calcite.

It is comparatively scarce in the heavy mineral fraction of Miocene-age sand and calcarenites from Lupina near Kulen-Vakuf (Magdalenić and Šćavničar 1973).

Č. Jovanović (1972) described titanite in Pliocene-age sands of the Prijedor basin, where it was determined by Z. Sijerčić in the heavy mineral fraction.

Titanite occurs in three different horizons in the Pliocene-age sands of the Kreka coal basin, however in small quantities (Šćavničar and Jović 1962). It is characterised by a high relief, strong birefringence and vivid (blue and yellow) interference colours. It has incomplete extinction, is optically positive, and has a strong dispersion of optic axes. It probably originates from granites or metamorphic rocks. These authors have also identified titanite in Eocene sandstones and Miocene clastic sediments.

Pavlović and Ristić (1971) have found titanite in the heavy mineral fraction of the coarse quartz sand in the Bijela Stijena deposit near Zvornik.

The content of titanite in the heavy mineral fraction of sands from the Tuzla basin is ca. 0.2-1 % (Ristić, Likić and Stanišić 1968).

C. M. Paul (1879) determined titanite in diabases from Mt. Majevica.

Use

When titanite is available in substantial quantities, it can be used for the extraction of titanium metal.

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CHLORITOIDFe2

2+AlAl3[(OH)4|O2|(SiO4)2]

OTTRELITEMn2AlAl3[(OH)4|O2|(SiO4)2]

Crystal system and class: Monoclinic, occasional triclinic symmetry within the same crystal (chloritoid).Properties: distinct cleavage along {011}, weaker along {110}. Colour is greenish-black to black. Lustre is vitreous. Hardness more than 6, specific gravity = 3.4-3.6. X-ray diffraction data for chloritoid:Triclinic d 4.449 (100), 2.456 (90), 1.5804 (80)Monoclinic d 4.449 (100), 2.963 (90), 1.5813 (80)IR-spectrum: 450 518 552 590 612 672 750 805 870 908 962 1105 1650 2980 3340 3450 cm-1 (chloritoid, Galgenberg near Leoben, Austria).

CHLORITOID IN BOSNIA AND HERCEGOVINA

A u t h o r s: Foullon (1893), Katzer (1924 and 1926), Kišpatić (1904b), Šćavničar and Jović (1962), Tajder and Raffaelli (1967), Tućan (1957).

Since some of the referenced publications do not distinguish chloritoid from ottrelite, we have placed both mineral names and their formulas in the title of this section. Chloritoid occurs in Bosnia and Hercegovina in the schist mountains of central Bosnia and in the clastic sediments of the Kreka coal basin.

1. Schist mountains of central Bosnia

Earliest information on the occurence of chloritoid in the so-called “ottrelite schists” from Čemernica can be found in the publication by H.B.v. Foullon (1893, p. 3), although the author did no further investigations of this mineral. On the other hand, M. Kišpatić gives in his “Petrographic notes from Bosnia” (1904b) a rather detailed macroscopic and microscopic description of chloritoid, a significant and frequent constituent of the “chloritoid phyllites located between Fojnica and Čemernica” (pages 44-47). According to Kišpatić, this chloritoid has a platelike habit, black in colour with an almost metallic lustre – macroscopically very similar to biotite. In crushed samples of rock, chloritoid platelets can be seen – these have a hexagonal shape and the basal pinacoid (001), the prism (110) and pinacoid (010) can be recognized. The platelets are 0.3-0.5 mm in diameter.

In the referenced publication, Kišpatić also gives a desciption of the microphysiographic characteristics of chloritoid: it has characteristic pleochroism

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in blue-green (X), blue (Y) and yellow-green (Z) colour. Sections parallel to the c axis have angular extinction of 20°. The measured maximum birefringence Nz – Nx = 0.011.

Katzer, in his ‘Geology of Bosnia and Hercegovina’ (1924 and 1926) gives an account of the schist mountains of central Bosnia and the distribution of “ottrelite schists” (pages 109-113). Katzer’s description of chloritoid is quite similar to the earlier description given by Kišpatić. Nevertheless, Katzer writes that chloritoid platelets sometimes are as large as 9.8 mm in diameter. Katzer was somewhat poetic in comparing these chloritoid platelets with stars shining on a dark night’s sky (Katzer 1926, p. 112).

Katzer also mentions the chloritoid-containing schists at Čemernica, between the antimonite mine and the Povitine creek; near Ščitovo, Putljevac creek and Bukovica forest. Similar schists occur also in the Busovača area, and elsewhere.

More data on chloritoid in the schist mountains of central Bosnia can be found in the more recent publication by M. Tajder and P. Raffaelli (1967). According to these authors, chloritoid occurs in quartz-muscovite schists in the form of porphyroblasts some 2 mm in diameter. Crystals have a shortprismatic shape with a basal pinacoid. In thin section, a bluegreen pleochroism can be observed, as well as twinning parallel to the base, good cleavage, high indices of refraction and a strong r > v dispersion in convergent light. The authors did not identify the location from which the chloritoid was obtained, but refer to Katzer’s data on the distribution of these schists.

2. Occurences in the Kreka coal basin

B. Šćavničar and P. Jović (1962) have determined small quantities of chloritoid in the heavy mineral fraction of Pliocene-age sand from the Kreka coal basin. Chloritoid has also been found in Eocene sandstones of this area. The maximum content of chloritoid in the heavy mineral fraction was 5.3%.

DATOLITECaB[OH|SiO4]

Crystal system and class: Monoclinic, prismatic class.Lattice ratio: a : b : c = 1.264 : 1 : 0.632, β = 90° 9’,Unit cell parameters: ao = 9.66, bo = 7.64, co = 4.83, Z = 4.Properties: datolite has no distinct cleavage. Hardness = 6.5, specific gravity = 3.0. Colourless and transparent, pale-green or yellowish, occasionaly white and milky.

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Streak is white, lustre vitreous.X-ray diffraction data: see table in text.IR-spectrum: 455 478 505 533 550 578 692 788 853 885 930 955 965 1015 1050 1102 1260 3490 cm-1

A u t h o r s: Đorđević and Stojanović (1972 and 1974), Trubelja, Šibenik-Studen and Sijarić (1975, 1975a and 1976).

Datolite occurs in Bosnia and Hercegovina in basic rocks of the Bosnian serpentine zone mostly as a gangue mineral. It was first mentioned by Đorđević and Stojanović (1972) but the authors gave no information on the locality. Two years later the same authors provide a more detailed account on datolite which occurs in diabase rocks at Bojići near Hrvaćani and Banja Luka. The mineral association also contains some zeolite minerals and calcite. Datolite crystalizes within thin veinlets in the rock (Đorđević and Stojanović 1974).

This comparatively rare mineral was determined by the authors using optical microscopy, XRD and thermal analysis.

In thin section, datolite appears in the form of densely packed grains of ca. 1 mm in size, showing a high relief and vivid interference colours. Frequent intergrowths with natrolite and calcite can be observed.

X-ray diffraction data for datolite from Bojići are given in Table 10. They correspond well with the ASTM-card 11-70 data.

Figure 6. DTA curve of datolite and natrolite. Sample from Bojići, near Banja Luka (Đorđević and Stojanović 1974)

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The DTA curve of a mixture of datolite and natrolite (Figure 6) shows a strong endothermic peak at 710°C, and two weaker peaks at 860°C and 920°C. Datolite was also determined during the investigation of mineral associations in veins of the diabase-spilitic rocks of Mt. Ozren (Šibenik-Studen, Sijarić and Trubelja 1976; Trubelja, Šibenik-Studen and Sijarić 1975, 1975a and 1976). It occurs together with prehnite and rhipidolite in outcrops along the road leading from Gornji Rakovac to Gornja Bukovica. Datolite and the associated minerals were identified by XRD.

Table 10. X-ray diffraction data for datolite, Bojići near Banja Luka

Datolite, Bojići Datolite, ASTM-card 11-70d (Å) I d (Å) I6.02 10 5.98 74.85 20 4.83 163.76 40 3.763 453.41 45 3.404 303.11 100 3.114 1002.98 40 2.986 352.86 40 2.855 652.52 50 2.524 302.41 15 2.409 9

The genesis of datolite crystallizing in veinlets within basic rocks of the Bosnian serpentine zone is probably related to hydrothermal processes involving solutions enriched in boron.

HEMIMORPHITEZn4[Si2O7|(OH)2] . H2O

A u t h o r s: Jurković (1961a), Katzer (1924 and 1926), Koechlin (1922), Kunštek (1940), Tajder (1936), Tućan (1930, 1957)

In 1853 Kenngott gave hemimorphite its names, because of its distinctly hemimorphic shape, characteristic for crystals of this minerals (greek – hemi, half and morphe, form). It has orthorhombic symmetry, rhombic-pyramid class.

Hemimorphite is a very rarely occuring mineral in Bosnia and Hercegovina. To this date it has been identified only in the iron ore mine of Ljubija near Prijedor. First crystallographic data were provided by R. Koechlin (1922). Other authors only give reference to Koechlin’s data. In 1917 Koechlin obtained two small samples from the Ljubija mine and determined that the grey-white aggregates on limonite were a mixture of hemimorphite and smithsonite.

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The hemimorphite crystals are up to 2 mm long, and have a platelike shape along {010}. Koechlin’s measurements of two crystals identified the presence of the following crystal forms: a {010}, m {110}, θ {102}, s {101} and t {301}. The shape of the crystal is shown in a drawing (Figure 7).

Figure 7. Crystal of hemimorphite from the Ljubija iron mine (Koechlin 1922)

The presence of the two Zn-bearing mineral, hemimorphite and smithsonite, can be explained by the weathering of sphalerite contained in the siderite ore from Ljubija (Koechlin 1922). This sphalerite was again later mentioned by Tućan (1930), while Tajder (1936) provides a crystallographic and chemical analysis.

Jurković (1961a, p. 162), in his exhaustive account of the iron minerals of Ljubija, lists hemimorphite as a mineral formed during hypergenic processes.

Use

Hemimorphite can be used for zinc production, when it occurs in larger quantities.

SUOLUNITECa2H2[Si2O7] . H2O

A u t h o r s: Đorđević and Stojanović (1972), Stojanović (1973), Stojanović, Đorđević and Đerković (1974).

Suolunite is a very rare mineral (hydrated calcium silicate) in Bosnia and Hercegovina. It was first determined in the Banja Kulaša region in the Bosnian serpentine zone and mentioned by Đorđević and Stojanović (1972), but without

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precise data on the location of the occurence. Stojanović (1973) published detailed X-ray diffraction data on suolunite occuring in the diabase rock from Kulaš. A chemical and thermal analysis of this suolunite were also done. One further report by Stojanović, Đorđević and Đerković (1974) also mentions suolunite from the same locality, occuring together with tobermorite.

Table 11. X-ray diffraction data for suolunite from Kulaš.

d (Å) measured I d (Å) calculated hkl5.12 20 5.107 1114.96 8 4.961 040

4.856 2204.13 100 4.129 1313.70 5 3.704 2403.174 80 3.173 1513.120 4 3.118 311

2.873 0222.851 65 2.849 331

2.843 2602.784 5 2.784 4002.681 50 2.680 4202.642 30 2.642 2022.552 38 2.553 2222.498 40 2.498 1712.479 10 2.480 0802.473 12 2.471 3512.428 10 2.428 4402.331 15 2.332 2422.270 2 2.266 2802.224 40 2.223 062

2.130 4602.108 20 2.109 3712.076 15 2.076 5112.063 20 2.064 2622.034 10 2.035 1911.998 10 1.999 4221.991 30 1.991 5311.958 4 1.960 1131.889 10 1.8881 1331.887 25 1.8880 4421.866 2 1.8693 2 10 01.850 30 1.8521 480

1.8481 5511.824 4 1.8245 6201.808 8 1.8087 282

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SILICATES

1.806 10 1.8078 3911.763 12 1.7647 1531.758 10 1.7550 3131.737 3 1.7385 640

1.7373 4621.706 12 1.7074 1 11 11.701 10 1.7025 3331.679 10 1.6814 571

1.6556 0 10 21.651 8 1.6538 0 12 01.619 3 1.6187 660

1.6178 1731.615 15 1.6160 4 10 01.610 16 1.6103 353

1.5869 2 10 21.584 18 1.5853 2 12 0

1.5788 6021.577 10 1.5764 4821.564 3 1.5665 3 11 11.558 5 1.5592 6221.533 8 1.5333 7111.515 3 1.5163 5911.504 15 1.5045 6421.498 18 1.5012 004

Suolunite from Kulaš near Doboj occurs in cracks in the diabase rocks, at a depth of 45 meters, in veinlets and aggregates. Crystals are transparent, colourless or yellowish. The thickness of the veins is 2-8 mm.

In thin section the suolunite is colourless, and crystals have an elongated shape. Optical constants for soulunite are as follows: Nz = 1.6227; Ny = 1.6199; Nx = 1.6120; -2V = > 30°.Unit cell dimensions (after H.F.W. Taylor) are: ao = 11.13, bo = 19.82, co = 6.00 Å, space group Fdd2. R. Veličković determined the chemical composition of suolunite: SiO2 = 43.35% CaO = 42.22% H2O = 14.05%Specific gravity = 2.631Spectral analysis revealed the presence of the following elements: Mg, Al, K, N, S, Ti, Cr, Mn, Fe, Li, B, F, Na, P, Cl, V, Ni, Co, Zn, Sr, Ba and others.

The DTA curve of suolunite shows a strong endothermic peak at 390°C, implying water loss and a transformation into xonotlite. The exothermic reaction peak at 810°C corresponds to a transformation into β-wollastonite (Stojanović, Đorđević and Đerković 1974).

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Concerning the genesis of suolunite and tobermorite, the referenced authors believe that the two minerals were formed by hydrothermal processes. The temperature was comparatively low (ca. 175°C) and tobermorite was the first to crystallize, followed by suolunite.

CLINOZOISITE – EPIDOTE

Crystal system and class: Monoclinic, prismatic class.

Clinozoisite and epidote are similar minerals, differing in the amount of iron present in them. Their axial ratios and unit cell dimensions are very similar. Epidote contains a greater amount of trivalent iron substituting aluminum (isomorphic substitution). While clinozoisite contains up to 10 mol.% of Fe, epidote (pistazite) contains 10-30%. Consequently, the refractive indices and birefringence of epidote is greater than those of clinozoisite.

Properties: perfect cleavage along {001}. Hardness = 7. Specific gravity = 3.3-3.6 (increases with Fe content). Colour is greenish to greenish-grey (clinozoisite); yellow, brown-green to black (epidote). Streak is white (greyish-white), lustre is vitreous. Optical constants are as follows:epidote Nx = 1.720-1.734, Ny = 1.724-1.763, Nz = 1.734-1.779 Nz – Nx = 0.014-0.045clinozoisite Nx = 1.710-1.723, Ny = 1.715-1.729, Nz = 1.719-1.734 Nz – Nx = 0.005-0.011X-ray diffraction data for epidote: d 2.872 (100), 1.635 (85), 2.393 (85)X-ray diffraction data for clinozoisite: d 2.884 (100), 1.631 (65), 2.385 (65)IR-spectrum: 455 520 570 650 720 838 860 885 950 1040 1080 1115 3360 cm-1

CLINOZOISITECa2Al3[O|OH|SiO4|Si2O7]

A u t h o r s: Džepina (1970), Đorđević and Mojičević (1972), Katzer (1924 and 1926), Kišpatić (1910), Pamić (1957, 1960, 1960a, 1961a, 1961b, 1962, 1969a, 1971, 1971a, 1972a and1972d), Pamić and Buzaljko (1966), Pamić and Maksimović (1968), Pamić and Papeš (1969), Pamić, Šćavničar and Međimorec (1973), Pamić and Tojerkauf (1970), Podubsky (1968 and 1970), Sijerčić (1972a), Simić (1966), Šibenik-Studen (1972/73), Tajder and Raffaelli (1967), Trubelja (1957 and 1960), Trubelja and Pamić (1957 and 1965), Varićak (1966).

Minor quantities of clinozoisite in Bosnia and Hercegovina occur in igneous and metamorphic rocks. Inspite of its wide distribution, there is a very limited

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amount of detailed data on this mineral. Clinozoisite is mentioned only in those papers dealing with the petrography of igneous rocks of the spilite-keratophyre association, and rocks from the Bosnian serpentine zone.

1. Mid-Triassic spilite-keratophyre association

Epidote and clinozoisite can be found in the products of mid-Triassic magmatism in the Jablanica and Prozor regions (Pamić 1960, 1961a and 1961b). It occurs frequently in albite diabases of the Crima creek near the village of Lug. Here, after being transformed from plagioclase, it forms a mixture with prehnite, calcite and sericite.

Clinozoisite is also a member of contact parageneses at the same locality. Here it is associated with the central sections of the contact zone, and occurs in the form of irregular and patchy aggregates within a finegrained marble. In thin section, interference colours are low, the optic axial angle 2V = +64° to +83°.

Clinozoisite also occurs in the doleritic gabbroid rocks near Kukavica village on Kupres (Pamić and Papeš 1969).

There is an occurence of clinozoisite at the contact of mid-Triassic igneous rocks with limestones at Bijela near Konjic (Pamić and Maksimović 1968).

Clinozoisite is a frequent constituent of the products of the mid-Triassic magmatism in the area of Ilidža – Kalinovik (Pamić 1957, 1960a and 1962), and around Čajniče (Pamić and Buzaljko 1966).

2. The Bosnian serpentine zone

Clinozoisite seems to be a comparatively frequent constituent of igneous and metamorphic rocks of the Bosnian serpentine zone and the surrounding diabase-chert formations – Džepina (1970), Đorđević and Mojičević (1972), Pamić (1969a, 1971, 1971a, 1972a and1972d), Pamić, Šćavničar and Međimorec (1973), Pamić and Tojerkauf (1970), Podubsky (1968 and 1970), Sijerčić (1972a), Šibenik-Studen (1972/73), Trubelja (1957 and 1960), Trubelja and Pamić (1957 and 1965).

As a typical vein-filling mineral, clinozoisite frequently occurs in gabbroid rock from the Višegrad area (Trubelja 1957 and 1960). Its formation is associated with hydrothermal events during which the hydrothermal solutions reacted with primary ferromagnesian silicates, followed by an exsolution of clinozoisite, prehnite, zeolites, chlorite and others.

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At Pavitina (Suha Gora), clinozoisite crystallized in veins of up to 2 cm thick. It is usually pink in clour, but also yellow-green (epidote). Clinozoisite frequently forms needle-like, radial aggregates.

In thin section, clinozoisite has a high relief, with characteristic interference colours of blue and lavender. Following optical constants were measured on a rotating stage microscope:

c : X = 2 3.5° 2° ----2V = 88.5° 86.5° 79° 83°

According to the measured optical constants, the mineral is partly clinozoisite, partly epidote (pistazite).

A monomineralic aggregate of pink clinozoisite has been found at Lahci, near Višegradska Banja. In thin section, this clinozoisite is optically positive, 2V = 85¼°, 85°, 77°. Needlelike and finegrained aggregates regularly display lavender interference colours.

Clinozoisite and epidote are frequently found in basic igneous and some metamorphic rocks (amphibolites) from Vareš, Zavidovići and Maglaj (Pamić 1972a).

A finegrained aggregate consisting of prehnite, clinozoisite and calcite has formed as a result of retrograde metamorphism of basic plagiocalese in amphibolite rocks of Mt. Skatovica (Pamić 1969a). Pamić determined clinozoisite in amphibolites, diabases and spilites around Rudo (Pamić 1972d).

3. Clinozoisite in other rocks

M. Kišpatić (1910) determined clinozoisite and epidote in gabbro-diorite rocks of Bijela Gromila, south of Travnik. The same fincing was made by F. Katzet (1924 and 1926).

M. Tajder and P. Raffaelli (1967) described clinozoisite in altered porphyre-keratophyres of the schist mountains of central Bosnia.

Podubsky (1968 and 1970) determined clinozoisite and epidote to be regular accessory minerals occuring in the Paleozoic-age metamorphites of eastern and northwestern Bosnia. Their presence in Carbon-age rocks is of particular interest.

Clinozoisite is a rather frequent constituent of rocks of Mt. Motajica impacted by contact metamorphism. As concerns igneous rocks, only lamprophyres contain clinozoisite (Varićak 1966). Here, clinozoisite occurs either as an essential

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or accessory constituent of the following rocks: amphibole gneisses, biotite and pyroxene cornites, hornblendites, amphibolites and amphibole schists, albite-actinolite-epidote schists and glaucophanites.

Clinozoisite is present in amphibolites and amphibole schists in quantities up to 6.5%. It can be an essential constituent of glaucophanites. Optic axial angles 2V = +86°, c : X = 3°.

EPIDOTECa2(Fe3+,Al)Al2[O|OH|SiO4|Si2O7]

A u t h o r s: Arsenijević (1967), Barić (1970a), Behlilović and Pamić (1963), Cissarz (1956), Čelebić (1967), Čutura (1918), Džepina (1970), Đorđević (1958 and 1969), Đorđević and Stojanović (1972), Đurić (1963a), Foullon (1893), Gaković and Gaković (1973), Jovanović (1972), Jurković (1954a, 1956, 1957 and 1962a), Jurković and Majer (1954), Karamata (1957), Katzer (1924 and 1926), Kišpatić (1897, 1900, 1904, 1904b, 1910 and 1912), Koch (1908), Magdalenić and Šćavničar (1973), Majer (1963), Majer and Jurković (1957 and 1958), Marić (1927 and 1965), Milenković (1966), Mojsisovics, Tietze and Bittner (1880), Nöth (1956), Pamić (1957, 1960, 1960a, 1961a, 1961b, 1962, 1963, 1969, 1969a, 1971, 1971a and 1972a), Pamić and Buzaljko (1966), Pamić and Kapeler (1969), Pamić and Maksimović (1968), Pamić and Papeš (1969), Pamić and Trubelja (1962), Pavlović, Ristić and Likić (1970), Petković (1961/62), Podubsky (1968 and 1970), Podubsky and Pamić (1969), Ramović (1957, 1963, 1966 and 1968), Ristić, Likić and Stanišić (1968), Sijerčić (1972 and 1972a), Simić (1966 and 1968), Šćavničar and Jović (1961 and 1962), Šćavničar and Trubelja (1969), Šibenik-Studen and Trubelja (1967), Šibenik-Studen, Sijarić and Trubelja (1976), Tajder (1951/53 and 1953), Tajder and Raffaelli (1967), Trubelja (1960, 1962a, 1963a, 1963c, 1966a, 1969, 1971a, 1972 and 1972a), Trubelja and Miladinović (1969), Trubelja and Pamić (1957 and 1965), Trubelja and Sijarić (1970), Trubelja and Slišković (1967), Trubelja and Šibenik-Studen (1965), Trubelja, Šibenik-Studen and Sijarić (1974), Tućan (1912, 1928, 1930 and 1957), Varićak (1956, 1957, 1966 and 1971), Živanović (1963).

In Bosnia and Hercegovina, epidote is a common mineral of igneous, sedimentary and metamorphic rocks. It is usually formed by metamorphosis – regional, contact or hydrothermal is commonly associated with rocks impacted by such metamorphism. It occurs frequently in the form of thin veinlets crystallizing in fractures or similar spaces. It is an essential constitutent of epidote schists.

In spite of its common occurence, detailed data on epidote is very scanty. Many petrographic publications do mention epidote, but with no reference to its optical, chemical, thermal and other analytical data.

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1. Epidote in igneous and metamorphic rocks

Oldest data on the occurence of epidote in igneous and metamorphic rocks of Bosnia and Hercegovina can be found in the paper by C. v. John (Mojsisovics, Tietze and Bittner 1880). The author made a microscopic determination of epidote in a coarsegrained diorite from Kladanj, in effusive rocks from Srebrenica, and in diabase porphyrites of the Vrbas river valley between Donji Vakuf and Jajce as well is in other rocks from this area. The epidote is green or greenish-yellow in colour.

In all mentioned rocks the epidote is associated with late- or post-magmatic phases, formed by transformation of ferromagnesian silicates and plagioclase. According to John, biotite is the source of epidote in effusive rocks of from Srebrenica.

M. Kišpatić (1897, 1900, 1904, 1904a and 1904b) made microscopic determinations of epidote in various rocks of the Bosnian serpentine zone, in products of Tertiary-age volcanism around Srebrenica and the Bosna river valley as well as in schists from other regions.

Epidote occurs frequently in basic igneous rocks (gabbro, diabase) of the Bosnian serpentine zone. It can be found in diabases from Doboj, Mt. Majevica, and in the troctolite from Ravni Potok. Plagioclase is the source of epidote in the troctolite.

Kišpatić determined epidote in metamorphic rocks of the Bosnian serpentine zone from several localities. Zoisite is found much less frequently. In amphibolites from Mehmedov creek the few epidote crystals are elongated and fractured. Epidote and amphibole are essential constituents of the epidote amphibolite from Raljevac on Mt. Ljubić. Here it occurs in the form of colourless, irregular or (rarely) elongated grains.

According to more recent investigations of the Bosnian serpentine zone, epidote occurs in limited quantities in basic igneous rocks and amphibolites. Data on epidote can be found in publications of the following authors: Džepina (1970), Đorđević and Stojanović (1972), Đorđević (1958), Majer (1963), Pamić (1969a, 1971, 1971a and 1972a), Pamić and Kapeler (1969), Pamić and Trubelja (1962), Trubelja (1960), Trubelja and Pamić (1965), Trubelja, Šibenik-Studen and Sijarić (1974).

According to Trubelja (1960), in the Višegrad area epidote occurs together with labrador and albite in gabbropegmatites of Banja creek, near Višegradska Banja – the crystals are prismatic and have a high relief. Together with albite and prehnite, they are usually incorporated into a finegrained saussurite matrix. It is of hydrothermal genesis. Epidote (pistazite) occurs together with clinozoisite at Pavitine (Suha gora).

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According to Pamić (1972a) iron-rich epidote crystallizes in veins within basic rocks in the areas of Vareš, Zavidovići and Maglaj. Epidote is accompanied by clinozoisite. The authors provides XRD data for the epidote from Vareš.

Epidote and clinozoisite occur together also in the metamorphic rock series on the southern flanks of Mt. Ozren, near Kobilovac (Pamić 1971).

We have recently published information about epidote from several localities within the Bosnian serpentine zone (Trubelja, Šibenik-Studen and Sijarić 1974). Epidote occurs together withe prehnite and calcite on the southeastern flanks of Mt. Konjuh, in the area called Karaule (creek Blizanci).

Epidote is also found in the form of thin yellowish veinlets in the valley of the Trnava creek on the northern flanks of Mt. Kozara. These veinlets can be observed very well in the dolerite from Gornji Podgradci.

M. Kišpatić (1904a) determined epidote microscopically in dacite from Protin Han (Srebrenica). This epidote sometimes occurs as quite large crystals.

In the effucive rocks outcropping in the valley of the Bosna river, epidote occurs at sevela localities (Kišpatić 1904).

M. Tajder (1953) describes epidote occuring in altered schists and normal and propilitized effusive rocks of Tertiary age in the Srebrenica region. Epidote in the Srebrenica paragenesis was also mentioned by M. Ramović (1963).

According to M. Kišpatić (1904), epidote occurs in greenschists from Polom and Lonjina on the river Drina, as well as chlorite schists from mVilenica near Travnik. Here, epidote occurs in finer or larger grains. There is a substantial quantity of epidote in chlorite schists outcropping between Fojnica and Čemernica. Here the epidote is finegrained, colourless or yellow in colour. Interference colours are vivid in thin section.

Epidote is also present in various rocks from Mt. Motajica and Mt. Prosara (Koch 1908; Katzer 1924 and 1926; Varićak 1956, 1957 and 1966).

F. Koch determined epidote microscopically in granites, gneisses, micaschists and amphibolites. In the Mt. Motajica granite the epidote is of green colour. In the gneiss of Studena Voda it occurs either as individual crystals or as aggregates. It formed as a result of tourmaline and orthoclase metamorphosis. It is yellow in colour, quite pleochroitic and has a strong birefringence. The epidote in biotite schists of Puljane Kose has the same properties as in the previously described rock, and is altered biotite.

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Numerous data on epidote and clinozoisite from Mt. Motajica was given by Varićak (1966). The granitoids, contact-metamorphic rocks and surrounding rock series contains epidote both as an essential or accessory constituent.

The quantity of epidote in the chlorite-epidote schists amounts to ca. 20%. The epidote in granitoid rocks is normally of hydrothermal or pneumatolitic genesis. Rocks altered by contact metamorphism always contain some epidote. Occasionally, the quantity of epidote is significant, like in albite-actinolite-epidote schists.

According to Varićak (1956 and 1957), epidote occurs in carbonate schists, green rocks and quartz-porphyres of Mt. Prosara.

Čutura (1918) mentions epidote in various igneous rocks of southwestern Bosnia. It occurs in the form of aggregates – together with sericite – in granitoid rocks of Mt. Komar. Both minerals were formed from feldspar. Epidote is also found in basic effusive rocks from Babino Selo, as well as in similar igneous rocks around Jajce.

Epidote is a common constituent of igneous rocks from other areas of the schist mountains of central Bosnia (Jurković 1954a; Jurković and Majer 1954; Kišpatić 1910; Majer and Jurković 1957 and 1958; Šibenik-Studen and Trubelja 1967; Trubelja and Šibenik-Studen 1965).

Epidote and zoisite are constituents of the albite rhyolite from Sinjakovo. They also occur at the contact of this albite rhyolite and Paleozoic-age limestones at Alinovac, near Jezera. The mineral association located closest to the contact consists mainly of chlorite, actinolite and epidote (Jurković and Majer 1954). In a rather similar series of magmatites in the Janj creek, close to the village of Perkovići near Jezera, epidote was identified by XRD and IR-spectroscopy (Šibenik-Studen, Sijarić and Trubelja 1976). The IR spectrum of this epidote is shown in Figure 8.

Figure 8. IR-spectrum of epidote, Perkovići near Jezera (Šibenik-Studen, Sijarić and Trubelja 1976).

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Epidote and zoisite are constituents of the augite-labrador andesite from Orašin, southeast of Bakovići (Jurković 1954a).

The gabbro-dioritic rocks of Bijela Gromila also contains epidote and zoisite (Kišpatić 1910; Majer and Jurković 1957 and 1958). A detailed microscopic study of epidote from Tovarnica was done by L. Marić (1927). This epidote is associated with magnetite. He also investigated the epidote contained in gabbros from the confluence area of the Rama and Neretva rivers. At Tovarnica, epidote of a yellow-green colour occurs together with calcite and quartz. In thin section, epidote grains are rounded or slightly elongated. Some grains are brownish-green in colour and have a stronger pleochroism and higher refractive indices than the yellowish-green ones. The pleochrotoic colours are: X = yellowish, Z = greenish-brown. The difference in pleochroitic colours is a consequence of a variable amount of trivalent iron. Cleavage is distinct in the case of elongated grains. Occasionally epidote is accompanied by chlorite. Marić believes that the epidote is of secondary genesis. M. Ramović (1968, p. 168) also mentions epidote from this locality.

The genesis of epidote and other minerals occuring at the contact of the Jablanica gabbros and surrounding carbonates and other sediments (Tovarnica near Jablanica) has been studied by several authors (Cissarz 1956; Nöth 1956; Čelebić 1967).

According to A. Cissarz (1956), the gabbroic rocks have impacted the surrounding rocks (in the southwestern flanks of the gabbro body) through contact metamorphism. The paragenesis also contains epidote, which crystallized during the later stages of the paragenesis. The amount of epidote is substantial and thus one of the main constituents of the paragenesis, together with garnet, calcite and magnetite (see Figure 2).

According to Čelebić (1967) the epidote, together with zoisite and other accessory minerals at the Tovarnica locality comprose a contact-metasomatic paragenesis. Sometimes, a zonal interchange between epidote and magnetite can be observed, resulting in a ‘zebra-like’ texture. Its colour is olivegreen to yellowish, and single-mineral aggregates are frequent (epidosite). The grainsize is in the range from several micrometers to several millimeters.

In the Jablanica and Prozor areas, the spilite-keratophyric rock series sometimes contain also clinozoisite in addition to epidote (Pamić 1960, 1961a and 1961b). In the case of keratophyres, small epidote grains are dispersed in the rock mass. The epidote is yellowish, with a very high relief, and intereference colour in thin section are vivid. The average optic axial angle value 2V = +70°.

At the contact zone, in Crima creek near the village of Lug south of Prozor, epidote is a constituent of the contact paragenesis together with garnet, albite,

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chlorite, clinozoisite, prehnite, magnetite and other minerals. Grains are irregularly shaped, elongated crystals are infrequent. Relief is high. Pleochroitic colurs: X = light-yellow, Y = Z = greenish-yellow. Elongated grains have a parallel extinction. In thin section, intereference colours are high, +2V = 68° (iron-rich epidote).

Epidote also occurs in mid-Triassic age magmatites around Kupres, Borovica (Vareš), Tjentište, Čajniče, Zvornik, along the transect Ilidža-Kalinovik and elsewhere (Behlilović and Pamić 1963; Đurić 1963a; Karamata 1957; Pamić 1957, 1962, 1963 and 1969; Pamić and Buzaljko 1966; Pamić and Papeš 1969; Simić 1966 and 1968; Trubelja 1962a, 1963, 1963a, 1969 and 1972a; Trubelja and Miladinović 1969; Trubelja and Slišković 1967).

The epidote in keratophyres from the Trešanica gorge (near Bradina in Hercegovina) contains some 30 mol.% of FeIII (Barić 1970a). It occurs as irregular grains ca. 0.1 mm in diameter, within or outside the hornblende matrix. Pleochroitic colours are light- to vivid-yellow, with occasional green overtones. Sometimes a single epidote crystal has distinctly different sections. Interference colours are vivid. The optic axial angle varies in the range 2V = -69.5° to -74.5°.

In the vicinity of Tarčin, in the Crna Rijeka river valley near Gunjani village, beautiful epidote crystals were discovered in fractures of igneous rocks (Šibenik-Studen, Sijarić and Trubelja 1976). Some crystals are up to 10 cm long and 5 mm thick, the colour is greenish to yellow-brown and different sectors of one crystal can have different colouration. The epidote was determined by XRD and chemical analysis.

The epidote from Crna Rijeka has the following chemical composition (analyst M. Janjatović):

SiO2 = 38.03 TiO2 = --- Al2O3 = 28.90 Fe2O3 = 7.18CaO = 24.30 H2O

+ = 2.29 H2O- = 0.16 Total = 100.86

Epidote is a regular accessory constituent of the Paleozoic-age rock series in northwestern Bosnia (consisting of semimetamorphites and metamorphites). Of particular interest is the occurence of epidote and clinozoisite in Carbon-age rocks (Podubsky 1968). Substantial concentrations of epidote occur in epidotized metasandstones and metamorphised igneous rock in the area of the Ljubija ore deposits (Podubsky and Pamić 1969).

Rocks impacted by metamorphic processes (epidotization, chloritization, albitization) are frequent in the mid-Carbon-age rock formations of eastern Bosnia (Podubsky 1968 and 1970; Katzer 1924 and 1926). Epidote and clinozoisite are normally present as accessory minerals in sediments, semimetamorphites and metamorphites, but occasional enrichments in epidote have been identified in rocks around Šutorina Rijeka and Mlječvanska Rijeka.

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More recently, data on epidote in altered porphyrite-keratophyres and other schists in the schist mountains of central Bosnia have been published (Tajder and Raffaelli 1967; Trubelja and Sijarić 1970).

According to Tajder and Raffaelli, the stilpnomelane-bearing albite-epidote schists from Neretvica creek, epidote occurs in the form of large, almost idiomorphic grains, crystallizing in veinlets present in the rock. A significant variance in the mineral and chemical composition is characteristic of these veins (quartz-epidote-calcite; quartz with a minor amount of calcite, stilpnomelane, epidote and chlorite; chlorite, epidote, stilpnomelane; stilpnomelane-epidote-chlorite with a minor amount of calcite and quartz).

2. Epidote in sedimentary rocks

In contrast to the amount of data on epidote in igneous and metamorphic rock, information on epidote in sedimentary rocks is very scanty – Foullon (1893), Gaković and Gaković (1973), Jovanović (1972), Katzer (1924 and 1926), Kišpatić (1912), Magdalenić and Šćavničar (1973), Marić (1965), Pavlović, Ristić and Likić (1970), Ristić, Likić and Stanišić (1968), Sijerčić (1972), Šćavničar and Jović (1961 and 1962), Tućan (1912).

According to Foullon (1893), epidote sometimes occurs in mineral concentrates in formations in the schist mountains of central Bosnia.

Epidote was also identified in the insoluble residue of Triassic-age carbonates from the outer Dinarides (Gaković and Gaković 1973).

Epidote is a frequent accessory mineral in quartz sands and other sedimentary rocks of the Tuzla basin (Pavlović, Ristić and Likić 1970; Ristić, Likić and Stanišić 1968).

Z. Sijerčić found epidote in the heavy mineral fraction of the Eocene-age flysch deposits on the western flanks of Mt. Majevica. Based on this identification, Jovanović (1972) determined epidote also in the heavy fraction of the Pliocene-age sands in the Prijedor basin.

According to B. Šćavničar and P. Jović (1961 and 1962), epidote occurs in several horizons of the Pliocene-age sands of the Kreka coal basin, especially the B and C horizons. The grains are irregular in shape, yellowish-green in colour and have a vitreous lustre. It has a high relief, strong pleochroism and vivid interference colours. It is almost always associated with zoisite – both minerals originate from metamorphic rocks. Epidote also occurs in Eocene-age sandstones in this area.

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Z. Magdalenić and B. Šćavničar (1973) have identified epidote in clastic rocks around Kulen Vakuf.

M. Arsenijević (1967) analysed the epidote from Mt. Motajica granitoids for their Sn and Nb content and found ca. 100 g Sn/ton and 900 g Nb/t as maximum concentrations.

M. Kišpatić (1912) microscopically identified epidote in the bauxites from Studena Vrela (Duvno), while Tućan (1912) found it in terra rossa from Eminovo selo. Marić (1965) gives reference to both authors in his paper.

Use

Green-coloured epidote (pistazite) can be used as a gemstone.

ALLANITECa(Ce,Th)(Fe3+,Mg,Fe2+)Al2[O|OH|SiO4|Si2O7]

Crystal system and class: Monoclinic, prismatic class.Lattice ratio: a : b : c = 1.5507 : 1 : 1.7684, β = 115° 01’,Unit cell parameters: ao = 8.98, bo = 5.75, co = 10.23, Z = 2.

Synonyms: the mineral belongs to the epidote group. It was first discovered on Greenland by Gieseke. It was analysed in 1810 by Thomson, a chemist in Glasgow, and named after the scottish mineralogist Allan. Berzelius called it orthite (greek orthos, upright) because crystals found in the Finbo mine (near Falun, Sweden) had an orthogonal shape. He also used the name pyrorite because some crystals – when heated – would continue smoldering (because of the bitumonous matter present). This was particularly true for crystal found at Kararfvet in the Falun area. Other names which have been used at various times: ksantorite (greek ksanthos, yellow), bodenite (after Boden, in Sachsen, Germany), muromonite (latin muro, wall, and mons, mountain) after the Mauresberg mine near Marienberg in Sachsen, tautolite (greek tautos, same and lithos, stone), bucklandite (after Buckland, a professor at Oxford).

The name bagrationite came to be as follows. The russian count Bagration found black, opaque crystals of a mineral in the Akhmatovskij mine, in the Zlatoust area of the Ural mountains. They were first investigated by Koksharov in 1847 and named bagrationite. Subsequently, Koksharov (1858) realized that there was no difference between “bagrationite” and allanite, based on measurement of the angles between crystal faces.

The name wasite was used for a very weathered allanite found at Rönsholm island near Stockholm. In 1863 Bahr believed that this mineral contained a new

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element (wasium). Bahr wanted to name both the element and the mineral after the swedish royal dynasty of Wasa.

X-ray diffraction data: d 2.91 (100), 2.92 (90), 2.86 (50); d 2.90 (10), 1.64 (9), 2.70 (7); d 2.91 (10), 1.64 (8), 3.47 (6).

A u t h o r s: Markov and Mihailović-Vlajić (1969), Mihailović-Vlajić (1967), Varićak (1966).

Up to now, in Bosnia and Hercegovina allanite has been found only in the granite rocks of Mt. Motajica. According to Varićak (1966) allanite is an accessory mineral in normal granite, leucocratic granite and granite-porphyres. In the latter rock, allanite is of a primarily zonal structure. Twinning along (100) is rare. The interfacial angle between the faces (100) and (001) is 115°. The following optic data has been obtained in thin section:Nx : c = 35.5°, Nz : a = 55-60°, 2V = -74° to -75°

Pleochroitic colours are as follows: Nx = yellowish-greenish-brown; Nz = darkbrown-reddish.

According to Mihailović-Vlajić (1967, p. 196) four varieties of allanite are present in the Mt. Motajica granite.a) the dark to black variety of allanite is most common. The somewhat elongated

crystals have a prismatic shape, and are between 0.1 and 0.5 mm long. Their surface is sometimes covered with an earthy alteration crust.

b) a red-brownish variety of allanite is present in biotite-gneisses and leucocratic granite. It is usually xenomorphic.

c) a pinkish-brown variety occurs in pegmatites. The occasionally present crystals are shortprismatic in shape with a visible cleavage. Grains are partly covered on the surface with an alteration crust.

d) the brown-reddish variety of xenomorphic allanite with a resinuous lustre and conchoidal fracture surfaces occurs only in some parts of the muscovite-granite formation. An alteration crust is usually present. This allanite is more radioactive than the first three varieties, and contains ca. 1750 ppm (0.175%) of niobium. Six samples have been analyzed for trace elements – data is given in Table 12.

Allanite has been retrieved from rock samples of more than 100 kg in weight (Mihailović-Vlajić 1967, p. 192), the same way as for thorite.

In a later paper, Markov and Mihailović-Vlajić (1969, p. 257) confirm the occurence of allanite in Mt. Motajica granites.

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Use

Hisinger named in 1811 this mineral cerine, because of its cerium content.

Table 12. Concentration of trace elements in allanites from the Mt. Motajica granite (Mihailović-Vlajić 1967)

Biotite-gneiss

Main granite body

Muscovite-granite

Finegrained granite

Pegmatite Muscovite-granite

Sample number94.991 95.012 95.219 94.990 95.223 33.600a

Mn 3500 ppm 3160 ppm 3160 ppm --- 4000 ppm 1%Pb 60 39 134 25 100 60V 170 316 720 170 --- 500Ga 40 40 90 50 90 12Sn --- 37 50 --- --- 80Nb --- --- --- --- --- 1750Y 1200 660 790 1200 4000 600Yb + + + + + +Dy + - - + - -Er + - - + - -La 1% 1% 1% 1% 1% 1%Ce + + + + + +++Zr 300 1000 1000 600 631 600Ni - - 5 - - 9Cr 140 - - 60 - 80Co - - 11 - - -Cu 7 4 32 7 20 40Sc 300 340 340 400 400 340Ba 30 traces 700 140 355 400Sr 80 650 2240 800 1130 2500

ZOISITECa2Al3[O|OH|SiO4|Si2O7]

Crystal system and class: Orthorhombic, rhombic-dipyramidal class.Lattice ratio: a : b : c = 2.879 : 1 : 1.791Unit cell parameters: ao = 16.24, bo = 5.58, co = 10.10, Z = 4.Properties: perfect cleavage along {001}. Hardness = 6.5, specific gravity = 3.3. Colour is gray, sometimes pink or green. Streak is white, lustre vitreous (pearly on cleavage planes). Refractive indices are high, birefreingence medium to small.X-ray diffraction data: d 2.703 (100), 2.869 (100), 1.615 (75)IR-spectrum: 410 443 470 512 575 595 620 655 695 715 755 780 865 900 975 1040 1115 3140 cm-1

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A u t h o r s: Čelebić (1967), Džepina (1970), Đorđević (1958), Golub (1961), Jurković (1954a), Jurković and Majer (1954), Karamata and Pamić (1964), Katzer (1924 and 1926), Kišpatić (1897 and 1900), Magdalenić and Šćavničar (1973), Majer (1962), Majer and Jurković (1957 and 1958), Mojsisovicz, Tietze and Bittner (1880), Pamić (1971), Petković (1961/62), Ristić, Panić, Mudrinić and Likić (1967), Šćavničar and Jović (1962), Trubelja (1960 and 1966a), Trubelja and Pamić (1965), Varićak (1966), Vasiljević (1969).

Zoisite is one of those rock-forming minerals which have not been sufficiently investigated in Bosnia and Hercegovina, and only a limited amount of data is available. It occurs mainly in metamorphic rocks, either as an essential mineral (zoisite schists) or as an accessory. Some igneous rocks, which have sustained alteration, do contain zoisite. Some zoisite has been found to occur in sedimentary rock, but very limited information is available.

1. Zoisite in metamorphic and igneous rocks

The first determinations of zoisite in hornblende-zoisite schists, from Čemlija around Zvornik, were done by John (Mojsisovics, Tietze and Bittner 1880). In some schists the zoisite dominates with respect to hornblende, in other rocks the opposite is the case. The zoisite is of a white or red colour.

The zoisite amphibolite from Mamići (Kalesija), studied by Kišpatić (1897 and 1900) is very similar to the schists from Zvornik investigated by John. In the Mamići amphibolite, zoisite is colourless and very refractive. In thin section, the grains have an irregular shape and two cleavage systems are visible. Birefringence is low, as are the gray interference colours. This epidote shows parallel extinction.

Katzer (1924 and 1926) mentions zoisite in rock from the area of the Kamenica river, south of Zvornik. The zoisite and amphibolite rocks are probably altered basic magmatites. Zoisite is an essential mineral of the amphibole-zoisite schists from the Krušik creek, near Boljanići village at Mt. Ozren (Trubelja and Pamić 1965). Outcrops of zoisite-bearing rocks are located 400 to 500 m upstream, towards the village of Konopljište. Zoisite and an amphibole from the termolite-actinolite series are the only two rock-forming minerals. For zoisite, 2V = +54° to 60°. Refractive indices are higher than those of the amphibole, so is the relief. Extinction is parallel, and cleavage clearly visible.

Zoisite and epidote are also found in similar schists on the southern flanks of Mt. Ozren, near Kobilovac (Pamić 1971).

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According to microscopic investigations by D. Džepina (1970), zoisite occurs in basic rock altered by regional metamorphism (southern flanks of Mt. Borja).

The following authors have mentioned zoisite in igneous rocks of the bosnian serpentine zone: Đorđević (1958), Golub (1961), Karamata and Pamić (1964), Majer (1962), Ristić, Panić, Mudrinić and Likić (1967), Trubelja (1960 and 1966a).

Accessory zoisite occurs in some granites at Mt. Motajica (Varićak 1966).

Zoisite and epidote occur in gabbro-dioritic rocks of Bijela Gromila, south of Travnik (Majer and Jurković 1957 and 1958). They also occur in the augite-labrador-containing andesites of Orašin, southeast of Bakovići (Jurković 1954a)

Zoisite and epidote are constituents of the albite rhyolite from Sinjakovo. They are also found at the contact of this rock and Paleozoic-age limestones at Alinovac, near Jezera (Jurković and Majer 1954).

Zoisite, epidote and some ither minerals are constituents of the metasomatically altered contact paragenesis within the magnetite body of Tovarnica, near Jablanica (Čelebić 1967). This zoisite occurs as coarse grains.

M. Petković (1961/62) mentions zoisite in the spilite rocks at Borovica (Vareš).

2. Zoisite in sedimentary rocks

Very limited information is available on zoisite in the heavy mineral fractions of clastic sediments (Magdalenić and Šćavničar 1973; Šćavničar and Jović 1962).

Zoisite (together with tourmaline and epidote) has been identified as an essential constituent of Miocene-age sandy calcarenites from Lupina near Kulen Vakuf (Magdalenić and Šćavničar 1973). B. Šćavničar and P. Jović (1962) identified zoisite in the Pliocene-age sands of the Kreka coal basin, within several horizons.

R. Vasiljević (1969) describes the zoisite occurence in sedimentary quartzites at podrašnica (Mrkonjić Grad), based on microscopic determination by S. Pavlović and D. Nikolić.

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PUMPELLYITECa2(Al,Mg,Fe2+)3[(OH)2|SiO4|Si2O7]

Pumpellyite has monoclinic symmetry. It is a member of the epidote group of minerals. Hardness = 5.5, specific gravity = 3.2. Bluish-green colour. It is best determined by x-ray diffraction: d 2.90 (100), 2.74 (50), 3.79 (40).

A u t h o r s: Trubelja, Šibenik-Studen and Sijarić (1974, 1975 and 1975a), Šibenik-Studen, Sijarić and Trubelja (1976).

Pumpellyite has only recently been discovered in Bosnia and Hercegovina – at Vareš and Jablanica where it is associated with Triassic-age magmatites. At Vareš, it occurs together with prehnite in veins and amygdales of altered melaphyres. It has been identified by XRD (Trubelja, Šibenik-Studen and Sijarić (1974, 1975 and 1975a).

Pumpellyite occurs together with chlorite, amphibole and stilbite in veins of the gabbro at Jablanica (Ploče quarry). Pumpellyite and the other mentioned minerals have formed on stilbite (Šibenik-Studen, Sijarić and Trubelja 1976). The minerals were identified by XRD.

VESUVIANITECa10(Mg,Fe)2Al4[(OH)4|(SiO4)5|(Si2O7)2]

Vesuvianite (idocrase) occurs at a single locality only in Bosnia and Hercegovina – in the rodingite-altered basic garnet-bearing rocks at Mt. Borja (between the bridge at Velika Usora and Crkvena). It was discovered by Džepina (1970). According to this author, vesuvianite is accompanied by hydrogarnet, calcite, epidote, zoisite, serpentine, chlorite and ksonotlite.

AXINITECa2(Mn,Fe)Al2[BO3|Si4O12|OH]

The only information about axinite in Bosnia and Hercegovina was provided by T. Jakšić in an unpublished study of arsenic ores at Hrmza near Kreševo (Jakšić 1930), where he claims that axinite occurs in these ores. He maintained that “this is a mineral which was previously been regarded as fluorite”. According to Barić (1942, p. 43), this claim was not supported by any kind of evidence. In a microscopic study of these ores, Barić determined an optically isotropic mineral with a refractive index below the one of Canada balm. The violet colouration of the mineral is patchy. The determined properties do not correspond to axinite (see fluorite).

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BERYLBe3Al2[Si6O18]

Crystal system and class: Hexagonal, dihexagonal-dipyramidal class.Lattice ratio: a : c = 1 : 0.4985. Unit cell parameters: ao = 9.23, co = 9.19, Z = 2.Synonyms: none, except for gemquality varieties – emerald, aquamarine, vorobievite or morganite, heliodor, golden beryl, goshenite or rosterite, bixbiite, green aquamarine (more information in the section on the use of beryl).

Properties: weak cleavage along the base (pinacoid). The fracture surface is irregular or scalelike. Hardness = 7.5-8, specific gravity = 2.63-2.80. Refractive indices: ω = 1.57-1.60, ε = 1.56-1.59. Lustre is vitreous. Occurs colourless or in various colurs. Transparency is variable.

X-ray diffraction data: d 2.87 (100), 3.25 (95), 7.98 (90). ASTM-file 9-430.IR-spectrum: 415 440 497 530 595 655 685 745 810 (918) 975 1025 1086 1210 cm-1

A u t h o r s: Barić (1960), Gojković and Nikolić (1967), Katzer (1924 and 1926), Kišpatić (1902), Koch (1899, 1902 and 1908), Markov and Mihailović-Vlajić (1969), Mihailović-Vlajić (1967), Mikinčić (1955), Nikolić (1962 and 1963), Pilar (1882), Ristić, Antić-Jovanović and Jeremić (1965), Trubelja and Pamić (1957), Varićak (1966).

In Bosnia and Hercegovina, Mt. Motajica is the only location where beryl has been found. It occurs in pegmatite veins in the granite quarry between the villages of Vlaknica and Brusnik, upstream of the Bosanski Kobaš village. This granite was first described by John (Mojsisovics, Tietze and Bittner 1880), and two years later by Pilar (1882). There is no mention of beryl at Mt. Motajica in these papers. Beryl was first mentioned by Koch (1899, 1902 and 1908, p. 4). Koch did his investigation on material deposited at the Museum of Mineralogy and Petrology in Zagreb – the material comes from the Veliki Kamen quarry near Vlaknice village. The material from this quarry was used for road construction and the Sava river embankment; beryl-bearing pegmatite veins were found in this granite. Koch provides only inconsistent information as to how the material arrived in the museum in Zagreb. In one place Koch claims that the material was collected by Pilar himself (Koch 1899, p. 1). The same information can be found in the paper by Barić (1960, p. 71). However, in his later paper (Koch 1908, p. 1) the author maintains that Pilar did not visit Mt. Motajica and that the material was brought to Pilar by the surveyor Uhlig – and that Koch used these specimens in his investigations. Pilar (1882, p. 15) indeed notes this gift, but does not mention beryl. Katzer (1924 and 1926) maintains that a pegmatite “nest” with beautiful beryl crystals was open in the quarry for more than

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40 years. Katzer believes that several samples of these crystals – which Koch used for his studies – were saved by surveyor Uhlig.

According to Koch, two varieties of beryl occur at Mt. Motajica – colourless and a coloured variety. The coloured one is of a bluish-green colour, and larger crystals are fairly translucent. Smaller crystals have a fair degree of transparency. The crystals are in all cases elongated parallel to [0001], and crystals 10 cm long and 4-5 cm thick were found. The lower size range is 6-7 mm in lenght and 3-5 mm in thickness. Only the crystal faces of the basal pinacoid {0001} and the protoprism {101-11} can be observed. The pinacoid faces occur more frequently and have irregular etching marks. Larger crystals often have numerous fractures and cracks, what lowers their transparency. The cracks have nonspecific directions, and are seldom parallel to the basal pinacoid. Attempts to cleave the crystals result in an uneven cleavage – part of the cleavage surface is parallel to {0001}, while the other part is uneven.

The colourless variety occurs less frequently than the coloured one. This variety occurs as crystal aggregates (while the coloured variety occurs rather as solitary crystals) always separated from the coloured type. The colourless and transparent crystals have a short-prismatic shape and are usually 1.5-2 mm long and thick, although the largest crystals are 5-6 mm long and 2-3 mm thick. Some can only be seen with the aid of a loupe. The smaller the crystals are, the more elaborate is the combination of crystal forms. Sections perpendicular to the axis [0001] are usually not perfect hexagons – the crystals are mostly elongated along one co-axis. Basal cleavage can normally not be seen on these crystals. Koch measured 5 crystals and identified – in addition to {0001} and {10-11} – also the following crystal forms: {10-11}, {11-21} and {31-41}. Koch used the lattice ratio a : c = 1 : 0.49886 (the value established for beryl by Kokšarov). Koch also mentions a deuteroprism {11-20} but provides no further information on this form.

Koch described his measurements in great detail, but provided very little quantitative data. He concludes that the beryl from Mt. Motajica is optically biaxial, hence certainly of lower that hexagonal symmetry, probably monoclinic or triclinic. He maintained that the beryl consists of lamellae which have oblique extinction, and that the apparently hexagonal habit of the crystals is a consequence of a mimetic twinning of these lamellae. In convergent light, the center of the dark cross is concentrically surrounded by coloured fringes (isochrome rings). When the crystal is rotated, the dark cross disintegrates into two hyperbolae only slightly separated so that their dark blue fringes remain in contact. The separation of the hyperbolae is smaller in the central section than towards the rim of the thin section. The fine striation on the prism faces should, according to Koch, be regarded as twinning striae.

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Liquid inclusions in beryl from Mt. Motajica are very common. Two phase (gas bubble) inclusions occur most frequently, those without the gas bubble are rarer. The smallest gas-bubble inclusions are circular with an average diameter of 0.0023 mm. For the larger ones, the size range is 0.1978-0.437 mm (length) and 0.0506-0.0092 mm (width). The inclusions are located along the edges of the pinacoid {0001} and the prism {10-10}. The elongation direction of the inclusions is always parallel with the edges.

The gas-bubble inclusions are immobile, even when the thin sections are moved or shaken. Upon heating, the gas bubbles become smaller and finally disappear, and become again visible when the thin section cools down. According to Koch, the gas in the bubbles is – without any doubt – carbon dioxide CO2.

Solid inclusions are muscovite, sometimes with clearly visible crystals.

A chemical analysis, done by Koch on fresh samples of coloured and colourless beryl. The results of the analysis are given in Table 13.

Three years later, Kišpatić (1902) also writes about this beryl. In the zone between {0001} and {10-11} he identified one further very narrow face with a blurred signal. He measured an angle of 3° 4’ between the normal of this face and the one for the basal pinacoid. He therefore concluded that this was a new crystal form for beryl {1.0.-1.12}. It should be noted that the measured angle of 3° 4’ would better correspond to {1.0.-1.11}. The polar distance for this form, when the lattice ratio a : c = 1 : 0.49886 is applied for beryl, is 2° 59’ i.e. only 5’ less than the value measured by Kišpatić. However, a calculation for the form {1.0.-1.12} gives a polar distance of 2° 45’ and this fact was also noted by Kišpatić. The difference between the measured and calculated value is 0° 19’, and since Kišpatić agreed that the reflection from this face was rather blurred, we maintain that there is insufficient evidence for the attribution of the form {1.0.-1.12} to beryl.

Table 13. Chemical composition of beryl from Mt. MotajicaColoured beryl Colourless beryl

SiO2 65.735 65.685Al2O3 14.581 14.688BeO 11.483 11.550Fe2O3 (FeO) 2.838 2.682CaO 0.320 0.309MgO 0.447 0.428K2O 0.387 0.325Na2O 0.773 0.681H2O 0.188 0.178Loss on ignition 2.533 2.362

Total 99.285 99.888

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Spectrographic analysis of beryl from Mt. Motajica

Ristić, Antić-Jovanović and Jeremić (1965) published data on a qualitative spectrographic analysis of the Mt. Motajica beryl (with a semiquantitative estimate after Hasler-Harvey)

Mg 0.3-3% Sr 0.003-0.3% Cr 0.0001-0.0016% V 0.001-0.01% Cu 0.0003-0.003%Ca 0.1-1% Ba --- Mn 0.03-0.3% Fe 0.3-3% Co, Ni ---

There was no evidence for the presence of Ti, Zn, Sc, Cd, W, Pb, Sn, Y, Ta, Nb. The same authors ran a plame photometric analysis on alkali elements, using a Beckman photometer, and obtained the following: Li = 0.001%, Na = 0.62%, K = 0.10%, Rb = 0.009%, Cs = 0.093%.

According to these analyses and information provided by Koch, it appears that the beryl from Mt. Motajica contains a very limited amount of alkalies. An uptake of these elements into the beryl structure is accompanied by a substitution of Si with Al in the SiO4 tetrahedra and an increase in the anionic charge. The large cations of the alkali elements occupy positions within the structural channels of beryl, parallel to its [0001] axis. One beryl from Madagascar contained as much as 11% of CsO.

Recent research

Lj. Barić (1960) made some further research on the beryl from Mt. Motajica. On several collected samples he identified small, colourless or bluish beryl crystals as overgrowths on smoky quartz. The beryl crystal were 3-4 mm long and 1-2 mm thick. They have an elongated shape, parallel to [0001], a feature common to beryl. Crystal with a thicker platy habit, parallel to the basal pinacoid, were found on some samples only. The crystals had developed numerous terminal faces at their ends. Barić made measurements on 23 crystals and identified many forms which were previously unknown for the Mt. Motajica beryl: {0001}, {10-10}, {11-20}, {10-11}, {11-23}, {11-22}, {22-43}, {11-21}, {7.5.-12.12} (a new general form for beryl) {21-31}, {31-41}, {51-61}, {11.2.-13.2}, {19.1.-20.1}. The faces of the forms {0001} and {10-10} are usually the best developed ones. Faces of the deuteroprism are narrow in all cases. In the cas of the various hexagonal dipyramids, {10-11} and {11-21} are most prominent. The average lattice ratio for this beryl, based on 23 individual measurements is a : c = 1 : 0.4985. A beryl crystal from Mt. Motajica is depicted in Figure 9.

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Figure 9. Beryl from Mt. Motajica (Barić 1960)

As concerns the optical properties of the Mt. Motajica beryl, Barić investigated 15 thin sections of beryl parallel to {0001} and determined by conoscopic microscopy that the beryl was uniaxial and negative, as opposed to Koch’s conclusion. The view that the beryl had lower symmetry due to mimetic twinning was not supported by Barić’s measurements. The twinning observed by Koch is probably a twinning of several individual hexagonal crystals. Refractive indices were measured on two crystals in Na-light: ω = 1.5755 ω = 1.5758 ε = 1.5691 ε = 1.5695the corresponding maximum birefringence value being 0.0063. This birefringence was also measured using a compensator, and the value was 0.0066.

The specific gravity (determined by the suspension method) is 2.683 and 2.687. Control measurements using a Berman-type microbalance gave s.g. values of 2.677, 2.679 and 2.695.

Low refractive indices and a comparatively low specific gravity determined for the Motajica beryl are in accordance with chemical analysis data indicating low concentrations of alkali metals.

The beryl-bearing pegmatite nest in the Veliki Kamen quarry near Vlaknica was quickly destroyed (Katzer 1926, p. 72) and for some time it seemed that no more beryl would be found (Kišpatić 1902, p. 50). However, beryl was again found as operations in the quarry continued. Katzer writes that when he visited this area in 1909, together with his assistant I. Turina, they found a fragment of a large bluish bery crystal on a waste dump. In the Brusnik creek, they also found a block of granite which had a thin vein with crystals of beryl and quartz in it. Katzer maintained that beryl was not uncommon in this part of the Mt. Motajica area. The mentioned vein

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from the Brsunik area was only 3 cm thick, and the beryls were ca. 2-5 mm long and of a short-prismatic habit, with a combination of hexagonal prosm and basal pinacoid usually visible. These beryl crystals had a honey-yellow colour, while only some were bluish and fully transparent. These blusih crystal had a vitreous lustre – the yellow ones appeared rather dull and the crystal faces seemed to be etched. This gives them a greasy lustre and less transparency.

Greenish-blue beryl crystals several centimeters long can be found in the quarry even today.

If we attempt to describe the genesis and formation of beryl in the Mt. Motajica area (but also elsewhere in the world), we must note the fact that beryl occurs in veins in granite. This implies that the granites formed from a granite-type magma. The crystallization of granite happens on the surface of larger plutonic granite formations. This surficial part of the granite body is frequently cracked and fractured due to cooling contractions, possible degassing processes and tectonics. These fractures could have been filled by very hot (gaseous or liquid) magmatic differentiates containing substantial amounts of silica, water vapour and other volatiles – leading to the formation of pegmatites (greek pegma, pegmatos – strongly bound).

According to the ideas of the famous Russian mineralogist Fersman, such pegmatites – in the form of dykes and veins – crystallized in a temperature range between 800° and 400°. The cooling process results in an initial crystallization around the rims of such a vein or cavity, and progresses later towards the interior. In this way, cavities and veins can be completely filled up with crystallized matter. Those closer to the edges and rims are older, the ones towards the central parts are younger in age. Occasionally very large crystal can form in such conditions, and intergrowths of quartz and feldspar are common. Intergrowths of dark quartz and light-coloured feldspar sometimes results in what is called Hebrew stone (hebraic pegmatite or graphic granite).

In some cases the central sections of cavities and veins remain hollow, and large crystals of quartz and feldspar can grow from the walls of these cavities. If the granite magma contained volatiles like boron, fluorine, alkali elements and beryllium, the pegmatites may contain crystals of tourmaline, topaz, various micas, beryl etc. This is a possible explanation for the formation of beryl in the Mt. Motajica area. The pegmatite veins of the Motajica granite normally consist of feldspar, quartz, muscovite and beryl – while tourmaline, albite, talc, fluorite, pyrite and psilomelane are accessories (Koch 1899, p. 1).

Varićak (1966, p. 101) notes that beryl is a component of the quartz veins in the Mt. Motajica area, that it occurs as idiomorphic shortprismatic crystals of 60 x 30 mm in diameter. The commonly occuring quartz relicts in and around the

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beryl crystals are a strong indication that their crystallization happend in the later, metasomatic phases of the alteration process (Varićak 1966, p. 104).

Nikolić (1962 and 1963) maintained that the Motajica beryl was formed by two different processes. A limited amount of beryl formed in the pegmatite phase, while the main quantities of bery are the result of metasomatism (albitization).

Mihailović-Vlajić (1967, p. 202) and Markov and Mihailović-Vlajić (1969, p. 257) briefly mentioned beryl in the Mt. Motajica pegmatites.

Gamma spectrometry was applied for uranium and thorium determination in the beryls from the quarry at Mt. Motajica. The green-blue beryls carry 2.1 g/ton of uranium and 1.2 g/ton of thorium. This is an average of 3 individual measurements (S. Gojković and D. R. Nikolić 1967).

Use

Clear and transparent beryl is termed gem-quality beryl and is widely used as a gemstone in jewelry. Emerald is particularly popular as a gem – this is a largely transparent variety of green colour, the colour being due to trace amounts of chromium. The greek name for emerald is smaragdos (greek smaragdos = green stone), but the etymology of the names smaragdos and beryllos are not well understood. Light green varieties of emerald contain 0.15-0.2 % of chromium as Cr2O3, the darker coloured varieties 0.5-0.6 %. The beautiful green colour reminds one of spring meadows. Pliny the Elder/Plinius Secundus (23-79 AD), who died during the eruption of Mt. Vesuvius on 25 August 79, wrote in his “Historia Naturalis” that emerald is an excitement for our eyes because no other colour in nature is as vivid as the green colour of emerald. Emerald emanates its glow far and wide, and even seems to give its colour to the surounding air.

Completely transparent and flawless crystals are so rare that they attain fantastic prices, even surpassing the value best-quality diamonds. The American Gem Society listed prices (for the year 1960) for emeralds between 1 and 8 carats, which amounted to 250-5000 dollars per carat. The price of larger and flawless crystals rises faster than their weight. Large emeralds are literally priceless. One famous emerald is the one which was presented to the Duke of Devonshire by the Brazilian Emperor of Brazil Dom Pedro I, in 1831. The natural crystal is a highly included, deep-green hexagonal prism, terminated on one end with an irregular fracture surface, and a hexagonal base on the other. It is ca. 6 cm high and 5 cm in diameter (see Figure 10).

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Figure 10. The Duke of Devonshire emerald

This beautiful crystal is one of the most famous emeralds in the world, with a weight of 1383.95 carats (5 carats = 1 gram). It was found in the famous Colombian emerald mine of Muzo. Another famous crystal of 24 carats is in the Russian Royal Treasury. The French traveller and jeweler Tavernier (1605-1689) writes that he saw – among other jewels – some 60 emeralds on the throne of the Grand Moghul Emperor of India. Each of these emeralds had around 60 carats. Another wonderful gem is the 24.38 ct “Napoleon” emerald, which Napoleon presented in 1800 to his wife Josephine de Beauharnais.

Because of its beauty, transparency and resilience against external influences, magic and healing powers have been attributed to emerald (and other gemstones as well). Native populations of Peru have allegedly regarded an emerald, as large the egg of an ostrich, as a deity. The russian author Aleksandar I. Kuprin (1870-1930) wrote that snakes and scorpions would not approach a person wearing an emerald.

Some fascinating jewellery with emeralds is kept in the Victoria and Albert Museum in London i.e. a collier with 12 emeralds and a matching set of earrings, each set with 2 magnificent emeralds. Every emerald in the jewellery set is surrounded with diamonds, which enhance the beauty of the emeralds even more. It is a “fin de 18eme siecle” masterpeices of a Russian jeweller. Precious pieces of art and jewellery with emeralds are kept in the treasury of the Zagreb cathedral.

Emeralds were first mined in the ancient mines (2000 B.C. – 1200 A.D.) of the Eastern desert in Egypt, east of Aswan and near the Red Sea (Wadi Gimal, Wadi Nuqrus, Wadi Sikait, Gebel Zubara, Gebel Umm Kabu). The mines were

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rediscovered in 1818 (thousands of open pits and underground workings). Egypt was the source of almost all emerald in ancient times. Emerald material was found in mummies of the Pharaohs, and Empress Cleopatra had her portraits made in emerald (as gifts for high-ranking persons). The mines in Egypt were worked also during the Roman times, and continued by the Arabs and Turks. Today, most of the emerald comes from Colombia – from the famous mines at Muzo, Chivor and Cosquez. Other sources are northern Transvaal in the Republic of South Africa, Zimbabwe (Southern Rhodesia), India, Brasil, Australia and Russia (previously the Soviet Union – the emerald mines along the right banks of the Takovaya river in the Ural mountains).

Aquamarine, the blue to greenish-blue variety of beryl, is also a popular gemstone. The name aquamarine comes from Latin (aqua = water, mare = sea), because the colour of aquamarine reminds of the colour of the sea. The biggest aquamarine ever mined was found in a pegmatite vein near the city of Marambaia, Minas Gerais, Brazil, in 1910. It weighed over 110 kg, and its dimensions were 48.5 cm long and 42 cm in diameter. It was fragmented into smaller pieces which were cut into gems, and this single aquamarine crystal satisfied the world demand for this gem for three years.

Morganite (or vorobievite) is a red to pinkish-violet beryl with a high caesium and lithium content (Cs2O = 3.10; Li2O = 1.39; H2O = 1.92). Crystals are usually of a pyramidal shape, sometimes tabular (vorobievite). Apparently, morganite (vorobievite) was first found in the mines near the village of Lipovaya, northeast of Sverdlovsk in the eastern part of the Ural mountains. Vernadsky proposed that it be named after the Russian mineralogist V. I. Vorobiev (1875–1906) who did first crystallographic measurements of ther mineral. It was later also found on Madagascar, near the town of Maharitra, in the valley of the Sahatony river, and in the Pala area of San Diego county in southern California. Upon recommendation of the American mineralogist and gemmologist George F. Kunz, the name morganite was adopted in USA, in memory of the collector J. Pierpont Morgan.

The colourless, transparent variety of beryl – called goshenite (after the locality Goshen, Massachussetts, USA) – is also a popular gemstone. The name heliodor (greek helios = sun, doros = gift) was given to a golden yellow variety of beryl first found in the Rössing mine on the Swakopmund – Windhoek railway line in Southwest Africa (now Namibia). Similar in colour is the golden beryl from Serro Juiz de Fora, Minas Gerais, Brazil and from USA (Litchfield, Massachussetts and Amelia Court, Virginia). In general, the coloured varieties of beryl make popular and beautiful gemstones, if these are sufficiently transparent and free from flaws.

Aquamarine, morganite, goshenite, heliodor, golden beryl etc. are popular gemstones because of their beautiful, warm colours. Their hardness – greater than quartz – is also a property which makes the suitable for use as gems in jewellery.

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Today, beryl is used not only as a gemstone and in jewellery, but also for other purposes. Large, nontransparent crystals, i.e. material which is not of gemstone quality is used in Spain as door-posts. Rolff reported in 1994 that a beryl crystal weighing ca. 200 tons was found in the state of Paraiba in Brasil. Another large crystal 9 m long and weighing 61 tons was found near Keystone in the Black Hills of South Dakota (USA). A beryl crystal found in a pegmatite near Albany, Maine (USA) was 5.5 m long and 1.2 m thick – the estimated weight was 18 tons.

Beryl is also used as an ore in the production of beryllium metal. This is a silver-grey coloured metal, brittle at room temperature. The specific gravity is 1.81, melting point at 1285°C. Beryllium is lighter than aluminium which has a specific gravity of 2.712. It is used in industry in the production of beryllium bronzes and other alloys. An alloy containing 2.0% Be, 0.5% Co and 0.1% Si, the rest being copper, is used for the production of highquality wires and spirals. The wrought high strength alloys contain 1.6 to 2.0% beryllium and approximately 0.3% cobalt. The cast, high-strength alloys have beryllium concentrations up to 2.7%. The high conductivity alloys contain 0.2-0.7% beryllium and higher amounts of nickel and cobalt. These alloys are used in applications such as electronic connector contacts, electrical equipment such as switch and relay blades, control bearings, housings for magnetic sensing devices, non sparking applications, small springs, high speed plastic molds and resistance welding systems. Cast beryllium coppers are frequently used for plastic injection molds. The cast materials have high fluidity and can reproduce fine details in master patterns. Their high conductivity enables high production speed, while their good corrosion and oxidation resistance promotes long die life.

A mixture of beryllium and radium was used as a neutron generator in nuclear chemistry laboratories, since beryllium releases a neutron and transforms to carbon when bombarded by alpha particles.

The occurence of beryl at Mt. Motajica is interesting only for mineralogical reasons, and is of no other significance.

CORDIERITEMg2Al3[AlSi5O18]

Crystal system and class: Orthorhombic, rhombic dipyramidal class.Lattice ratio: a : b : c = 1.748 : 1 : 0.954Cell parameters: ao = 17.13, bo = 9.80, co = 9.35, Z = 4Properties: poor cleavage along {010}, parting parallel to {001}. Hardness = 7, specific gravity = 2.55-2.75 and increases with increasing iron content. Colour is light blue to blue violet, also colourless, grey, brown or yellow. Refractive indices

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also increase with increasing Fe content. RI very close to those of Canada balm. Birefringence is small, increases with increasing Fe content.X-ray data: depent on structure ordering (Tröger 1967, p. 355 and 358)d 8.58 (100), 3.05 (85), 4.09 (73) – mid temperature varietyd 3.04 (100), 8.53 (69), 3.37 (47) – low temperature varietyd 8.49 (100), 4.10 (54), 3.04 (54) – high temperature varietyIR spectrum: 415 434 448 487 515 577 675 768 925 965 990 1023 1105 1170 1650 cm-1

Cordierite is a typical constituent of metamorphic rocks. In Bosnia and Hercegovina it occurs only in the cornite rocks of Mt. Motajica (Varićak, 1966). According to this author, cordierite is a significant constituent of biotite cornites which form the inner part of the contact zone.

Cordierite occurs here mostly in the form of individual grains, and only occasionally shows cyclic twinning. The grains are small and not quite suitable for further microscopic investigations. Its alteration product is muscovite (sericite). The compositional percentage of cordierite in the cornites is rather variable within a range 0-20%.

Apart from cordierite, the following minerals are present in the cornites: quartz, acidic plagioclase, garnet, tourmaline, apatite, zircon, magnetite, hematite, ilmenite and titanite (all accessory minerals).

The genesis of the cornites of the inner part of the contact zone at Mt. Motajica is mainly bound to thermal alteration, but sometimes also to alkaline metasomatic alteration (Varićak 1966, p. 122 and 123).

Clear blue cordierite is frequently used as a gemstone.

TOURMALINEXY3Z6[(BO3)3│Si6O18│(OH)4]

The complicated chemical composition of tourmaline can be defined by the general formula as given above, where X is occupied by large ions like Na and Ca, Y is occupied by Mg, Li, Al, Fe2+, Mn, while Al, Fe3+, Ti3+, Cr3+ are present at position Z. The significant variation in chemical composition results in a corresponding variation in properties (unit cell parameters, axial ration, optical properties, specific gravity).

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Crystal system and class: Trigonal, ditrigonal-pyramidal class.Lattice ratio: a : c = 1 : 0.446 – 1 : 0.453Cell parameters: ao = 15.84-16.03, co = 7.10-7.25, Z = 3

Nomenclature: the varieties of tourmaline have different names and refers mainly to colour. The name tourmaline originates from the sinhalese language (turamali), and was first used for zircon. The name torumaline was first mentioned by Garmann in his book Curiöse Speculationes bei Schlaflosen Nächten – von einem Liebhaber der immer gern Speculiert (Curious speculations during sleepless nights – by a connosieur who likes speculating), Chemnitz and Leipzig 1707, p. 269. This name was used for the orange-red variety brought from Sri Lanka (Ceylon) by the Dutch in 1703. The name schorl was already used in Europe for the dark coloured variety of the mineral. The czech name of škoril or skoril is based on schorl (Katzer 1926, p. 68). Nowadays this name is used for the dark iron-rich variety. Achroite (greek ahroos = colourless) is a colourless or faintly greenish tourmaline which shown no pleochrosim in thin section. Achroite crystals from the island of Elba (thus the name elbaite) are often dark coloured at one end – such varieties are referred to as negro’s head. Rubelite (latin rubellus – reddish) or siberite (after Siberia) or apyre (greek apyros – fireproof, since it does not melt under a blowpipe) is red tourmaline, indigolite is blue, verdelite (italian verde – green) is green. Crystals which are red on one end are called turkish head in Brazil. The chrome-rich varieties from the Ural mountains are deep green. Dravite is the magnesium rich variety (brownish to greenish in colour) found in the gneiss rocks at Dobrava near the city of Dravograd in Slovenia. The mineralogist Tschermak gave this variety this name in honour of the river Drava. The black tourmaline from Kragerö in Norway is sometimes referred to as africite (greek afrizo – to foam) because it foams when heated with a blowpipe Properties: cleavage along {11-20} and {10-10} is very weak. The colour of tourmaline depends on its chemical composition. Refractive indices vary – No 1.639-1.692, Ne 1.620-1.657, maximum birefringence is 0.017-0.046, specific gravity 3.0-3.25. Mohs hardness is 7-7.5. Crystals can be fully transparent to opaque. Tourmaline has distinct pyro- and peizoelectric properties. In his abovenamed book, Garmann notes that the tourmaline brought to Europe by the Dutch in 1703 at first attracts the ash of burning peat, but releases it immediately thereafter. Because of this, the Dutch called it Aschentrecker, meaning one who attracts ash. A similar, but unsuccessful attempt at nomenclature was by Ž.Vukasović in 1864 when he wanted to name tourmaline „vucipepeo“ (ash-attracter).

TOURMALINE IN BOSNIA AND HERCEGOVINA

A u t h o r s: Čelebić (1967), Đorđević (1969), Foullon (1893), Gaković and Gaković (1973), Jakšić (1927), Jeremić (1963 and 1963a), Jurković (1954, 1956, 1958, 1958a, 1961 and 1962), Jurković and Majer (1954), Jović (1965), Katzer

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(1924 and 1926), Kišpatić (1912 and 1915), Koch (1899 and 1908), Magdalenić and Šćavničar (1973), Marić (1927 and 1965), Marić and Crnković (1961), Markov and Mihailović-Vlajić (1969), Mihailović-Vlajić (1967), Mudrenović and Gaković (1964), Pavlović (1962, 1963 and 1964), Pavlović, Ristić and Likić (1970), Podubsky (1968 and 1970), Primics (1881), Ramović (1957), Ristić, Likić and Stanišić (1968), Šćavničar and Trubelja (1969), Tajder and Raffaelli (1967), Tućan (1911 and 1912), Varićak (1966), Zarić, Đorđević and Vilovski (1971).

1. Mt. Motajica

It seems that Koch (1899 and 1908) was the first to describe tourmaline from a pegmatite vein mainly composed of feldspar, quartz, muscovite and beryl. In addition to tourmaline, the other accessory minerals are stilbite, talc, fluorite, pyrite and psilomelane. This vein was found in the Veliki Kamen quarry near Vlaknica. According to Koch, the mineral is black, occuring in the form of aggregates attached to the feldspar. Koch maintains that this tourmaline is brittle and parts easily along {0001}, and that good cleavage can be seen under the miscroscope. It appears that Koch misinterpreted parting for cleavage in this case. Zonation can be seen along the [0001] axis. A blue-grey to yellow-brown colour can be seen in thin section. Koch also mentions pleochroism which cannot be interpreted with known optical properties of tourmaline. For the blue-grey tourmaline he notes the following pleochroism – a = yellowish-grey // c = darkgrey. For the yellow-brown tourmaline the pleochroism is a = reddish-yellow // c = black. The first argument against the obeservations made by Koch is that absorption along the c axis = [0001] i.e. for the extraordinary ray, would be stronger than for the ordinary ray. This situation has never been identified for tourmaline, and all observations indicate the opposite case, i.e. pleochroism O > E.

The second argument against Kochs observation lies in the fact that he described the second vibrational direction as being in the plane of the three crystallographic axes perpendicular to [0001]. Such a specification is incorrect in terms of optical theory. The absorption for this vibrational direction is independent of its propagation within the plane perpendicular to [0001], as long as it is confined to this plane. Therefore, the description of the pleochroism of tourmaline from the Veliki Kamen pegmatite as given by Koch could probably be corrected in saying that the pleochrosim is as follows – along [0001] yellowish-gray to reddish-brown // perpendicular to [0001] bluish-grey to black, as is the case for schorl.

In a later report Koch (1908, p. 4) writes that tourmaline occurs only infrequently in the granite of Veliki Kamen, and then incorporated into feldspar and quartz. However, tourmaline is common in the pegmatite veins of this granite, contrary to Koch’s statements (1899, p. 12).

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Tourmaline of a bluish colour occurs in the muscovite granite in the Brusnik quarry. It is of a very fine grain and is usually contained within orthoclase (Koch 1908, p. 5). It can be sometimes seen in the biotite granite-gneiss from Židovski potok (Koch 1908, p. 6). Some sections of the muscovite gneiss from Studena Voda contain considerable amounts of pink tourmaline with a strong pleochroism (Koch 1908, p. 7). Pegmatite veins, ca. 1 cm thick, are common within this gneiss and they are mainly composed of black tourmaline, dark quartz, sometimes also orthoclase. The thin and needlelike tourmaline crystals appear like a fabric and are often incorporated in the quartz. They show high pleochroism.

The highly weathered biotite gneiss from the Osovica creek near Šeferovac contains minor amounts of tourmaline in the form of thick hexagonal or prismatic crystals of deep pink colour (Koch 1908, p. 10). Koch (1908) also mentions tourmaline in micaschists of Mt. Motajica – in the biotite schists of Puljana kosa, and from the Manastirica and Osovica creeks near Šeferovac. In thin section these tourmalines are bluish or greenish-blue and display strong dichroism. Short prismatic crystals are found in Manastirica creek and Šeferovac, some of them have terminal pyramidal forms. Substantial amounts of tourmaline can be found in the micaschists outcropping between Galešna kosa and Vinograc near Davor (Koch 1908, p. 15). Some crystals have terminal pinacoid or pyramidal forms, sometimes a hemimorphic habit. Thin, needlike crystals can occasionally be seen – these are often bent or broken.

The chiastolite schists of Vinograc contains greenish-blue, prismatic tourmaline crystals of a hemimorphic habit and with a characteristic parting. Koch mentions that larger crystals contain some finegrained black carbon-like material. This finding also warrants caution, as it seems more likely that this material are opaque iron minerals which are frequently found in a dispersed form in alteredosed schists (Tröger 1967, p. 192). Koch also mentions significant amounts of tourmaline in the argillaceous schists in Osovica creek. The crystals are very small, sometimes displaying terminal faces. They are mainly of a brown colour, but also pink and violet sections can be seen indicating a variable dichroism. Zonal structure of the crystals is common.

Koch’s data have been referenced by Katzer (1924 and 1926) who mentions that black tourmaline is a frequent accessory mineral of the Mt. Motajica granite. Sometimes, ‘tourmaline stars’ (radial aggergates of needlelike crystals) can be seen.

Using the Fersman diagrams for granites and pegmatites (1932, p. 320 and 361; 1939, p. 258-259), the conclusion can be made that the fractionation of tourmaline in the Mt. Motajica granite occurred within a broad range of temperatures. The ‘tourmaline stars’ (schorl) indicate a high fractionation temperature (ca. 800 °C, around boundary conditions for the magmatic/epimagmatic phases). The prismatic

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tourmaline noted by Koch imply lower temperatures, i.e. the pegmatitic phase of the pneumatolite sequence (ca. 600°C). Even lower temperatures were suitable for the formation of transparent brown, green and pink tourmalines, while the needlike shorls of the Galešina kosa schists formed during the hydrothermal stage (temperatures around and below 400°C).

Ramović (1957, p. 38) briefly mentions black tourmaline in pegmatite veins at Vlaknica quarry, occuring in association with feldspar, quartz, beryl, fluorite, pyrite, zeolite and molybdenite.

Varićak (1966, p. 64-165) describes tourmaline as a significant constituent of pegmatites and pneumatolites in normal granite, leucocratic granite, aplite granite, granitic porphyres and vein rocks. The torumaline contained in these vein rocks (Varićak 1966, p. 101) has strong pleochroism – darkgreen (ordinary ray), brownish-pinkish (extraordinary ray). Grains are up to 15 x 3 mm in size. Markov and Mihailović-Vlajić (1969, p. 256) note that tourmaline is widely distributed in the Mt. Motajica pegmatites.

2. Brestovsko

Jurković (1954) mentions tourmaline as a constituent mineral of the actinolite-epidote schists at Hrastovi hill near Brestovsko in the schist mountains of central Bosnia. These schists feature a barite vein with an average thickness of 30-40 cm (the range being 10-100 cm). This schist forms part of a transitional pneumatolite to hydrothermal ore-body, and displays significant alteration features, including the presence of tourmaline. However, the barite also contains another tourmaline phase which crystallized within a higher temperature range. This ‘older’ tourmaline occurs in the form of short prismatic crystals in a size range between 8 x 35 to 50 x 200µm. Microscopic investigations on mostly idiomorphic grains revealed the presence of typical cracks. The crystals usually have pyramidal terminal faces, while sections perpendicular to the c axis have trigonal habit. Extinction is parallel, the pleochroism is very intense – pinkish-brown parallel to the c axis, and dark green perpendicular to the c axis. In reflected light, the tourmaline has a stronger degree of reflection than barite and quartz. Bireflection is significant (light grey parallel to c, dark grey perpendicular to c). The ore body underwent significant tectonic activity, which is the reason for the orientation of tourmaline (also magnetite and pyrite) parellel to the flanks of the vein.

Jeremić (1963a, p. 32) notes that in the Potplane – Kreševo area tourmaline occurs less frequently and that it is related to the Palaeozoic-age barite ore body. Small quantities of tourmaline are also present – together with magnetite and other high-temperature minerals – in the Podljetovik – Brestovsko barite formation.

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3. Vrtlasce – east of Fojnica, Trošnik – south of Fojnica and Čemernica

Jurković (1958a, p. 311) describes the occurrence of tourmaline in the flanks of the ore vein at the Vrtlasce ore body near the village of Klisac, where it comes as a primary mineral in dark grey sericite-quartz schists, chlorite schists and sericite-containing quartzporphyres. The alteration process resulted in the formation of tourmaline, rutile, sericite, quartz and albite. The same author believes that tourmaline is the high-temperature primary mineral in the Trošnik ore body near Fojnica, where the tourmaline occurs together with rutile, zircon and apatite, although a microscopic investigation of these rocks did not reveal the presence of tourmaline.

Jurković (1956 and 1962, p. 143, 149) also identified tourmaline in the antimonite ore body in the area of Čemernica creek, 3 km north of Fojnica in quartz veins within schist rocks. Most rocks in the Zahor ore complex – the Završće creek area, Donje Selo (Ormanov creek) and Selišće – are significantly tourmalinized.

4. Banjak and Hrmza

Jurković (1961, p. 205) identified tourmaline as a common mineral in the realgar- and auripigment-containing formations, where it occurs in the flanks of the ore body. The tourmaline crystals are prismatic, in a size range between 10 x 60 µm and 40 x 150 µm. Pleochroism is strong – dark green parallel to c, light brown perpendicular to c.

Jurković (1961, p. 221) noted a similar occurrence of tourmaline at the Hrmza ore body. The prismatic tourmaline crystals are associated with rutile, sometimes also fluorite.

5. Mt. Vranica

Foullon (1893, p. 7) mentions torumaline as a very rare accessory mineral in the quartz-porphyres of Mt. Vranica, with no mention of precise locations where it was found. The small and ill-formed crystals are of a dark blue colour in transmitted light. This information was later referenced by Katzer (1926, p. 185). Foullon also identified tourmaline in the mining concentrates left over at the abandoned mine of Crvena zemlja, as well as in the clayey soils from the northern flanks of Nadkrstac, in the sand from the stream sediment of the Ljuti potok creek, in the clays of Tješilo near Fojnica and in the sands from a limestone-hole called Bosanska Idrija on Mt. Zec where cinnabar was mined (Foullon 1893, p. 32 and 33). This tourmaline is brownish-pink in colour, displaying sharp edges of its hemimorphic crystals. Due to the fact that Foullon found such tourmalines in all schists from the area (i.e. Rosin, Čemernica) his conclusion was that it was genetically associated with the schists.

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6. Alinovci near Jezero

Jurković and Majer (1954, p. 224) noted an occurrence of tourmaline in the 10-30 cm thick vein at the contact of a schistlike rhyolite (quartzporphyre) and limestone. According to these authors, the amount of tourmaline is highest in the central portion of the contact vein, diminishing towards the sections closer to the contact. They also mention tourmaline in the barite deposits of the schist mountains of central Bosnia, at Kolovoje (Deževica), Ljetovik (Kiseljak) and Brestovsko (Busovača), as well as at the antimonite-sphalerite ore body at Selišće (Fojnica) and the pyrrhotite-cassiterite deposit at Vrtlasce (Fojnica). According to these authors, the presence of tourmaline in these formations indicates a close relationship between Permian magmatic activity resulting in the formation of the quartzporphyres and the mentioned ore bodies.

Tourmaline in rocks of the schist mountains of central Bosnia was also mentioned by Šćavničar and Trubelja (1969) and Tajder and Raffaelli (1967).

7. The Jablanica gabbro and Tovarnica

Marić (1927, p. 53) identified short prismatic torumaline crystals within cracks in the weathered protions of the gabbro, at their contact with Werfen-age schists, near the village of Čehar on the left bank of the Neretva river. The inner surfaces of these cracks are covered with green epidote crystals, intergrown with tourmaline. The formation of these minerals is related to intense weathering of both rock types. Marić (1927, p. 55) dismisses the possibility of a contact-metamorphic zone in this area, even though igneous rocks are in close proximity.

Cissarz (1956) later found that a zone of contact metamorphism was evidently present, especially on Tovarnica (a more detailed description of this are was given in the section on garnets).

During a geological mapping campaign in this area (Pavlović 1962, 1963 and 1964), tourmaline and wollastonite were identified in the magnetite-bearing section of the metamorphic contact-zone. The tourmaline occurs in the form of regular hexagonal prismatic crystals up to 3 mm in size and bluish-grey in colour, displaying strong pleochroism. This information was later corroborated by Čelebić (1967, p. 97-99).

8. Srebrenica

Đorđević (1969) identified tourmaline-bearing rocks within an area od 2 km2 at the Srebrenica mine. The younger dacite and andesite rocks are affected by alteration processes (mainly sericitization, kaolinization, calcitization, silification) contain tourmaline as well as the older Palaezoic-age metasandstones and argillaceous schists).

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The tourmaline-quartz containing rocks show a high degree of silification and thus macroscopically resemble proper quartzites. The rocks are usually very hard with a cavernous texture, grey or greyish-yellow in colour. Veins composed of quartz and tourmaline intersect these host rocks in various directions. Microscopic investigations of these mostly dark veins show a microgranitic matrix with occasionally corroded quartz crystals and tourmaline, probably implying alteration of older dacites. More finegrained rocks without phenocrystals and composed of quartz, tourmaline and mica are also found. The amount of tourmaline in some thin sections approaches 70%.

Tourmaline usually occurs in the form of radial aggerates. Prismatic crystals are comparatively rare, although – when found – their size is in the range of 0.1 to 1 mm. It displays uniaxial-negative optical properties, with parallel extinction. Pleochroism is distinct – greyish-blue to dark blue. Refractive indices, established by the immersion method are Ne = 1.625, No = 1.648. Small prismatic crystals with no discernible pleochroism can also be found. The presence of tourmaline was also determined by XRD, DTA and spectrographic measurements.

The 0.1-0.2 size fraction of tourmaline showed endothermic peaks at 150°C, and between 430 and 480°C and 750-770°C indicating a loss of water upon heating. A broad endothermic peak at 950-1000°C implies a loss of B2O3.

X-ray diffraction using CuKα1 radiation (λ = 1.540 A) and a Ni filter indicates a rubelite (Li tourmaline) composition for the tourmaline.

The B content, established by spectrographic techniques, is around 10000 ppm (1%).

9. South-western Bosnia

In south-western Bosnia tourmaline occurs in sedimentary rocks as an authigenic mineral. In the area around Kulen-Vakuf tourmaline was found in the Permian-age sandstones and red clastic rocks with gypsum. Tourmaline was identified in the heavy mineral fraction and is present in amounts ca. 0.1-1.5%. Magdalenić and Šćavničar (1973, p. 141) established that this heavy mineral fraction consists primarily of zircon and tourmaline. The authigenic greenish or bluish tourmaline frequently grows upon older tourmaline, parallel to the c axis = [0001] and in the same optical orientation. Individual crystals of authigenic green tourmaline are less frequently found. The older tourmaline fractions are usually abraded and subangular, with no terminal faces. Their size is in the range 0.05-0.20 mm. Their colour is mostly brownish, sometimes brownish-green, with a black carbon-like filling of some hollow crystals. In this case also, this black material probably are opaque iron minerals (see the section on Koch’s investigations of the tourmaline from Mt. Motajica). This tourmaline has strong pleochroism (O = dark brown, dark green

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to black, E = brown, greenish-brown). Refractive indices are No = 1.645-1.648, Ne = 1.624-1.627. The autigenic tourmaline commonly occurs in the form of composite, rod-like crystals which grow at different growth rates so that their terminal faces show a sawtooth-like habit. The optic character is negative, the refractive indices being No = 1.646 ± 0.001, Ne = 1.621 ± 0.001. The pleochroism is fairly strong – O = intense green or dark bluish-green, E = pale green or pale brown. The ratio of detrital and authigenic tourmaline varies in the range 1:0.2 to 1:4.5.

The newgrown sections of the tourmaline are completely preserved, inspite of their delicate texture, indicating that they grew in the same position in which they are found today. There are no indications that this tourmaline formed elsewhere and was redeposited in quartz sandstones.

Jović (1965) identified authigenic tourmaline in the heavy mineral fraction of Miocene-age sandy calcarenites from Lupina near Kulen-Vakuf. Epidote and zoisite are further common constituents of this fraction. The core of the detrital tourmalines is mostly green, while the overgrowth of authigenic tourmaline shows a pale blue or no colour at all. The crystal faces of authigenic tourmaline are sometimes slightly pitted on the surface. The occurrence of authigenic tourmaline in Miocene sediments of the Kulen-Vakuf area should be understood in terms of the hydrothermal activity of boron.enriched groundwaters (Magdalenić and Šćavničar 1973, p. 119). The boron enrichment is probably related to the underlying evaporites in the area.

10. Tourmaline in other rocks

Kišpatić (1912, p. 539) identified tourmaline in bauxites of Studena Vrela near Županjac. The tourmaline grains are ca. 0.05 x 0.015 in size and display distinct pleochroism – O = blue, E = colourless to grey.

Tućan (1912, p. 424) found tourmaline as an accessory mineral in dark red and yellowish crljenica soil (terra rossa) near Eminovo Selo, close to Županjac. The attractive short-prismatic and hemimorphic crystals are up to 0.1 mm in size and display the following pleochroism – O = greenish or brownish, E = colourless, light green to light brown. In a later paper Kišpatić (1915, p. 54) briefly describes the finding of tourmaline in bauxite from the hill on which the abbey of Lištica (Široki Brijeg) in Hercegovina is located, noting that tourmaline is ubiquitously present, but in minor amounts. Jakšić (1927, p. 95) describes the location of the finding as Dubrava Greda, south-east from the abbey, at Stražnica (362 m a.s.l.).

According to Tućan (1911, p. 798) the source of tourmaline in terra rossa and bauxite of our karst regions are the limestones and dolomites which contained small amounts of tourmaline as an accessory, primary and authigenic mineral. Tućan (1912, p. 405) believes that the red soil (terra rossa) is nothing but the insoluble residue which remains after the weathering and erosion of these limestones and

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dolomites. Kišpatić (1912) maintained that terra rossa and bauxite are identical, due to the similarity of their mineral compositions. In his treatise of terra rossa, Marić (1965) also notes the tourmalines identified by Kišpatić and Tućan.

Some small, prismatic tourmaline crystals were found in the insoluble residue of limestone from Varoški potok, the left tributary of the Zalomska river between Kifina Sela and Gacko in Hercegovina. They show well preserved crystal forms, indicating very little or no transport at all (Mudrenović and Gaković 1964, p. 143). This location has also been described by J. Gaković and M. Gaković (1973, p. 137).

Marić and Crnković (1961, p. 144 and 156) found some crushed tourmaline crystals in the dark Paleozoic-age schists of the Brdo surface mine in the mining area of Ljubija.

Podubsky (1968) also notes the occurrence of tourmaline in Paleozoic rocks of north-western Bosnia – as an accessory mineral in argilaceous schists and metasandstones of lower Palezoic age (Carbon-aged rocks at Mala Rijeka close to Trnova), in the Permian-Triassic sandstones and schists as well as sediments of lower Triassic age – sandstones and schists containing feldspar, hematite, limonite, quartz and sericite (Podubsky 1968, p. 174-189).

Podubsky (1970) gives similar information also for eastern Bosnia. Here the Paleozoic-age phyllites and phyllite-schists, clay schists and metasandstones contain tourmaline an accessory mineral. The biotite-tourmaline-epidote-quartz-amphibole schists of Mlječvanska Rijeka were apparently formed by alteration o tuffs (Podubsky 1970, p. 160-169).

Pavlović, Ristić and Likić (1970, p. 232 and 235) described the heavy mineral fraction (ca. 1.5%) of quartz sands from the Miladije and Bukinje ore bodies in the Tuzla basin, noting that about half of this fraction consists of opaque minerals and picotite, while the rest is composed of tourmaline, iron oxides, epidote, amphiboles, garnets, rutile, pyroxene and other minerals. Likewise, the heavy mineral fraction of the sarmatian-pontian sands of the Tuzla basin, contains 2.7-4.1 % tourmaline (Ristić, Likić and Stanišić 1968).

Irregular and corroded grains of tourmaline are the accessory mineral phase of sandstones outcropping near Banja Slatina, some 10 km north-east of Banja Luka (Zarić, Đorđević and Vilovski 1971, p. 217). The tourmaline has distinct pleochroism in pale green and dark green colours.

It is interesting to note that the earliest information on tourmaline was provided by Primics (1881) related to its occurrence in extrusive rocks around Žepče and Maglaj.

The various coloured varieties of tourmaline are regularly used as gems.

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PIGEONITE(Mg, Fe2+, Ca)2 [Si2O6]

Crystal system and class: Monoclinic, prismatic class.Cell parameters: ao = 9.69 -9.71, bo = 8.92 - 8.96, co = 5.24-5.25, β = 108° 33’Properties: pigeonite is the term for an isomorphous series between clinoenstatite and diopside. The main difference from other pyroxenes is the small optic axial angle which shows a large variation range; +2V = very small to 40°.X-ray data: almost identical with clinoenstatite (Tröger 1967, p. 388)

A u t h o r s: Pamić (1957), Simić (1964), Šibenik-Studen and Trubelja (1967 and 1971).

Pigeonite, a member of the monoclinic pyroxene minerals, has not been studied in any detail in Bosnia and Hercegovina. Pamić (1957) notes that pigeonite occurs together with augite and other minerals in dolerites (diabases) of Donja Grkarica on Mt. Bjelašnica. As opposed to augite which has an angle 2V = + 58° and an extinction angle of 44°, pigeonite has a substantially smaller 2V angle = + 36°, and an extinction angle of 32°. Simić (1964) noted similar optical constants for pigeonite in basic igneous rocks from the Rača creek near Sarajevo. The 2V angle of this pigeonite is 36°, the extinction angle c : Z = 37°.

Šibenik-Studen and Trubelja (1971) identified pigeonite phenocrystals in dense porhyric diabase from the locality of Kovačići, on the eastern part of Mt. Konjuh. The same authors made a microscopic identification of pigeonite in basalts of the village of Đihanići in the valley of the river Vrbas, between Donji Vakuf and Jajce.

DIOPSIDECaMg [Si2O6]

Crystal system and class: Monoclinic, prismatic class.Lattice ratio: a : b : c = 1.092 : 1 : 0.589; β = 105° 50’Cell parameters: ao = 9.73, bo = 8.91, co = 5.25, Z = 4Properties: pronounced cleavage parallel to {110}, with occasionally distinct parting along {100} or {001}. A variety of diopside with very clear parting along {100} was earlier referred to as diallage, which was also the variety enriched in Al and Fe. Hardness is 6, the specific gravity 3.25-3.55 and increases with Fe content. The varieties depleted in Fe are colourless or white, or dark green to black (hedenbergite) when enriched with Fe. Lustre is vitreous. Streak white to grey. Refractive indices are high: Nx = 1.650-1.698 Ny = 1.657-1.706 Nz = 1.681-1.727X-ray data: d 2.99 (100), 2.53 (40), 2.89 (30) – ASTM-card 11-654IR-spectrum: 405 475 512 635 672 868 925 970 1080 cm-1

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DIOPSIDE IN BOSNIA AND HERCEGOVINA

A u t h o r s: Baumgärtel (1904), Džepina (1970), Foullon (1893), Golub (1961), Katzer (1924 and 1926), Kišpatić (1897, 1900, 1904b), Majer (1962), Marić (1927), Pamić (1969a, 1970, 1971, 1971a, 1972, 1972c, 1972d, 1973 and 1974), Pamić, Šćavničar and Međimorec (1973), Pamić and Trubelja (1962), Ristić, Pamić, Mudrinić and Likić (1967), Schiller (1905), Sijarić and Šćavničar (1972), Tajder (1953), Trubelja (1960, 1961), Trubelja and Pamić (1965), Varićak (1966).

Diopside is widely distributed in Bosnia and Hercegovina, mainly within the Bosnian serpentine zone (BSZ), where it is an important constituent of basic and ultrabasic as well some metamorphic rocks.

Outside of the BSZ diopside is often the predominant mineral of some differentiates of the gabbro complex near Jablanica, as well in certain dacites around Srebrenica. Diopside has also been found in rocks at Mt. Motajica.

Available information on diopside is still relatively scant and incomplete, although the mineral is mentioned in numerous articles dealing with various petrographic issues in Bosnia. The reason for this probably lies in the fact that researchers were unable to precisely determine monoclinic pyroxenes solely on the basis of microscopic investigations. Therefore, numerous publications make reference to diopside-diallage or some other similar nomenclatorial combination.

1. Diopside in rocks of the Bosnian serpentine zone

Kišpatić (1897, 1900, 1904b) investigated microscopically numerous samples of serpentine-peridotite rocks (lherzolites) originating from the Bosnian serpentine zone (BSZ), finding diopside in all of these rocks. According to this author, diopside is the dominant mineral in lherzolites from various localities at Mts. Kozara, Uzlomac, Borje, Ljubić and Ozren as well as around the town of Višegrad. Diopside also occurs in troctolites at Snagovo near Zvornik and in pyroxene amphibolites from Mt. Borje.

The treatise by Kišpatić (1897 and 1900) deals mainly with microscopic determinations of diopside, but contains also two quantitative chemical analyses of this mineral (Table 14)

Table 14. Chemical composition of diopside from the Bosnian serpentine zone

Sample 1 Sample 2SiO2 50.62 50.84Al2O3 3.98 0.42FeO 7.20 7.17

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CaO 19.39 21.48MgO 15.76 16.54Cr2O3 traces tracesLoss on ignition 3.20 4.23

100.15 100.68Sample 1: green diopside from the Milakovac chromium mineSample 2: green diopside from lherzolite rock, Pobilje, Vareš

Diopside in the pyroxene amphibolite of Mt. Borja is of a colourless or green variety, occuring as large foliated crystals (Kišpatić 1904b). It has no pleochroism. The extinction angle is 41°, maximum birefringence Nz – Nx = 0.027.

Golub (1961) provides some more recent data about diopside in ultrabasic rocks of Mt. Kozara. The diopside in lherzolite samples from Jovača creek is of a finely crystalline variety and a variable 2V angle in the range +54° – +57°. The average value of the extinction angle is 37.8°. In lherzolites from the Vrela creek, diopside has an average 2V angle of +54º, and an extinction angle c : Z = 37°. It shows a good prismatic cleavage and parting along [100].

Majer (1962) found minor amounts of monoclinic pyroxene with diopside characteristics in amphibole and garnet gabbros, as well as hornblendites in the BSZ section between the Bosna and Vrbas rivers.

Pamić (1969a, 1972c) identified an omphacite-type diopside in the amphibolites of Mt. Skatovica. This diopside has an elevated 2V angle between +60° and +62° and an extinction angle of 36° to 43°. Diopside from metamorphic rocks often has distinct pleochroism in different saturations of green. Greenish diopside of the omphacite type (enriched with the jadeite molecule) occurs also in pyroxene schists which outcrop on Mt. Skatovica together with the amphibolites and peridotites. According to Pamić, diopside in ultrabasic rocks has somewhat different properties than the one in amphibolites – the ultrabasic diopside has no pleochroism and a 2V angle in the range +53° to +55°. Pamić, Šćavničar and Međimorec (1973) published the results of three chemical analyses of diopside from metamorphic rocks (Table 15):

Table 15. Chemical composition of clinopyroxene from Mt. Skatovica and Mt. Čavka

Sample 1 Sample 2 Sample 3SiO2 51.2 51.1 49.9TiO2 0.38 0.45 0.60Al2O3 6.1 5.8 6.3FeO 8.3 10.6 10.7MnO 0.09 0.09 0.11MgO 11.3 10.5 10.5

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CaO 20.4 18.2 20.4K2O 0.03 0.03 0.03Na2O 1.7 2.8 1.4

99.50 99.57 99.94Composition Di62Hd26Jd12 Di56Hd24Jd20 Di59Hd31Jd10

Samples 1 and 2: Mt. Skatovica, Banja Luka; Sample 3: Mt. Čavka, Teslić

Džepina (1970) found diopside to be the dominant mineral of the garnet-bearing metamorphic rocks from the souther flanks of Mt. Borja. A microscopic study showed that in thin section the diopside is colourless to pale green, while the more intensely coloured varieties have a larger percentage of the jadeite molecule. Peripheral alteration into hornblende can sometimes be seen. This author maintains that diopside is a component of different parageneses found in various locations. For example, the paragenesis of the Crni potok creek is of the hornblende-diopside-garnet-plagioclase type; that of Velika Usora is a diopside-plagioclase-hornblende-garnet paragenesis; while that of Borovnica is of the hornblende-diopside-garnet-prehnite type.

Pamić (1971a) found diopside to be a common mineral in amphibolites associated with ultrabasic rocks in the Krivaja – Konjuh area.

Baumgärtel (1904) identified a green chromediopside in the lherzolites of Duboštica. Pamić (1970) provides a more detailed account and chemical analysis data of this diopside – SiO2 = 51.11, TiO2 = 0.15, Al2O3 = 0.68, Fe2O3 = 1.16, Cr2O3 = 0.81, FeO = 2.19, MnO = 0.15, MgO = 18.80, CaO = 22.42, Na2O = 1.24, K2O = 0.38, H2O

- = 0.27, Total = 99.96

Pamić maintains that chromdiopside often is the only indicator of chromite ore deposits. It is of minor importance in the Rakovac area, but occurs frequently at Borak, Šabanluke and other localities around Duboštica. It is easily recognized by its shining, almost emerald-green colour. However, chromamphibole is of a very similar colour, and when the two minerals occur together macroscopic identification may prove difficult. The chromediopside sometimes forms monocrystals of centimeter length, with clear parting along the pinacoid. Pleochroism can be seen only sometimes, in thicker thin sections. The 2V angle is +63°, the extinction angle 38°, and the maximum birefringence Ny – Nx = 0.033.

Sijarić and Šćavničar (1972) have made XRD determinations of diopside in numerous serpentinized peridotites from Mt. Konjuh which are associated with the Miljevica magnezite veins. Ristić et al. (1967) have performed microscopic determinations and chemical analyses of monoclinic pyroxene from the Dinkovac

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lherzolites. Their chemical composition is as follows – SiO2 = 48.98, TiO2 = 0.10, Al2O3 = 4.01, Fe2O3 = 1.96, FeO = 5.61, MnO = 0.10, CaO = 20.43, Na2O = 0.12, H2O

- = 0.75.

Trubelja (1961) gives data on diopside in ultrabasic rocks from the south-eastern part of Mt. Konjuh. Here, diopside is the dominant mineral in the lherzolites from the locality of Lisac (970 m a.s.l.) and Zečji vrat, as well from the source area of the Grabovica creek. In thin section, most of the diopside grains in the Lisac lherzolite display clear prismatic cleavage and parting along (100) or (010). The extinction angle, measured on several grains, has a stable value of 42°. The diopside is optically positive – 2V angle measurements on three grains gave the following values: 56°, 57° and 61.5°. The monoclinic pyroxene from the locality of Zečji Vrat has properties characteristic of diopside. However, measurements in thin section revealed the presence of grains with a small 2V angle, thus indicating that they belong to the isomorphous series of diopside-clinoenstatite. For diopside, 2V = 47.5° and 52.5°, c : Z = 32.5°.

Diopside from Grabovica displays clear prismatic cleavage and parting along (100) and (010). The angle between the cleavage planes (110) : (1-10) = 86.5°, the extinction angle is 39° to 43°, the measured 2V angle varies in the range +56° to +60°.

Pamić (1974) determined an iron-rich diopside in gabbro-type rocks of the Krivaja – Konjuh ultrabasic complex. This diopside has a 2V angle = +56° to +58°, c : Z = 40-46°.

Diopside (diallage) is very common in the ultrabasic rocks of Mt. Ozren. This diopside has the following optical properties: c : Z = 38-40°, average 2V angle is +60º. It has prismatic cleavage and parting along (100). Based on microscopic determinations, diopside was found in the following rocks: serpentinized harzburgite in the Krivaja creek, serpentinized lherzolite from Malo Selište, harzburgite from Jadrina river valley, lherzolite from Pištalo creek, lherzolite from Gostilje. More detail can be found in the publications by Kišpatić (1897, 1900), Pamić and Trubelja (1962), Trubelja and Pamić (1965) and Pamić (1973).

Trubelja (1960) determined clinoenstatite-diopside in the Lahci basalts near Višegradska Banja. In thin section, distinct cleavage and very narrow parting lamellae can be seen. The measured 2V angles are in the range 47.5-62°, the c : Z extinction angles = 30-44°. The twinning angle (100) : (1-10) is 90°. In many cases the pyroxene core is surrounded with amphibole, indicative of the process of uralitization.

In Bosnia and Hercegovina salite (diopside enriched in Fe2+) occurs only in BSZ and on Mt. Motajica. Kišpatić (1897, 1900) determined salite in pyroxene amphibolites. It occurs less frequently in amphibole pyroxenites, actinolite schists

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and crystalline limestone. Kišpatić identified pyroxene amphibolite on the following locations: Rudine creek, Reljevac, Ozren Manastir, Mala Bukovica, Velika Bukovica, Ravna Rijeka near Duboštica. Salite was also found in the Buletić amphibole pyroxenite, the actinolite schists outcropping between Dragovac and Prisjeka and in the crystalline limestones of Salkići. Kišpatić (1897) found that salite occurs together with titanite in this limestone. The c : Z angle is 38°.

Salite is often found to be a significant constituent of pyroxene amphibolites, where – in thin section – the grains are colourless or pale green. Diopside (salite) is found in the pyroxene cornites of Mt. Motajica (Varićak 1966).

2. Diopside in rocks outside the Bosnian serpentine zone

Marić (1927) determined diopside and other pyroxenes (augite, hyperstene) in the Jablanica gabbro rocks. The extinction angle of this diopside is 38°, the pleochroism Nz = pale yellow, Nx = brownish-yellow. Maximum birefringence = 0.023, 2V is ca. 60°.

Tajder (1953) identified diopside in certain extrusive rocks around Srebrenica – the dacites from the village of Diminići and the Kiselica creek. In the Diminići dacite diopside is so uncommon that it could be identified only in some thin sections in the form of idiomorphic, prismatic, colourless crystals with good cleavage. The extinction angle is 36-38°. On the other hand, diopside is a significant constituent of the Kiselica dacite, where it occurs in the form of idiomorphic, prismatic crystals of ca. 0.3 x 0.1 mm in size. The colour is pale green and it has a high relief. The extinction angle is 38°, 2V = 59-60°. Twinning can be seen on some crystals. A carbonate corona is present in some cases indicating hydrothermal alteration.

Foullon (1893) mentioned diopside in ore concentrates in the schist mountains of central Bosnia.

DIALLAGE IN BOSNIA AND HERCEGOVINA

A u t h o r s: Brajdić (1964), Đorđević (1958, 1960), Golub (1961), Hauer (1879), John (1879, 1880, 1888), Kišpatić (1897, 1900), Pamić (1971, 1972), Pamić and Antić (1964), Pamić and Trubelja (1962), Pilar (1882), Primics (1881), Ristić, Pantić, Mudrinić and Likić (1967), Schiller (1905), Trubelja (1957, 1960, 1961), Trubelja and Pamić (1965).

In Bosnia and Hercegovina diallage is a ubiquitous mineral in gabbroid rocks of the Bosnian serpentine zone (BSZ). John (1888) is the only author who mentions this mineral in the Jablanica gabbro in Hercegovina.

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1. Diallage in rocks of the Bosnian serpentine zone (BSZ)

Hauer (1879) and John (1879) provide the first data on diallage in the olivine gabbro rocks in the Bosna river valley, between Maglaj and Žepče. Samples of these rocks were collected by Anton Rzehak and microscopic determinations were done by John. More detailed data can be found in the subsequent publication by C. John (1880). In additon to data on diallage from the Maglaj-Žepče olivine gabbros, John investigated also similar rocks from Barakovac in the Vrbanja river valley, troctolites and gabbros from the Višegrad area. Diallage is a significant constituent in all of the mentioned rocks.

Diallage is very common in the olivine gabbros from Višegrad. Its colour is brown with a metallic lustre; the cleavage is alomost perfect. In thin section the diallage is mostly fresh and often incorporates large crystals of feldspar and olivine. John paid a lot of attention to the alteration products of diallage, pointing out that hornblende is the most common alteration product. The darker variety of diallage, common in olivine gabbro, alters into brown hornblende, which has strong pleochroism. The lighter diallage varieties alter mostly into fibrous, almost colourless hornblende.

Pilar (1882) also provides a description of diallage in gabbro-type rocks from Vrbanja/Barakovac near Banja Luka and from Mt. Kozara.

Early microscopic determinations of diallage in rocks of the BSZ were done by Primics (1881), Schiller (1905) and Kišpatić (1897, 1900). Kišpatić investigated the entire BSZ, while Primics and Schiller confined their research on the Duboštica and Višegrad areas only.

Substantial research on these rocks was done after the II World War, and a considerable amount of microscopic and other data can be found in various petrologic treatises. Golub (1961) provides a significant set of microscopic measurements of diallage in the rocks of Mt. Kozara. Here, diallage is a constituent of troctolite, olivine gabbro, actinolite gabbro – rocks which have extensive outcrops on the southern flanks of Mt. Kozara.

The diallage (3.5 vol.%) from Jovača creek troctolite shows good cleavage and parting. The average 2V angle value is +60°, the extinction angle is 42.5°. In the Jovača olivine gabbros diallage is of a light pinkish colour, quite pleochroitic (Z = pinkish, Y = reddish, X = pinkish-red. The angle between cleavage planes is 88.5-89.5°. The extinction angle based on several measurements lies in the range 40-42°, while the 2V angle = 56-58°. The maximum birefringence Nz – Nx = 0.0277, while the partial birefringences are as follows: Nz – Ny = 0.0219 and Ny – Nx = 0.0058. This optical data indicate that the diallage is enriched with titanium.

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Reddish-brown platelike inclusions can be seen within the cracks resulting from parting, and this material is probably hematite.

The diallage from the olivine gabbros of the Kozara creek has similar optical characteristics as the one previously described. It shows prismatic cleavage and parting. The extinction angle is 42-44°, 2V° +60° (average value of six individual measurements). The maximum birefringence, measured on two grains, is Nz – Nx = 0.0271 and 0.0273. The pleochroitic colours are Z = pale red, Y = yellowish-red, X = pinkish-red. In the gabbros of Kozara creek the diallage has a pinkish-grey colour and a weak pleochroism. The 2V angle lies in the range 59-60°, the extinction angle is 36-38°. It has less inclusions than the former diallage. The diallage contained in the actinolite gabbro has similar 2V angles, while the extinction angles are somewhat lower.

Pamić and Trubelja (1962) and Trubelja and Pamić (1965) have determined diallage in the gabbro-type rocks of Mt. Ozren. Microscopic determinations, using the Fedorov method on a rotating stage, provided data of the fundamental optical constants. Diallage in the olivine gabbro from Paklenica has a 2V angle of +59°, an extinction angle of 46°. The angle between the two sets of cleavage lamellae is 87.5º.

More recent petrographic investigations of the gabbro-type rocks of Mt. Konjuh, the Krivaja river valley and the Duboštica area were done by Pamić and Antić (1964), Ristić et al. (1967), Brajdić (1964) and Trubelja (1961). Thus, Trubelja (1961) and Brajdić (1964) found diallage to be a constituent of olivine and uralite gabbros, gabbro-diorites and gabbro-pegmatites of the Mt. Konjuh complex. In the olivine gabbros from the Stupančica creek close to the village of Bjeliš, the diallage is fresh and has a poikilitic structure with enclosed small grains of rhombic pyroxene. Almost all investigated grains show good prismatic cleavage and pinacoidal parting. The average 2V angle is +56°, the c : Z extinction angle = 40.8°. B1/2 twinning can be observed on some grains.

In the uralite gabbros, which are located immediately next to the olivine gabbro, diallage has undergone alteration into uralite, and can be identified only in some central sections of the uralite phylla. A similar situation is encountered in the case of gabbro-diorite where diallage has altered both into uralite and chlorite.

Within the ultrabasic complex of Mt. Konjuh, differentiation of some crystalline gabbro-pegmatite can be observed. The diallage grains in such rocks are often several centimeters in diameter. Brajdić (1964) determined diallage in a pegmatite vein from Bjeliš, near Olovo. This diallage has an extinction angle of 40-41°, and 2V angle of +56°. Parting along (100) is clearly visible. Almost all grains are affected by alteration processes (uralitization).

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Ristić et al. (1967) investigated the gabbro-pegmatites from Katranička river at Mt. Konjuh. XRD data of diallage is as follows: d 2.99 (10) 2.51 (9) 2.12 (6) 1.68 (8) 1.42 (7).

Đorđević (1958, 1960) determined microscopically diallage from the basic

intrusive rocks from the Vareš area. He found diallage in gabbros, anorthosites and gabbro-pegmatites. The extinction angle of this diallage is 42-43° but can also be much smaller (28°) in which case it is probably pigeonite. The authors data from the paper published in 1960 are more detailed. The diallage grains are some 4.5 x 3.5 mm in size, and display distinct parting along (100). Pleochroitic colours are very weak. The 2V angle lies in the range 48-60°, the c : Z extinction angle = 36-42°. Maximum birefringence of 0.0296 was measured on one grain. Table 16. shows the chemical analysis data.

Table 16. Chemical analysis data and ion formula units of diallage from basic rocks (Vareš)Diallage (gabbro) Diallage (gabbro-pegmatite)

SiO2 47.26 Si = 1.753 41.29 Si = 1.565TiO2 0.60 Ti = 0.016 0.75 Ti = 0.023Al2O3 5.32 Al = 0.231 9.40 Al = 0.419Fe2O3 2.60 Fe3+ = 0.072 3.17 Fe3+ = 0.091FeO 4.46 Fe2+ = 0.138 7.90 Fe3+ = 0.250MnO 0.09 Mn = 0.02 0.12 Mn = 0.004MgO 19.00 Mg = 1.049 19.65 Mg = 1.109CaO 17.57 Ca = 0.696 11.40 Ca = 0.462Na2O 0.93 Na = 0.066 0.82 Na = 0.066K2O 0.51 K = 0.023 0.36 K = 0.017H2O+ 1.94 4.88H2O- 0.24 0.67

100.52 100.41

The diallage from the gabbro-pegmatite has considerably larger grains (15 x 12 mm). The 2V angle is in the range +47-60°, the extinction angle 37-48°. The maximum birefringence measured on one grain is 0.02877.

The above chemical analysis shows a fairly high amount of water in both diallage samples, particularly in the gabbro-pegmatite which is an indication that this diallage has undergone substantial alteration.

Trubelja (1957, 1960) established that diallage is a common mineral of the basic intrusive rocks from the Višegrad area. It occurs in small amounts in troctolites, while its percentage in normal and olivine gabbro is higher. The gabbro-pegmatites of this area also contain diallage. In uralite gabbros diallage is substantially altered into amphibole.

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The gabbros from the village of Pijavice contain mostly plagioclase and diallage. The diallage shows characteristic parting along (100) and, to a lesser extent, along (010). In this section it is of pale green colour, and often surrounded by uralite. Some grains show evidence of cracking or bending. Twinning is not common. The extinction angle is 40-43°, the 2V angle lies in the range +58-62°. The olivine gabbros from the village of Mirilovići contain diallage which has clear prismatic cleavage and parting along (100). Some grains show alteration effects into bastite and brown hornblende. Its 2V angle lies in the range 53-61°, the extinction angle = 39.3-44.3°.

The olivine gabbros from Rijeka near Velika Gostilja contain pyroxenes with pronounced characteristics of diallage, including clear parting along the (100) pinacoid and less pronounced prismatic cleavage. Grains mostly represent individual crystal but twinning is occasionally present according to the B1/2 law. In this case, both twins share common crystallographic axes [001] and [010]. The angles between the Z and X vibrational directions of the optical indicatrix are 81° which corresponds to the extinction angle value multiplied by two. The diallage grains are 1-2 mm in diameter. The extinction angle lies in the range 38-42°, the 2V = 48.5-56.5°.

The troctolites from Lahci village in the valley of the Banja creek contain ca. 3 vol.% of diallage. It has identical constants with the previously described diallages.

The gabbro-pegmatite vein within the harzburgite rock series of Karaula Kosa near Dobrun, the diallage grains, grey to dark green in colour, often attain sizes of more than 10 cm in length. It displays perfect parting along (100) – crystal faces of this form have a strong light reflectance capacity. This parting is so conspicuous that it resembles the cleavage pattern of micas. Thin sections, when cut parallel to (100) have a parallel extinction, while one of the optic axes is almost perpendicular to this face. The prismatic cleavage is perfect, and parting along (010) is often very good. The extinction angle lies in the range 37.5-43º, the +2V angle is 57.5-59.5º. The grains are mostly fresh but sometimes show alteration into finegrained uralite. Other alteration products include chlorite and bastite. Olivine and magnetite inclusions have been observed in this diallage. The chemical composition of very clear grains is as follows (analyst: F.Trubelja): SiO2 = 49.13, TiO2 = 0.60, Al2O3 = 4.78, Fe2O3 = 1.08, Cr2O3 = 0.15, FeO = 3.89, MnO = 0.25, MgO = 16.85, CaO = 19.79, Na2O = 1.15, K2O = 0.01, H2O

+ = 2.05, H2O- = 0.50, Total = 100.23

The somewhat elevated percentage of water is the result of alteration processes.

The albite-bearing gabbro-pegmatites from Višegradska Banja contain diallage which shows signs of mechanical stress and deformation. Parting is clearly visible. Larger diallage grains, sometimes altered into chlorite and amphibole, are often surrounded with microbreccias. The optical values of this diallage are as follows: the c : Z extinction angle lies in the range 41-45°, the +2V angle = 53.5-54°. A partial Ny – Nx birefringence has been measured as 0.003-0.005.

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2. Diallage in the gabbro from Jablanica

John (1888) has given a detailed account of the diallage contained in the gabbro series from Jablanica in Hercegovina. In thin section this diallage is of a light brown colour and shows very weak pleochroism. Prismatic cleavage and pinacoidal parting is clearly visible. The measured extinction angle is 45°. Inclusions of hornblende, biotite, magnetite and hematite are present in diallage grains.

AUGITE(Ca,Na) (Mg,Fe2+,Fe3+,Ti,Al) [(Si,Al)2O6]

Crystal system and class: Monoclinic, prismatic class.Lattice ratio and Cell parameters: almost identical to diopside.Properties: pronounced cleavage parallel to {110}, as is the case with all pyroxenes. Other properties are similar to those of diopside.X-ray data: d 2.99 (100) 1.62 (100) 1.43 (100) – ASTM-card 3-0623IR-spectrum: 410 465 477 515 637 676 860 875 915 970 1070 1630 3425 cm-1

AUGITE IN BOSNIA AND HERCEGOVINA

A u t h o r s: Barić (unpublished data), Čelebić (1967), Čutura (1918), Golub (1961), Hauer (1879), John (1879, 1880, 1888), Jurković (1954a), Karamata (1953, 1957, 1960), Karamata and Pamić (1960), Katzer (1903, 1924, 1926), Kišpatić (1897, 1900, 1904b, 1910), Majer and Jurković (1957, 1958), Marić (1927), Pamić (1957, 1960, 1960a, 1961a, 1961b, 1962, 1963, 1969, 1969a, 1971, 1971a, 1972c, 1972d), Pamić and Antić (1964), Pamić and Buzaljko (1966), Pamić and Jurić (1962), Pamić and Kapeler (1969, 1970), Pamić and Maksimović (1968), Pamić and Papeš (1969), Pamić and Trubelja (1962), Paul (1879), Petković (1961/62), Pilar (1882), Ramović (1957), Ristić, Pamić, Mudrinić and Likić (1967), Schafarzik (1879), Sijerčić (1972a), Simić (1964, 1966), Šibenik-Studen and Trubelja (1967, 1971), Trubelja (1960, 1961, 1962, 1962a, 1963, 1966a, 1972/73), Trubelja and Miladinović (1969), Trubelja and Pamić (1957, 1965), Trubelja and Slišković (1967), Trubelja and Šibenik-Studen (1965), Tućan (1928, 1957), Varićak (1966).

Augite is a rock forming mineral with a complex chemical composition. In Bosnia and Hercegovina augite is quite ubiquitous, particularly in vein-type and effusive basic and intermediary igneous rocks such as diabase, spilite, porphyrite and keratophyres. Augite-bearing rocks have a regional distribution along the entire Bosnian serpentine zone (BSZ), and its peripheral sections known as the diabase-chert series.

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Augite is also an important constituent in the rocks resulting from Triassic-age magmatic events. These rocks are to be found in numerous locations in Bosnia and Hercegovina. Diabases, spilitic rocks, porphyrites, keratophyres and other rock belonging to spilite-keratophyre series of mid-Triassic age are located mainly in the Vrbas river valley, at Kupres, and in the Konjic – Jablanica – Prozor area. These rocks are alos to be found in the Borovnica – Vareš – Čevljanovići area, in south-eastern Bosnia near Čajniče and Tjentište, as well as in the Ilidža – Kalinovik area.

A substantial amount of literature data is available for augite, both in older and in more recent publications. The information provided is based mainly on microscopic determinations, including rotating-stage measurements.

1. Augite in rocks of the Bosnian serpentine zone (BSZ) and the diabase-chert series (DCS)

The earliest data on augite occurences in rocks of the BSZ and its peripheral parts were provided by Hauer (1879), John (1879, 1880), Kišpatić (1897, 1900, 1904b), Paul (1879), Pilar (1882) and Schafarzik (1879). The mineral augite was determined mainly by microscopic methods in transmitted polarized light. Some of the above authors provide also quantitative measurements – i.e. Kišpatić (1904b, p. 53) gives optical constants for augite in the diabase-porphyrite from Dobrljin:

c : Z = 41° Nz – Nx = 0.020 2V = +56° A large amount of data can be found in the treatise by Kišpatić (1897, 1900). He determined and measured augite in numerous rock samples from Mts. Kozara, Prisjeka, Skatovica, Uzlomac, Borja, Ljubić, Ozren, from the Bosna river valley and the Višegrad area. He established that the augite has commonly altered into amphibole and chlorite. This alteration process and transformation of augite into amphibole is so widespread that augite completely disappears and transforms into fibrous amphibole.

A number of papers published after the II World War contain qualitative and quantitative data on augite: Golub (1961), Karamata and Pamić (1960), Pamić and Kapeler (1969), Pamić and Trubelja (1962), Ristić, Pamić, Mudrinić and Likić (1967), Šibenik-Studen and Trubelja (1971), Trubelja (1960, 1961, 1962, 1966a, 1972/73), Trubelja and Pamić (1965).

a) Bosanski Novi area and Mt. Kozara

Trubelja (1962) finds that augite is contained in the spilitic rocks in the north-western part of BSZ. In addition to augite, titanoaugite is an important constituent of the biotite-spilite from Torić creek. In thin section and when the nicols are not in

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a crossed position, the titanoaugite has a vivid violet colour which is characteristic for this mineral. The +2V angle lies in the range 48-52.5°. The extinction angle is comparatively large at 48-50°. Some alteration into chlorite was noticed.

Golub (1961) identified augite in the uralite gabbros from Kozarački creek on Mt. Kozara. Most of the augite here is altered and transformed into uralite. Parting, so characteristic for diallage, is missing while the cleavage lamellae intersect at an angle of 89.5°. The augite is colourless to pale green, the extinction angle is 39-42.5º, the +2V angle is 46-52º. The coarsegrained augite from the Kotlovača creek gabbro-pegmatite is fractured and weathered, of a pale green colour and very weak pleochroism. The extinction angle is 41-43º, the +2V angle 56-59º. Augite from diabase from this same area has an extinction angle of 45°. Pamić and Kapeler (1969) made similar measurements on these augites.

Trubelja (1966a) found that augite-bearing diabase-dolerite rocks have a wide distribution on the northern flanks of Mt. Kozara. Much of the augite is transformed into amphibole or chlorite (i.e. in the Bukovica and Trnova creeks). The dolerites from Trnova creek carry augites as rather large individual crystals showing a substantial degree of alteration into amphibole. In thin section, good prismatic cleavage can be seen. Pleochroism is either very weak or completely absent. The +2V angle = 50°, the extinction angle is 42°. Plagiocale and augite are the predominant minerals in the diabases found in the source area of the Bukovica creek. The augite grains are irregular in shape and fill the intergranular space of the plagioclase. Most of the augite is chloritized or uralitized. Prismatic cleavage is visible, the +2V angle is 56°.

b) Mt. Ozren, Mt. Konjuh and the Doboj area

Pamić and Trubelja (1962) and Trubelja and Pamić (1965) identified augite to be a common constituent of diabases and spilitic rocks in the peripheral parts of the large peridotite-serpentine complex of Mt. Ozren. It was microscopically determined in the porpyric amphibole-dolerite from the Krivaja creek, in the spilitc rocks from Rakovac, Brezica and Konopljište villages. In the Krivaja series, the augite in amphibole-dolerite rock is considerably altered to uralite, and relicts of augite are encountered only occasionally.

At Konopljište, augite and albite are the predominant minerals in the spilites. Augite normally occupies the space between prismatic albite grains. It is frequently fresh and there is only minor alteration into chlorite and amphibole. The augite is colourless to pale brownish, the pleochroism is weak, and prismatic cleavage is a characteristic feature. The +2V angle, measured in convergent light, is 56°. Grains which are sectioned perpendicular to the c axis have octogonal shapes with distinct prismatic cleavage lamellae. The relief and interference colours are much higher

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than those of albite and other minerals in the rock. Augite in other spilitic rocks has the same or very similar microphysiographic characteristics – the c : Z angle is 38-40º, +2V = 56-60°.

Augite is also the principal mineral of diabases from Mt. Konjuh (Trubelja 1961, Šibenik-Studen and Trubelja 1971). In thin sections prepared from dolerites from the Blizanci creek, the augite is almost colourless but heavily included with dark inclusions. Prismatic cleavage and parting along (001) and (010) is distinct. The +2V angle (measured on several grains) lies in the range 58-59.5°, the extinction angle is 42°. Augite grains are commonly surrounded with green or brown hornblende. Some alteration into acicular or foliated uralite occurs.

Ristić et al. (1967) determined augite in the gabbroid veins of Mt. Konjuh. The +2V angle lies in the range 54-63°, the extinction angle is 40-44°.

John (1879, 1880), Hauer (1879) and Schafarzik (1879) found augite to be an important mineral component of diabase on which the old fortress of Doboj (Gradina) is erected. The determination of augite is largely due to the efforts of C. John. This well known petrographer and microscopist maintained that augite had the structure of diallage (John 1879). Recently, Barić (unpublished results) made microscopic measurements (using a Fedorov-type rotating stage) on augite from the Gradina diabase. Measurements made on six individual grains gave a +2V angle in the range of 47-52¼°, and the c : Z extinction angle 39-43¼°. A red > violet dispersion of optic axes was determined in convergent light.

c) the Višegrad area

Kišpatić (1897, 1900) and Trubelja (1960 and 1972/73) provide data on augite in rocks from the Višegrad area in eastern Bosnia. Augite in diabases matrices is here also mostly converted into uralite. On the other hand, the prehnitized diabase (on the road Višegrad – Dobrun) the augite is fresh.

2. Augite in products of Triassic magmatism

a) Schist mountains of central Bosnia – Konjic, Jablanica and Prozor

Augite is an important constituent of gabbros, diorites, diabases, andesites and other rocks in the schist mountains of central Bosnia. Jurković and Majer (1957, 1958) provide data on augite which occurs in rocks of the gabbro-dioritic complex of Bijela Gromila south of Travnik. Augite in diorite from a location near the village of Kopila is largely idiomorphic and of a greenish colour. Twinning along (100) is common. The +2V angle lies in the range 51-56°, the extinction angle is in the range 40-43°.

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Marić (1927) identified augite in a gabbro rock series in the southern part of the Jablanica complex. It has a weak pleochroism (Z = pale brown, X = greyish). The extinction angle is 44°, the +2V = 59° 50’, and the maximum birefringence is 0.025. One of the measured grains showed a higher extinction angle of 45° 20’.

Jurković (1954a) finds that in the augite-labrador bearing andesite of Orašin (south of Bakovići) augite occurs as small grains, although some of these are ca. 1 mm in size. In thin section the augite grains have isometric or octogonal shapes and carry magnetite inclusions. Some augite grains are surrounded by plagioclase. Ten grains were used for measurement – the +2V angle lies in the range 50-62° while the c : Z extinction angle varies from 42° to 50°. Some twinning along (100) is observed. Some augite grains have a zonal texture. Metamorphic alteration results in a conversion of augite to chlorite and calcite.

Trubelja and Šibenik-Studen (1965), Šibenik-Studen and Trubelja (1967) and Pamić and Papeš (1969) describe augite in rocks from the Kupres and Bugojno areas and from the Vrbas river valley between Donji Vakuf and Jajce. Here, augite is an important constituent of spilitic rocks, porphyr-diabase, andesite and trachyte. Augite is commonly altered into chlorite.

In the area of Konjic, Jablanica and Prozor, augite occurs as a common constituent of rocks which are products of Triassic magmatism, such as basalts, diabases, spilites, keratophyrs etc. Data on augite and other minerals in these rocks can be found in publications by Katzer (1903), Čelebić (1967), Čutura (1918), John (1880, 1888), Kišpatić (1910), Pamić (1960, 1961a, 1961b), Pamić and Maksimović (1968) and Tućan (1928).

Tućan (1928) microscopically determined augite in the Vrata andesite. The augite is often idiomorphic in shape and shows sharp egdes of crystal faces. Some grains were rather large (3.59 x 1.83 mm) in size, with some zonation present. The extinction angle is 44°, the Ny refractive index = 1.7099, the Nz – Nx maximum birefringence = 0.0262, the +2V angle = 59° 51’.

Substantial information on augite in various igneous rocks from this area can be found in the publications by J. Pamić. His investigations showed that augite in basalts is commonly allotriomorphic and that octogonal shapes are comparatively rare. Twinning along (100) is often present, and the angle between twinning lamellae is typically 87.5°. In thin section the augite grains have a pale green colour. The +2V angle is in the range 54-60°, while the c : Z extinction angle varies in the range 40-48°. Interference colours are usually high. In andesites (i.e. the andesite from Vrata near Sovići) the augite has very similar microphysiograpic features to the augite described above. The main difference lies in the fact that alteration of augites in andesites is more pronounced than in basalts. The alteration process can

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result in a more or less complete conversion of augite to chlorite (pseudomorphic chlorite). Augite in spilitic rocks has a +2V angle of 59° and an extinction angle of 44°. Progressive alteration of augite to chlorite is also typical for spilites.

b) the Borovica, Vareš and Čevljanovići area and the Sarajevo district

Karamata (1953, 1960), Pamić (1963), Petković (1961/62) and Ramović (1957) identified augite as one of the important constituents of Triassic effusive rocks and veins of Vareš and adjacent areas. It is interesting to note that Kišpatić (1897) made no determination of augite in the melaphyrs around Vareš, but points out that some vacuoles in these rocks are shaped like augite or plagioclase crystals (which may have been destroyed as a result of surface weathering). Karamata also identified phenocrystals of augite in the basic effusive rocks of Vareš. In thin section these augites are colourless and have distinct cleavage, and often contain inclusions of plagioclase crystals. Measurements of optical constants provide following values: the +2V angle is in the range 51-53.5°, the c : Z extinction angle is in the range 36-43°. The largest augite phenocrystal was 2.88 x 2.70 mm in size.

Augite is likewise an important constituent of Triassic diabases and spilites from the Čevljanovići area. Pamić measured a +2V angle of 52° and an extinction angle of 41°, these being averages of several measurements.

The effusive rocks of the Sarajevo district also have augite as a significant mineral constituent (Pamić 1957, 1960a, 1962) and Simić (1964, 1966). Augite in dolerites (diabases) from Donja Grkarica is mostly allotriomorphic and thin sections reveal distinct prismatic cleavage. The average angle between cleavage planes is 86.5°. Twins along (100) are uncommon. In thin section this augite is colourless; the average value for the +2V angle is 58° and 44° for the extinction angle. The augite in the Govnište dolerites has similar characteristics (+2V = 59º and c : Z = 42°). Both of these localities are on the north-eastern flanks of Mt. Bjelašnica.

Simić (1964, 1966) determined augite in the basic effusives at Babin Dol and Durmiševica on Mt. Bjelašnica, and in the basic igneous rocks in the area of the Rača creek, north of Sarajevo.

Pamić (1962) identified augite in the spilites from the Godinja village near the source of the Željeznica river. Here augite occurs together with albite, but in considerably smaller amounts compared to the plagioclase. The augite grains are very small, allotriomorphic to hipidiomorphic in shape. In thin section this augite is colourless and fractured; the extinction angle is in the range 41-45°.

Pamić (1960a) determined augite to be an important and common mineral in the Kalinovik diabases, picrite-diabases and basalt-andesite rocks. On the other hand, the effusive rocks bearing alkaline plagioclase, contain almost no augite.

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c) South-eastern Bosnia

Trubelja (1962a, 1963), Pamić and Buzaljko (1966), Trubelja and Slišković (1967) and Trubelja and Miladinović (1969) determined augite as a significant constituent in the products of Triassic magmatism in the area of Tjentište, Sutjeska and Čajniče in SE Bosnia. The andesites at Crvene Prljage, south of the village of Čurevo and in the Hrčavka river valley contain augite. At Janjina Rijeka, near Čajniče, the andesites contain augite phenocrystals. Some grains display typical cleavage features. The +2V angle is in the range 58-60°, the extinction angle is between 38-40° and there is no pleochroism. Augite grains are partly or completely altered into chlorite.

Augite was also determined in thin sections of dacites (quartzporphyrites) from Crni Potok and in crystalline tuffs from Ponikve in the Čajniče area.

3. Other occurrences of augite

Varićak (1966) identified augite in the amphibolites and amphibole schists of Mt. Motajica. The determination of augite is based on 2V and c : Z measurements. The extinction angle is 42-42.5° and the +2V angle in the range 53-60°.

Karamata (1957) found that augite occurs, but is not very common, in keratophyrs from the Zvornik region. The augite is always altered into chlorite. The +2V angle is 61° and the extinction angle = 43-44°.

OMPHACITE(Ca,Na) (Mg,Fe2+,Fe3+,Al) [Si2O6]

Omphacite is a variety of augite which occurs mainly in highly altered schists i.e. eclogites.

In Bosnia and Hercegovina omphacite occurs in metamorphic rocks of the Bosnian serpentine zone (BSZ). Kišpatić (1897, 1900) made first determinations of omphacite in eclogite rocks from Mts. Skatovica and Mahnjača and the Kruševički creek, as well as in the eclogite pyroxenite of Ravna Rijeka and Vidaković creek.

Omphacite occurs as irregular grains in the amphibole eclogite from Mt. Skatovica. In thin section it is almost completely fresh and of a pale green colour, and prismatic cleavage is well developed. The Mt. Skatovica eclogite contains a significant amount of omphacite.

The eclogite amphibolite of Ravni Potok contains small amounts of a green monoclinic pyroxene. According to Kišpatić, this pyroxene is omphacite or salite.

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Omphacite is a fairly common mineral in the metamorphic rocks of the Višegrad area. It is the predominant mineral in the eclogite pyroxenite from Vidaković creek. It is of a lush green colour and is sometimes included in garnet. The omphacite in the Kruševički creek eclogite is similar to the one described above.

The Ravna rijeka eclogite pyroxenite contains omphacite in the form of smaller and larger grains of a green colour. There is no pleochroism and no clear cleavage, while the extinction angle is large. Pamić (1969a, 1971a, 1972c) and Pamić and Kapeler (1970) provide more recent data on the occurrence of omphacite in the BSZ, particularly the amphibolites and eclogites of Mt. Skatovica and from the Vijake – Vareš area, as previously described by Kišpatić.

Pamić and Kapeler (1970) also note that the clinopyroxene in amphibolites of the Krivaja – Konjuh complex is probably omphacite. In thin section, this mineral has a pale green colour and distinct pleochroism. The +2V angle is in the range of 60-61.5°, the extinction angle 39-42°.

Tućan (1957), in his famous textbook of mineralogy, mentions the same locations for omphacite as Kišpatić.

ENSTATITE Mg2 [Si2O6]

BRONZITE(Mg,Fe)2 [Si2O6]

HYPERSTHENE(Fe,Mg)2 [Si2O6]

Crystal system and class: Orthorhombic, rhombic dipyramidal class.Lattice ratio and Cell parameters: vary with chemical compositionProperties: the orthorhombic pyroxenes enstatite, bronzite and hypersthene have a distinct prismatic cleavage as well as parting developed along the pinacoids. They represent an isomorphous series between MgSiO3 and FeSiO3. The colour depends on the chemical composition. Enstatite contains up to 5% FeO and its colour is grey, brownish or greenish. Bronzite contains 5-15% FeO and is of brown colour. Hypersthene contains more than 15% FeO and is usually dark green to black. Hardness = 6, specific gravity = 3.2-3.9 and increases with increasing iron content. The streak is white to grey, lustre is vitreous (bronze-like in the case of bronzite). Refractive indices also increase with increasing Fe content, usually in the range 1.65-1.78.

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X-ray data: Enstatite: d 2.873 (100) 3.168 (50) 2.470 (45) d 3.17 (100) 2.87 (87) 2.49 (51) ASTM-card 7-216Hypersthene: d 3.14 (100) 1.47 (80) 2.86 (60)

IR spectrum: Enstatite: 410 460 505 535 655 695 722 745 763 852 908 940 1020

1056 1180 1640 cm-1

Bronzite: 410 455 508 540 565 650 695 722 745 860 930 1015 1065 1125 cm-1

Hypersthene: 408 456 508 536 562 635 650 692 725 760 855 872 895 945 1028 1070 cm-1

ENSTATITE IN BOSNIA AND HERCEGOVINA

A u t h o r s: Đurić and Kubat (1962), Golub (1961), Majer (1962), Pamić (1969a, 1970, 1971, 1972, 1972c, 1972d), Pamić and Antić (1964, 1968), Pamić, Šćavničar and Međimorec (1973), Pamić and Trubelja (1962), Primics (1881), Ristić, Pamić, Mudrinić and Likić (1967), Schiller (1905), Sijarić and Šćavničar (1972), Simić (1966), Sunarić and Olujić (1968), Šćavničar and Jović (1961, 1962), Trubelja (1957, 1960, 1961), Trubelja and Pamić (1965).

Enstatite occurs almost exclusively in ultrabasic rocks of the Bosnian serpentine zone (BSZ) – in peridotites and serpentinized peridotites. Since these rocks have a wide regional distribution in Bosnian inner Dinarides, so is the amount of enstatite substantial. Together with olivine and monoclinic pyroxene, enstatite is an important mineral of all bosnian ultrabasic rocks. It occurs in the lherzolites and harzburgites of north-western, central and eastern Bosnia. Enstatite also occurs in the ultrabasic rocks of Mt. Kozara, and those of BSZ between the rivers Bosna and Vrbas. It can be present in very substantial amounts in peridotites of Mts. Ozren, Konjuh and other areas of the central ophiolite zone. Enstatite is an important mineral in lherzolites and harzburgites of eastern Bosnia in the Višegrad area.

Outside of BSZ, enstatite occurs in the alkaline effusive rocks at Mt. Bjelašnica.

The information available on enstatite is not overwhelming, although enstatite is among the most omnipresent rock-forming minerals of the BSZ. Perhaps the main reason for this lies in the fact that earlier researchers considered enstatite to be bronzite (i.e. Kišpatić 1897, 1900). Microscopic investigations of orthorhombic pyroxenes – without the use of a Fedorov-type rotating stage and no data on their chemical composition – were insufficient for discriminating between enstatite and bronzite.

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Consequently, data on enstatite can be found only in papers published after the II World War. It is, however, interesting to note that Primics (1881) was the only one to identify enstatite, in ultrabasic rocks from the Krivaja-Duboštica area. This determination is most probably the first identification of this mineral in the ultrabasic rocks of Bosnia.

1. Mt. Kozara

Golub (1961) microscopically determined enstatite in the lherzolites from Jovača and Vrela creeks on Mt. Kozara. In the Jovača lherzolite, enstatite occurs as grains of more than 1 cm in diameter. Cleavage is not distinct, but parting along (010) is usually present. Some alteration of enstatite into bastite and talcum is usually seen within the parting fractures. The +2V angle is in the range 78-84°. The 2V angle measurement implies that this enstatite contains about 9% of the FeSiO3 component. In thin section enstatite has a parallel extinction and the angle between the two prismatic cleavage planes is 87.5-88.5°.

In the Vrela lherzolite, enstaite also occurs in the form of large grains. Again, cleavage is not distinct but parting along (010) is visible. The measured +2V angle is in the range 80-90°, indicating a 11% enrichment with FeSiO3

. In the described rocks, enstatite can be easily recognized with the naked eye.

2. The area between the Vrbas and Bosna rivers

Đurić and Kubat (1962), Majer (1962), Pamić (1969a, 1972c), Pamić and Antić (1968), Pamić, Šćavničar and Međimorec (1973) provide data on enstatite in the ultrabasic rocks of the spacious area between the rivers Vrbas and Bosna. Peridotites and their serpentinized product belong to the most widespread rocks in this area. Particularly interesting are the porphyric varieties of peridotites where large (up to 3 cm) enstatite grains occur within a cryptocrystalline olivine matrix. Majer (1962) found the quantity of enstatite in these rocks to be variable.

The ultrabasic rocks of Mt. Skatovica are often associated with amphibolites. Enstatite is an important constituent of these rocks, and has an average 10% of FeSiO3, and a +2V angle of 85°. Enstatite commonly alters into serpentine (Pamić 1969a, 1972c; Pamić, Šćavničar and Međimorec 1973).

Pamić and Antić (1968) found enstatite to be a signficant constituent of serpentine-websterites and harzburgites in the area of Teslić and Prnjavor on Mt. Čavka. In thin section the enstatite is of hipidiomorphic shape and platelike habit. It is colourless and displays clear prismatic cleavage and an angle of 87° between the cleavage planes. The measured +2V angles of around 80° indicate about 8% of FeSiO3 in the enstatite molecule.

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3. Mt. Ozren and Mt. Konjuh

Pamić (1970), Pamić and Antić (1964), Pamić and Trubelja (1962), Primics (1881), Ristić, Pamić, Mudrinić and Likić (1967), Sijarić and Šćavničar (1972), Sunarić and Olujić (1968), Trubelja and Pamić (1965) provide data about enstatite which occurs in the ultrabasic rocks of Mt. Ozren and Mt. Konjuh. Here, together with olivine, enstatite is the predominant mineral in these rocks.

Trubelja and Pamić (1965) have invesetigated in detail the peridotite rocks of Mt. Ozren, including the enstatite which is an important constituent of the lherzolites, harzburgites and their intermediates. The enstatite from the Velika Ostravica harzburgite shows in thin section low interference colours. It has a well developed prismatic cleavage; the extinction is parallel. Some grains have inclusions of olivine or thin lamellae of a monoclinic pyroxene. The +2V angle of 78.5° was measured in convergent light.

Enstatite is the predominant mineral in the serpentinized harzburgite from the Krivaja creek. It is usually allotriomorphic, less frequently hipidiomorphic. The prismatic cleavage is well developed, as is parting along (010). Thin twinning lamellae can be seen under crossed nicols in most grains, parallel to the pinacoid face. The average +2V angle is 79° corresponding to 10% FeSiO3. Some grains show signs of alteration into serpentine.

The lherzolite from the Pištalo creek contains large enstatite grains which can be seen with the naked eye. Next to olivine, enstatite is the second most important mineral constituent of this rock. It has a lamellar structure which makes measurements on the rotating stage rather difficult. The +2V angle is 88°. Occasional alteration into bastite was observed. Enstatite in other rocks of the Mt. Ozren series has similar properties to the one described above.

Several authors referenced earlier have investigated the enstatite contained in ultrabasic rocks of the Krivaja – Mt. Konjuh complex. Pamić and Antić (1964) found that enstatite is a constituent of the lherzolite lenses within the Gostovička Rijeka (close to Zavidovići) series of gabbroid rocks. The +2V angle of this enstatite is 90° (14% FeSiO3).

Pamić (1970, 1971) determined that enstatite is an important mineral in the ultrabasic rocks of the Krivaja complex, associated with the Duboštica chromium ore body. Enstatite is the predominant mineral in single-mineral pyroxenites (vein-like formations), such as the enstatite-dunite rock from the Tribija river valley.

Enstatite is often closely associated with chromite ore of the Duboštica area, in which case it has a characteristic honey-yellow colour. The grainsize of these enstatites is usually 0.5-1 mm.

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Trubelja (1961), Ristić et al. (1967), Sijarić and Šćavničar (1972) provide data on the enstatite in ultrabasic rocks from Mt. Konjuh. Trubelja (1961) found that enstatite is less common than olivine in the Lisac lherzolite. The grains show perfect prismatic cleavage, and parting along (010) – as well as very thin lamellae of monoclinic pyroxene. Some enstatite grains are altered to bastite, while many of them contain olivine inclusions. Wavy extinctions can be observed on most enstatite grains. The measured +2V angle is 83-85°. In the case of enstatite from the Zečji Vrat (1275 m a.s.l.) lherzolite, the +2V angle is 83-86° corresponding to 10.5-12% FeSiO3. The angle between the two cleavage planes (110) : (1-10) is 89°.

Enstatite grains up to 1 cm in diameter occur in the Grabovica creek enstatite. A wavy extinction is commonly observed in thin section. Inclusions of monoclinic pyroxene and polisynthetic lamellae are parallel to (010). Olivine inclusions in enstatite are a common feature, impying that the enstatite is a reaction product of magmatic processes involving previously crystallized olivine (Trubelja 1961). Sijarić and Šćavničar (1973) have determined enstatite by X-ray diffraction in numerous samples of ultrabasic rocks from Miljevac on Mt. Konjuh.

4. The Višegrad area

Trubelja (1957, 1960) found enstatite to be a common and important constituent of ultrabasic rocks in the area of Višegrad. It is commonly found in harzburgites of Bosanska Jagodina (river Rzava valley). Thin sections of the mineral show low interference colours and parting along (010), and parallel inclusions of monoclinic pyroxene – much like in enstatites in other rocks of the BSZ. Alteration of enstatite to bastite is a common feature and many grains have retained enstatite only in their cores. The measured +2V angle is in the range 79.5-88° corresponding to 9-13 % FeSiO3. The harzburgite from Karaula Kosa near Dobrun contains enstatite which has very similar properties to the one described above. However, some pressure twinning of enstatite has been observed in several samples. The +2V angle is in the range 74-86° corresponding to 7.5-12% FeSiO3.

Enstatite grains can be observed with the naked eye in ultrabasic rocks from the Višegrad area – due to its bronze colour and semimetallic lustre.

Pamić (1972d) investigated the enstatite in lherzolites from the area of Rudo (valley of the river Lim). This enstatite contains some 7% FeSiO3 (based on +2V measurements).

5. Enstatite in other areas

Simić (1966) reports on enstatite occurrences outside of the BSZ, mainly in basic extrusive rocks of Triassic age on Mt. Bjelašnica (the localities of Durmiševica and Gornja Grkarica). The measured +2V angle is in the range 54-58°, refraction

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indices Nz = 1.664, Nx = 1.565 ± 0.002, maximum birefringence Nz – Nx = 0.008. The enstatite is colourless and almost idiomorphic.

Enstatite is also a constituent of some clastic sedimentary rocks. Šćavničar and Jović (1961,1962) found enstatite in Pliocene sands of the Kreka coal basin, using powder XRD, but provide no further information. Ristić et al. (1968) report on the occurrence of enstatite in sands from the Tuzla basin. We believe that in both cases the enstatite originates from the ultrabasic rocks of adjacent areas of the Bosnian serpentine zone.

BRONZITE IN BOSNIA AND HERCEGOVINA

A u t h o r s: Baumgärtel (1904), Hiessleitner (1951/52), Kišpatić (1897, 1900), Pavlović (1899), Roskiewicz (1868), Tscherne (1892), Walter (1887).

Early publications mention bronzite as an important constituent of the rocks in the Bosnian serpentine zone (BSZ). Hiessleitner (1951/52) describes bronzite occurrences in rocks of the chromium ore-body of Duboštica and Krivaja (p. 94), based on earlier papers by Walter (1887), Baumgärtel (1904) and Kišpatić (1897, 1900). The largest amount of relevant information pertaining to bronzite occurrences in BSZ can be found in the two publications by Kišpatić. He maintained that bronzite is an important mineral constituent of all lherzolites – from Mt. Kozara in the north-west to the Višegrad area in the south-east. It needs to be mentioned that in the period when Kišpatić (but also earlier investigators) did their research, it was not possibly do differentiate between bronzite and enstatite only by microscopy. Results of more recent investigations – based on 2V angle measurements on a Fedorov-type rotating stage – indicate that most of what was determined as bronzite is, in fact, enstatite. Thus, bronzite probably occurs less frequently in bosnian ultrabasic rocks than previously believed (by Kišpatić).

Kišpatić (1897) made a chemical analysis of the orthorhombic pyroxene hosted in the Pobilje lherzolite (near Vareš):

SiO2 56.00Al2O3 0.72FeO 8.98CaO 0.59MgO 32.44LOI 1.77Total 100.50

The results of this analysis indicate that the Pobilje lherzolite indeed contains bronzite, since FeO is above 5%. The obvious conclusion, based on this example, is that a chemical analysis is a prerequisite (in additon to optical data) for a determination of orthorhombic pyroxenes.

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Roskiewicz (1868) was apparently the first to mention bronzite in rocks of the BSZ, in the Vareš area (referenced by Kišpatić 1897, p. 96).

Tscherne (1892) described the occurence of sepiolite on Mt. Ljubić near Prnjavor, mantioning the occurrence of bronzite in surrounding sepiolite rocks.

HYPERSTHENE IN BOSNIA AND HERCEGOVINA

A u t h o r s: Katzer (1924, 1926), Kišpatić (1897, 1900, 1904b, 1910), Majer and Jurković (1957, 1958), Marić (1927), Pamić (1971, 1971a), Pamić and Kapeler (1970), Pamić, Šćavničar and Međimorec (1973), Primics (1882), Ramović (1961,1962,1966), Schiller (1905), Tajder (1953), Trubelja (1960, 1961)

In Bosnia and Hercegovina hypersthene occurs in some rocks of the Bosnian serpentine zone (BSZ), in certain Triassic igneous rocks and in andesite-dacite rocks in the area of Srebrenica.

Kišpatić (1897, 1900, 1904b, 1910), Pamić (1971, 1971a), Pamić and Kapeler (1970), Pamić, Šćavničar and Međimorec (1973), Primics (1882), Ramović (1961,1962,1966), Schiller (1905), Trubelja (1960, 1961) report on hypersthene occurrences in basic and ultrabasic rocks of the BSZ – olivine gabbros, lherzolites and amphibolites.

Hypersthene occurs in products of Triassic magmatic events in rocks of the schist mountains of central Bosnia – Bijela Gromila, as well as in the Jablanica gabbro complex. Several authors have reported on the above – Katzer (1924, 1926), Kišpatić (1910), Majer and Jurković (1957, 1958), Marić (1927).

Kišpatić (1904a), Tajder (1953) and Ramović (1961, 1962, 1966) have determined hypersthene in in Tertiary andesites and dacites from the Srebrenica areas.

1. The Bosnian serpentine zone (BSZ)

The already referenced publications by Kišpatić provide most information on the occurrence of hypersthene in igneous and metamorphic rocks of the BSZ. He made microscopic determinations of hypersthene in the pyroxene amphibolite of Velika Bukovica on Mt. Ozren, in the olivine gabbro from Gostovići, in the eclogite amphibolite of Ravanka (near Gornje Vijake and Vareš). It is likely that hyperesthene also occurs in the lherzolite from the Ljučica creek on Mt. Kozara.

Kišpatić (1897) found that the hypersthene in the Velika Bukovica amphibolite has poor cleavage but strong pleochroism. The hypersthenes from the

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Ravanka eclogite amphibolite, and from the Turjački creek olivine gabbros have similar properties. The hypersthene from Turjački creek displays distinct pleochroism in brownish-red, yellowish-red and green-grey colours (Kišpatić 1897).

Trubelja (1960) found that the feldspar-peridotite from Bosanska Jagodina contains only small amounts of hypersthene. In thin section, this hypersthene displays distinct psimatic cleavage and parting along (010). Some alteration into brown hornblende is visible. The measured -2V angle is 82-84°.

Schiller (1905) determined hypersthene in gabbro from Višegrad. It is optically negative and contains at least 15% FeSiO3.

Trubelja (1961) mentions an ocurrence of hypersthene in the olivine gabbro from Stupčanica creek, near the village of Bjeliš on Mt. Konjuh. The negative 2V angle of 86° was measured on one hypersthene grain included in a diallage crystal.

Pamić (1971, 1971a), Pamić and Kapeler (1970), Pamić, Šćavničar and Međimorec (1973) identified minor amounts of hypersthene (ca. 5-15%) in the amphibolites of the Krivaja – Konjuh metamorphic complex. Hypersthene is associated with alkaline plagioclase, garnet and edenite-pargasite hornblende. Pleochroism is distinct in thin section. The negative 2V angle of 63° and 64° corresponds to 40% FeSiO3.

Pamić (1971) found variable amounts of hypersthene in amphibolite schists in the souther part of Mt. Ozren.

2. Hypersthene in Triassic intrusive rocks

Kišpatić (1910), Katzer (1924, 1926), Majer and Jurković (1957, 1958) provide data on the occurrence of hypersthene in gabbro-diorite rocks of Bijela Gromila, near Travnik. Majer and Jurković (1957, 1958) found that the diorite of Kopile contains plate-like grains of hypersthene which display distinct pleochroism (Nz = greenish, Nx = pinkish-red). The measured 2V angle is -66° corresponding to ca. 25% FeSiO3. Inclusions of plagioclase are common. Some alteration to uralite was observed. Hypersthene was also found in diorites from the source area of the Zasenjak creek. Here the hypersthene is highly altered.

Kišpatić (1910) was the first to report on the occurrence of orthorhombic pyroxene in the gabbro rocks of the Jablanica complex. No further details on the mineral were given in this paper. Marić (1927) investigated the minerals in these rocks and found that hypersthene was an important constituent of basic rocks in the central parts of the massif. Hypersthen occurs together with olivine and diopside. Pleochroism is distinct in thin section (Nz = redish-brown, Nx =

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colourless to grey). The maximum birefringence has a value of 0.019. The grains are elongated along the c axis, and sections parallel to (100) have a platelike habit. Some circumferential alteration of the grains (into hornblende and chlorite) was observed. Dispersed inclusions of magnetite are common. In one thin section of the gabbro from Bukov Potok on the left bank of the Neretva river, hypersthene grains completely enclose olivine.

3. Hypersthene in the effusive rocks of Srebrenica

Kišpatić (1904a) provide the first data on the occurrence of hypersthene in the products of Triassic magmatism in the Srebrenica area. Hypersthene was microscopically determined in andesite rocks from Potočari, Sikirić and Crveni Potok.

In the Sikirić andesite, hypersthene is fairly common – particularly in the rock groundmass while phenocrystals are rare. In thin section the grains have a columnar habit with distinct prismatic cleavage and cross-fracturing. No pleochroism and a low birefringence were determined. Kišpatić’s measurement of the 2V angle of -50° indicates an FeSiO3 content of 54%. Hypersthene in Potočari andesite has quite similar properties. A maximum birefringence of 0.014 was measured.

Tajder (1953) provides data on hypersthene occurrences in his treatise on the effusive rocks of Srebrenica. It was found only in the bytownite dacite from the village of Diminići, and then only in minor amounts in the form thin idiomorphic crystals. Alterations into biotite, chlorite and amphibole were observed. Some hypersthene grains are completely converted to chlorite.

TREMOLITECa2Mg5 [Si8O22] (OH)2

ACTINOLITECa2(Mg,Fe2+)5 [Si8O22] (OH,F)2

Crystal system and class: Monoclinic, prismatic class.Lattice ratio: a : b : c = 0.545 : 1 : 0.292; β = 104° 42’ – tremolite a : b : c = 0.544 : 1 : 0.295; β = 105° 00’ – actinoliteCell parameters: ao = 9.84, bo = 18.05, co = 5.575, Z = 2 – tremolite ao = 9.86, bo = 18.11, co = 5.34, Z = 2 – actinoliteProperties: perfect cleavage parallel to {110}, with occasionally distinct parting along one of the pinacoids. In terms of chemical composition, an isomorphous series between the Mg end-member (tremolite) and the Fe end-member (ferrotremolite).

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The white to grey tremolite, in which a small amount of Mg can be substituted with Fe, converts into green actinolite. The chemistry of the isomorphous series is much more complex due to other possible substitutions resulting in the formation of other amphiboles i.e. hornblende. The specific gravity is given as 2.98-3.35, but increases with the iron content. The streak is white, the lustre vitreous. The refractive indices are moderately high, increasing with the iron content. The birefringence shows a small increase with an increase of Mg.

X-ray data: actinolite d 2.709 (100) 3.120 (70) 2.535 (55) tremolite d 1.438 (10) 1.047 (9) 2.710 (8)IR-spectrum: actinolite (405) 425 445 462 507 540 645 660 686 758 920 952 1000 1060 1105 3430 3540 3654 3668 cm-1

tremolite 410 425 455 470 515 532 550 646 670 690 723 757 924 955 995 1020 1105 1640 cm-1

TREMOLITE AND ACTINOLITE IN BOSNIA AND HERCEGOVINA

A u t h o r s: Baumgärtel (1904), Džepina (1970) , Golub (1961), Jurković (1954, 1956, 1957), Jurković and Majer (1954), Katzer (1924, 1926), Kišpatić (1897, 1900), Koch (1908), Kubat (1964), Majer (1962, 1963), Maksimović and Antić (1962), Marić (1927), Mojsisovics, Tietze and Bittner (1880), Pamić (1969a, 1971, 1974), Pamić and Kapeler (1969), Pilar (1882), Primics (1881), Šćavničar and Jović (1962), Šibenik-Studen and Trubelja (1971), Šibenik-Studen, Sijarić and Trubelja (1976), Tajder and Raffaelli (1967), Trubelja (1960, 1961, 1963a, 1966a), Trubelja and Pamić (1965), Trubelja and Sijarić (1970), Varićak (1957, 1966, 1971).

Tremolite, actinolite and other members of the isomorphous series are very common rock-forming minerals in Bosnia and Hercegovina. Nevertheless, these minerals have not been researched to any great extent. The available data is based only upon microscopic determinations or measurements of 2V and c : Z angles done using a Fedorov-type rotating stage. These minerals are often referred to just as ‘amphiboles’ or – with slightly more precision – ‘amphiboles of the tremolite-actinolite isomorphous series’. Detailed accounts of these minerals are very scarce.

The available data on the tremolite-actinolite series has been published mainly in papers dealing with the petrology and mineralogy of the Bosnian serpentine zone (BSZ), where these minerals contribute to the composition of basic and ultrabasic intrusive rock, as well as some metamorphites

Outside the BSZ, the tremolite-actinolite minerals occur in the metamorphic rocks of Mt. Motajica and Mt. Prosara and in the rocks of the schist mountains of central Bosnia. The are also found in Triassic igneous rocks (the Jablanica gabbro complex and the granites of Čajniče) and in some clastic sedimentary formations.

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Tremolite in rocks of the BSZ has been mentioned by several authors – Baumgärtel (1904), Kišpatić (1897, 1900), Golub (1961), Maksimović and Antić (1962). Kišpatić determined tremolite in the olivine gabbros from Vodoplav on Mt. Ljubić, in the troctolites from Krušička Rijeka on Mt. Ozren and the troctolites from Ravni creek and from the village of Lahci near Višegradska Banja. Tremolite also occurs in actinolite schists in Vidakovićev Potok near Višegrad. In most of these rocks tremolite formed as an alteration product of plagioclase, in the presence of olivine.

Tremolite is usually colourless and without pleochroism in thin section. The results of more recent investigations give rise to our doubts that Kišpatić dealt only with pure tremolite in all cases, and not with the isomorphous series tremolite-actinolite.

Golub (1961) did microscopic investigations of troctolites and uralitized gabbros from Mt. Kozara in which he was able to identify tremolite. In the Jovača creek troctolite, tremolite is prismatic, acicular or fibrous. No pleochroism was observed in thin section, it is colourless but with a high relief. Measurements on two larger grains showed the mineral to be optically biaxial and negative. The extinction angle in unoriented sections was 17° or less. Tremolite and actinolite were also identified in the corona around olivine grains in the uralite gabbro from Kotlovača creek. Baumgärtel (1904) determined tremolite in the secondary incrustations within fractures in the ultrabasic rocks of the Duboštica area.

The amphiboles of the tremolite-actinolite series are mostly formed as a result of pyroxene alteration into uralite or as products of the reaction between olivine and alkaline plagioclase. The tremolite-actinolite amphiboles are important constituents of gabbros, olivine gabbros, uralite gabbros, feldspar-peridotites and some harzburgites from the Višegrad area (Trubelja 1960). The harzburgites from Bosanska Jagodina in the Rzava river valley carry tremolite and actinolite which were formed by uralitization of enstatite and amphibolization of olivine. A keliphytic rim indicates a reaction process between olivine and relicts of weathered plagioclase. In thin section tremolite grains display distinct prismatic cleavage. The measured extinction angle c : Z is 20°. Tremolite and actinolite in the feldspar-peridotites of Bosanska Jagodina were here also formed by alteration of hypersthene and diallage into uralite or by alteration of olivine. The tremolite and actinolite are located within the keliphytic corona around pyroxene and olivine. The negative 2V angle is 86-87°.

Needlelike tremolite/actinolite occurs in the olivine gabbro from Rijeka – Velika Gostilja, at the contact of olivine and plagioclase grains. They are also

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important constituents of the uralite gabbro from Smrijeće. Here they were formed by the alteration of diallage into uralite. There are so few relicts of pyroxene in the rock that we can conclude that the process of uralitization is more or less complete. In thin section, it appears that the alteration process prgressed in steps – the first step would be the formation of a thin keliphytic rim at the contact of pyroxene and plagioclase; the second step would involve the uralitization of the whole grain. The 2V angle was determined to be -88°, the extinction angle = 13°.

Tremolite and actinolite were found in the gabbro rocks from the village of Pijavice. The negative 2V angle was determined as 80.5-81.5°, the extinction angle = 19°. Prismatic cleavage is distinct, while twinning along (100) can be seen on some grains only.

Trubelja (1961) identified the amphiboles of the tremolite-actinolite series in the diabases of Mt. Konjuh. These amphiboles and plagioclases are the predominant minerals of the porphyric diabase from the Blizanci creek. In thin section they are mostly pale green in colour, sometimes with a hint of blue. Some grains are pale brownish, and these display distinct pleochroism. Prismatic cleavage is apparent on homogeneous grains – the angle between the two cleavage planes is 57°; the extinction angle lies in the range 8¼-12¼°; the negative 2V angle is 87°.

Šibenik-Studen and Trubelja (1971) determined the tremolite-actinolite amphibole in diabase from the village of Kovačići. They occur in two different modes – either as independent ‘nests’ or as alteration rims around augite grains. In both cases the amphiboles are the results of augite uralitization. Pamić (1974) reports on the presence of tremolite-actinolite amphiboles in gabbros from the Krivaja – Konjuh complex of ultrabasic rocks.

Trubelja and Pamić (1965) found that this type of amphiboles are significant constituents of some igneous and metamorphic rocks of the Mt. Ozren series. Tremolite-actinolite amphiboles in the amphibole-zoisite schists from Krušik creek (near the village of Boljanići) are colourless or pale green in thin section, with no apparent pleochroism but dislaying distinct prismatic cleavage. The grains are comparatively large and fresh, making them appropriate for rotating stage measurements. The negative 2V angle is 86-88°, the extinction angle 17¼° to 18¼°. These amphiboles seldom occur as homogeneous grains in the spilites from Konopljišt, rather forming pale green, fibrous aggregates.

Trubelja (1966a) and Pamić (1969a, 1971, 1972c) report on the occurence of amphiboles in rocks on Mt. Kozara, Mt. Skatovica and in other parts of the BSZ.

C. John (referenced in Mojsisovics et al. 1880) was apparently the first investigator to report the occurrence of actinolite in Bosnia – he determined it

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microscopically in the amphibolite from Rudo. His findings were confirmed some years later by Primics (1881), Pilar (1882) and Kišpatić (1897, 1900) who identified actinolite in rocks throughout the BSZ. Golub (1961) determined actinolite in numerous basic rocks in the southern part of Mt. Kozara. In the actinolite gabbros from Kotlovača creek, actinolite is important as a constituent mineral and either builds up the alteration ‘corona’ around olivine grains, or occurs as granular or radiating aggregates with apparent pleochroism (Z = pale green, Y = yellowish-green, X = colourless). The maximum extinction angle which could be measured on some grains was never in excess of 20°. The negative 2V angle = 66°. Actinolite in the Jovača troctolite is also pleochroitic with the same colour as given above.

Golub determined amphiboles of the actinolite-hornblende series in uralite gabbros from Kozarački creek and in the Kotlovača gabbro-pegmatite. The amphiboles are only in part primary minerals, while the rest formed by alteration ofmonoclinic pyroxene. In thin section, the primary amphiboles are present as allotriomorphic grains (2-3 mm in size) showing distinct prismatic cleavage. Pleochroitic colour are Z = greenish, Y = yellowish-green, X = yellowish. The c : Z extinction angle is 22°, the negative 2V angle = 74°.

The uralite gabbros from Kozarački creek contain amphiboles which again belong to the actinolite-honblende series. They formed by alteration of augite into uralite. Pleochroism is quite strong (Z = bluish-green, Y = green, X = pale green). The negative 2V angle was measured on two larger grains (grain I -2V = 88°, c : Z = 19°, grain II -2V = 85°, c : Z = 18°).

Pamić and Kapeler (1969) report on the occurrence of actinolite in the gabbro-dolerite rocks at Mt. Kozara.

Majer (1962) and Kubat (1964) note the occurrence of actinolite in the BSZ, in the area between the Vrbas and Bosna rivers. Trubelja (1960) determined actionlite microscopically in basic rocks from the Višegrad area. This author maintains that actinolite forms by alteration of monoclinic pyroxene into uralite, and that actinolite occurs mainly in diabase-doleritic rocks. The actinolite in diabase (dolerite) from the Rzava river (near Višegrad) is greenish in colour, with distinct pleochroism (Z = brownish-green, Y = dark green, X = light green). Prismatic cleavage is good, the angle between the two cleavage planes is 56°. The c : Z extinction angle is in the range 15.3-16.8°, the negative 2V angle in the range 74.5-75.3°. B1/2 twinning = ̂ (100) was observed. Similar properties have the actinolites from other rocks.

2. Mt. Motajica and Mt. Prosara

Koch (1908), Katzer (1924, 1926) and Varićak (1966) report on actinolite in rocks of Mt. Motajica. Koch described the actinolite schists from Osovica creek (near

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Šeferovac) where actinolite occurs in the form of fibrous aggregates. It is colourless or pale green in thin section; pleochroism is weak but apparent – in pale green and blue-green. The extinction angle is somewhat greater than 15°. This actinolite was also noted by Katzer (1924, 1926).

Varićak (1966) reports on the presence of actinolite in amphiboles and amphibole schists of Mt. Motajica. Actinolite is an important constituent of metamorphic rocks which belong to the 'facies of green rocks' which is ubiquitous – although in small masses only – at Mt. Prosara (Varićak 1957).

3. The schist mountains of central Bosnia

Jurković (1954, 1956, 1957), Jurković and Majer (1954), Tajder and Raffaelli (1967), Trubelja and Sijarić (1970) and Varićak (1971) determined actinolite in rocks of the schist mountains of central Bosnia.

Tajder and Raffaelli (1967) maintain that actinolite is an important constituent of green schists. The actinolite is green-blue in colour with strong pleochroism. This iron-rich actinolite appears to be similar to the green-blue hornblende of the epidote-amphibolite facies. the hornblende, however, has higher concentrations of Al and Na than actinolite. Since distinguishing between these two amphiboles is not straightforward, it is possible that amphibole schists belong to the epidote-amphibolite facies, not to the 'facies of green rocks'. On the other hand, the paragenesis of pelitic schists which are associated with the amphibole schists, provides more arguments for the 'green rock' theory. Other important constituents of green schists are quartz, chlorite, epidote and magnetite.

Jurković (1954, 1956) noticed the presence of actinolite in the pneumatolytic-hydrothermal baryte vein near the village of Hrastovi and Brestovsko. The baryte has formed within an extensively altered actinolite-epidote schist. Jurković determined, in thin section, that the actinolite occured in a coxcomb texture with tiny prismatic grains up to 0.3 x 0.7 mm in size, or as radiating, acicular aggregates. The actinolite has perfect cleavage parallel to [001] – in basal sections the two cleavage planes intersect at at angle of 124°. The extinction angle c : Z is 11-14°. Pleochroism is strong (Z = dark green, X = greenish-yellow).

Jurković and Majer (1954) investigated the occurrence of actinolite in altered rhyolites (quartzporphyres) from Busovača, Kreševo and Fojnica. These authors also note the formation of actinolite by contact metamorphosis at the albite-rhyolite/Paleozoic limestone interface, from Alinovci near Jajce.

Šibenik-Studen, Sijarić and Trubelja (1976) report the occurrence of actinolite asbestos at Tarčin near Crna Rijeka. The fibrous aggregate was determined

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as actinolite by X-ray diffraction, chemical analysis and IR-spectroscopy. The chemical analysis was done by M. Janjatović – SiO2 = 50.96; TiO2 = 0.22; Al2O3 = 3.05; Fe2O3 ---; FeO = 5.52; CaO = 11.47; MgO = 22.43; K2O ---; Na2O = 0.40; H2O

- = 0.69; H2O

+ = 5.57; Total = 100.41

4. Other occurrences

Marić (1927) determined actinolite in the Jablanica gabbro. Šćavničar and Jović (1962) found actinolite to be a common mineral in Pliocene-age sands of the Kreka coal basin.

Use

Amphiboles of the tremolite-actinolite series can form fibrous aggregates (amphibole asbestos). These materials have been used widely as fire-proof fabrics, insulators, building blocks, additives in car-brake linings etc. Due to their environmental impact and extremely detrimental effect on human health, asbestos materials are being phased out of all industrial or technical applications.

HORNBLENDECa2[(Mg4,Fe4

2+)(Al,Fe3+)] [Si7AlO22] (OH)2

Crystal system and class: Monoclinic, prismatic class.Lattice ratio: a : b : c = 0.548 : 1 : 0.296; β = 105° 44’ (for common hornblende)Cell parameters: ao = 9.87, bo = 18.01, co = 5.33 different for other varieties of hornblende Properties: perfect cleavage parallel to {110}, hardness = 6, specific gravity is given as 3.0-3.4, but increases with the iron content. The colour is dark green, brown or black. The streak is white, the lustre vitreous. The refractive indices are fairly high, birefringence is moderate. Hornblende belongs to the group of monoclinic amphiboles. The chemical composition of hornblende is variable and complex, so that trace elements – like titanium and others – frequently enter into its structure. The varieties of hornblende have different names such as edenite, ferro-edenite, tchermakite, pargasite, hastingsite etc.X-ray data: substantial differences depending on variety of hornblende (see Tröger 1967, p. 423-473 and other handbooks)IR-spectrum: common hornblende 445 505 540 635 655 695 725 778 880 900 990 1010 1110 1146 cm-1 basalt hornblende (415) 465 510 630 680 740 (908) 955 980 1050 1650 cm-1

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HORNBLENDE IN BOSNIA AND HERCEGOVINA

A u t h o r s: Barić (1970a), Behlilović and Pamić (1963), Boué (1870), Čutura (1918), Džepina (1970), Đorđević (1958, 1960), Đurić and Kubat (1962), Foullon (1893), Golub (1961), Hlawatsch (1903), John (1880, 1888), Katzer (1903, 1924, 1926), Kišpatić (1897, 1900, 1904, 1904a, 1904b, 1910), Koch (1908), Kubat (1964), Majer (1962, 1963), Majer and Jurković (1957, 1958), Marić (1927), Marković and Takač (1958), Mojsisovics, Tietze and Bittner (1880), Pamić (1960, 1963, 1969a, 1970, 1971, 1971a, 1972c, 1972d, 1973, 1974), Pamić, Dimitrov and Zec (1964), Pamić and Kapeler (1969, 1970), Pamić, Šćavničar and Međimorec (1973), Pamić and Trubelja (1962), Paul (1897), Pavlović (1889), Pavlović and Ristić (1971), Ramović (1957, 1961, 1962, 1963, 1966, 1968), Roskiewics (1868), Simić (1964, 1966), Šćavničar and Jović (1962), Šćavničar and Trubelja (1969), Šibenik-Studen (1972/73), Tajder (1953), Trubelja (1957, 1960, 1961, 1963, 1963a, 1963c, 1966a), Trubelja and Pamić (1956, 1965), Varićak (1957, 1966), Walter (1887).

In Bosnia and Hercegovina hornblende is one of the most common and ubiquitous rock-forming minerals. Hornblende is a constituent mineral of numerous igneous and metamorphic rocks, even in some sedimentary ones. Several varieties of hornblende occur in different basic, intermediate i acidic igneous rocks from many areas in Bosnia and Hercegovina. They occur both in intrusive and effusive rocks. Some hornblende types and varieties are characteristic and essential constituents of many amphibolites and amphibolite schists of the Bosnian serpentine zone (BSZ).

The author has encountered some difficulty in writing this chapter on hornblende, because many petrographic publications do not refer to hornblende as a separate mineral species – rather as a member of the amphiboles. This implies that data – by which we could distinguish between the various types of hornblende – is relatively scarce.

1. Hornblende in rocks of the Bosnian serpentine zone

C. John (1880) was the first (or certainly one of the first) investigators who microscopically determined hornblende in rocks of the Bosnian serpentine zone (BSZ). This author reports occurrences of hornblende in diorites from Čelinci and Kladanj, epidiorites from the Maglaj area and Barakovac in the Vrbanja river valley. Fibrous brown hornblende occurs in the gabbros from Višegrad (of which John published a chemical analysis – table 17). The hornblendes in gabbros and olivine gabbros from Višegrad formed by alteration of diallage. Different diallage grains results in the formation of different hornblende varieties. For example, diallage of a dark colour converts into brown, very pleochroitic hornblende, while lightly coloured diallage results in the formation of fibrous, almost colourless hornblende.

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Table 17. Chemical composition of hornblende from the area of VišegradPlumose hornblende Fibrous hornblende

SiO2 50.22 50.50Al2O3 5.64 5.90FeO 21.79 21.78CaO 12.42 12.30MgO 9.81 9.55LOI 1.17 1.20

101.05 101.23

Kišpatić (1897, 1900) provides a substantial amount of data derived from microscopic measurements of amphiboles from various rocks of the BSZ. It is interesting to note that Kišpatić never mentioned hornblende as a separate mineral entity. The authors hesitation in this respect is difficult to percieve since we know that the various amphiboles could have been distingusihed and classified by their extinction angles in thin section. In the cited publication, Kišpatić paid particular attention to microscopic determinations of various metamorphic rocks from the BSZ, in which amphiboles are essential – and sometimes the only constituent minerals.

In a separate publication with the title ‘Petrographic notes from Bosnia’ Kišpatić (1904) also provided numerous results of microscopic determinations of amphiboles, without distinguishing their types and varieties.

Kišpatić reports results of two chemical analyses for 3-4 cm long columnar amphibole crystals from Nemila in the Bosna river valley (Table 18). The analyst was F. Tućan.

Table 18. Chemical analysis of amphibole from Nemila, Bosna river valley1 2

SiO2 44.37 44.63Al2O3 24.66 24.97Fe2O3 6.79 1.78FeO n.d. 4.51MgO 8.55 8.81CaO 11.09 11.31H2O 3.49 3.36Total 98.95 99.37

A substantial amount of data based on microscopic determination and chemical analyses of hoirnblendes from BSZ was collected and published in the period after the II World war.

Marković and Takač (1958) determined pale green and weakly pleochroitic hornblende in rocks of the Višegrad area. Trubelja (1957, 1960) investigated the

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hornblende in olivine gabbros from Bosanska Jagodina where the hornblende is an alteration product of pyroxenes. This author maintains that hornblende occurs mostly as an essential constituent (in some cases only as an accessory mineral) of feldspar-peridotites, troctolites, olivine gabbrosand diabase-doleritic rocks. Hornblende has a characteristic mode of occurrence in veins such as pegmatites and hydrothermal veins in the Višegrad area.

Green and brown hornblende occurs in the feldspar-peridotites of Bosanska Jagodina in the Rzav river valley. In thin section the brown hornblende is highly pleochroitic (Z = brown, X = pale brown), the c : Z extinction angle is 19.3°. Prismatic cleavage is good and the angle between the two cleavage planes is 57.3°. Another hornblende grain in the same thin section has following properties: pleochroism (Z = light bluish, X = pale green); the extinction angle is 22.5°.

Some hornblende formed as a result of pyroxene alteration into uralite, in troctolites from Gornji Dubovik and olivine gabbros from Mirilovići.

Amphiboles (hornblende) are predominant minerals in the Banja Potok diabases near Višegradska Banja. Here also they are products of pyroxene alteration. Pyrite and ilmenite inclusion are common. Pleochroism is strong (Z = bluish-green, X = light green). Hornblende grains are homogeneous and the measured extinction angle is in the range 19.8-25.5°, the negative 2V angle is in the range 72-82°.

Hornblende occurring in dolerites from the Rzav valley river, on the Dobrun – Smrijeće road, displays distinct pleochroism (Y = light brown, X = light green). The extinction angle is 22°, the negative 2V angle is in the range 79-82.5°.

At Suha Gora (Pavitine) the hornblende is associated with clinozoisite and prehnite. The grains are columnar or foliated and display distinct prismatic cleavage. Prismatic faces are observed on columnar crystals. Measurements done on a rotating stage gave following values: the c : Z extinction angle is in the range 9-24.5°, the negative 2V angle 73-82°. Plewochroism is distinct (Z = pale green, X = light green). A cleavage plane was used for angle measurement with a reflexion goniometer. The angle between the prism faces was measured (110) : (1-10) = 55° 09’

The occurrence of hornblende and associated minerals in the rocks at Pavitine should be understood in terms of postmagmatic processes which followed the extrusion of basaltic rocks through older gabbro series.

Green hornblende, occurring at the Lahci gabbro quarry, formed under similar paragenetic conditions as the one at Suha Gora. This hornblende has foloowing optical constants: the c : Z extinction angle is in the range 11-23º, the

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negative 2V angle between 86° and 88.5°. Twinning (B1/2 = ^ [100]) is common; pleochroism (Z = bluish-green, X = light green).

Pamić, Šćavničar and Međimorec (1973) made a detailed investigation of various hornblendes from amphibolitic rocks of the BSZ. Microscopy, chemical analysis and X-ray diffraction methods were employed in this study. Seven samples of hornblende from amphibolites of Mt. Skatovica near Banja Luka (sample numbers 0, 1, 1’, 2, 4, 5 and 7), three hornblende samples from the Krivaja – Konjuh amphibolites (sample numbers 8, 9 and 10) and one sample from the amphibolite schists near Rudo (sample number 11). The research methods used (measurement of optical constants on a rotating stage, chemical analyses and other procedures) including structural formula calculations, enabled the authors to determine several types and varieties of hornblende. The authors findings are as follows:

2V angle Extinction angle c : ZBrown hornblende -77.5° 16.5°Green hornblende -84.5° 19.3°Pargasite hornblende +86° 19°

In addition to the above results, the authors were able to distinguish several transitional varieties of hornblende – i.e. green-edenite hornblende, green-brown hornblende etc.

The chemical analysis of 11 hornblende samples is given in Table 19. Calculated formula units are given in Table 20. Table 21 gives the composition of the hornblende samples, defined by their end-member percentages. The ‘pure’ hornblendes or end-member varieties can be clearly distinguished from ‘composite’ types. For example, sample no. 10 is a pure pargasite (from a corundum-bearing amphibole schist). The 2V angle of this pargasite is +83°, the extinction angle is 18.5°, the refractive index 1.670 ± 0.005. The pargasite is completely colourless in thin section.

Sample no. 8 is interesting because of its comparatively high Ti content (5.35% TiO2) and was therefore classifies as kersutite or titanium-pargasite. This amphibole was also extracted from amphibole schists of the Krivaja – Konjuh metamorphic complex. The 2V angle is -77°, the extinction angle 16°, the refractive index 1.670 ± 0.005. Pleochroitic colours are X = Y = light grey, Z = light brown. Pamić (1970) identified green edenite-hornblende (chromium-amphibole) in rocks of the chromium ore body at Duboštica. This hornblende could, however, be identified only on two localities – Borak and Šabanluke where it occurs in the form of foliated and finegrained aggregates in alternating layers with chromite. In thin section this hornblende is completely colourless and displays distinct prismatic cleavage. The angle between the two cleavage planes is 124°. The 2V angle is -86°

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to -86.5°, the extinction angle is 18-19°. It chemical composition is as follows:SiO2 = 50.47; TiO2 = 0.03; Al2O3 = 5.17; Cr2O3 = 0.33; Fe2O3 = 2.79; FeO = 6.79; MnO = 0.07; MgO = 17.92; CaO = 13.42; Na2O = 1.40; K2O = 0.23; H2O

+ = 1.56; H2O

- = 0.01; Total = 110.19

The following ionic numbers (formula units) were calculated: Si + Al = 8.00; Al + Cr + Fe3+ + Fe2+ + Mn + Mg = 5.14; Ca + Na + K = 2.48; OH = 1.47

Table 19. Chemical composition of amphiboles from the Bosnian serpentine zone0 1 1’ 2 4 5 7 8 9 10 11

SiO2 43.5 45.71 39.5 45.48 42.28 42.28 46.75 38.52 44.80 41.92 42.51TiO2 1.7 0.33 0.09 0.08 0.22 0.03 0.34 5.35 0.77 --- 0.35Al2O3 12.7 12.45 15.7 11.38 13.25 9.81 6.34 13.55 8.48 15.47 14.70Fe2O3 6.9 1.46 7.6 6.20 2.29 5.51 1.70 5.69 3.35 3.69 1.04FeO 6.4 13.44 7.5 4.15 11.46 3.34 6.75 7.48 10.40 3.71 7.86MnO 0.09 0.29 0.04 0.19 0.28 0.01 0.11 0.24 0.26 0.08 0.11MgO 12.90 10.08 11.2 15.80 12.58 21.96 20.67 10.87 18.17 17.05 17.81CaO 11.0 11.20 11.2 12.72 14.76 11.90 12.50 12.70 9.48 14.00 10.60Na2O 2.1 2.46 3.3 1.09 0.92 1.20 1.48 2.51 1.81 2.96 1.94K2O 0.43 0.10 0.23 0.16 0.19 0.68 0.14 0.71 --- 0.43 0.28H2O

+ n.d. 1.21 n.d. 2.43 1.39 2.98 2.45 1.98 1.71 0.92 1.99H2O

- n.d. 0.39 n.d. 0.32 0.13 0.42 0.53 0.21 0.53 0.15 0.52P2O5 n.d. 0.16 n.d. 0.04 0.16 0.09 0.09 --- --- 0.10 0.18Total 97.72 99.28 96.36 100.04 99.91 100.49 99.85 99.81 99.76 100.48 99.89

Table 20. Structural formulas of amphibole – based on 230 atomsSample 0 1 2 4 5 7 8 9 10 11

ANa 0.49 0.470 0.132 0.269 0.164 0.416 0.718 0.509 0.811 0.542K 0.08 0.018 0.029 0.034 0.126 0.026 0.013 0.073 0.052Ca 0.060 0.355 0.511 0.511 0.364 0.36 0.298 0.118 0.250

X

Ca 1.74 1.765 1.896 1.974 1.328 1.560 1.993 1.176 2.00 1.350Na 0.09 0.229Fe2+ 0.20 0.006 0.104 0.026 0.408 0.440 0.007 0.825 0.650Mg 0.264

Y

Ca 0.013Mn 0.01 0.034 0.023 0.034 0.017 0.030 0.041 0.007 0.014Fe2+ 0.58 1.648 0.397 1.386 0.378 0.923 0.438 0.444 0.297Mg 2.80 2.202 3.394 2.756 4.501 4.465 2.410 3.929 3.606 3.817Ti 0.19 0.038 0.012 0.029 0.005 0.046 0.297 0.105 0.048Fe3+ 0.75 0.159 0.672 0.248 0.489 0.048 0.636 0.366 0.393 0.153Al 0.48 0.881 0.490 0.518 0.407 0.016 0.537 0.623

Z

Ti 0.300Fe3+ 0.115 0.138Al 1.69 1.281 1.442 1.774 1.684 1.083 1.962 1.496 2.049 1.874Si 6.31 6.719 6.558 6.226 6.201 6.779 5.783 6.504 5.951 6.126H2O 0.595 1.168 0.685 1.447 1.184 0.983 0.827 0.434 0.956

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Table 21. Composition of amphiboles expressed as end-member ratiosSample # Composition0 Ed16.6 Pa36.9 Ts32.1 Ho14.4

1 Ed34.5 Pa13.7 Ts14.7 Ho37.1 (Ed26.3 Pa21.1 Ts18.0 Ho23.4 Gl11.2)

1’ Pa26 Ts28 Gl10

2 Ed12.1 Pa9.6 Ts34.9 Ho43.4

4 Ed14.7 Pa50.9 Ts26.7 Ho7.7

5 Ed16.4 Pa64.0 Ts15.6 Ho4.0

7 Ed63.0 Pa17.6 Ts4.3 Ho15.1

8 Kersutite (titanium-pargasite 84%)9 Ed40.9 Pa38.4 Ts10.1 Ho10.6

10 Pa100.0

11 Ed10.7 Pa74.1 Ts13.4 Ho1.9

Ed = edenite (ferro-edenite); Pa = pargasite (ferro-pargasite, Mg-hastingsite); Ts = tschermakite (ferro-tschermakite); Ho = common hronblende; Gl = glaucophane.

The unit cell parameters of the investigated hornblendes are given in Table 22.

Table 22. Unit cell parameters of amphiboles (Pamić, Šćavničar and Međimorec 1973)Sample # * a0 (Å) b0 (Å) c0 (Å) β (º) V0 (Å

3)2 9.810 18.039 5.282 105.13 902.343 9.811 17.998 5.267 105.27 897.155 9.833 17.994 5.269 105.29 899.266 9.863 18.106 5.295 105.17 912.617 9.800 18.019 5.270 105.19 898.108 9.892 18.085 5.347 105.23 923.019 9.814 18.010 5.269 105.22 898.6510 9.783 17.973 5.278 104.96 894.8111 9.796 17.998 5.273 105.28 897.38

* Chemical analysis was not done on samples No. 3 and 6 (loc. Mt. Skatovica, Banja Luka)

In a short preliminary report on amphibolites in the Krivaja – Konjuh area Pamić (1971a) notes the folowing amphiboles: brown hornblende, green hornblende, edenite and pargasite.

Pamić and Kapeler (1970) microscopically determined pargasite-hornblende to be an essential constituent of schists and corundum-bearing amphibolites from Donja Vijaka near Vareš. In thin section this hornblende is colourless, the measured +2V angle is in the range 76-78º, while the extinction angle varies between 15° and 21º. Macroscopically, the hornblende has an emerald-green colour. The green hornblende has following optical constants: the 2V angle is negative and in the range -76° to -80°, c : Z = 13-20°. The pargasite-edenite hornblende has a negative 2V angle of -87° to -88°, and is colourless in thin section.

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Pamić (1974) notes the occurrence of brown hornblende in gabbro-type rocks of the Krivaja – Konjuh ultrabasic complex, but provides no further data.

Đorđević (1958, 1960) studied in some detail the occurrence of hornblende in basic rocks of the Vareš area. In the coarse-grained amphibole gabbro hornblende is present in the form grains from 2.7 x 1.0 mm to 12 x 3 mm in size. It is of a dark green colour, or somewhat paler in the case of weathered grains. Following observations were made in thin section: pleochroism (Z = green, Y = yellow-green, X = pale yellow-green); the negative 2V angle is in the range -77° to -88° ; the extinction angle c : Z is in the range 12.5-23.5°. The angle between the (110) and (1-10) cleavage planes is 125.5°.

The hornblende contained in finegrained amphibole gabbro occurs as crystals up to 0.3 mm in size, and has a dark green colour. In thin section, the observed pleochroitic colours are Z = green, Y = yellow-green, X = pale yellow. The negative 2V angle is in the range -83° to -89°, the extinction angle is in the range 12-15.5°. The measured (110) : (1-10) is 125°. The chemical composition of this hornblende is given as: SiO2 = 42.73; TiO2 = 1.25; Al2O3 = 14.22; Fe2O3 = 6.05; FeO = 9.27; MnO = 0.18; MgO = 13.02; CaO = 9.05; Na2O = 0.92; K2O = 0.52; H2O

+ = 2.90; H2O

- = 0.21; Total = 100.32

Based on the above chemical analysis, the structural formula of the hornblende is (Ca1.419 Mg0.363 Fe2+

0.145 Na0.131 K0.048 Mn0.022)2.127 (Mg2.483 Fe2+0.992 Al0.727

Fe3+0.662 Ti0.136)5 - (Si6.267 Al1.733)8 O22 (OH)2

The end-member percentages of the analyzed hornblende are as follows: ferro-tschermaikte 31.5%; ferro-hastingsite 4.0%; hastingsite 14.0%; tschermakite 22.5%; Mg-gedrite 23.5%; Fe-gedrite 1.0%; kupferite 3.5%.

The chemical composition of hornblende from the finegrained amphibole gabbro is given as (Đorđević 1960, p. 115): SiO2 = 41.16; TiO2 = 2.00; Al2O3 = 13.70; Fe2O3 = 1.83; FeO = 7.88; MnO = 0.14; MgO = 17.83; CaO = 10.23; Na2O = 1.57; K2O = 0.66; H2O

+ = 2.54; H2O- = 0.47; Total = 100.01

Based on the above chemical analysis, the structural formula of the hornblende is (Ca1.618 Mg0.583 Na0.441 Fe2+

0.146 K0.122 Mn0.017)2.927 (Mg3.327 Fe2+0.827 Al0.423

Ti0.220 Fe3+0.203)5 - (Si6.061 Al1.939)8 O22 (OH)2

The end-member percentages of the analyzed hornblende are as follows: ferro-tschermaikte 3.3%; ferro-hastingsite 10.0%; hastingsite 36.7%; tschermakite 17.1%; Mg-gedrite 21.2%; Fe-gedrite 5.4%.

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The genesis of amphibole formation in amphibolites and amphibole schists is closely related to the formation of the entire mineral association in these rocks. At this stage we cannot provide a final theory on the genesis of amphibolites or the amphiboles contained in them. The occurence of corundum in some of these rocks makes things even more difficult. The amphibolites could be products of regional but also of contact metamorphism. It needs to be said that both edenite and pargasite are typical minerals for contact metamorphism.

Trubelja (1961) determined brown and green hornblende in the olivine gabbros from Stpčanica creek, near the village of Bjeliš. In thin section, the green hornblende is pleochroitic in the colours Z = light green, X = dark green; the extinction angle is 17.5°. The brown hornblende has the following pleochroitic colours – Z = light brown, X = dark brown; the extinction angle is 17° , the 2V angle is -75° . Both hornblendes have good cleavage. Overgrowths on diallage are common. Brown and green hornblende also occurs in the dolerites from the Blizanci creek, where overgrowths upon augite are frequently observed. The author maintains that these overgrowths and reaction rims are the consequence of magmatic melts reacting with previously crystallized augite, so that he considers the amphiboles (hornblendes) to be primary minerals formed in a normal sequential crystallization process. The brown hornblende has a 2V angle of -79° while the extinction angle is 26.8°. For the green hornblende these values are – extinction angle = 18.8°, pleochroism Z = light green, X = light green.

Trubelja and Pamić (1965) and Pamić (1973) found hornblende to be a common mineral also in the basic rocks at Mt. Ozren. Hornblende is an essential constituent of the porpyric amphibole-dolerites from the Krivaja creek. In thin section the hornblende is pleochroitic (Z = yellow-brown, Y = yellowish, X = light yellow). The average 2V angle is -65°, the c : Z extinction angle = 18°. The hornblende formed by alteration from augite.

The pyroxene amphibolites of Gornja Bukovica carry fresh and homogeneous brown hornblende. Pleochroism is Z = brown, X = light brown. The 2V angle = -77°, the extinction angle c : Z = 14°.

Amphiboles from the amphibolic dunites from Vijenac (east of Mt. Ozren) were microscopically determined as hornblende with an increased kersutite content (Pamić 1973). The 2V angle = -81° to -82°, the extinction angle c : Z = 13-17°. The amphibole is probably the source of Ti (TiO2 = 1.05%). The same hornblende occurs also in the harzburgite from this locality. Pamić also mentions peridotites with pargasite (?) hornblende with these constants: 2V angle = -86° to -88°, the extinction angle c : Z = 18° to 22°.

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Majer (1962) provides some additional information on amphiboles in igneous and metamorphic rocks of the BSZ. Green and black hornblende is an essential constituent of amphibole gabbros, garnet-bearing gabbros and hornblendites. Majer classifies these rocks as igneous, although others believe them to be typical metamorphic rocks.

Majer (1963) identified hornblende to be the dominant mineral of albite granite, present in the form of pebbles within the diabase-chert series. Such pebbles are abundant near the village of Prisoje on the Doboj – Banja Luka railroad. The hornblende grains are columnar, the extinction angle is 14°. Pleochroism is blue-green to greenish-yellow.

Đurić and Kubat (1962) and Kubat (1964) have investigated the copper mineralizations on Mt. Čavka, finding hornblende in garnet-bearing amphibolites. Its extinction angle is 18°, the 2V angle -88°.

Hornblende is an essential mineral in numerous igneous rocks of Mt. Kozara, as observed by Golub (1961) and Trubelja (1966a). Hornblende occurs in the diabases from the Bukovica creek and dolerites from Trnava creek. In both cases the hornblende seems to have formed by alteration of augite. Pleochroism is Z = greenish-brown, X = pale greenish-brown. The 2V angle = -69°, the extinction angle c : Z = 12°

2. Hornblende in products of Triassic magmatism

Many authors mentioned at the beginning of this chapter have reported on the presence of hornblende in various products of Triassic magmatism. Roskiewics (1868) and Boué (1870) provide the earliest accounts.

Marić (1927) made detailed determinations of hornblende occurring in gabbro-type rocks of Jablanica gabbro complex. He found hornblende to be the third most common mineral in these rocks, i.e. after feldspar and pyroxene. Green hornblende is closely associated with monoclinic pyroxene, and overgrowths are a common feature. Replacement of pyroxene by hornblende is sometimes so extensive (or even complete) that psudomorphic hornblende is frequently observed. Green hornblende also has the propensity to replace augite, and this is the case in rocks outcropping between Zlato and the Tovarnica magnetite mine, and around the confluence of the Rama and Neretva rivers.

Hornblende’s prismatic cleavage can best be observed in longitudinal sections. Pleochroism – Z = greenish, Y = brownish-yellow, X = pale yellow. Maximum birefringence = 0.022. The green hornblende is much more common than the yellow-brown variety which occurs in the central part of the massif. This hornblende is also optically negative like the green variety, but the extinction angle is larger.

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Green hornblende with somewhat different optical characteristics occurs in in the northern part of the massif, along the right bank of the Neretva river. The grains are 0.15 x 0.005 mm in size. Pleochroism – Z = greyish-green, Y = brownish-yellow, X = pale yellow. The maximum birefringece is slightly smaller, at Nz – Nx = 0.019.

Large hornblende crystals can be found in fractures and cracks within the gabbro rock at Bukov Pod. The columnar hornblende crystal are up to 10 cm long and 1.5 cm thick. They are of a dark green colour – fresh cleavage planes have a metallic lustre. Prismatic cleavage can be observed macroscopically on some crystals. The hornblende from the Jablanica massif has been described with more or less detail by a number of other authors (Hlawatsch, 1903; John 1888; Katzer 1903; Kišpatić 1910; Ramović 1968; Roskiewics 1868).

Data on hornblende occuring in various igneous rocks in the schist mountains of central Bosnia can be found in publications by the following authors – Barić (1970a), Čutura (1918), John (1888), Katzer (1924, 1926), Kišpatić (1910), Majer and Jurković (1957, 1958), Mojsisovics et al. (1880).

Majer and Jurković (1957, 1958) determined the green hornblende in the gabbro-dioritic massif of Bijela Gromila, south of Travnik. John (1888) made a microscopic determination of hornblende from the diorite rocks between Donji Vakuf and Jajce, as well as from the Tešanica (probably Trešanica) diorite from Bradina in Hercegovina.

Barić (1970a) also reports a determination of the Bradina hornblende, a common hornblende from a keratophyre rock from Trešanica cliff. We are not quite sure whether John referred to this hornblende or not. The hornblende occurs as phenocrysts in the keratophyre and has a distinct pleochroism – Z = green, Y = pale yellowish-green, X = colourless to pale yellow. The 2V angle was measured on two hornblende grains (using a rotating stage, on a section where both optic axes were visible) and lies in the range -74° to -74.5° with a red > violet dispersion of optic axes. The 2V angle was measured on several other sections which showed only one optic axis, and the measured values are in the range from -73° to -77.5°. The optical extinction angle c : Z varies in the range 14.3° to 18.7°. Twinning along (100) is rarely observed.

Data on hornblende in products of Triassic magmatism in other parts of Bosnia and Hercegovina is relatively scarce (Behlilović and Pamić 1963; Boué 1870; Pamić 1960, 1963; Simić 1963, 1964; Trubelja 1963, 1963a) although hornblende appears to be a common mineral in these rocks.

Trubelja (1963a) measured optucal constants on hornblende from the amphibolic granites of the Čajniče area (village of Dublje). The measured 2V angle = -78.5° to -84°, the optical extinction angle is 15-16°.

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3. Hornblende in products of Tertiary magmatism

Hornblende is an essential constituent of volcanic rocks in the area of Srebrenica. This area was investigated in detail by M.Tajder and relevant information is provided in his treatise on the petrology of this area (Tajder 1953). This publication contains extensive information about optical properties of hornblende, derived mainly from measurements of the optical axis angle, the extinction angle and determination of pleochroism.

The amphibole dacites of Diminići village contain amphiboles in the form of common hornblende. The average c : Z extinction angle is 17°, the 2V angle is in the range -85° to -88°. Twinning along (100) is fairly common. Pleochroism is strong, in yellow and brown.

Dacites at Kiselica creek contain green hornblende as idiomorphic, hipidiomorphic and irregularly shaped elongated crystals up to 1.4 x 0.7 mm in size. Pleochroism in yellow-green and dark green is distinct. The extinction angle c : Z = 16°, the 2V angle = -82°. Green hornblende also occurs in amphibole dacites in the area of Srebrenica.

John (1880), Kišpatić (1904a), Pavlović (1889) and Walter (1887) report on hornblende occurrences in Tertiary effusive rocks in the Srebrenica area. John (1880) determined optically the hornblende contained in the trachytes of Šušnjara, in the quartzpropilites of Srebrenica, the Ljubovija dacite and the hornblende andesites of Zvornik. Kišpatić (1904a) corrected John’s findings with regard to the trachyte from Šušnjara, maintaining that the rock is a hypersthene andesite (Kišpatić does not distinguish between various amphiboles in his publication). The hornblendes from Srebrenica were also studied by Ramović (1957, 1961, 1962, 1963 and 1966).

The Tertiary effusive rocks outcropping in various locations in the Bosna river valley carry hornblende which is often an essential constituent of these rocks. Data on these hornblendes can be found both in older and more recent publications John (1880), Kišpatić (1904), Paul (1879), Trubelja and Pamić (1956, 1965). John (1880) microscopically determined hornblende in the trachyte upon which the Maglaj fortress is erected. Trubelja and Pamić (1956, 1965) determined brown and green hornblende in the amphibole dacite near the village of Parnice and the town of Maglaj. The hornblendes occur as regular idiomoprhic crystals, also as foliated aggregates. Some grains show evidence of magmatic resorption. Zonar structure is often observed in thin section. Twinning is according to the B1/2 = ^ (100) system. Such twins are characteristic insofar as the individual crystals share the vibration direction (Y), the crystallographic axis c [001] and the prismatic cleavage. The extinction angle c : Z is in the range 18-19.9°, the 2V angle is 75° to 83°. Pleochroism is in green and greenish-yellow.

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4. Hornblende in rocks of Mt. Motajica and Mt. Prosara

Not much data is available on hornblende at Mt. Motajica and Mt. Prosara. The first report is by C. John (1880) on hornblende in the granites of Mt. Motajica. Here, hornblende is common and sometimes an essential constituent of various metamorphic rocks. Koch (1908) reports about the occurence of amphiboles in the Kamen Potok amphibolite (near Kobaš) but gives no further details about its mineralogical classification, although it is probably hornblende since the optical extinction angle he measured is 23°.

Varićak (1966) gives a fairly detailed account of the hornblende occurrence in amphibole gneisses, honblendites, amphibolites and amphibole schists of Mt. Motajica. Hornblende in amphibole gneisses is quite pleochroitic (Z = dark green, Y = green, X = pale yellow-green). The extinction angle c : Z = 18.5°, the 2V angle = -80°. The hornblendites carry hornblende which is also strongly pleochroitic (Z = greenish-brown, Y = olive-green, X = pale yellow-brown), but grains with different pleochroitic colours are also present. It is interesting to note that hornblendes with different pleochroisms also have different optical constants and the range of values is considerable (extinction angles are in the range 15-17.5°, the 2V angles are in the range between -70° and -86°).

Hornblendes in amphibolites and amphibole schists also have distinct pleochroism (Z = olive-green, Y = yellow-green, X = pale yellowish-green). The c : Z = 17.5-19.5°, the 2V angles are -74° to -85°.

At Mt. Prosara hornblende occurs infrequently and only in the so-called 'green rocks' (Varićak 1957).

5. Hornblende in other rocks

According to John (1880), hornblende is an essential constituent of amphibole-zoisite schists at Zvornik and the amphibolites from Rudo. Information on the occurrences of hornblende in sedimentary rocks in Bosnia and Hercegovina is scant, and refers mainly to the Tertiary age Tuzla basin and the quartz-sand deposit at Zvornik (Šćavničar and Jović 1962; Pavlović and Ristić 1971). The Pliocene sands of the Kreka coal basin carry hornblende and actinolite withn the B and C horizons. Šćavničar and Jović determined the hornblende to be pleochroitic i green and brown-greene. The angle of oblique extinction is is between 18° and 20°. The hornblendes originate from metamorphic rocks of the 'facies of green rocks' and amphibolites.

The 'Bijela Stijena' deposit of quartz sand from the area of Zvornik carries hornblende as a constituent of the heavy mineral fraction (Pavlović and Ristić 1971). No further information is provided.

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Hornblende has been identified in the insoluble residue of some carbonate rocks in Hercegovina (Gaković and Gaković 1973).

GLAUCOPHANENa2[(Mg3,Al2) [Si8O22] (OH)2

A u t h o r s: Foullon (1895), Kišpatić (1897, 1900, 1902, 1904b), Pamić, Šćavničar and Međimorec (1973), Pavlović and Milojković (1958), Tajder and Herak (1972), Tućan (1919, 1930, 1957), Varićak (1966).

Glaucophane belongs to the group of alkaline amphiboles. H.B. Foullon (1895) authored first information about glaucophane in Bosnia and Hercegovina. Foullon compared the chemical composition of the glaucophane asbestos of Halilovac in western Bosnia with the same mineral from the greek island of Rhodos, which he referred to as rhodusite. Kišpatić (1902) investigated the same material some years later, confirming that it was a fibrous glaucophane i.e. glaucophane asbestos. Pavlović and Milojković (1958) use the name krokydolite (alternative spelling is crocydolite) and krokydolite asbestos for this mineral.

Kišpatić (1897, 1900) in his well known treatise about rocks of the Bosnian serpentine zone mentions a single occurrence of glaucophane only, in the olivine gabbro from Omarski creek at Mt. Kozara. An amphibole resembling glaucophane occurs in the greenschists of Polom on the Drina river.

Varićak (1966) finds glaucophane to be an essential constituent of glaucophanites at Mt. Motajica, in the area of Mramorje, where they are associated with albite gneisses. Microscopic investigations showed the glaucophane to have a short prismatic habit, and a distinct cleavage along (110). The angle between the two cleavage planes is 124.5°. Some alteration into chlorite, albite and epidote was observed. The pleochroism is – Z = blue to blue-violet, Y = pale indigo-blue, X = colourless. The optical axis plane is parallel to (010). the average extinction angle = 6°, the 2V angle = 34°. The described glaucophanite contains also epidote, clinozoisite, garnets, ilmenite and titanite.

CROCYDOLITE – RIEBECKITENa2[(Fe3

2+Fe23+) [Si8O22] (OH)2

A u t h o r s: Foullon (1895), Grimmer (1897), Joksimović (1903) Kišpatić (1902), Pavlović and Milojković (1958), Tućan (1919, 1930, 1957).

The term crocydolite is today used for the fibrous variety of the mineral riebeckite, a member of the amphibole group (Deer, Howie and Zussman 1963).

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There is only one known occurrence of crocydolite in Bosnia and Hercegovina, near Halilovac in the Japra river valley. Some information about this crocydolite has been recently published by Pavlović and Milojković 1958, based upon XRD, optical microscopy and differential thermal analysis (DTA). Chemical analysis of two samples was also done.

Older publications (Foullon 1895; Grimmer 1897; Kišpatić 1902) considered this material to be asbestos, glaucophane asbestos or simply ‘blue asbestos’ becuase of its bluish colour. According to these authors, limited amounts of this material (soft as cotton) were mined at Halilovac – in ancient times but also after the II World War. Macroscopically, the crocydolite asbestos from Halilovac occurs in a complex, filiform, silky aggregate. The length of the silky-thin fibers is 1-7 cm. The fibers are soft, flexible (pliable) but tough. Pavlović and Milojković have determined the density of the material = 3.249 and approximate refractive indices (n = 1.620 for Na-light). The glass melt of the material, prepared by melting in an electric arc, had a refractive index n = 1.609. Powder XRD data are given in Table 23:

Table 23. X-ray diffraction data of the crocydolite asbestos from HalilovacI d (Å) I d (Å)10 8.7 2 2.323 4.98 3 2.176 4.58 2 2.068 3.44 1 2.013 3.28 2 1.658 3.13 1 1.612 3.03 3 1.582 2.81 2 1.5110 2.73 1 1.302 2.61 3 1.294 2.54

A comparison of the XRD data for the Halilovac crocydolite with literature data reveals some differences in the d values. The authors believe this to be a consequence of variations in the chemical composition.

Several chemical analyses of the crocydolite asbestos from Halilovac have been published (Table 24).

The structural formula of crocydolite from Halilovac is given below: (Si7.35Al0.62)7.97 (Fe3+

1.60Fe2+0.91Mg2.00Ca0.39)4.90 (Na2.32K0.26)2.58 (OH2.76O21.24)24.00

The crocydolite asbestos from Halilovac, as named by Pavlović and Milojković (1958), has a somewhat different chemical composition from ‘normal’

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crocydolite (riebeckite) since it contains more magnesium. It could be defined as a Mg-crocydolite, approaching glaucophane from the chemical point of view. However, the paragenesis and origins of the crocydolite are not quite clear. The authors write “ ... we found that the underlying structure is composed of granular gypsum and some dolomite. The overlying layer is composed of ill-smelling, black, bituminous limestone. In between is a fractured, clayey mass impregnated with water up to 2 m thick, with aggregated soft asbestos material of a dirty green colour. Other portions of these aggregates are brick-red, which is the colour of the clay. This entire clayey mass reminds us of a land-slide’’.

In our opinion, the description of the paragenesis and other available information is still insufficient to explain the origin of this rare and interesting occurrence.

Table 24. Chemical analysis of the crocydolite asbestos, Halilovci1 2 3 4 5 impure 6 pure

SiO2 54.10 52.35 54.51 54.65 50.28 50.22Al2O3 --- 5.47 2.68 2.53 3.75 3.59Fe2O3 15.75 15.36 13.60 15.34 12.41 14.54FeO 7.33 --- 7.33 6.66 7.53 7.46MgO 12.60 10.39 10.60 10.95 8.46 9.19CaO 1.44 --- 2.59 1.13 2.41 2.46Na2O 5.40 --- 5.47 5.33 8.59 8.24K2O 0.45 4.37 0.38 0.78 3.71 1.46CO2 0.09 --- 0.59 0.23 --- ---Water --- 4.18 --- --- --- ---LOI 2.81 6.07 2.09 2.43 2.83 2.84

99.98 98.19 99.84 100.03 99.97 100.00

Source: 1. Foullon 1895 (analyst L. Schneider), 2. Grimmer 1897 (analyst S. Bošnjaković), 3. and 4. Kišpatić 1902, 5. and 6. Pavlović and Milojković 1958 (analyst R. Milojković).

WOLLASTONITECa3 [Si3O9]

Wollastonite is a typical mineral of contact metamorphism. It occurs very rarely in Bosnia and Hercegovina. There is only one known occurrence of wollastonite – in the magnetite ore deposit at Tovarnica near Jablanica (Čelebić 1967). Here, the wollastonite is either incoporated in garnets and epidotes or included in the kornite silicate matrix.

Wollastonite is widely used in the manufacture of ceramics and refractories, and as filling agent in paint.

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TOBERMORITECa5Si6 [O,OH]18 .5H2O

Crystal system and class: Orthorhombic, disphenoidal class.Lattice ratio: a : b : c = 1.542 : 1 : 3.083 Cell parameters: ao = 11.3, bo = 7.33, co = 22.6 Z = 4 Properties: very finegrained, white mass. Refractive index Ny = 1.558

A u t h o r s: Đorđević and Stojanović (1972), Stojanović (1973), Stojanović, Đorđević and Đerković (1974).

Tobermorite is a rare hydrated calcium silicate and only occurrence has been identified in Bosnia and Hercegovina – at Banja Kulaša in the Bosnian serpentine zone (Stojanović 1973; Stojanović, Đorđević and Đerković 1974). Suolunite also occurs at this locality.

Tobermorite occurs in diabases, at depths between 40 and 95 m, in the form of thin veins and globular aggregates. One variety is crystalline tobermorite of an acicular, radiating habit with needles ca. 3 mm long growing from the inner surfaces of nodular geodes. The other variety is microcrystalline tobermorite in the form of thin veins with a layered texture. Individual tobermorite grains can in such aggregates be identified only under the microscope. In thin section tobermorite is colourless and displays parallel extinction. The refractive index is greater than that of Canada balm.

Powder XRD data of both crystalline and microcrystalline (11 Å tobermorite) varieties are given in Table 25. Some differences in the intensities have been observed.

Table 25. Powder XRD data of tobermorite from Banja Kulaši (Stojanović et al. 1974)

Crystalline tobermorite

ASTM-card 10-373

Microcrystalline tobermorite

ASTM-card 19-1364

d (Å) I d (Å) I d (Å) I d (Å) I

11.5 100 11.3 100 11.5 100 11.3 80

5.74 10 5.72 8 5.67 4

5.55 5 5.55 90 5.55 4

5.46 30 5.46 25 5.48 25

3.82 25 3.84 20 3.78 8 3.78 6

3.63 6 3.64 8

3.55 30 3.57 70 3.54 20 3.53 20

3.32 8 3.34 20 3.32 20 3.31 18

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3.24 20

3.08 30 3.11 70 3.08 80 3.08 100

2.97 30 2.99 70 2.97 60 2.98 65

2.86 60 2.86 102.82 80 2.83 100 2.82 30d 2.82 402.80 10 2.80 402.72 15 2.75 20 2.72 10 2.73 102.52 20 2.53 60 2.52 15 2.52 122.44 10 2.45 50 2.44 20 2.43 102.31 25 2.32 70B 2.30 20 2.297 82.29 50 2.29 60 2.28 20 2.266 14

The two varieties of tobermorite also demonstrate different behaviour if heated for the purpose of identifying possible phase changes (thermal analysis). Chemical analysis of the Banja Kulaši tobermorite: SiO2 = 54.19; CaO = 40.70; H2O

+ = 13.55Some of the calcium is due to the presence of admixed calcite. The presence of K, Al, Mg, Na, Ti, Cr, Fe, Sr, Li, Be and other elements was determined by spectrochemical analysis.

According to Stojanović et al. (1974) the Banja Kulaši tobermorite is of hydrothermal origin. Tobermorite (and subsequently suolunite) crystallized at comparatively low temperatures (around 175°C), in an alkaline (high pH) environment.

XONOTLITECa6 [Si6O17] (OH)2

Crystal system and class: Monoclinic, prismatic class.Lattice ratio: a : b : c = 2.332 : 1 : 0.958; β ~ 90º (based on unit cell) Cell parameters: ao = 16.56, bo = 7.34, co = 7.04 Z = 2Nomenclature and synonyms: named after the discovery site of the mineral Tetela de Xonotla in the state of Puebla in Mexico. Taylor (1954) determined that xonotlite is identical with the mineral jurapaite which was identified as a new mineral from Crestmore, near Riverside in California (Eakle 1921).

Properties: fibrous mineral. Properties are discussed in the section on its occurrence in Bosnia.

A u t h o r s: Džepina (1970), Đurić and Nikolić (1969), Majer and Barić (1973), Trubelja (1971b, 1972/73, 1975).

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1. The Teslić region

Xonotlite was first identified in Bosnia and Hercegovina in 1965/66 by Dušan Džepina, during a field-work assignment related to his diploma (baccalaureate) thesis. His task was to collect samples from Mt. Borje (near Teslić) for mineralogical and petrological investigations. The xonotlite he found occurs in a rodingitized metamorphic garnet-bearing rock (Džepina 1970, p. 138-139). The colour is snowy-white, sometimes with pale pink overtones and a silky-vitreous lustre. It forms fibrous and radiating aggregates in cracks and vacuoles 1-3 cm in size within the rock. In thin section, xonotlite is optically biaxial and positive, with a parallel extinction. Cleavage is apparent and parallel to the axis of the fibrous crystals. Džepina reports the following refractive indices: Nz = 1.593, Nx = 1.584, birefringence Nz – Nx = 0.009.

The powder diffraction data obtained by Džepina (assisted by S. Đurić) is given in Table 26.

Table 26. Powder XRD data for xonotlite from TeslićI d (Å) I d (Å)5 6.88 7 2.661 6.49 2 2.636 4.24 5 2.4972 3.91 4 2.3267 3.71 4 2.2417 3.23 7 2.03210 3.08 8 1.9428 2.82 3 1.833

Đurić and Nikolić (1969) made some further determinations on the material provided by Džepina. XRD data was used to calculate the unit cell dimensions:ao = 16.80, bo = 7.34, co = 7.05; β approximately 90°

The specific gravity is 2.57. The authors also did a differential thermal analysis of the material. The mineral appears to release water at 830°C (there is a small endothermic peak in the DTA curve at this temperature). Thermogravimetry was used to establish the rate of loss-of-water. The inflexion of the TGA curve at 830°C corresponds to a loss of 2.24-2.41% of water. The general appearance of the curve implies a continuous release of water which could be moisture trapped within the fibrous aggregate of xonotlite.

Chemical analysis of the xonotlite from Teslić gave the following percentages: SiO2 = 48.65; TiO2 = 0.02; Al2O3 = 0.23; FeO = 0.42; MgO = 0.21; CaO = 46.53; Na2O = 0.04; H2O

1000° = 3.84; H2O100° = 0.33; Total = 100.27

The calculated structural formula for this xonotlite is: (Ca6.06Mg0.03Fe0.04)6.13Si5.91Al0.03O18.00 x 1.02H2O

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In the calculation the authors took into consideration only the 2.50% water, determined by thermal analysis to be constitutional (crystal) water. Traces of V, Ba and Mn were determined by spectrochemical methods.

Đurić and Nikolić (1969) regard the xonotlite from Mt. Borja near Teslić to be the last product of the autometamorphism of basic and ultrabasic rocks.

2. The Višegrad region

Two separate occurrences of xonotlite have up to now been identified in the area around Višegrad. One occurrence is on the Višegrad-Dobrun road ca 1.5 km from Višegrad. The second occurrence of xonotlite is in the diabases of Bosanska Jagodina.

The occurrence of xontlite at Višegrad was first reported by Trubelja (1971b, 1972/73, 1975). Xonotlite here occurs in prehnitized diabases in the form of thin veins (several mm up to 1 cm thick) and fillings of cracks and cavities in the rock mass. It forms white, fibrous aggregates – the fibres are subparallel to parallel with the walls of the cavities. In thin section, the needle-like crystals are elongated parallel to the b axis (010), and the exctintion is parallel also. The mineral is optically positive and either uniaxial or the 2V angle is very small.

Refractive indices were determined using the immersion method, in sodium light. Nz = 1.589 ± 0.002, Nx = 1.570 ± 0.002. Therefore, the birefringence Nz – Nx = 0.010.

The specific gravity (determined by picnometry) is 2.746 g/cm3 (at 18°C). The xonotlite was also studied by thermal analysis – the DTA curve shows two endothemic peaks (at 820°C, and a weal peak at around 700°C). Trubelja (1972/73, 1975) believes this to be a dehydroxilation of xonotlite and its conversion to wollastonite.

The infra-red absorption spectrum (400-4000 cm-1) of the xonotlite from Višegrad is given in Figure 11. Characteristic absorption maxima, related to the vibrations of Si-O and O-H bonds, are given in Table 27.

Table 27. Absorption maxima in the IR spectrum of xonotlite from Višegradcm-1

410 635 928 1065537 671 975 1203611 741 1010 3618

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Figure 11. IR spectrum of xonotlite fromVišegrad (Trubelja 1972/73)

Based on the above determinations, and the presence of the 3618 cm-1 peak, Trubelja (1972/73, 1975) concludes that this xonotlite formed during the hydrothermal phase, at comparatively low temperatures. The 711 cm-1 absorption is probably due to admixed calcite.

Powder XRD investigations of the xonotlite were done using both the film technique and diffractometry.

XRD data obtained by the film technique are given in Table 28. The data corresponds to d and intensity values for xonotlite in the literature.

Table 28. XRD data for xonotlite fromVišegrad (film technique)Nr. d (Å) I relative Nr. d (Å) I relative

1 8.525 w 17 1.838 vs2 7.00 s 18 1.824 mm3 4.25 s 19 1.774 mm

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4 3.91 mm 20 1.749 m5 3.632 s 21 1.707 s6 3.495 w 22 1.679 m7 3.227 s 23 1.637 mm8 3.09 vvs 24 1.597 m9 2.822 vs 25 1.575 m10 2.690 vs 26 1.519 ms11 2.622 w 27 1.421 w12 2.503 s 28 1.390 ms13 2.331 m 29 1.334 w14 2.245 m 30 1.319 mm15 2.036 vs 31 1.3055 mm16 1.987 vs 32 1.2520 m

Intensities were estimated visually.

A comparison of the XRD data with ASTM-card 3-0568 shows some differences in the intensities of certain lines, particularly the most characteristic ones. For example, the d = 3.09 line has an intensity 100 in the ASTM-card, but was of low intensity in our diffractogram. We have the opposite case with the line at d = 7.00 Å. These variations, and those observed using the diffraction vs. film technique, may be explained by preferred orientation of the samples.

Chemical analysis (analysts F. Trubelja and M. Janjatović) of xonotlite gave following reults: SiO2 = 49.79; CaO = 46.37; Na2O = 0.20; H2O

+ = 3.50; H2O- = 0.27; Total = 100.13

The corresponding structural formula is Ca5.91Na0.02(OH)2.72Si5.92O17.00

Xonotlite from the Višegrad region is of hydrothermal origin. Hydrothermal waters circulated through the host rocks induced the alteration of alkaline plagioclase and the migration of certain ions into the hot hydrothermal solutions. The comparatively high concentration of calcium and silica in these solutions facilitated the crystzallization of xonotlite, but also of prehnite and zeolites (Trubelja 1972/73, 1975).

At Bosanska Jagodina, xonotlite also crystallizes within cracks and cavities in the diabase host rock (left bank of the Rzav river, in the abandoned quarry). This xonotlite was also investigated by XRD and IR spectroscopy.

All identified occurrences of xonotlite in Bosnia are within the Bosnian serpentine zone. Majer and Barić (1973) have reviewed the then available data on xonotlite from Bosnia.

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SILICATES

RHODONITECaMn4 [Si5O15]

Crystal system and class: Triclinic, pinacoidal class.Lattice ratio: a : b : c = 0.625 : 1 : 0.541 α = 85° 10’ β = 94° 04’ γ = 111° 29’Cell parameters: ao = 7.99, bo = 12.47, co = 6.75 Z = 2Properties: perfect cleavage along {001} and {100}. Hardness = 5.5-6.0. Specific gravity = 3.4-3.68. Colour is pink, pinkish-red, brownish-red. Streak is white, lustre vitreous.X-ray data: d 2.77 (100) 2.98 (65) 2.92 (65) – ASTM-card 13-138IR-spectrum: 415 455 495 507 537 563 578 650 670 695 723 876 902 920 950 1003 1035 1064 1160 3440 3660 cm-1

A u t h o r s: Jurković (1956), Katzer (1906, 1907, 1924, 1926)

Rhodonite is an exceptionally rare mineral in Bosnia and Hercegovina. Accoridng to available literature, rhodonite occurs only in two locations – in the ore province of Bitovnja (locality Budišna Ravan) and in the area of Čevljanovići.

The rhodonite from Budišna Ravan was first mentioned by F. Katzer (1907, 1924, 1926). Katzer maintains that the origin of this rhodonite is related to a variety of igneous rock which he named quartzporphyrfelsite.

Jurković (1956) roports that the locality of Budišna Ravan is 15 km north-west of Konjic and 8 km north-east of Ostrožac, between the creeks Klisac and Vranjić. This locality is known for its occurrence of the mineral tetrahedrite. Other minerals are also found here (malachite, azurite, psilomelane, pyrolusite and rhodonite).

Katzer (1906) is the only author to report on the occurrence of rhodonite at Čevljanovići. His report deals with manganese mineralizations, and he believes rhodonite to be a very rare mineral.

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PYROPHYLLITEAl2 [Si4O10] (OH)2

Crystal system and class: Monoclinic, prismatic class.Lattice ratio: a : b : c = 0.577 : 1 : 2.084; β = 99° 55’Cell parameters: ao = 5.15, bo = 8.92, co = 18.59 Z = 4Properties: good cleavage on {001}. The lamellar crystals are flexible but inelastic. Hardness is 1-1.5. Colour is white or pale yellow, red or brownish (from admixed iron oxides). Streak is white, lustre pearly on cleavage planes.

X-ray data: d 3.05 (100) 9.16 (40) 4.46 (40)

IR-spectrum: 420 465 485 522 542 580 627 815 837 855 910 951 1070 1121 1635 3440 3640 3668 cm-1

A u t h o r s: Barić and Tajder (1955, 1956), Barić and Trubelja (1971, 1975), Čelebić (1967), Čičić (1975), Muftić and Čičić (1969), Podubsky (1955), Simić (1972), Tajder and Herak (1972).

Only one occurrence of pyrophyllite is known today in Bosnia and Hercegovina, near the village of Parsovići in the Konjic area. Simić (1972) reports on the presence of pyrophyllite in early Triassic clastic rocks near Sarajevo, but is not sure if it is pyrophyllite or hydromica-muscovite.

The pyrophyllite at Parsovići is one of the essential constituents of the pyrophyllite schists where the mineral association comprises also quartz, dolomite, calcite, kaolinite, muscovite, gypsum and some other less abundant minerals. Pyrophyllite, quartz and the carbonate minerals are essential constituents of the rock and their percentage varies in different sections of the deposit. This pyrophyllite schist body was discovered some twenty years ago when first publications on this mineral became available (Barić and Tajder 1955, 1956; Podubsky 1955). It was discovered in the valley of the Šćukovac creek, a tributary of the Neretvica river. The schist was investigated microscopically and by chemical analysis by Barić and Tajder who found that the following minerals were present in the schist: quartz = 44.2%; pyrophyllite = 35.3%; carbonates = 3.9% and limonite = 1.3%. Čelebić (1967) found the percentage of pyrophyllite to be 58.86%.

Simultaneously with the first paper by Barić and Tajder (1955), Podubsky (1955) also published a report on the pyrophyllite from Parsovići. He found that the schist contained quartz, illite (muscovite, sericite), some carbonate and montmorillonite, in addition to pyrophyllite. The determination was based on DTA and XRD data. The paper contains 3 DTA curves and one diffraction pattern. The presence of montmorillonite was not confirmed by powder XRD analysis (diffraction analysis by S. Šćavničar and K. Kranjc).

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SILICATES

Microscopy of the pyrophyllite in thin section, done by Barić and Tajder, showed that pyrophyllite had a high birefringnce (and displayed vivid interference colours) and that the refractive index was greater than that of Canada balm. The grains display parallel extinction and have a positive character of elongation.

Čelebić (1967) believes that these pyrophyllite schists are of Permian age, representing a lateral equivalent of the red schistose sandstone facies. Their origin is supposedly hydrothermal.

Muftić and Čičić (1969) report that the pyrophyllite schists were mined since 1963, for the requirements of paper, ceramics and rubber industries, as well as for the production of plant protection chemicals. Čičić (1975) estimates that the quantity of pyrophyllite schist is around 15 million tons. He mentions pyrophyllite from the village of Repovac, but the rock was shown to be a hydromuscovite schist (Barić and Trubelja 1971, 1975).

Use: Pyrophyllite is an important industrial mineral. It is used in the manufacture of ceramics (tiles), refractories, fillers, plastics, rubber, paint, insecticides and glass. Dense varieties of pyrophyllite (also known under the names agalmatolite or pagodite) have been used in China since ancient times for carvings and similar purposes.

TALCMg3 [Si4O10] (OH)2

Crystal system and class: Monoclinic, prismatic class.Lattice ratio: a : b : c = 0.578 : 1 : 2.067; β = 100°Cell parameters: ao = 5.27, bo = 9.12, co = 18.85 Z = 4Properties: good cleavage on {001}. The lamellar crystals are flexible but inelastic. Hardness is 1, specific gravity = 2.82. Colour is pale green, white or grey. Streak is white, lustre pearly on cleavage planes. Refractive indices are generally above thos of Canada balm. Birefringence is high.

X-ray data: d 9.34 (100) 3.12 (100) 4.66 (90)IR-spectrum: 428 445 457 466 537 674 (700) 1020 1050 1640 3435 3655 3670 cm-1

A u t h o r s: Čičić (1975a), Đorđević (1969a), Đurić (1968), Golub (1961), Ignjatović (1973), Ilić (1954), Jakšić (1938a), Jurković (1956), Karamata (1953/54), Katzer (1924, 1926), Kišpatić (1897, 1900), Koch (1899), Majer and Jurković (1957, 1958), Maksimović and Antić (1962), Muftić and Čičić (1969), Pamić (1970, 1970a, 1971), Pamić and Olujić (1974), Podubsky (1955), Ristić, Panić, Mudrinić and Likić (1967), Soklić (1957), Šćavničar and Trubelja (1969), Trubelja and Pamić (1965), Vakanjac (1962, 1964).

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Occurrences of talc in Bosnia and Hercegovina are not common. Talc occurs mostly in the Bosnian serpentine zone (BSZ) where its origin is related to the alteration of femic minerals (olivine, pyroxene). Relevant occurrences of talc are found in the area of Bosansko Petrovo Selo.

1. Occurrences of talc in the Mid-Bosnian schist mountains

A significant occurrence of talc was discovered in cracks and fractures within Palaeozoic phyllites outcropping near the village of Kupres (Busovača). The talc-serpentine-chlorite vein and the constituent minerals were studied by Šćavničar and Trubelja (1969). A block-diagram of this vein is shown in Figure 12.

Figure 12. 3-D Block-diagram of the talc-serpentine-chlorite bearing vein from Kupres village, near Busovača (Šćavničar and Trebulja 1969)

Talc occurs here in the form of a foliated aggregate with a pearly lustre. It is white in colour with greenish overtones. Occasional limonite encrustation gives the talc a brown colour. The talc foils (sheets) are elongated and look like bands up to 30 cm in length. The bands are mostly oriented perpendicular to the walls of the cracks (Figure 18).

The coarse-grained and monomineralic talc variety was appropriate for mineralogical and other investigations, in order to determine the chemical composition and the formula of the mineral. Results of these investigations are presented in the paper by Šćavničar and Trubelja (1969).

The chemical composition of talc is as follows: SiO2 = 62.04; TiO2 = ---; Al2O3 = 1.30; Fe2O3 = 0.15; FeO = 1.56; MnO = ---;

MgO = 30.24; CaO = 0.41; Na2O = ---; H2O+ = 4.55; H2O- = 0.04;

Total = 100.29

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The mineral formula was calculated on the basis of 24 (O,OH) Ca0.056(Mg5.736Fe2+

0.166Fe3+0.014Al0.096)(Si7.901Al0.099) O20.137(OH)3.836

There is only minor substitution of Si and Mg with Al and Fe. The talc sheets are very thin and deformed, and could not be used for single-crystal XRD. Powder XRD was done, but sample preparation was a problem (not unexpected) because of the mechanical and structural properties of talc. The talc was ground for 2 hours in a vibrating mill and the crystals were finely ground but retained their plumose habit. The problem of preferred orientation of crystals could be obviated only to some extent by filling a capillary, but not in preparing the sample for the diffractometer. XRD data is given in Table 29 (powder method/film technique).

Unit cell parameters, calculated from XRD data, are as follows:ao = 5.29 ± 0.007, bo = 9.170 ± 0.005, co = 19.08 ± 0.02β = 101.4° ± 0.2°

Based on the XRD data and calculation of cell parameters, Šćavničar and Trubelja were able to determine the indices for six Debye lines, previously unknown for talc (denoted with a star * in Table 29).

Table 29. XRD data for talc, KupresNo. hkl d (Å) I relative No. hkl d (Å) I relative

1 002 9.351 200 22 0.0.12 1.558 4 sh2 004 4.699 23 23 060, 3-32 1.528 703 020, 1-11 4.567 111 24 330, 062, 3-34 1.511 214 111* 4.318 17 b 25 1.3.10 1.461 3 a5 022* 4.130 14 b 26 2.0.10, 1.3.-12 1.391 19 a6 3.900 2 27 0.0.14 1.336 47 3.485 3 28 260* 1.3204 188 3.242 2 29 400* 1.2972 169 006 3.177 124 30 1.2716 610 2.720 2 b 31 1.248 3 b11 130* 2.636 32 32 1.191 2 b12 200 2.594 47 33 1.1686 113 132, 2-04 2.480 111 34 1.1189 214 2.331 1 35 1.050 115 2.271 1 36 1.042 416 134, 2-06 2.222 28 a 37 0.9948 1217 222, 204, 1-36 2.009 15 a 38 0.9789 118 136 1.941 4 b 39 0.9371 219 0.0.10 1.870 4 sh 40 0.9181 4b20 300* 1.729 17 41 0.8850 15 b21 138 1.683 19 a

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The IR spectrum of the Kupres talc shows three bands in the region of O-H vibrations, at 3666, 3652 and 3640 cm-1 (or splitting of one maximum). The appearance of only one maximum for the O-H vibration would expected in an ideal talc structure, since every oxygen atom in the hydroxyl ion should have an identical bond strength towards the three Mg ions symetrically arranged around the OH dipole (i.e. a threefold symmetry).

The 2V angle measured on a rotating stage = -7°.

The origin of talc and associated chlorite and serpentine can be explained in terms of general paragenetic relationships in this part of the schist mountains. The vein carrying talc and the other minerals is located within the phyllite host rock, while there are several hydrothermal quartz, Fe-dolomite and ankerite mineralizations. The hydrothermal solutions from which talc formed were rich in silicic acid and had a sufficient concentration of magnesium. Such conditions were favourable for the crystallization of coarse plumose talc. The zonar vein structure indicates that the crystallization process went through several steps, and that in each of these steps an almost monomineralic phase formed, depending on the composition and temperature of the hydrothermal solution. Chlorite was formed first, then serpentine with a small amount of talc and finally the plumose talc, being also the most abundant phase. Jurković (1956) reports an occurence of talc with dolomite and baryte at the locality of Trnjač near Kreševo.

Majer and Jurković (1957, 1958) report a secondary mineralization of talc in the diorites of the Zasenjak creek at Bijela Gromila, south of Travnik. Jakšić (1938) also mentioned an occurrence of talc in the Mid-Bosnian schist mountains, without providing details of localities.

2. Talc in the area of the Bosnian serpentine zone

Most of the cited authors have also reported on talc occurences in the ultramafic rocks of the Bosnian serpentine zone. The largest deposit, which is also commercially mines, is at Bosansko Petrovo Selo on the eastern slopes of Mt. Ozren. Đorđević (1969a) writes that the most important occurrences of talc in this area are at the localities of Mušići, Žarkovac and Tešanovići (Figure 13).

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Figure 13. Talc occurences at Mušići – Bosansko Petrovo Selo

Talc, or more precisely – the schistose talc rock, occurs in the Mušići creek near the village of Porečine ca. 5 km southeast of Bosansko Petrovo Selo. They are found at the contact between an altered granitoid rock and serpentinized peridotite. In addition to the schistose talc rock, talc also occurs in other host matrices such as talc- or carbonate-impregnated serpentinite, talc-bearing carbonates and pyrite-bearing schistose talc rock. The schistose talc rock has a schistose texture and a lepidoblastic structure. The talc flakes (0.05-0.5 mm in size) form compact masses. In thin section the talc shows vivid interference colours and a low relief. The rock contains also small amounts of chlorite, pyrite, chalcopyrite and pyrrhotite. The talc material was also subjected to DTA analysis.

The origin of talc in this area is related to the activity of hydrothermal solutions which affected and altered the peridotites along tectonic fracture zones. These solutions were also the source of SiO2 which is of importance since such an environment is normally deficient in silica.

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Pamić and Olujić (1974) and Pamić-Sunarić (Čičić 1975a) have recently reported on the talc-bearing hydrothermal-metasomatic listvenites from the northern part of Mt. Ozren, at the localities of Kloč and Tekućica. These occurrences have not been investigated in detail.

Trubelja and Pamić (1965) noted the presence of small talc flakes in harcburgites from the Jadrina river valley near Bosansko Petrovo Selo, where it was formed by alteration of olivine and orthorhombic pyroxene. A similar occurrence of talc in chloritized peridotites at Duboštica was described by Pamić (1970). Ignjatović (1973) identified schistose talc rocks and talc-serpentinites in the chrysotile asbestos deposit of ‘Delić-Brdo – Brđani’ near Bosansko Petrovo Selo. Ilić (1954) and Podubsky (1955) report on the occurrence of steatite talc at Žepče, noting that talc is incorporated into kaolinite-montmorillonite clays, at Ljeskovica between Zavidovići and Žepče.

Golub (1961) determined talc microscopically in the serpentinites of the Lubina creek, as well as in the lherzolites from the Jovača and Vrela creeks on Mt. Kozara. In thin sections prepared from these rocks, talc is optically biaxial and negative. In some cases the talc appears to be optically uniaxial, but this is probably caused by an oriented superposition of talc flakes. In samples from the Jovača creek, talc is found on the rims of enstatite grains and seems to be its alteration product.

It needs to be said that the first report on the occurrence of talc in rocks from the Bosnian serpentine zone was written by Kišpatić (1897, 1900). He determined talc in thin section, in the lherzolite from Mimići at Mt. Kozara. The talc is colourless and plumose in habit, and appears to have formed by the alteration of diopside.

Maksimović and Antić (1962) identified talc in the weathering zone of serpentinites and peridotites at Vardište in eastern Bosnia.

3. Talc in rocks of Mt. Motajica

Koch (1908) identified talc occurring together with beryl, orthoclase, kvarc and other minerals in the granite-pegmatite of Veliki Kamen near Vlaknica. The same information can be found the Katzer’s Geology of Bosnia and Hercegovina (1924, 1926).

Use: talc is an important industrial mineral. It is used either as a raw material (as talcum powder) or as roasted talc, as a filling material in paper, rubber and paint production. For cosmetic purposes talc is used in body powders and soap manufacture. Further uses are as lubricant and polishing powder. Due to its inertness towards acids and bases, it also finds use in the production of insulating materials, porcelain and glass.

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MUSCOVITEKAl2 [AlSi3O10] (OH)2

Crystal system and class: Monoclinic, prismatic class.Lattice ratio: a : b : c = 0.574 : 1 : 2.21; β = 95° 30’Cell parameters: ao = 5.19, bo = 9.04, co = 20.08 Z = 4Properties: good cleavage on {001}. The lamellar crystals are flexible and elastic. Occasional parting on {010} and {110}. Hardness is 2.5 (on the cleavage plane) and 4 ^ to the cleavage plane. Specific gravity = 2.8-2.9. Colour is white to silvery white. Streak is white, lustre vitreous to pearly. Resistant to acids. Refractive indices are higher than those of Canada balm. Maximum birefringence is very large.X-ray data: d 10.014 (100) 3.351 (100) 2.562 (75)IR-spectrum: 415 435 480 535 692 750 800 828 930 1030 1060 1635 3430 3620 cm-1

A u t h o r s: Arsenijević (1967), Barić (1969, 1970a), Barić and Tajder (1955, 1956), Cissarz (1956), Čelebić (1963, 1967), Čutura (1918), Džepina (1970), Đorđević (1969a), Đorđević and Mijatović (1966), Đurić (1963a), Foullon (1893), Gaković and Gaković (1973), Ilić (1953), Jeremić (1960, 1963, 1963a), Č. Jovanović (1972), R. Jovanović (1957), Jurković (1954, 1956, 1958, 1958a, 1959, 1961, 1961a, 1962), Jurković and Majer (1954), Karamata (1953/54, 1957), Katzer (1924, 1926), Kišpatić (1897, 1900, 1904b), Koch (1908), Majer (1963), Majer and Jurković (1957, 1958), Majer and Pamić (1974), Magdalenić and Šćavničar (1973), Marić (1965), Marić and Crnković (1961), Mojsisovics, Tietze and Bittner (1880), Nöth (1956), Pamić (1957, 1960, 1961, 1961a, 1961b, 1962, 1970), Pamić and Buzaljko (1966), Pamić and Olujić (1974), Pamić and Papeš (1969), Pamić and Tojerkauf (1970), Pavlović and Ristić (1971), Petković (1962/62), Pilar (1882), Podubsky (1968, 1970), Podubsky and Pamić (1969), Popović (1930), Ramović (1957, 1961, 1963), Ramović and Kulenović (1964), Ristić, Pamić, Mudrinić and Likić (1967), Sijerčić (1972), Simić (1972), Stangačilović (1956), Šćavničar and Jović (1962), Šćavničar and Trubelja (1969), Šibenik-Studen and Trubelja (1967), Tajder (1953), Tajder and Raffaelli (1967), Trubelja (1962, 1962a, 1963, 1963a, 1963b, 1966a, 1967, 1969, 1970, 1970a, 1971, 1972, 1972a), Trubelja and Pamić (1957, 1965), Trubelja and Miladinović (1969), Trubelja and Sijarić (1970), Trubelja and Slišković (1967), Trubelja and Šibenik-Studen (1965), Tućan (1912), Varićak (1955, 1956, 1957, 1966), Vasiljević (1969), Vujanović (1962).

Muscovite is a typical representative of the mica group of minerals. It is usually pale in colour or colourless. It occurs as a primary mineral in granites, granite-pegmatites and similar rocks, as well as in metamorphites (gneisses, schists etc.). It is often incorporated in clastic sediments, due to its resistance and stability. It can also form through hydrothermal alteration of feldspars (orthoclase, microcline). Sericite is a hydrated microcrystalline variety of muscovite, depleted in potassium.

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Muscovite (and sericite) belong to the abundant rock-forming minerals in Bosnia and Hercegovina, occurring in igneous, metamophic and sedimentary rocks – especially in the Palaeozoic formations of north-west Bosnia, the Mid-Bosnian schist mountains and in the metamorphic rocks of eastern/south-eastern Bosnia. Muscovite is an essential constituent of igneous and metamorphic rocks at Mt. Motajica and Mt. Prosara (granites, gneisses, schists etc.). Muscovite and sericite are found in the products of Triassic magmatism and in Tertiary effusive rocks, as well as in some polymetallic ore bodies.

In spite of their extensive regional distribution and abundance, not much has been published about muscovite and sericite, which have been microscopically investigated mainly by the authors referenced earlier in this chapter.

1. Muscovite in rocks of Mt. Motajica and Mt. Prosara

Among the first determinations of muscovite were certainly those of C. John (according to Mojsisovics et al. 1880), in the muscovite granite of Kobaš at Mt. Motajica. A more detailed account of muscovite occurrences in the above rocks was written by Koch (1908). Muscovite is an essential constituent of the granites from Veliki Kamen at Mt. Motajica, and occurs in the form of larger greyish-green leaves. Parallel overgrowths with biotite are common. Quartz grains with muscovite leaves bent around them are frequently seen. A similar form of occurrence is in the case of the granites from Brusnik, while there is very little muscovite in the granite-gneiss from Židovski potok.

Arsenijević (1967) determined the following trace elements in the muscovite from Mt. Motajica: Be = 5 g/t, Sn = 62 g/t, Nb = 50 g/t.

The muscovite gneiss from Studena Voda contains muscovite as the predominant mineral in the rock. The muscovite leaves are arranged in parallel layers so that the rock has a schistose texture. On the other hand, muscovite occurs much less frequently in the garnet-gneiss from the Kamen creek near Kobaš.

Micaschists normally contain more biotite than muscovite, but the opposite case is also possible.

A substantial amount of data on muscovite in various rocks in Bosnia and Hercegovina can be found in the Geology of Bosnia and Hercegovina by Katzer (1924, 1926). Katzer mentions Koch’s data, but provides his own microscopic measurements of muscovite from various localities. In many instances Katzer speaks of microcrystalline sericite. He found muscovite to be an abundant mineral in muscovite granites, granitic pegmatites, quartz veins, aplitic veins, phyllites and

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SILICATES

orthogneisses. Tabular muscovite crystals up to 2 cm in size are common in veins. For muscovite occurrences in paragneisses and micaschists, Katzer mainly uses Koch’s data (1908).

Varićak (1966) made detailed investigations of muscovite from te Mt. Motajica area (granit-type rocks, igneous and sedimentary rocks altered by contact metamorphism. Muscovite is also found in granitic dyke rocks, leucocratic granites, rhyolites, graniteporphyres and lamprophyres. Sedimentary rocks altered by contact metamorphism – migmatites, gneisses, micaschists, gneissphyllites – contain muscovite and sericite either as essential or accessory constituents. Those of igneous origin – hornblendites, amphibolites, amphibole schists, glaucophanites, albite-actinolite-epidote schists – contain only minor amounts of sericite. Muscovite and sericite are common minerals in almost all rock types outcropping at Mt. Motajica. Varićak (1966) established that in the greisen-granites muscovite occurs in very twisted aggregates. The optical axis angle 2V (measured in conoscopy) is in the range of -35° to -37°. The sericite usually pseudomorphically replaces primary feldspars.

Muscovite from pegmatite veins is often deformed. The negative 2V angle = 39-40°; in albite gneisses the 2V angle is -40°. The Mt. Motajica muscovite was mentioned also by Pilar (1882 – reporting John’s data for the Kobaš muscovite) and Stangačilović (1956).

Katzer (1924, 1926) and Varićak (1956, 1957) report on muscovite occurrences in igneous and metamorphic rocks of Mt. Prosara. Varićak (1957) investigated in some detail the products of regional metamorphism and found muscovite (and sericite) to be a constituent mineral of gneisses, micaschists, gneiss-micaschists, quartzschists, phyllites, sericite- and chlorite-schists, quartz.schists of low crystallinity, marble, marble schists and green rocks. The author does not mention optical properties. Varićak’s 1956 paper describes the quartz porpyhres at Mt. Prosara, where muscovite is a primary mineral (ca. 0.5-2%) and sericite is secondary product of alteration.

2. Muscovite occurences in the Mid-Bosnian schist mountains (MBSM) and adjacent regions

Katzer (1924, 1926) found muscovite (and sericite) to be an essential constituent of various igneous and metamorphic rocks in the Mid-Bosnian schist mountains (MBSM). It needs to be mentioned here that his findings are based primarily on macroscopic observations of the rocks, and not on microscopic determinations. Even today, the information we have on this vast area (but also for other Palaeozoic regions in Bosnia) is rather basic. According to Katzer, muscovite occurs primarily in metamorphic rocks of MBSM – gneisses, micaschists, quartzites

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and quartzite sandstones, sericite-schists, phyllites and carbonate schists. The presence of muscovite leaves was also established in marbles, crystaline limestones and dolomites as well as sandstones. Sericite is present in sericitized quartz-porphyres, a very common rock in MBSM. This was also established earlier by Foullon (1893).

Muscovite and sericite are abundant in the Palaeozoic metamorphites of Jezera and Sinjakovo – in phyllites and clayey schists, phyllites, sandstones and quartz-porphyres. Katzer reports occurrences of sericite in igneous rocks from the Trešanica cliff near Bradina. This sericite was recently investigated by Barić (1970a) who classified the host rock as a keratophyre. The sericite is an alteration product of hydrothermal and other metamorphic processes. Sericite occurs also in the mineral paragenesis of the sinjakovo albite rhyolites and at the contact of these rocks with Palaeozoic limestones from Alinovac near Jezera. Such rhyolites (quartz porphyres) with sericite – which may justifiably be referred to as sericite schists – are very common in the MBSM, particularly north-west of Busovača and in the Fojnica – Kreševo area (Jurković and Majer 1954).

The muscovite and sericite in this area have been microscopically determined also by other authors (Tajder and Raffaelli, 1967; Šćavničar and Trubelja 1969; Trubelja and Sijarić 1970). The pyrophyllite schists from Parsovići, Hercegovina, contain 14.9% sericite (Barić and Tajder 1955, 1956). Kišpatić (1904b) found that muscovite is the predominant mineral in the chloritoide phyllite from Fojnica and Čemernica. The muscovite contained in this rock is microcrystalline and can be observed under the microscope – as minute colourless leaves with basal cleavage – only using large magnifications.

Muscovite is common in the ore mineralizations within MBSM (Barić 1969; Jeremić 1963, 1963a; Jurković 1956, 1958, 1958a, 1961, 1972; Popović 1930; Trubelja 1967; Vasiljević 1969). Jurković found sericite to be abundant around Busovača (localities Rog, Obla, Ravan, Jekanjska, Očenići, Kaćuni, Krnjača, Jela, Peska I, Rudno I and II, Slamina Kuća, Dolovi, Grude, Pridolci, Luke, Kozica, Rizvići, Šuplje Bukve and Oštra), Travnik and Ščitovo, and less abundant in other areas. Muscovite occurs only at a few localities (Busovača, Ščitovo, Brestovsko, Berberuša). Jurković (1956) reports also about a lithium mica associated with some katathermal quartz formations near Gruda. In the area of Ščitovo, sericite was found at following localities: Brezova Kosa, Dubrave, Crkvice, Gromiljak, Ivankovići, Pločari and Lopari. Some muscovite was found at Vrtlasce. In the area of Brestovsko, sericite occurs at the localities of Cigani and Gaj, while muscovite can be found at Hrastovo, Pobrđe and Datići. In the area of the Travnik ore mineralizations, sericite was found at following localities: Srednje Brdo, Kruščica Potok, Lupnica Potok, Gornje Grčice, Široki Do, Triljački Potok, Zaselje, Cakići, Zubići, Pečuj, Večeriska Gornja, Čehanovac, Bilkanov Potok, Kezik Potok, Varošluk, Ibrin Do, Vrelo potok, Njiva Potok, Zmajevački Potok, Podradola, Dubrave, Kremenje, Osoje, Katuništa,

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Vilenice, Heldovi and Slimena. In the area of Berberuša, sericite occurs at three localities: Močenik, Komari and Bukva, while muscovite can be found at Banjak, Bukva I and II and Podljetovik. In the area of Kreševo, sericite is not common but can be found at Sotnica, Vidici, Dubrave, Dugi Dol and Duge Njive. Jurković believes that both muscovite and sericite are of hydrothermal origin (meso-epithermal stage). At Busovača, sericite is mainly associated with katathermal quartz deposits. Together with the lithium mica, they form aggregates of microscopically small flakes, which are deposited as encrustations along the walls of the cracks within quartz grains.

The pneumatolytic and hydrothermal deposits of pyrrhotite at Vrtlasce contain abundant muscovite. Muscovite forms radiating aggregates of minute crystals (5 x 35 to 24 x 240 µm in size) with distinct cleavage. Some crstals are idiomorphic, others have irregular edges, and are incoporated in all sulphide minerals (less often in albite) – indicating a broad range for the crystallization temperature.

The sericite from Dubrave (on the Kreševo – Tarčin road) forms large block and aggregates weighing several tens of kilograms. This sericite is related to the nearby baryte deposits. The sericite aggregate is of a pale green to yellow-green colour and quite compact. It has an irregular fracture and a greasy feel. In thin section, the sericite flakes are colourless and transparent. The aggregate is monomineralic and apparently pure. The refractive index is higher than that of Canada balm. The second-order interference colours are vivid. A detailed chemical analysis and XRD investigation of the Dubrave sericite (on the Kreševo – Tarčin road) was done (Trubelja 1967).

Results of the chemical analysis (analyst F.Trubelja): SiO2 = 47.05; TiO2 = ---; Al2O3 = 36.43; Fe2O3 = 0.53; FeO = 0.17; MnO = ---; MgO = 1.61; Na2O = 1.51; K2O = 7.92; H2O

+ = 4.98; H2O- = 0.24; Total = 100.44

The structural formula based on the chemical analysis data and 24 (O,OH) atoms is: (K1.30Na0.37) (Al3.61Fe2+

0.01Fe3+0.05Mg0.31)3.98 (Al1.93Si6.07)8.00(OH)4.27

Powder XRD data are given in Table 30.

Table 30. Powder XRD of sericite from Dubraved (Å) I d (Å) I9.91 vs 3.32 vs4.98 m 3.19 m4.46 vs 2.98 m3.72 m 2.56 vs3.48 m 1.51 s

The specific gravity of sericite was determined by the pycnometric methods and is 2.790 (at 20°C). The sericite is of hydrothermal origin, like the baryte.

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Jeremić (1938) also noted the relationship between baryte and sericite in MBSM. Barić (1969) observed that the thin and tabular muscovite crystals occurs on the substratum on which hyalophane crystals developed (at Zagrlski potok near Busovača). Barić was able to measure the optic axial angle on one crystal: 2V = -37.5°.

Cissarz (1956), Nöth (1956) and Čelebić (1957) observed a sericite-magnetite paragenesis at Tovarnica, near Jablanica in Hercegovina.

3. Muscovite in Palaeozoic rocks of the Sana – Una and Ključ regions

Katzer (1924, 1926) observed the occurence of muscovite and sericite in various Palaeozoic metamorphic rocks of the Una – Sana region, rocks which are apparently similar to those in eastern Bosnia.

Jurković (1959) described the magnetite deposit at Muhamedbegov Prisjek near Ključ and surroundig rocks, observing that quartz-sericite schists are transformed into finegrained quartz-sericite sandstones. Sericite and muscovite have been found at several localities within the iron ore complex of Ljubija (Jurković 1961a; Marić and Crnković 1961; Jeremić 1960; Podubsky 1968; Podubsky and Pamić 1969). Jurković (1961a) believes the sericite to be a hypogenous mineral in the Ljubija paragenesis. Muscovite and sericite also occur at the Brdo and Nova Litica localities in the Ljubija complex (Marić and Crnković 1961). Podubsky (1968) provides a substantial amount of data on the occurrence and abundance of sericite and muscovite in Palaeozoic metamorphites of north-west Bosnia. He observed that the two minerals occur in rocks from lower Palaeozoic age to Permotriassic ones. In the older series, sericite is an essential constituent of clayey schists and metasandstones (subgraywacke and graywacke type sericite-chlorite-feldspar-quartz metasandstones). The Carbonian-age clayey schists are of the chlorite-sericite-quartz type. The abundance of mica minerals is variable (0.03-22.23%). The sericite is the product of the alteration of volcanic rocks of the Una – Sana Palaeozoic (Podubsky and Pamić 1969). Jeremić (1960) mentions a muscovite occurence in the ‘Žune’ baryte-fluorite deposit near Ljubija.

4. Muscovite in rocks of eastern and south-east Bosnia

Katzer (1924, 1926) and Podubsky (1970) made the observation that the low-metamorphic schists and some Palaeozoic sediments of eastern and south-east Bosnia contain variable amounts of muscovite and sericite. These minerals are essential constituents of phyllites, sandstones, limestones and sericitized quartz-porphyres in the areas of Pale, Prača, Trnova, Goražde, Foča, Srebrenica, Vlasenica and Zvornik. According to Podubsky (1970) the phyllites, phyllite schists and metasandstones of lower Palaezoic age contain small to substantial amounts of muscovite and sericite. Rocks of Carbonian and Permian age contain these two minerals mainly in metasandstones, sandstones, alevrolite and clayey schists.

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Information provided by Podubsky shows that the abundances of muscovite and sericite show large variations – between 0.7 and 9.57%. Samples used in this study were collected on several characteristic profiles of eastern Bosnia (Šutorina Rijeka, Vranječevići, Tegare, Zapolje – Zapoljska Rijeka, Nova Kasaba, Biljaša – Milić Brod, Mlječvanska Rijeka – Pašino Brdo and Brezovačka Rijeka. Kišpatić (1904b) observed that muscovite is not abundant in the quartz-phyllites from Polom on the Drina river, but that the flakes are easily observed in thin section (muscovite is pale green or colourless).

5. Muscovite and sericite in igneous rocks of Bosnia and Hercegovina

The various igneous rocks of Bosnia and Hercegovina contain sericite as a product of metamorphism (alteration) of feldspars (sericitization process). Sericite occurs in Triassic-age igneous rocks from the Vrbas river valley, from Kupres, Bugojno, Jajce, Komar, Kreševo, Jablanica, Prozor, Tjentište, Čajniče, Vareš, Čevljanovići, Ilidža – Kalinovik, Zvornik and other areas (Čutura 1918; Đurić 1963a; Jovanović1957; Karamata 1957; Majer and Jurković 1957, 1958; Pamić 1957, 1960, 1961, 1961a, 1961b, 1962; Pamić and Buzaljko 1966; Pamić and Papeš 1969; Petković 1961/62; Ramović and Kulenović 1964; Šibenik-Studen and Trubelja 1967; Trubelja 1962a, 1963, 1963a, 1969, 1972a; Trubelja and Pamić1957; Trubelja and Miladinović 1969; Trubelja and Slišković 1967; Vujanović 1962.

Some igneous rocks of the Bosnian serpentine zone (BSZ) and products of Tertiary volcanism contain muscovite and sericite. Such rocks are found at Mt. Borja near Teslić, at Mt. Ozren, in the Bosna river valley, near Srebrenica, Bosanski Novi, Mt. Kozara, Mt. Ljubić. Many authors have made observation on the occurrence of muscovite and sericite in rocks of the BSZ (predominantly grantoids and rhyolites), and in Tertiary dacite-andesites. However, very little data on optical properties or microscopic measurements pertaining to these two minerals are given (Đorđević 1969a; Karamata 1953/54; Majer 1963; Pamić 1970; Pamić and Olujić 1974; Pamić and Tojerkauf 1970; Ramović 1957, 1961, 1963; Tajder 1953; Trubelja 1962, 1963b, 1966a, 1971a, 1972; Trubelja and Pamić 1965; Varićak 1955).

6. Occurrence of muscovite and sericite in other rocks

Up to now we have not taken into consideration the occurrences of muscovite and sericite in some sedimentary rocks and matmorphic rocks from the Bosnian serpentine zone BSZ. The following authors have made observations on muscovite and sericite in these areas: Džepina (1970), Gaković and Gaković (1973), Jovanović (1972), Kišpatić (1897, 1900), Majer and Pamić (1974), Magdalenić and Šćavničar (1973), Pavlović and Ristić (1971), Ristić, Pamić, Mudrinić and Likić (1967), Sijerčić (1972), Simić (1972), Šćavničar and Jović (1962), Trubelja (1970).

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Papers by Džepina, Kišpatić, Majer and Pamić provide data on muscovite and sericite contained in amphibolites and similar rocks in the BSZ (Mt. Borja etc.). Gaković and Gaković investigated the abundance of muscovite in the insoluble residue of some carbonate sediments in the outer Dinarides. Jovanović (1972) mentions Pliocene sands of the Prijedor basin where the abundance of muscovite can be up to 15% (determined by Sijerčić 1972, p. 15). Magdalenić and Šćavničar determined that sericite occurs together with chlorite in the matrix of Permian red clastites from Kulen Vakuf. Pavlović and Ristić (1971) found muscovite occurring together with sericite (and some other minerals) in the gravels and sands of the ‘Bijela Stijena’ deposit near Zvornik. Ristić et al. (1967) found sericite to be an essential constituent of sericite schists from Miljevica at Mt. Konjuh, where talc schists also occur. Sijerčić (1972) found sericite in the arenite of Eocene flysch on the western slopes of Mt. Majevica near Tuzla. Šćavničar and Jović (1962) identified muscovite in in the Pliocene sand of the Kreka coal basin, as well as in Eocene and Miocene clastic sediments.

Simić (1972) established that muscovite is an abundant and essential constituent of lower Triassic clastic rocks in the Sarajevo area. The common paragenesis consists of muscovite, quartz and hydromica. Trubelja (1970) writes about the occurrence of sericite in clayey sediments related to diaspore bauxites from the village of Ljuša, near Donji Vakuf.

Pamić and Olujić (1974) determined Cr-muscovite (fuchsite) as a constituent of listvenites (hydrothermal-metasomatic rocks) from the northern part of Mt. Ozren. Fuchsite is macroscopically green in colour. In thin section, pleochroism is Z = dark green, X = light green; the 2V angle = -68°. Fuchsite is the product of spinel alteration, and pseudomorphic growth of fuchsite is known to exist. The XRD data for the fuchsite were also collected.

Tućan (1912) microscopically determined muscovite in the terra rossa from Eminovo Selo near Duvno. This observation was referenced by Marić (1965).

GLAUCONITEK0.8R

3+1.33R

2+0.67 [Al0.13Si3.87O10] (OH)2

Crystal system and class: Monoclinic.Lattice ratio: a : b : c = 0.578 : 1 : 2.208; β = 95° Cell parameters: ao = 5.25, bo = 9.09, co = 20.07 Z = 4Properties: occurs in the form of green, blue-green (to almost black) spheres and flakes. Hardness = 2. Specific gravity 2.5-2.8. Streak is green.

X-ray data: d 2.592 (100) 1.519 (80) 10.05 (60)IR-spectrum: 440 470 500 575 610 680 810 1030 1110 1270 1630 3410 3540 3560 cm-1

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SILICATES

Glauconite is a member of the phyllosilicate group of minerals. Its structure is similar to the structure of biotite. Chemically, it is a Fe-Al silicate with a highly variable chemical composition – especially in terms of potassium abundance. Celadonite has a similar composition and properties as glauconite.

A u t h o r s : Pamić (1972d), Šibenik-Studen and Trubelja (1967), Trubelja (1966a, 1969, 1972a), Trubelja and Barić (1970), Varićak (1966).

In Bosnia and Hercegovina, glauconite mostly occurs in the Hrčavka creek valley near Tjentište. This occurence has been investigated in some detail by Trubelja and Barić (1970).

1. Glauconite in the Hrčavka valley near Tjentište

In the Hrčavka valley near Tjentište, glauconite is a characteristic mineral of the lower Triassic series of rocks. The glauconite bearing veinlets are up to 10 cm thick and are mainly concentrated near the contact of the volcanic rock and sediment. It is also found in cavities and cracks within the rock itself. The tuffs and tuff-bearing sandstones have a greenish colour due to the presence of glauconite, which is finely dispersed in the rocks giving them the characteristic colour and names like ‘pietra verde’ or ‘green rock’.

Glauconite was determined by thermal methods (DTA and TG), X-ray diffraction and chemical analysis. The pure, bluegreen glauconite material was used for these laboratory studies.

The DTA curve is rather typical for glauconite, with two separate endothermic peaks: one at 150-200°C indicating a loss of adsorbed water, and the other one at 550-600°C (loss of structural water). The TG curve indicated a 9% weight loss, and corresponds to similar curves for glauconite published in the literature. The curve shows two distinct steps indicating water loss as a consequence of heating.

The X-ray diffraction data of glauconite are given in table 31.

Table 31. XRD data for glauconite from Hrčavka (column 1) correlated to literature data (Torre de Assuncao and Garrido, 1953 – column 2)

1 2No. d Å I Å I

1 10.01 2 10.01 22 4.52 10 4.50 103 3.66 2 3.64 24 3.33 10 3.29 105 3.07 1 3.07 1

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6 2.59 10 2.57 107 2.40 7 2.38 78 2.13 1 2.13 19 2.05 1 --- ---10 1.66 2 1.64 211 1.51 8 1.49 812 1.30 5 --- ---13 1.25 1 --- --

A quantitative chemical analysis (analyst F. Trubelja) gave the following results:SiO2 = 46.60; TiO2 = 0.07; Al2O3 = 17.69; Fe2O3 = 14.45; FeO = 0.36; MnO = 0.03; MgO = 5.45; CaO = 0.84; Na2O = 0.06; K2O = 5.92; H2O

+ = 5.74; H2O- = 3.54;

P2O5 = 0.03; Total = 100.78%

These results were used to calculate the number of ions in the crystal-chemical formula, based on 20 (O) and 4 (OH), assuming that 4% H2O are equivalent to 4 (OH). The rest of the water is given as nH2O, as usually done in the literature. The formula of glauconite this is: (K1.068Na0.017Ca0.129) (Al1.669Fe3+

1.550Fe2+0.043Mg1.171Ti0.008) Si6.990 Al1.310O20 (OH)3.840 x

nH2O

It is clear from the formula that this glauconite contains a substantial amount of aluminium. The aluminium partly substitutes silicon, and partly ferric iron in octahedral coordination.

The glauconite from the Hrčavka valley is of sedimentary origin, forming as a result of diagenetic processes occuring in finely bedded sediments within a mid-Triassic geosyncline. Mud and other clastic particles were being deposited in a shallow marine environment, at a slow rate of deposition. Submarine effusions of lava were the source of potassium and other elements neccessary for glauconite formation. Almost all of the iron is in the oxidized ferric state so that we may conclude that the depositional environment was not a reducing one.

2. Other occurences of glauconite (celladonite)

Glauconite (celladonite) occurs in sandstones in the valley of Crna Rijeka at Mt. Kozara at localities known as Bunik and Bukovi Vrh (Trubelja 1966a). Here glauconite occurs in the form of blue-greeen flakes evenly dispersed in the rock. Sometimes it forms veinlets or small amygdales. Glauconite was determined by XRD.

Glauconite can also be found at Kiprovac near Borovica (Vareš) where it is associated with mid-Triassic greenish tuff-containg rocks, similar in appearance to those in the Hrčavka valley. The greenish colour is caused by the presence of glauconite, identified here also by XRD (Trubelja 1969 and 1972a).

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Mid-triassic igneous rocks of the Vrbas river valley occasionally contain glauconite (Šibenik-Studen and Trubelja, 1967). Pamić (1972d) mentions glauconite occurrences in amygdales within albite-containing volcanic rocks of the same age.

Glauconite was identified, together with other minerals, in the arkose-graywacke type sandstones at Mt. Motajica (Varićak 1966). One large glauconite grain had the following characteristics when observed by microscope in transmitted light: cleavage along (001), high relief, strong pleochroism in lightgreen and olivegreen. The 2V angle is -23°; X : [001] = -2.5°. Interefrence colours are largely masked by glauconites own colour.

Use

Because of its high potassiom content, glauconite can be used as a fertlizer, either in its natural state or thermally processed. It has also been used as green pigment in paints, due to its chemical resistance. It is also used in water-softening technologies and for other industrial purposes as an ion-exchanger.

PHLOGOPITEKMg3 [AlSi3O10] (OH)2

Crystallographically similar to biotite.Properties: chemically, phlogopite could be decribed like an iron-free biotite. It is light brown in colour.IR-spectrum: 466 615 675 695 815 980 1010 1630 3440 3650 cm-1

A u t h o r s: Džepina (1970), Kišpatić (1915).

Phlogopite occurs rarely in In Bosnia and Hercegovina, and literature data is very scarce. Kišpatić (1915) first mentions phlogopite in the bauxites from Široki Brijeg (Lištica) in Hercegovina. This author was also able to identify small amounts of other minerals – gibbsite, rutile, zircon, tourmaline, anatase, periclase, kyanite and calcite. Kišpatić mentions ‘sporogelite’ as an important constituent of bauxite, but this mineral name has been discredited.

Džepina (1970) identified phlogopite in garnet-containing basic metamorphic rocks in the southern part of Mt. Borje. Garnet, hornblende, diopside and plagioclase are the dominant minerals in these rocks, while only minor amounts of phlogopite were found.

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BIOTITEK(Mg,Fe2+)3 [AlSi3O10] (OH)2

Crystal system and class: Monoclinic, prismatic class.Lattice ratio: a : b : c = 0.575 : 1 : 1.103; β = 99° 18’Cell parameters: ao = 5.31, bo = 9.23, co = 10.18 Z = 2Properties: distinct platelike habit with a predominant pinacoid, good cleavage on {001}. The lamellar crystals are flexible and elastic. Hardness is 2.5 (on the cleavage plane). Specific gravity = 2.8-3.4 depending on the iron content. Colour is darbrown to black. Streak is white or greyish, lustre vitreous to pearly, sometimes semi-metallic. Hot sulphuric acid dissolves biotite, but the SiO2 skeletal remains are resistant. Refractive indices are low to moderate. Usually Ny = Nz. Maximum birefringence is large.X-ray data: d 9.818 (100) 3.324 (71) 2.004 (14) d 10.01 (100) 3.346 (45) 2.631 (50) d 10.264 (100) 3.380 (80) 2.654 (70)IR-spectrum: 415 445 465 612 692 760 (975) 1000 1640 3440 3610 3650 cm-1

A u t h o r s: Arsenijević (1967), Barić (1966a), Behlilović and Pamić (1963), Čelebić (1967), Dangić (1971), Đorđević and Stojanović (1964), Foullon (1893), Gaković and Gaković (1973), Hlawatsch (1903), Ilić (1953), John (1880, 1888), R. Jovanović (1957), Jovičić (1891), Jurković (1954a, 1956), Jurković and Majer (1954), Karamata (1953/54), Katzer (1903, 1910, 1924, 1926), Kišpatić (1897, 1900, 1904, 1904a, 1910), Koch (1908), Luburić (1963), Luković (1957), Majer (1961, 1963), Majer and Jurković (1957, 1958), Majer and Pamić (1974), Marić (1927), Mudrenović and Gaković (1964), Nikolić, Živanović and Zarić (1971), Nöth (1956), Pamić (1961, 1971, 1971a), Pamić, Dimitrov and Zec (1964), Pamić and Đorđević (1974), Pamić and Kapeler (1969), Pamić and Olujić (1969), Pamić and Papeš (1969), Pamić, Šćavničar and Međimorec (1973), Pamić and Tojerkauf (1970), Pavlović (1889), Pavlović and Ristić (1971), Pavlović, Ristić and Likić (1970), Paul (1879), Pilar (1882), Podubsky (1968, 1970), Podubsky and Pamić (1969), Primics (1881), Ramović (1957, 1961, 1962, 1963, 1966, 1968), Ristić, Likić and Stanišić (1968), Sijerčić (1972), Šćavničar and Jović (1961, 1962), Tajder (1951/53, 1953, 1960), Trubelja (1962, 1963b, 1969, 1971a, 1972, 1972a), Trubelja and Paškvalin (1962), Trubelja and Sijarić (1970), Varićak (1955, 1957, 1966), Walter (1887).

Biotite is a very common and ubiquitous mineral in Bosnia and Hercegovina. It occurs in igneous, sedimentary and metamorphic rocks. It is common in igneous rocks associated with Tertiary-age volcanism – such as dacites, andesites. The granites, gneisses and micaschists of Mt. Motajica contain biotite in addition to other minerals. Biotite occurs also in other areas i.e. the Bosnian Serpentine Zone (BSZ), in granitoids, rhyolites and basic vein rocks. The gabbro-diorites and Palaeozoic-age

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rhyolites of the Mid-Bosnian schist mountains contain biotite either as a dominant or accessory mineral. Biotite was found also in the gabbros at Jablanica, as well as in various rocks in northwestern, eastern and central Bosnia. Biotite can occasionally be found in pyroclastic rocks of Triassic and Tertiary age. Clastic sediments and carbonate rocks in karst areas also contain some biotite.

1. Biotite in rocks associated with Tertiary-age volcanism

Biotite is an important mineral constituent of dacites, andesites and pyroclastic rocks in the Srebrenica area and in the Bosna river valley. Biotite-containing tuffs can be found also around Livno and Duvno, and in the Tuzla basin. Information on biotite contained in these rocks was reported by Barić (1966a), Dangić (1971), John (1880), Jovičić (1891), Kišpatić (1904, 1904a), Luburić (1963), Luković (1957), Pamić, Dimitrov and Zec (1964), Pavlović (1889), Paul (1879), Primics (1881), Ramović (1957, 1961, 1962, 1963, 1966), Tajder (1951/53, 1953, 1960), Trubelja (1970a, 1971a, 1972), Trubelja and Pamić (1956, 1957, 1965), Trubelja and Paškvalin (1962), Walter (1887).

John (1880) gives the first report on biotite and other minerals in Tertiary-age effusive rocks in the Srebrenica area. John identified biotite microscopically as black and darkgreen platelets in trachytes at Šušnjar (Kišpatić believes that the locality is at the village of Potočari), quartz-propylites at Srebrenica, dacites at Ljubovija and andesites at Zvornik (Veljava Glava). Walter (1887) noticed red-brown and green mica in the mentioned quartz-propilites. These rocks were later investigated by our petrographer Kišpatić (1904a). Almost all andesites and dacites investigated by Kišpatić contained biotite, fresh or altered.

In the period after the II World War, the Srebrenica effusive rock formations were investigated by Tajder who published his results in two short papers and one monograph (Tajder 1951/53, 1953 and 1960). He found that biotite is an important mineral constituent of most of the investigated dacite rocks, except those which have been altered by hydrothermal propilitization processes.

Biotite is found in the bytownite-containing dacite at Diminići, the biotite-dacites of Jamno creek, around the villages of Ažlice, Sase, Divljak, at Diminić creek and at the foot of Mt. Drmnik. All of these rocks contain substantial amounts of biotite, so that it forms the name of the rocks. Furthermore, biotite is found also in dacite rocks from the Kiselica and Majdan creeks, and in the amphibole-containing dacites around Srebrenica. These rocks contain lesser amounts of biotite Biotite is the most common ferromagnesian mineral of the bytownite-containg dacites from Diminići. It occurs as idiomorphic crystals displaying light yellow to dark brown pleochroism. Some crystals are rounded due to magmatic corrosion and these are often surrended with an omphacite layer. Crystals of

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plagioclase and apatite are often embedded in the biotite crystals. At Jamno creek, the biotite occurs as idiomorphic crystals which are sometimes up to 1.5 mm in length. These are mostly fresh and show distinct pleochroism.

Some dacites around Srebrenica contain chloritized and kaolinized biotite, so that some grains are pure chlorite. All investigated rocks show clear signs of opacitization.

Propilitization processes are common in biotite. The dacites of Drenovac creek contain completely chloritized biotite but also epidote, magnetite and carbonates. Only some biotite crystals still show characteristic pleochroism.

Biotite is the most common constituent of the lamprophyre dikes around the village of Sase near Srebrenica (Trubelja and Paškvalin 1962). It can be easily observed macroscopically in the form of brownish crystals with good cleavage along the base. Hexagonal crystals are comparatively rare. In thin section this biotite shows distinct pleochroism: Z = Y = dark brown, X = yellowish brown. It has a visible zonar texture so that the central sections of the biotite grains are much lighter in colour than other sections. It is optically negative with a small axial angle. It is altered to chlorite. Around the village of Bratunac in the srebrenica area, small amounts of biotite are found in kaolinized dacites at the Smoljave and Borići localities (Trubelja 1970a, 1971a and 1972; Dangić 1971).

The products of Tertiary-age volcanism in the Bosna river valley contain biotite as a common constituent. It was first determined by John (1880) who noted the biotites distinct pleochroitic colours (light yellow to black), especially in the trachytes from the Maglaj fortress. Similar rocks in the area were also investigated by Primics (1881). He identified biotite in the trachytes and green biotite-quartz-trachytes between Žepče and Maglaj.

Kišpatić (1904) provides more data on the biotite and other minerals in the andesites from the Bosna river valley. The andesites around Maglaj contain yellow and brownish phenocrystals of biotite with some embedded apatite. It is altered into chlorite and epidote, although it is mostly fresh in the investigated rocks. After the II World War, these rocks were extensively studied by F. Trubelja and J. Pamić (1956 and 1965). Biotite-containing dacites were found at Jelovac village in the Bosna river valley. Sanidine-containg dacites occur at Brusnička Rijeka near the village of Parnice. The biotite in the Jelovac dacites is largely fresh and idiomorphic, with some grain elongation along cleavage directions. The pleochroitic colours are very distinct – X = light yellow, Y = dark brown. Biotite from the sanidine-containing dacites has somewhat different properties: X = light yellow, Y = greenish brown. Extinction is parallel. It is frequently opacitized due to exsolved magnetite.

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Majer (1961) investigated the biotite in dacite-type rocks from the Blatnica creek near Teslić. Here the biotite forms phenocrystals together with plagioclase, and can be seen macroscopically. It is mostly fresh, with only occasional chloritization.

Biotite also occurs in pyroclastic rocks – in volcanic tuffs of the Neogene-age sediments around Tuzla (Luković 1957). It displays distinct pleochroism in golden yellow and dark brown colours.

Biotite is found also in tuffs of the Duvno and Livno area (Barić 1966a, Luburić 1963). Barić notes that biotite is common in the Tertiary-age rhyolite tuffs around Livno. Biotite occurs in the form of black hexagonal platelets, up to 2 mm in size. Investigations in thin sections have shown that the optical axes angle = 15° and negative. The biotite contained in tuffs from Vojvodinac is optically nearly uniaxial, or the optic axial angle is very small.

2. Biotite in rocks of the Bosnian Serpentine Zone

Rocks of the Bosnian serpentine zone (BSZ) do not contain substantial amounts of biotite. It occurs in acidic to neutral intrusive rocks and vein-type effusive rocks such as albite-containing rhyolite. It can also be found in basic igneous and metamorphic rocks. A limited amount of data on biotite can be found in the papers by Đorđević and Stojanović (1964), John (1880), Karamata (1953/54), Kišpatić (1897, 1900), Majer (1963), Majer and Pamić (1974), Pamić (1971, 1971a), Pamić and Kapeler (1969), Pamić and Olujić (1969), Pamić, Šćavničar and Međimorec (1973), Pamić and Tojerkauf (1970), Trubelja (1962, 1963b), Varićak (1955).

John (1880) was again the first author to identify biotite in the BSZ. Biotite occurs in the biotite-containg diabase around Žepče, close to Mt. Lupoglav. The biotite is of a red-brownish colour and strongly pleochroic. Kišpatić (1897 and 1900) identified a moderate amount of biotite in diabase rocks near Čelinac. He also identified a large biotite grain in the olivine gabbro from Miljkovačka Rijeka, near Buletići.

Biotite is an important mineral constituent of spilites near Bosanski Novi (locality Torić creek), according to Trubelja (1962). It occurs in the form of platelets or crystals elongated along cleavage directions. Larger crystal are frequently bent. Cleavage is perfect, with a parallel extinction in thin section. Pleochroism: X = light brown, Y = dark brown.

Karamata (1953/54) found biotite in albite rhyolites near Bosansko Petrovo Selo. It also occurs in keratophyres of Mt. Ljubić (Trubelja 1963b).

Several authors identified biotite in acidic granitoids and similar intermediary rocks of the BSZ. The albitic granite, found along the road Žepče – Maglaj close

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to Selište, contains smaller amounts of biotite with respect to leucocratic minerals (Đorđević and Stojanović 1964). Grains are 2.43 x 2.70 mm in size and display distinct cleavage and pleochroism (yellowish to dark brown). The optic axial angle, measured in thin section, is in the range of 0-6°, negative. Chloritization is occasionally present.

Pamić and Olujić (1969) identified biotite in albitic granite from Gostilje (Bosansko Petrovo Selo), where it is fresh and distinctly pleochroic (light yellow, yellow brown). Majer and Pamić (1974) found moderate amounts of biotite in altered shales in the northeastern part of ultramafic complex of Mt. Borje. The granitoid rocks of this area also contain some biotite (Pamić and Tojerkauf 1970). Some additional data on the occurence of biotite can be found in the publications by Pamić (1971, 1971a) and Pamić and Kapeler (1969).

Varićak (1955) identified biotite in thin sections of pebbles contained in the so-called red granite from Maglaj. This rock was described previously by Kišpatić (1897). Here, biotite occurs as platelike crystals which show signs of corrosion and mechanical deformation. Transformation into chlorite is frequent. Pleochroism is distinct – X = light yellow to greenish, Z = Y = green.

3. Biotite in rocks of Mt. Motajica and Mt. Prosara

Information on the occurences of biotite in various rocks of the Mt. Motajica and Mt. Prosara complexes can be found in publications by Arsenijević (1967), Ilić (1953), John (1880), Katzer (1924 and 1926), Koch (1908), Pilar (1882) and Varićak (1957 and 1966). First extensive information on biotite in rocks from Mt. Motajica was published by Koch (1908) – moderate amounts of biotite occur in the granite of Veliki Kamen near Vlaknica as well as in the muscovite granite from Brusnik. Biotite is an important constituent mineral of the granite-gneiss rock from Židovski creek. This biotite is of a light brown colour, showing good cleavage and distinct pleochroism. It contains some embedded quartz and apatite.

The muscovite gneisses of Studena Voda contain only minor amounts of biotite, which is – however – a major mineral constituent of biotite gneisses from the same locality. It also occurs in garnet-bearing biotite gneisses at Kobaš and Hercegov Dol near Bosanski Svinjar. The properties (cleavage, pleochroism) of these biotites are almost identical in thin section. Biotite also frequently occurs in micaschists, andalusite-bearing micaschists and amphibolites.

Katzer’s treatise on the Geology of Bosnia and Hercegovina contains a substantial amount of data on biotite in rocks of the Mt. Motajica and Mt. Prosara complexes, as well as in other areas of the Paleozoic-age rocks in Bosnia (Katzer

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1924, 1926). Most of his data is based on microscopic investigations done by F.Koch. Katzer (1926, p. 68) described the biotite in the granites from Mt. Motajica as follows: „among the mica minerals is biotite (lepidomelane), dark brown to black in colour and mostly fresh. It is dispersed within the rock, in the form of irregular grains or hexagonal platelets. Coarser granite varieties, especially pegmatite granites, contain biotite as hexagonal platelike crystals 1-2 cm in size, of a brown colour and strong, almost metallic lustre“. Biotite occurs also in other rocks found at Mt. Motajica (biotite-containg aplites, pegmatites, gneisses, micaschists and phyllites).

More recent petrographic investigations by Varićak (1966) provide a substantial amount of data on biotite in various rock of the Mt. Motajica complex. Biotite is an important constituent of regular granites, granite porphyres (2V = -5°), lamprophyres, contactolites of sedimentary origin, gneisses, biotite cornites and amphibolites. The granites from Mt. Motajica contain up to 25 g/t tin and up to 40 g/t beryllium (data by Arsenijević).

Katzer (1924, 1926) and Varićak (1956 and 1957) provide a treatment of biotite in the Mt. Prosara complex. Katzer only described the occurence of biotite in acidic igneous rocks, where biotite occasionally occurs in copious amounts. Varićak (1956) identified biotite as an essential constituent mineral in quartzporphyres of Mt. Prosara. It seldom occurs in the form of fresh grains, and is usually depleted in iron. This process is visible due to the pale colour of biotite and the iron hydroxide layers along cleavage fissures. Transformation into chlorite or epidote is of less importance. The size of individual grains lies in the range between 0.02 x 0.3 and 0.2 x 2 mm. The overall amount of biotite is 0.5-2%. Varićak (1957) mentions biotite occurences also in various metamorphic rocks of the Mt. Prosara complex – in gneisses, micaschists, quartzite schists, marbles and green rocks. Transformation into chlorite is common. This author provides no further details.

4. Biotite in rocks of the mid-Bosnian schist mountains

John (1880) was the first author to mention the occurence of biotite in the liparites (quartzporphyres or rhyolites) from Mt. Vranica. Jurković and Majer (1954), Katzer (1924, 1926) and Foullon (1893) identified biotite in similar rock types also in other regions of the mid-Bosnian schist mountains. According to Foullon, biotite occurs together with some potassium micas in certain quartzporphyres and metamorphic rocks of the Suhodol complex. Some information on biotite in gneiss-type rocks of Voljevac and Prosje are provided by Katzer (1926, p. 106).

Biotite is an essential mineral constituent of the biotite-chlorite-ankerite schists from the Ivanovica creek near Busovača, while moderate amounts can also be found in the albite-chlorite schists (Trubelja and Sijarić, 1970). The schist rocks in this area belong to the facies of green rocks. Biotite grains were extracted from these

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rocks and investigated in thin section. Chemical and x-ray diffraction analysis was also done. In thin section biotite displays its characteristic cleavage along the base, strong pleochroism and parallel extinction.

X-ray diffraction data for the biotite from Ivanovica creek are given in table 32.

Table 32. X-ray diffraction data for biotite from Ivanovica creek (Trubelja and Sijarić 1970)Nr. d Å I Nr. d Å I

1 14.343 just visible 13 2.534 medium2 10.100 very very strong 14 2.454 very strong3 7.115 medium 15 2.392 just visible4 4.493 medium 16 2.322 just visible5 4.051 medium 17 2.291 medium6 3.689 medium 18 2.190 strong7 3.545 medium 19 2.009 strong8 3.363 very strong 20 1.682 strong9 3.139 medium 21 1.546 very strong10 3.056 just visible 22 1.372 medium11 2.947 medium wide 23 1.333 medium12 2.639 very strong

Chemical analysis of the same biotite yielded following results:SiO2 = 33.66; TiO2 = 2.28; Al2O3 = 17.40; Fe2O3 = 9.51;FeO = 9.63; MnO = 0.19; MgO = 11.61; CaO = 0.93; Na2O = 2.10; K2O = 6.60; H2O

+ = 5.06; H2O- = 0.69; P2O5 = 0.18; Total = 99.84

The structural formula based on the chemical analysis data and 24 (O,OH) atoms is:(Ca0.14K1.24Na0.60)(Ti0.25Fe3+

1.14Fe2+1.19Mn0.02Mg2.55)(Si4.97Al3.03) O19.01(OH)4.99

In the area of mid-Bosnian schist mountains biotite also occurs in products of Triassic-age magmatism. This will be treated in a subsequent chapter.

5. Biotite in rocks of northwestern, eastern and southeastern Bosnia

In northwest Bosnia biotite occurs in schists of Paleozoic age as well as in some transformed basic volcanics. Data is very scarce, derived from only 2 publications (Podubsky 1968, Podubsky and Pamić 1969). According to Podubsky (1968), in NW Bosnia biotite occurs primarily in metasediments of Paleozoic age, where the degree of its preservation is rather low. Transformation into chlorite and hydromica is common. The schists from eastern and southeastern Bosnia contain minor amounts of biotite, usually as an accessory mineral species. Greater quantities of biotite are contained in orthometamorphic rocks of Mlječvanska Rijeka where it is an essential mineral in chlorite-biotite-feldspar-epidote-amphibole schists and biotite-tourmaline-epidote-quartz-amphibole schists (Podubsky 1970).

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6. Biotite in products of Triassic-age magmatic events

Biotite occurs frequently in various rocks associated with Triassic-age magmatic events. However, again the data is scarce. These biotites are mentioned in publications by Behlilović and Pamić (1963), Čelebić (1967), Hlawatsch (1903), John (1888), Jovanović (1957), Jurković (1954a), Katzer (1903, 1910, 1924, 1926), Kišpatić (1910), Majer and Jurković (1957, 1958), Marić (1927), Nöth (1956), Pamić (1961), Pamić and Papeš (1969) and Trubelja (1969, 1972a). Most of the available data pertains to biotite occuring in basic and other intrusive rocks. Certain differentiates of the gabbro complex at Jablanica contains varying amounts of biotite (Marić 1927). Magnetite is frequently embedded in biotite grains. The gabbro rocks near the locality of Zlato often contain hexagonal biotite sheets. The biotite occuring in the gabbro from the central sections of the complex has distinct pleochroism: X = pale yellow, Z = red brown. Maximum birefringence is Nz – Nx = 0.047. In northern sections of the complex the biotite is of a pale brown colour due to surface weathering. One fissure within the gabbro series (near Bukov Pod) contain almost idiomorphic biotite crystals, elongated and green to black in colour, but with weathered surfaces. Some gabbro veins, high above the Neretva river bed, contain biotite sheets 2.5 x 3 cm in size. Some crystal are up to 7 cm in length, and 0.5-1 cm thick. They are chloritized on the surface.

Information on biotite in the Jablanica gabbro complex can be found in publications of Čelebić (1967), Hlawatsch (1903), John (1888), Katzer (1903, 1910), Kišpatić (1910), Nöth (1956), Ramović (1968).

Majer and Jurković (1957, 1958), Katzer (1910, 1924, 1926) and Kišpatić (1910) investigted the biotite contained in gabbrodiorite from the Bijela Gromila complex south of Travnik, where it occurs both as an essential or accessory mineral.

Biotite is an essential mineral in diroites from Kopile and the Zasenjak creek (Majer and Jurković 1957, 1958). The biotite sheets are highly irregular in shape, as if subject to tearing. In thin section they display good basal cleavage and strong pleochroism (brown to red). Biotite also occurs in the olivine gabbros from Stajište (Novi Travnik).

Jurković (1954a) identified biotite in the augite-labradorite andesites from Orašin near Bakovići.

Jovanović (1957) and Pamić (1961) found biotite to be an essential mineral constituent – together with quartz and albite- of granites from the southern flanks of Mt. Prenj.

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According to available literature data, biotite was not found in effusive and vein-type rocks belonging to the series of Triassic-age magmatic differentiates in Bosnia and Hercegovina. However, biotite is contained in pyroclastic rocks (tuffs) which are spatially associated with the mentioned differentiates.

Behlilović and Pamić (1963) identified biotite in tuffs and volcanic breccias of Ladinian-age volcanogenic-sedimentary rocks from the Drežanka river valley in Hercegovina, as well as in the area of Kupreško Polje (Pamić and Papeš 1969). The biotite is usually transformed into bauerite and chlorite, accompanied by the exsolution of magnetite.

Trubelja (1969, 1972a) identified black biotite crystals in tuffs of mid-Triassic age at Borovica and Vareš. Biotite was also identified in volcanogenic-sedimentary rocks from the Smreka – south ore body at Vareš (Trubelja, unpublished results).

7. Biotite in sedimentary rocks

Very little data is available on biotite in sedimentary rocks, although some recent investigation have confirmed it occurence in these rocks – Gaković and Gaković (1973), Mudrenović and Gaković (1964), Nikolić, Živanović and Zarić (1971), Pavlović and Ristić (1971), Pavlović, Ristić and Likić (1970), Ristić, Likić and Stanišić (1968), Sijerčić (1972), Šćavničar and Jović (1961, 1962).

Gaković and Gaković (1964) identified biotite, together with other minerals, in the insoluble residue of Triassic-age carbonate rocks from some karstic areas in Bosnia and Hercegovina. Mudrenović and Gaković (1964) mention biotite in clays from Zalomska Rijeka in eastern Hercegovina.

Biotite is commonly found in the quartz-containing clastic sediments of the Tuzla basin – Pavlović, Ristić and Likić (1970), Ristić, Likić and Stanišić (1968), Sijerčić (1972), Šćavničar and Jović (1961, 1962).

Pavlović and Ristić (1971) found only minor amounts of biotite in the quartz sands from the „Bijela Stijena“ deposit near Zvornik. Nikolić et al. (1971) also found minor amounts of biotite in bentonite clays from Šipovo in the Pliva river valley.

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ILLITEK0.65Al2.00Al0.65Si3.35O10(OH)2

Crystal system and class: Monoclinic.Properties: perfect cleavage along {001}. The colour is white, specific gravity 2.6-2.9; hardness = 1-2.

Illite occurs as colourless pseudohexagonal platelets of very small dimensions. It is a typical representative of the illite group of minerals (illite clays). It was named after the state of Illinois in USA. Illite is structurally similar with the mica minerals. Some authors refer to illite as hydromuscovite (hydromica). The chemical composition is rather variable. Apart from aluminium, silica and the hydroxyl group, potassium is its main chemical component.

Illite can form in several different ways – by atmospheric weathering of potassium feldspars, alteration of muscovite, metasomatic exchange of magnesium and calcium in montmorillonite or by recrystallization of potassium-containing clayey sediments.

X-ray data: Hydromuscovite d 10.0 (VS) 3.34 (VS) 5.0 (S) 4.46 (S) 2.544 (S)Illite d 9.98 (VS) 4.47 (S) 2.56 (S) 3.31 (M) 2.38 (M)

A u t h o r s: Ćatović, Trubelja and Sijarić (1976), Čelebić (1963), Jurković (1961a), Marić and Crnković (1961), Pavlović (1975), Pavlović, Ristić and Likić (1970), Podubsky (1955, 1968, 1970), Ristić, Likić and Stanišić (1968), Sakač (1969), Sijarić (1975), Sijarić and Trubelja (1974), Stangačilović (1956, 1956a, 1969, 1970), Šćavničar and Jović (1962), Tasić (1975), Trubelja (1970), Vasiljević (1969).

Illite-type clays have a wide distribution in Bosnia and Hercegovina but literature data is scarce. Illite is a significant constituent of clays found in Prijedor and Sarajevo-Zenica basins. It occurs in Palaeozoic-age sediments of western, eastern and south-eastern Bosnia. Recent investigations dealing with bauxites have shown that illite is present in this matrix also. Illite is also commonly found in some clastic sediments (sands etc.).

1. Illite in Palaeozoic-age rocks

Illite-containing sediments are very common rocks in the Sana river and Una river area in western Bosnia (Marić and Crnković 1961, Jurković 1961a, Podubsky 1968). Illite occurs both as an important or accessory mineral in argillaceous and clay-schists and phyllites, together with quartz, muscovite, plagioclase relicts, and accesssory iron minerals.

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According to investigations by Marić and Crnković in the area of the Ljubija iron mine, illite is commonly found in the clay-schists of the Brdo and Nova Litica mineralizations. X-ray diffraction data of illite from these two mentioned localities is given in Table 33 and 34. This study has shown that illite is the dominant mineral in the rock, next to quartz, muscovite and feldspar. Microscopic determinations revealed that illite is the main component of the finegrained matrix. The dense illite mass sometimes contains rutile crystals which display characteristic twinning.

Jurković (1961a) found illite to be a common mineral in the iron parageneses of the Ljubija iron ore body. Here it is found at the following localities: Nova Litica – Trešnjica, Redak, Bregovi, Jakarina Kosa, Jerkovača, Baščine and Paljevine. Točak, Stojančići, Kliment and Gradina are localities in the Tomašica area.

Table 33. XRD data for the illite-containing rock from the Brdo mine (Marić and Crnković 1961)d Å Line intensity Mineral

4.45 Medium Illite4.22 Medium Quartz3.86 Weak Muscovite3.71 Weak Muscovite3.35 Strong Quartz (Illite 3.33)3.20 Very weak Illite, muscovite2.99 Weak Illite, muscovite2.56 Medium strong Illite, muscovite2.46 Medium strong Quartz, illite2.38 Weak Illite2.24 Weak Illite1.50 Medium strong Illite1.38 Weak Illite1.37 Medium Quartz1.29 Weak – diffuse Quartz, illite1.25 Weak Quartz, illite

Table 34. XRD data for the illite-containing rock from the Nova Litica mine (Marić and Crnković 1961)

d Å Line intensity Mineral5.00 Weak Muscovite, illite4.47 Medium Muscovite (illite 4.46)4.29 Medium strong Quartz, illite4.15 Weak Feldspars3.49 Weak Muscovite3.35 Strong Quartz2.57 Medium Illite, muscovite2.46 Medium Quartz, illite2.30 Medium Quartz2.23 Medium Illite (2.24), quartz (2.22)2.14 Medium Illite (2.12)1.82 Medium Quartz1.67 Medium Quartz, illite1.55 Medium Quartz

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SILICATES

1.51 Medium – diffuse Illite1.37 Strong Quartz, illite1.26 Medium Quartz1.24 Weak Illite

Note: the feldspar lines are located within following ranges: 4.09-4.20 Å, 3.81-3.94 Å, 3.73-3.77 Å, 2.97-3.01 Å, 2.61-2.67 Å, 2.40-2.41 Å.

Some illite was extracted in the form of insoluble residue from the limonitic ore from the Stojančići locality. Illite occurs as flakes 10-30 μm in size. This illite was studied by thermal methods.

Podubsky (1970) found illite in similar rocks in eastern and southeastern Bosnia, after this author made first findings of illite clays in Bosnia and Hercegovina in 1955 (Podubsky 1955). He found illite to be a constituent mineral of the pyrophyllite schist at Parsovići in Hercegovina and in halloysite schists in SE Bosnia, near the village of Bakije. Illite was determined by XRD and thermoanalytical methods.

2. Illite in the basins of Prijedor and Sarajevo – Zenica

Illite contained in Palaeozoic age argillaceous and clay-schists can migrate into surrounding basins where it can form thick layers of allochtonous clays of Tertiary age, as is the case in the basins of Prijedor and Sarajevo – Zenica. The mineralogical characteristics of these clays were investigted by several authors (Stangačilović 1956a, 1969 and 1970; Pavlović 1975; Tasić (1975).

In the Prijedor basin illite can be found at the following localities: Bišćani, Halilovci, Rizvanovići, Hambarine, Rakovčani, Carevina and Puharska. The parageneses commonly contain also kaolinite, montomorillonite and substantial amounts of quartz. The quantitative distribution of illite in argillaceous sediments of the Prijedor basin is given in Tables 35 and 36 (Pavlović 1975, Tasić 1975).

Table 35. Mineral composition (%) of clays from the Prijedor basin (Pavlović 1975)Sample Illite Montmorillonite Kaolinite Quartz

PC – 1 25.55 --- 23.80 49.51PC – 2 48.41 --- 23.80 24.93PC – 3 39.84 16.63 29.06 10.90PCM – 1 46.82 --- 24.38 23.65PCM – 2 45.71 --- 24.24 22.94PRC – 2/3 50.31 5.08 26.39 15.99PR – 1 51.58 3.21 22.01 21.92PR – 2 50.79 6.11 25.10 15.48PR – 3 47.61 5.24 20.52 23.75

Note: PC and PCM = locality Puharska (Crna dolina); PRC = Carevina locality; PR = Rakelić (Kurteš) locality.

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Table 36. Mineral composition (%) of clays from the Prijedor basin and Sarajevo – Zenica basin (Tasić 1975)

Sample Illite Montmorillonite Kaolinite QuartzPZ – 3 36.34 16.93 42.04 1.18PZ – 4 45.07 7.60 34.80 7.34PZ – 4a 45.71 8.46 40.02 2.08PZ – 5 43.65 4.80 23.88 23.61KL 61.98 --- 7.18 20.34

Note: PZ = locality Rizvanovići (left bank of the Sana river) KL = locality Klokoti (Sarajevo – Zenica basin)

The qualitative and quantitative composition of the clays is based on X-ray diffraction, thermoanalytical methods and chemical analysis. The clays from the Prijedor basin contain some montmorillonite and quartz and are important raw materials for the manufacture of tiles and other ceramics.

Stangačilović (1956a) investigated the illite clays in the Sarajevo – Zenica basin (Kobiljača nd Rakovica localities). These clays are of upper Tertiary age (Pontian). Other localities must also be mentioned – Busovača, Klokoti and Bilalovac. All these sediments have a compartively even clay mineral composition – illite, kaolinite, meta-halloysite and montmorillonite. The Kobiljača clays are of Tertiary age and occur at the west side of the Sarajevo – Zenica basin, some 18 km west of Sarajevo on the Sarajevo – Kiseljak road. These clays have been studied in detail by XRD, thermoanalytical and microscopic methods.

XRD analysis and microscopic determinations showed that the Kobiljača and Rakovica clays contain also quartz. The quartz grains are mostly tiny, but some idiomorphic crystals were identified. The clays also contain sericitized and kaolinized orthoclase, calcite, biotite, muscovite, zircon, tourmaline (nice crystals displaying pleochroism). Ilmenite, garnet and apatite are rare. These accessory minerals can provide an indication of the source rocks from which the clays formed. The source rocks are mostly quartzporphyres, but also other rocks similar to the ones within the Una and Sana river Palaeozoic complex could have provided material for the formation of clays.

The allochtonous clay deposits in the basins of Prijedor and Sarajevo – Zenica formed in peripheral region of the Pannonian basin, by deposition of clay minerals and subsequent formation of thin or thicker clay deposits of Miocene age. The deposits in the Prijedor area are characteristic for shallow-water, littoral environments. The material is mostly derived from rocks of Palaeozoic, possibly also Triassic age.

According to Stangačilović, the clays in the Sarajevo – Zenica basin contain some coal and formed under lacustrine conditions. This author also investigated the

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kaolinite clays of Mt. Motajica in which he found illite. More information can be found in the section dealing with kaolinite.

3. Illite in bauxites and other sediments

Detailed XRD investigations of bauxites from NW Bosnia (Grmeč, Srnetica) provide data on the qualitative and quantitative compositon and illite distribution in these matrices (Ćatović, Trubelja and Sijarić 1976, Sakač 1969, Sijarić 1975, Sijarić and Trubelja 1974).

Illite commonly occurs in Triassic-age bauxites from the Bjelaj locality at Mt. Grmeč. The illite content is in the range between 3.3-19.9%. Other bauxites contain less illite. Trubelja (1970) identified illite in clays associated with the diaspore bauxites of Ljuša near Jajce.

Pavlović et al. (1970) and Ristić et al. (1968) identified illite in sediments of the Tuzla basin. This finding is based on powder diffraction, DTA and TG measurements. Šćavničar and Jović (1962) made an x-ray diffraction determination of illite in the rocks associated with the coal series of the Kreka basin.

Ćelebić (1963) identified illite in some iron-ore deposits around Konjic. The sedimentary quartzites of Podrašnica near Mrkonjić Grad contain some sericite and illite, based on microscopic determinations by S. Pavlović and D. Nikolić (Vasiljević 1969).

Use: Illite is an important industrial mineral used in ceramics production and brick manufacture. It can also be used as a fertilizer, due to its high potassium content (ca. 6%).

HYDROMUSCOVITE(K,H2O)Al2[(H2O,OH)2 │AlSi3O10]

A u t h o r s: Barić and Trubelja (1971, 1975), Sijerčić (1972) Hydromuscovite is a rare mineral in rocks of Bosnia and Hercegovina. According to scarce literature, the mineral has been identified near the village of Repovci close to Bradina (Barić and Trubelja 1971, 1975) and on the western flanks of Mt. Majevica (Sijerčić 1972).

1. The occurence at Repovci

Hydromuscovite seems to be an essential mineral constituent of a hydromuscovite schist found near the village of Repovci, close to Bradina in

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Hercegovina. Some veins within this rock appear to contain a monomineralic hydromuscovite phase. The mineral has been identified using microscopic methods, powder diffraction, thermal and chemical analysis and IR spectroscopy.

The optical properties of hydromuscovite are almost the same as for sericite, but detailed investigations have shown that it is not sericite. The optic axial angle 2V = -20.75°, -19° and -24°. The Ny refractive index = 1.581 ± 0.002 was measured by the immersion method using monochromatic sodium light.

The cited paper does not contains data on hydromuscovite shales and not on monomineralic hydromuscovite, so that the results of the other analyses are not presented here. The reader is referred to the publications by Barić and Trubelja (1971, 1975).

2. The occurence at Mt. Majevica

Sijerčić (1972, p. 106) identified hydromuscovite in arenite sands belonging to Eocene-age flysch deposits on the western flanks of Mt. Majevica. No further data is provided by the author.

HYDROBIOTITE(K,H2O)(Mg,Fe2+)3[(H2O,OH)2 │AlSi3O10]

X-ray data: d 12.3 (100) 3.5 (7.8) 23 (70) 3.02 (21) 2.73 (16) d 11.4 (100) 3.41 (80) 2.62 (80) 4.56 (20) 3.34 (20) 1.533 (60)

A u t h o r s: Pamić and Đorđević (1974), Sijerčić (1972)

Hydrobiotite is a rare mineral in Bosnia and Hercegovina and data is very scarce. Only Pamić and Đorđević (1974) mention this mineral entity found in rocks of the Bosnian serpentine zone. The hydrobiotite occurs in albitic rocks associated with the gabbro-dolerite complex of Bakinci. The authors maintain that hydrobiotite is an alteration product of biotite (p. 133).

Sijerčić (1972, p. 106) also mentions hydrobiotite in arenite sands belonging to Eocene-age flysch deposits on the western flanks of Mt. Majevica. No further data on this mineral is available.

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SILICATES

STILPNOMELANE(K,H2O)(Fe2+Fe3+Mg, Al)<3[OH)2 │Si4O10] x nH2O

Crystal system and class: Monoclinic.Properties: good cleavage on {001}. Hardness = 3. Specific gravity = 2.8-3. Colour is dark green to black. Refractive indices are highly variable (1.58-1.73).X-ray data: date for minerals of the stilpnomelane series: d 12.07-12.18 (100) 4.04 (50) 3.03 (40)

According to available literature, stilpnomelane has been identified on one location only in Bosnia and Hercegovina – in altered pophyres-keratophyres (orthoschists) from the Neretvica creek in Hercegovina (Tajder and Raffaelli 1967). Stilpnomelane is also believed to be a constituent of mineral aggregates in veins within rocks belonging to the greenschist facies.

Stilpnomelane is an essential constituent of the orthoschists outcropping in the central part of the Neretvica creek near the Parsovići pyrophyllite mine. One vein contains particularly well developed radial aggregates or bent platelets of stilpnomelane, in addition to epidote, quartz, chlorite and calcite. In thin section, stilpnomelane is distinctly pleochroic (X = yellowish-brown, Y = Z = brown to greenish-brown). Tajder and Raffaelli believe that this stilpnomelane should be classified as ferristilpnomelane.

Within the matrix of the host rock, stilpnomelane is present as tiny platelets with strong pleochroism (X = golden yellow, Y = Z = dark brown). The rock may contain also ferrostilpnomelan with different pleochroic colours.

MONTMORILLONITE(Al1.67Mg0.33) [(OH)2│Si4O10]

-0.33Na0.33 x nH2O

Crystal system and class: Monoclinic.Cell parameters: ao = 5.17, bo = 8.94, co = 15.2 Z = 2 β ~ 90°Properties: occurs as earthy masses, gray to greenish-gray in colour, sometimes yellow or white. Hardness is 2-2.5. Specific gravity = 2.0-2.7 and decreases with increasing water content. Streak is white, lustre greasy. Strong absorption of water (and other liquids) i.e. swelling is a characteristic of this mineral.

X-ray data: d 13.6 (100) 4.47 (18) 3.34 (10) d 15.0 (100) 4.50 (80) 5.01 (60)

IR-spectrum: 470 525 630 850 920 1040 1100 1650 3430 3628 cm-1

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A u t h o r s: Barić (1966), Čičić and Pudar (1973), Đorđević (1969a), Đurić (1963), Filipovski and Ćirić (1963), Ilić (1954), Jakšić, Vuletić and Vrlec (1971), Jurković (1961a), Luburić (1963), Maksimović and Crnković (1968), Nikolić, Živanović and Zarić (1971), Pavlović (1975), Pavlović, Ristić and Likić (1970), Podubsky (1955), Ristić, Likić and Stanišić (1968), Soklić (1957), Stangačilović (1969, 1970), Tasić (1975), Trubelja (1966).

Montmorillonite belongs to the group of clay minerals. In Bosnia and Hercegovina montmorillonite clays are widely distributed, but have not been sufficiently investigated. According to available literature data, montmorillonite clays occur in the Tertiary-age Prijedor basin, around the Ljubija ore deposits, around the city of Livno and elsewhere. It is a common constituent of soils, particularly those associated with underlying basic rocks (in the Bosnian serpentine zone).

1. Montmorillonite in argillaceous sediments of the Prijedor basin

Stangačilović (1969, 1970) provided first data on the occurence of montomorillonite in illite clays of the Prijedor basin. Montmorillonite is less abundant than other clay minerals. Pavlović (1975) and Tasić (1975) have done x-ray diffraction studies and thermal analysis of the argillaceous sediments of Prijedor basin. Pavlović investigated sediments from the localities of Crna Dolina, Carevina and Rakelić where the montmorillonite content is 3-16%. Tasić studied the clays of the Rizvanovići deposit on the left bank of the Sana river finding that the content of montmorillonite is approximately the same i.e. 4.8-16.9%. More data on the clays of Prijedor basin are given in the section on illite.

2. Montmorillonite in the Brdo deposit at Ljubija

Montmorillonite was identified in the iron mineral parageneses of the Ljubija deposit. Jurković (1961a) maintains that montmorillonite is a hypergene mineral in this deposit, since it is a ubiquitous associate, together with quartz, of goethite in the Brdo ore body. The variable content of these two minerals results in varying silica and alumina contents of the iron ore. Jurković performed thermal analysis on this montmorillonite.

3. Montmorillonite from Livno

Trubelja (1966) and Barić (1966) report on the occurence of montmorillonite at Podhum village, south of Livno, even though Luburić (1963) was the first to mention the tuffs and bentonites in this area. This authors wrote „in the Livno basin there are substantial outcrops of the newly discovered tuff layers. These outcrops can be seen from the village of Guber (SW of Livno) and further on towards Površje, Potok, Mandak (Podhum), Vojvodinac and Mt. Mala tušnica, for about 10 km. In the Duvno basin the tuff layers can be seen south of Duvno. Thin bentonite layers were observed at Podhum, Potok and Mandak – close to Vojvodinac – where the layer has a thickness of 30 cm“. Trubelja (1966) provides more laboratory data on this montmorillonite. He finds that this montmorillonite is associated with the rhyolite

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tuffs, close to their contact with marls and limestones. The tuffs are primarily made up of volcanic glass, and the montmorillonite has formed as an alteration product of these tuffs. The tuffs are probably eolian in origin and of mid- to late-Miocene age, deposited in the lacustrine environment of the basin together with other sediments. The montmorillonite is usually mixed with calcite.

Chemical analysis of almost pure montmorillonite gave following results:SiO2 = 49.95; TiO2 = 0.30; Al2O3 = 18.43; Fe2O3 = 2.16;FeO = 0.06; MnO = ---; MgO = 3.33; CaO = 2.07; Na2O = traces; K2O = traces; H2O

+ = 6.65; H2O- = 16.87; P2O5 = 0.18;

Total = 100.00The DTA curve is given in Figure 14.

Figure 14. DTA curve of montmorillonite from Podhum near Livno (Trubelja 1966)

4. Beidellite – montmorillonite clays of Šipovo near Jajce

Nikolić et al. (1971) identified montmorillonite in the Tertiary-age Šipovo basin near Jajce. The bentonite clays of this area contain mostly beidellite, but also some montmorillonite (in the Grabež deposit, borehole BŠ-4, at a depth of 38.60-41.10 m). Results of chemical analysis of this montmorillonite, based on 24 (O,OH) cations are given in Table 37.

Table 37. Chemical analysis of montmorillonite from the Grabež deposit % Number of ions

SiO2 51.13 Si 7.678.00

TiO2 0.15 Al 0.33Al2O3 17.39Fe2O3 3.46 Al 2.73

4.28MnO 0.02 Ti 0.02MgO 4.28 Fe3+ 0.58CaO 2.00 Mg 0.95Na2O 0.07K2O 0.29 Ca 0.31

0.38H2O- 12.72 Na 0.02

H2O+ 8.66 K 0.05

Total 100.17 OH 4.33

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XRD data are given in Table 38.

Table 38. X-ray diffraction data for the montmorillonite from Šipovod Å I d Å I

15.30 10 3.03 55.08 1 2.57 64.50 9 1.69 23.33 7 1.50 53.21 1

5. Other occurences of montmorillonite

Podubsky (1955) provided first data on the occurence of montmorillonite clays in Bosnia and Hercegovina, on the right bank of the Bosna river between Zavidovići and Žepče (Ljeskovica locality). The village of Ljeskovica is located 2.5 km from the train station of Vinište, on the Doboj – Sarajevo railroad. Kaolinite occurs together with montmorillonite, so that these formations may be classified as kaolinite-montmorillonite clays. Thermal and XRD analysis showed that this material contained also a moderate quantity of carbonate and talc. The clays from Ljeskovica was previously studied by Ilić (1954) who regarded them as a talc formation.

According to Stangačilović (1969, 1970), moderate amounts of montmorillonite occur also in the illite-kaolinite-metahalloysite clays of the Sarajevo – Zenica basin (deposits at Busovača, Klokoti, Bilalovac, Kobiljača). It is interesting to note that Tasić (1955) did not identify montmorillonite in the clays at Klokoti and Kobiljača.

Pavlović et al. (1970) identified small amounts of montmorillonite in the clay fraction in the quartz sand of the Tuzla basin. Soklić (1957) mentions the montmorillonite deposits at Mt. Majevica, as alteration products of Tertiary-age (Helvetian) tuffs.

Đorđević (1969a) found montmorillonite occuring together with talc near the village of Mušići at Mt. Ozren.

Maksimović and Crnković (1968) identified Cr-montmorillonite and Cr-kaolinite as hydrothermal alteration products of ultrabasic rocks at Slatina near Teslić.

Jakšić et al. identified montmorillonite within the clay fraction of the soils associated with serpentine rocks at Svatovac on Mt. Ozren. Montmorillonite was identified by XRD in the 0.2-2 μm fraction.

Čičić and Pudar (1973) note the occurence of montmorillonite in bentonite clays of Bosnia and hercegovina, but provide no further data on the mineral.

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BEIDELLITEAl2[(OH)2│Al0.5Si3.5O10]

-0.5(CaNa)0.3 x nH2O

A u t h o r s: Caillere and Šibenik-Studen (1969), Đurić (1963), Jakšić, Vuletić and Vrlec (1971), Nikolić, Živanović and Zarić (1971).

Beidellite is a member of the montmorillonite-type clays. In Bosnia and Hercegovina it has been investigated in some detail in the Šipovo area.

1. Beidellite at Šipovo in the Pliva river valley

Caillere and Šibenik-Studen (1969) first mentioned the occurence of beidellite, a prominent mineral in bentonite clays found in the area of Šipovo near Jajce. These clays occur together with other sediments (sandstones, sandy clays and coal) in the lacustrine Tertiary-age basin of Šipovo. The sample in which beidellite was identified is from a borehole (depth 22.30-23.00 m).

Laboratory analyses of the beidellite sample included thermal and chemical analysis, as well as x-ray diffraction. The DTA curve shows three endothermic peaks (at 100°, 500° and 900°C) and one exothermic effect between 940° and 1000°. A reverse run was done in view of a possible identification of quartz, but no effect was noted indicating that the amount of quartz present in the clay is negligible (less than 1%). The TG curve indicates a total weight loss of beidellite of 16%, within the following intervals – 10% between 0-270°, 5% between 275-600° and 1% between 600-900°. The TG curve, published in the mentioned publication, also indicates that montmorillonite is stable up to 500°C. XRD data are given in Table 39.

Table 39. X-ray diffraction data for the iron-containing beidellite from Šipovod Å I

15.10 104.50 82.59 81.50 8

The XRD pattern contains the most intensive line at around 15 Å, but after sample impregnation (and subsequent swelling) with ethylene-glycol the line moves to the 17.44 Å position. After heating for 2 hours at 300°C this interlattice distance diminishes to 10.2 Å, characteristic for beidellite. The XRD pattern shows also some weak lines belonging to quartz.

Results of chemical analysis are as follows:SiO2 = 51.20; Al2O3 = 19.00; Fe2O3 = 5.80; FeO = traces; MgO = 3.70; CaO = 1.35; Na2O =0.15; K2O = 0.80; TiO2 = 1.00; H2O

+ = 6.15; H2O- = 11.30; Total = 100.45

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The small amount of quartz was not taken into account for the structural formula calculation of the iron-containing dehydrated beidellite

(Si3.71Al0.29)(Al1.34Fe3+0.31Mg0.30Ti0.05)O11Mg0.10Ca0.10Na0.02K0.08

It follows that the mineral is dioctahedral and that the Si4+ vs. Al3+ substitution in the tetrahedral layer is too large for montmorillonite. On the other hand, the amount of iron is too small for the mineral to be identified as nontronite.

Two years after the first paper on the Šipovo beidellite was published, Nikolić et al. (1971) investigated with substantially more detail the beidellite-montmorillonite clays of the Šipovo basin. Four clay samples were analyzed in detail – three of those were beidellite while the fourth one was montmorillonite. Results of chemical analyses and XRD are presented in tables 40-42. Nikolić et al. (1971) came to the conclusion that the amount of clays in the upper Miocene-age argillaceous sediments is between 70 and 90%. Other minerals present are quartz, calcite, feldspar, muscovite, biotite, chlorite, staurolite, tourmaline, zircon, rutile, kyanite, garnet, pyrite and magnetite. The authors maintain that the clays formed from some pyroclastic material of unknown origin (perhaps of Miocene age or older).

Table 40. X-ray diffraction data for beidellite from Šipovo (Nikolić et al. 1971)

BŠ – 1 BŠ – 5 BŠ – 11d Å I d Å I d Å I

15.50 8 14.50 10 14.50 107.20 1 4.50 8 4.50 84.45 10 4.22 1 4.22 13.57 3 3.34 9 3.34 93.34 7 2.58 6 2.58 62.57 6 1.81 1 1.81 12.35 2 1.68 3 1.68 31.68 3 1.50 7 1.50 71.50 4 1.37 2 1.37 2

1.29 2 1.29 2

BŠ – 1 Grabež deposit, borehole, depth 27.5 mBŠ – 5 Grabež deposit, borehole, depth 41.5 mBŠ – 11 Sarići deposit, borehole, depth 5.20-6.30 m

Table 41. Chemical analysis of the beidellite from Šipovo (Nikolić et al. 1971)BŠ – 1 BŠ – 5 BŠ – 11

SiO2 46.30 46.53 47.31Al2O3 25.06 21.00 18.76Fe2O3 5.64 6.73 5.89MnO 0.03 0.02 0.03

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MgO 2.16 2.66 2.19CaO 1.36 1.92 3.47Na2O 0.07 0.07 0.07K2O 0.33 0.75 0.34H2O

100° 8.46 9.36 11.36H2O

1000° 10.71 10.37 9.76Total 100.47 99.80 99.56

Table 42. Calculation of the number of cations based on 24 (O, OH) for the Šipovo beidellite (Nikolić et al. 1971)

BŠ – 1 BŠ – 5 BŠ – 11Si 6.68

8.006.89

8.007.17

8.00Al 1.32 1.11 0.83Al 2.92

4.02

2.55

3.93

2.55

3.75Ti 0.03 0.04 0.04Fe3+ 0.61 0.75 0.67Mg 0.46 0.59 0.49Ca 0.21

0.250.30

0.460.56

0.63Na 0.01 0.02 0.02K 0.03 0.14 0.05OH 5.15 5.11 4.94

2. Beidellite from the Višegrad area

Đurić (1963) idenfied beidellite in clastic oolite sediments of the Zlatibor zone, in the area of the town of Višegrad. This author mentions the structural formula of beidellite as follows (Si3.21Al0.79)(Al1.56Ni0.36Cr0.16Mn0.09Ti0.09)O9.89Ca0.15(OH)2.11

3. Beidellite from Mt. Ozren

Jakšić et al. (1971) identified beidellite in the clay fraction from the soil overlying the serpentine-peridotite rocks at Mt. Ozren, Svatovac locality. XRD showed also the presence of montmorillonite and nontronite in the 0.2-2.0 μm fraction.

NONTRONITEFe3+[(OH)2│Al0.33Si3.67O10]

-0.33 Na0.33 x nH2O

X-ray data: d 15.4 (100) 4.56 (90) 1.52 (90)IR-spectrum: 435 455 497 600 685 824 850 1035 1110 1640 3425 3568 cm-1

A u t h o r s: Filipovski and Ćirić (1963), Đurić (1963), Jakšić, Vuletić and Vrlec (1971), Maksimović and Antić (1962), Trubelja (1971a, 1972).

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Nontronite is a member of the montmorillonite clays. It may be fregarded as beidellite which contains Fe(III) instead of Al in the octahedral layer.

Literature data on the distribution of nonotronite in Bosnia and Hercegovina is very scarce and makes any such evaluation very tenuous. It occurs mainly within the Bosnian serpentine zone (BSZ) and in the dacites of Bratunac near Srebrenica.

1. Nontronite in the Bosnian serpentine zone

Maksimović and Antić (1962) identified nontronite in relicts of the weathering cap of ultrabasic rocks in the Vardište and Višegrad areas (localities Prijevorac and Bijelo Brdo) in eastern Bosnia. Laboratory analyses including x-ray diffraction, chemical and thermal analyses showed that the mineral is an aluminum-bearing nontronite. Two samples were analyzed, one from the weathering crust and the other one from iron-bearing clay material. Their structural formulas are as follows:

Nontronite 1 (from the weathering crust)(Si3.68Al0.32)(Fe3+

1.63Al0.17Cr0.05Ni0.06Mg0.05Mn0.01Ti0.02)O9.97(OH)2.03Ca0.20Na0.02K0.03Nontronite 2 (from the iron-bearing clay)(Si3.1Al0.9)(Fe3+

1.51Al0.26Cr0.13Ni0.15Mg0.23Mn0.02Ti0.01)O9.87(OH)2.13Ca0.10Na0.03K0.03

X-ray diffraction data of the two nontronite samples are given in table 43.

Table 43. X-ray diffraction data of nontronite (Maksimović and Antić 1962)Nontronite 1 Nontronite 2

d Å I d Å I14.4 10 14.7 10

*7.30 4 4.55 74.55 7 2.524 9

*3.65 6 2.45 22.54 8 1.72 4

1.526 9 1.305 21.31 5

The sample nontronite-1 contains also serpentine (*), while nontronite-2 contains goethetite and magnite in addition to serpentine.

Đurić (1963) mentions nontronite in oolitic clastic sediments from this same area. Jakšić et al. (1971) identified nontronite in the clay fraction from the soil overlying the serpentine-peridotite rocks at Mt. Ozren, Svatovac locality. XRD showed also the presence of montmorillonite and beidellite in the 0.2-2.0 μm fraction.

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SILICATES

2. Nontronite in kaolinized dacites of Bratunac

Trubelja (1971a, 1972) was able to identify small amounts of nonotronite in the dacites from Bratunac (Srebrenica area). The nontronite is almost completely altered into kaolinite.

SAPONITE(Mg3-2.25Fe0-0.75)Σ3 [(OH)2│Al0.33Si3.67O10]

-0.33 (Ca,Na)0.33 x nH2O

Saponite also belongs to the montmorillonite group of clay minerals. In Bosnia and Hercegovina saponite was found on one location only – in the troctolite from Jovača creek on Mt. Kozara (Golub 1961). Here it occurs as a product of the alteration of olivine, occasionally replacing complete olivine grains as observed in thin section. It is present in the form of yellowish-brown to greenish-brown fibrous aggregates, optically uniaxial and negative.

VERMICULITEMg2.36Fe3+

0.48Al0.16 [(OH)2│Al1.28Si2.72O10]-0.64 Mg0.32 x nH2O

X-ray data: d 13.6 (100) 2.82 (40) 1.52 (40)

A u t h o r s: Barić (1966a), Jakšić, Vuletić and Vrlec (1971)

Jakšić et al. (1971) identified vermiculite in the clay from the soil overlying the serpentine-peridotite rocks at Mt. Ozren, Svatovac locality. Vermiculite was identified by X-ray diffraction.

Barić (1966a) determined by microscopic methods vermiculite in tuffs from the Livno area. The mineral is colourless and a product of biotite alteration.

CHLORITE GROUP

SUDOITE Al2 [AlSi3O10] (OH)2 x Mg2Al(OH)6PENNINE (Mg,Al)3 [Al0.5-0.9Si3.1-3.5O10] (OH)2 x Mg3(OH)6CLINOCHLORE (Mg,Al)3 [AlSi3O10] (OH)2 x Mg3(OH)6SHERIDANITE (Mg,Al)3 [Al1.2-1.5Si2.5-2.8O10] (OH)2 x Mg3(OH)6RHIPIDOLITE (Mg,Fe,Al)3 [Al1.2-1.5Si2.5-2.8O10] (OH)2 x Mg3(OH)6CORUNDOPHYLLITE (Mg,Fe,Al)3 [Al1.5-2.0Si2.0-2.5O10] (OH)2 x Mg3(OH)6DAPHNITE (Fe2+,Al)3 [Al1.2-1.5Si2.5-2.8O10] (OH)2 x Fe3(OH)6KAEMMERERITE (Fe2+,Fe3+)3 [AlSi3O10] (OH)2 x (Fe,Mg)3(O,OH)6

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The term chlorite encompasses a group of minerals with many types of Mg-Al-Fe phyllosilicates. The chemistry of chlorites is very complex. The abovenamed chlorites are all mentioned in the text which follows, and the formulae have been written according to Strunz (1966). According to this author, sheridanite is almost identical to grohauite, rhipidolite to prochlorite, and daphnite to bawalite. The layered structure of chlorites closeley resembles that of the mica group of minerals.

Properties: chlorites are monoclinic (prismatic class). The platelike crystals have a pseudohexagonal habit. Cleavage is excellent along the base{001}. The plates can be bent but are not elastic. The most common type of occurence is as flaky aggregates. Rocks carrying chlorite minerals have a pearly lustre on their surface. The chlorites are green in colour, with different hues. The hardness is low. They are mostly products of hydrothermal alteration of Mg-Fe minerals in igneous rocks. They occur also as chloritic schists and in sedimentary rocks, in association with clay minerals.

X-ray data of some chlorites: Sudoite d 14.2 (100) 4.40 (70) 4.78 (60) 2.32 (50) 2.55 (4) 1.493 (10)Pennine d 7.18 (100) 4.79 (100) 3.59 (100) 14.3 (60) 2.87 (60) 1.539 (20)Clinochlore d 7.12 (100) 3.548 (80) 3.56 (80) 14.3 (70) 4.63 (70) 1.535 (80)Rhipidolite d 7.07 (89) 3.535 (89) 14.4 (54) 4.714 (43) 2.828 (22) 1.5447 (6)

IR-spectrum: Pennine 417 445 460 525 660 755 820 960 990 1050 1080 3430 3590 cm-1

Clinochlore 415 445 460 525 655 820 960 1002 1058 1085 1635 3460 3620 cm-1

Rhipidolite 425 460 550 655 760 820 990 1640 3425 3560 cm-1

Chamosite 430 462 540 618 670 990 1080 3410 3550 cm-1

Minerals of the chlorite group are very common in rocks in Bosnia and Hercegovina. Although the number of available literature references is substantial, the minerals have not been investigated in detail. Most authors deal with the chlorites as a group, and investigations of specific chlorites are lacking.

A u t h o r s: Atanacković, Mudrenović and Gaković (1968), Barić (1970a), Behlilović and Pamić (1973), Burić and Vujnović (1970), Buzaljko (1971), Cissarz (1956), Ćatović, Trubelja and Sijarić (1976), Čelebić (1963, 1967), Čutura (1918), Džepina (1970), Đorđević (1969a), Đorđević and Mojičević (1972), Đorđević and D.Stojanović (1972), Đorđević and V. Stojanović (1964), Đorđević, Buzaljko and Mijatović (1968), Đurić (1958, 1963a, 1968), Foullon (1893), Gaković and Gaković (1973), Golub (1961), Grafenauer (1975), Hauer (1879), Ilić (1953), Jakšić, Vuletić and Vrlec (1971), Jeremić (1961), John (1879), R. Jovanović (1957), Jurković (1954, 1954a, 1957, 1959, 1962), Karamata (1953, 1957), Karamata and Pamić (1960,

208

SILICATES

1964), Katzer (1910, 1924, 1926), Kišpatić (1897, 1900, 1904, 1904a, 1904b, 1917), Koch (1908), Kubat (1964, 1969), Magdalenić and Šćavničar (1973), Majer (1961, 1962, 1963), Majer and Jurković (1957, 1958), Majer and Pamić (1974), Marić (1927), Marić and Crnković (1961), Milenković (1966), Mojsisovics, Tietze and Bittner (1880), Nöth (1956), Olujić, Vuletić and Pamić (1971), Pamić (1957, 1960, 1960a, 1961a, 1961b, 1962, 1963, 1969, 1969a, 1970, 1970a, 1971, 1972a, 1972c, 1972d, 1974), Pamić and Buzaljko (1966), Pamić and Kapeler (1969, 1970), Pamić and Maksimović (1968), Pamić and Olujić (1974), Pamić and Papeš (1969), Pamić and Trubelja (1962), Petković (1962/62), Podubsky (1968, 1970), Podubsky and Pamić (1969), Popović (1930), Ramović (1957, 1962, 1963), Ristić, Likić and Stanišić (1968), Ristić, Pamić, Mudrinić and Likić (1967), Sijarić (1975), Sijarić and Šćavničar (1972), Sijarić and Trubelja (1974, 1974a), Sijarić,Trubelja and Šćavničar (1976), Sijerčić (1972, 1972a), V. Simić (1956), M. Simić (1966, 1968), Šćavničar and Jović (1962), Šćavničar and Trubelja (1969), Šibenik-Studen (1972/73), Šibenik-Studen and Trubelja (1967, 1971), Šinkovec and Babić (1973), Tajder (1953), Tajder and Raffaelli (1967), Trubelja (1957, 1960, 1961, 1962a, 1963, 1963b, 1963c, 1966a, 1969, 1970, 1971a, 1972, 1972a, 1972/73), Trubelja and Miladinović (1969), Trubelja and Pamić (1956, 1957, 1965), Trubelja and Paškvalin (1962), Trubelja and Sijarić (1970), Trubelja and Slišković (1967), Trubelja and Šibenik-Studen (1965), Tućan (1928), Varićak (1955, 1956, 1957, 1966, 1971), Vasiljević (1969), Veljković (1971).

Chlorites occur in Bosnia and Hercegovina in a variety of rocks in the serpentine zone and products of mid-Triassic and Tertiary-age magmatic events. In the case of igneous rocks, the chlorite is formed by alteration processes of pyroxenes and other ferromagnesian minerals. Basic igneous rocks (gabbros) of the Bosnian serpentine zone (BSZ), which have been subjected to hydrothermal alteration processes, contain chlorites in monomineralic veins. Chlorite forms foliated aggregates within veins in rocks associated with corundum-bearing amphibolites.

Paleozoic-age rocks of northwestern, central and eastern Bosnia – sediments and schists of a low level of metamorphism, all contain chlorites as essential constituents. Chlorite bearing rocks are quite common at Mt. Prosara and Mt. Motajica.

Chlorite platelets occur in various clastic sediments and in bauxites. Chlorite

formed by hydrothermal processes occur also in association with ore formations in central Bosnia (schist mountains, Srebrenica area etc.).

1. Chlorite in rocks of the Bosnian serpentine zone (BSZ)

The earliest investigations on chlorites in Bosnia and Hercegovina were done by Hauer, John and Kišpatić. Hauer (1879) and John (1879) mention chlorite in the diabase structure of the Doboj fortress, and in these rock outcropping between Maglaj and Žepče. The monograph by Mojsisovics et al. (1880) mentions John’s

209


microscopic determinations of chlorite in various rocks – diabase from Mt. Majevica, diorite from Kladanj, diabase from Žepče. The biotite-bearing diabases from Žepče (Mt. Lupoglav) contain chlorite in the form of flakes and leaves. It is a product of the alteration of biotite, elicts of which are still present in the rock.

Kišpatić (1897, 1900) determined chlorite in different rocks – in the granite from Mt. Maglaj, in diabases, melaphyres, gabbros, amphibolites and garnet-bearing phyllites from various locations. In all cases the chlorite is of secondary origin, formed by alteration processes of biotite, augite and garnet. Chlorite is most abundant in the garnet-bearing phyllites from Čamlija, next to quartz. In thin section this chlorite is green in colour, distinctly pleochroic.

Chlorites in rocks of the BSZ is mentioned in more recent investigations. Pamić and Kapeler (1970) note the occurence of chlorite minerals in the serpoentinites of the Krivaja – Konjuh complex. At Donje Vijake, close to the contact zone between serpentinites and corundum-bearing amphibolites, veins carrying silvery-white chlorite aggregates are quite common. A preliminary chemical analysis indicated that the chlorite is a Al-Mg chlorite with ca. 5% iron oxide. Chlorites are accessory constituents of hydrothermally altered rocks (talc – listvenites) outcropping on the northern reaches of the Mt. Ozren serpentinite-peridotite complex. Prochlorite and corundophyllite were identified by Pamić and Olujić (1974).

Golub (1961) identified micaceous aggregates of chlorite within plagioclase crystals hosted in the andesitic basalts from Brnjačin Jarak at Mt. Kozara. The chlorite also occurs in the matrix of the rock and within amygdales filled with calcite. The chlorite is optically uniaxial and negative. Pleochroic colours are green and blue green. Interference colours are grayish to lavender. The author maintains that the chlorite in this rock is of primary origin.

Trubelja (1957, 1960, 1963c) found chlorite to be a fairly common constituent of igneous rocks in the Višegrad area. The paper published in 1960 provides the most data on chlorite. Occurences in feldspar-bearing peridotites from Bosanska Jagodina, uralite gabbros from the village of Smrijeća, gabbros from Pijavica, diabases from Banja Potok and dolerites from the Rzav river valley are described. These rocks carry only minor amounts of chlorite. Interference colours are bluish.

More chlorite is found in the gabbro-pegmatites and hydrothermally altered veins within basic igneous rocks. In the gabbro-pegmatites chlorite has formed as a product of diallage alteration during the hydrothermal phase. At Višegradska Banja, whole grains of diallage have been transformed into a fibrous aggregate of chlorite,

210

SILICATES

which is isotropic in thin section. Lavender interference colours are indicative for chlorite. Close to the village of Lahci above Višegradska Banja, chlorite occurs in veins within the gabbro host rock. The chlorite sheets are up to 0.5 x 1.0 cm in size with good cleavage along (001). The colour is grayish to silvery white. In thin section, irregular extinction is commonly observed. The 2V angles were measured in convergent light: +2V = 73.3° to 65.3°. There is a low r<v dispersion of optic axes.

Occurences of chlorite in various rocks of the BSZ have been described also by the following authors: Buzaljko (1971) – Goražde and Rudo; Džepina (1970) – the Borje metamorphic complex; Đorđević (1969a) – Mušići and Mt. Ozren, associated with talc; Đorđević and Mojičević (1972) – the albitic syenites of Borje; Đorđević and Stojanović (1964) – Mts. Konjuh, Ozren and Uzlomac; Đorđević and Stojanović (1972) – Bojići, Banja Luka, associated with natrolite; Đorđević et al. (1968) – Bosansko Petrovo Selo; Đurić (1958) – Vardište; Đurić (1968) – Mt. Ljubić, associated with cinnabar; Jakšić et al. (1971) – in soils at Mt. Ozren; Karamata and Pamić (1964) – granites, Vijaka and Vareš; Kubat (1964) – Mt. Čavka; Majer (1962) – the serpentine zone between the rivers Bosna and Vrbas; Majer (1963) – in pebbels of the albitic granite of Prisoje; Majer and Pamić (1974) – altered shales from Borje; Olujić et al. (1971) – in ankerite-chlorite-augite dolerite; Pamić (1969a, 1970, 1970a, 1971, 1972a, 1972c, 1972d, 1974) – various rocks in various sectors of the BSZ; Pamić and Kapeler (1969, 1970) – in gabbro-dolerites from Mt. Kozara; Pamić and Trubelja (1962) and Trubelja and Pamić (1965) – igneous rocks of Mt. Ozren; Ristić et al. (1967) – in diabases from Mt. Konjuh; Sijarić and Šćavničar (1972) – serpentines from Mt. Konjuh; Sijerčić (1972a) – igneous rocks from Mt. Kozara; Šibenik-Studen (1972/73) – the Višegrad area; Šibenik-Studen and Trubelja (1971) and Trubelja (1961) – basic rocks from Mt. Konjuh; Trubelja and Pamić (1957) – various igneous rocks.

2. Chlorite in products of mid-Triassic and Tertiary-age magmatic events

Chlorite commonly occurs in various rocks of mid-Triassic rocks (as essential or accessory constituent) in southeastern Bosnia, in the areas of Konjic, Jablanica and Prozor, Borovica, Vareš, Čevljanovići.

Cissarz (1956), Čelebić (1963, 1967), Marić (1927), Nöth (1956), Pamić (1960, 1961a, 1961b), Pamić and Maksimović (1968) and Tućan (1928) describe the occurence of chlorite in Triassic-age volcanic rocks in the area of Konjic, Jablanica and Prozor.

Pamić (1961b) determined chlorite in basalts, andesites, spilites, keratophyrs, vein-type albitic rocks and tuffs. Chlorite is often contained within amygdales, together with calcite and other minerals.

211


The spilites from Jablanica and Prozor carry chlorite sometimes as an essential constituent. In thin section it is of a grass green colour, without pleochroism, and apparantly isotropic. In some sections chlorite has a yellowish colour and weak pleochroism. Interference colours are yellowish, and the 2V angle lies in the range +28° to +34° (prochlorite). In spilite-type rocks, chlorite is often embedded in phenocrystals of low-temperature albite, together with other secondary minerals like prehnite, calcite and sericite. This asociation indicates that chlorite cannot be regarded as a primary mineral of a late magmatic phase. The keratophyres in the valleys of the Rama and Doljanka rivers contain prominent amounts of chlorite, in the form of irregular flakes (Pamić 1961b). The chlorite sometimes has an elongated habit, inferring possible formation through alteration of primary amphibole. Here it has a green colour, pleochroic colours are yellow green to green. The 2V angle is in the range +64° to 74°, indicating clinochlore composition. Some of these chlorites show no pleochroic colours and are seemingly isotropic under crossed nicols. It should be noted that the presence of more than one variety of chlorite has bot been observed in keratophyres.

The clinochlore in keratophyres from Lušac creek near Gračac probably formed from pyroxene, whose relicts are still present in the rock matrix. Pamić (1961b) investigated the quartz-bearing keratophyres from Mt. Lovin near Gračac where the chlorite (pennine) has a -2V angle in the range 26° to 36°, and a weak pleochroism (X = greenish, Y = Z = yellow green). Similar rocks from Mt. Krstac (village of Lug) contain chlorite as an essential constituent. The flakes are rather elongated and indicate formation through amphibole alteration.

Marić (1927) investigated microscopically the chlorite from the veins in the gabbro rocks at Jablanica (Bukov Pod). The association comprises chlorite, green hornblende, feldspar and quartz. It occurs as fragile aggregates consisting of subhedral platelets which disintegrate easily. In thin section no pleochroic colurs were observed, the birefringence being weak. Pyroxene alteration into chlorite has been observed in some instances (in the central part of the gabbro complex). This chlorite has a higher birefringence and occurs in the form of fibrous aggregates, with green-blue pleochroism. The interference colours (blueish) seem to be characteristic for pennine.

Cissarz (1956), Čelebić (1963, 1967) and Nöth (1956) investigated the magnetite deposit at Tovarnica where chlorite is prominent in the paragenesis of the contact zone. Here it is a product of garnet and biotite alteration.

The albitic diabases near the village of Lug, south of Prozor, are altered by contact metamorphism and contain substantial amounts of chlorite in the form of coarser aggregates. In thin section the green-yellow chlorite shows no pleochroism, and has a -2V angle of 14-34°. It is probably pennine.

212

SILICATES

Occurences of chlorite in various rocks associated with mid-Triassic-age magmatic events have been described also by the following authors: Behlilović and Pamić (1963) – in the tuffs of Drežanka; Čuture (1918) – in igneous rocks of SW Bosnia; Jeremić (1961) – Triassic-age deposits of barite; Jurković (1954a) – the andesites from Orašin; Karamata (1953) – in melaphyres from Vareš; Karamata (1957) – in keratophyres from Zvornik; Katzer (1910) – in siderites from Vareš; Majer and Jurković (1957, 1958) – in gabbrodiorites from Bijela Gromila near Travnik; Mojsisovics et al. (1880) – in igneous rocks from Jajce and Donji Vakuf, according to determinations by John (1879); Pamić (1957, 1960, 1960a) - in spilite- and keratophyre-type rocks from Ilidža and Kalinovik; Pamić (1963) – in igneous rocks from Čevljanovići; Pamić and Buzaljko (1966) – keratophyres and similar rocks from Čajniče; Pamić and Maksimović (1968) – in quartz-albite diabases from Bijela-Konjic; Petković (1961/62) – in igneous rocks from Borovica-Vareš; M. Simić (1966) – basic effusive rocks from Mt. Bjelašnica; Šibenik-Studen and Trubelja (1967) – igneous rocks in the Vrbas river valley; Trubelja (1962a, 1963) – keratophyres and quartz-keratophyres from Čajniče; Trubelja (1969, 1972a) – in spilites from Borovica-Vareš; Trubelja and Miladinović (1967), Trubelja and Slišković (1967) – in igneous rocks from Tjentište and Sutjeska river; Trubelja and Šibenik-Studen (1965) – in granites and similar rocks from Komar and the Vrbas valley); Veljković (1971) – in the barite deposit at Veovača –Vareš.

Very limited data on chlorite in products of Tertiary-age magmatic events is provided by following authors: Kišpatić (1904, 1904a), Ramović (1957, 1962, 1963), Tajder (1953), Trubelja (1971a, 1972), Trubelja and Pamić (1956) and Trubelja and Paškvalin (1962). These authors mention occurences of chlorite in dacites, andesite dacites and kaolinized dacites outcropping in the Bosna river valley and around Srebrenica.

3. Chlorite in Paleozoic-age rocks

Chlorite is a prominent mineral in various rocks of Paleozoic age, throughout Bosnia and Hercegovina. However, litearture data is very limited. Chlorite is often mentioned by Katzer (1924, 1926) and Varićak (1956, 1957 and 1966). Contributions to the knowledge about chlorite were provided by the following: Barić (1970a), Ilić (1953), Kišpatić (1904b), Koch (1908), Marić and Crnković (1961), Podubsky (1968, 1970), Podubsky and Pamić (1969), Simić (1956), Šćavničar and Trubelja (1969), Tajder and Raffaelli (1967), Trubelja and Sijarić (1970). Some investigations by the above named authors included chemical and thermal analysis and determinations by x-ray diffraction.

Koch (1908) investigated the rocks at Mt. Motajica where chlorite occurs in biotite-bearing granites and gneisses from Židovski Potok, the garnet-biotite gneiss from Studena Voda and Kobaš, biotite gneiss from Hercegov Dol near Bosanski

213


Svinjar, biotite schists from Puljana Kosa and Studena Voda, micaschists from Kamen Potok near Kobaš and Šeferovac, andalusite schists from Resavac creek near Svinjar. All these rock contain minor amounts of chlorite which is a product of biotite and garnet alteration. Koch’s data on chlorite from Mt. Motajica can also be found in Katzer’s monograph on the Geology of Bosnia and Hercegovina (1924, 1926).

Varićak (1966) made detailed microscopic investigations of various sedimentary, igneous and metamorphic rocks from Mt. Motajica, but provides little information about chlorite. Substantial amounts of chlorite (up to one third of the rock mass) are contained in the chlorite-epidote schists of the Osovica river. At Mt. Prosara Varićak (1956, 1957) determined chlorite in quartz-porphyres and various schists (gneiss, micaschists, green rocks). In quartz-porphyres chlorite is a product of biotite alteration.

Katzer (1924, 1926) mentions occurences of chlorite in various rocks from the

schists mountins of central Bosnia – in phyllites, argillaceous shales, carbonaceous phyllites, conglomerates (with chloriteschist pebbles), sandstones, quartzporphyres, diabases. According to Katzer, chlorite causes the green colour of some of these rocks. No further details are provided.

Barić (1970a) determined chlorite in the keratophyres from Trešanica, near Bradina in Hercegovina. The chlorite is a product of alteration of hornblende or pyroxene. In thin section, this chlorite shows weak pleochroism (yellow and green), weak birefringence and brownish-violet interference colours (in section 0.03-0.04 mm thick). It is optically uniaxial and positive.

Tajder and Raffaelli (1967) determined chlorite in altered porphyres and keratophyres in central Bosnia. In some cases, chlorite is an essential constituent of these rocks. Metamorphic rocks with chlorite belong to the low-temperature sector of the greenschist facies. The orthoschists from the Neretvica creek have chlorite aggregating in veins within the rock. It is green in colour, shows distinct pleochroism and anomalous interference colours (indigo). It is probably pennine. The schist from Željeznica creek, Neretvica creek and river Vrbas contains a substantial amount of chlorite formed from hornblende or biotite. It is green in colour (also pleochroic colours). Interference colours are anomalous (brown). It is probably prochlorite.

Chlorite also occurs in paraschists, which are common in the area of central Bosnian schist mountains. In most cases it is prochlorite. Trubelja and Sijarić (1970) investigated in some detail the chlorite from biotite-chlorite-ankerite schists and albite-chlorite schists from Ivanovica creek near Busovača. Chemical and thermal analyses, as well as x-ray diffraction were done. In thin section the chlorite shows distinct pleochroic colours in various hues of green. Powder diffraction data indicate that the chlorite is prochlorite.

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The talc-serpentine-chlorite vein in the phyllites from Kupres contains chlorite deposited directly on the surface of the rock. Chlorite was determined by microscopy, powder diffraction and chemical and thermal analysis. Diffraction data were compared with literature (Brown 1961) and indicated that the material investigated had an ordered structure but the three diffraction signals could not be assigned to chlorite (table 45, lines 7, 8 and 14). However, the relative intensities of the postivie and negative index would indicate a chlorite with orthochlorite structure (Schoen 1962; Petruk 1964).

The powder diffraction pattern of the chlorite from Kupres had very sharp diffraction lines so that the dimension of the unit cell could be calculated: a0 = 5.327±0.005 Å; b0 = 9.236 ± 0.005 Å; c0 = 14.39 ± 0.01 Å; β = 97.2° ± 0.2°

Table 44. X-ray diffraction data for chlorite (Ivanovica creek, Busovača)d Å I d Å I

14.329 Medium 2.403 Medium7.140 Very very strong 2.337 Just visible4.750 Medium 2.284 Medium4.040 Medium 2.206 Just visible3.910 Just visible 2.127 Just visible3.785 Just visible 2.086 Just visible3.677 Medium 2.016 Medium3.558 Very very strong 1.909 Medium3.386 Just visible 1.837 Medium3.215 Very strong 1.763 Just visible2.966 Very weak 1.733 weak2.803 Weak 1.680 Just visible2.761 Weak 1.627 Medium2.648 Just visible 1.565 Medium2.615 Medium 1.518 Medium2.565 Medium 1.474 Just visible2.472 Medium 1.422 Just visible

1.400 Medium

The chemical analysis of chlorite yielded following results:SiO2 = 31.19; TiO2 = 0.86; Al2O3 = 12.36; Fe2O3 = 4.30; FeO = 3.37;MnO = 0.07; MgO = 32.63; CaO = 1.94; Na2O =0.48; K2O = 0.38; H2O

+ = 11.92; H2O

- = 0.41; P2O5 = 0.03; Total = 99.94

The structural formula of this chlorite is:(Ca0.204Na0.091K0.048)(Mg4.775Fe2+

0.277Fe3+0.244Al0.495Mn0.006Ti0.063)(Si3.064Al0.936)

O10.195(OH)7.805

The analyzed chlorite sample is a clinochlore. The zonar and concentric texture of the mineral association within the vein in the phyllite rock indicates that

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the deposition of material occured in several phases of hydrothermal activity. Each of these phases resulted in the crystallization of a mostly monomineralic product, depending on the composition and temperature of hydrothermal solutions – chlorite was the first mineral to crystallize, before a finegrained and finally a coarsegrained variety of talc.

Table 45. Powder diffraction data for chlorite from KupresNo. hkl d Å I No. hkl d Å I

1 001 14.301 6 28 1.3034 1.52 002 7.138 10 29 1.2923 33 003 4.763 7.5 30 1.2777 0.54 020 4.585 4.5 31 1.2265 25 004 3.567 8.5 32 0, 0, 12 1.1935 1.56 005 2.856 3 33 1.1807 0.57 2.722 0.5 34 1.0969 1.58 2.647 0.5 35 1.0468 1.59 131 202 2.585 5 36 1.0369 1.510 132 201 2.540 9 37 1.0025 1.511 132 203 2.440 8 38 0.9921 212 133 202 2.382 4 39 0.9811 113 133 204 2.262 4 40 0.9569 1.514 2.200 0.5 41 0.8952 215 134 205 2.070 1 42 0.8884 216 135 204 2.0085 7 43 0.8602 2b17 135 206 1.8886 3 44 0.8526 118 136 205 1.8282 3

b = broad lined = diffuse linevisual intensity estimate

19 136 207 1.725 1d20 137 206 1.6684 1.521 137 208 1.5718 422 060 331 1.5390 823 062 331 333 1.5024 3.524 063 332 334 1.4642 1.525 139 208 1.4017 4b26 065 1.3531 127 400 139 401 1.3214 3

Kišpatić (1904b) described several schist-type rocks which contained chlorite as essential or accessory components. The green schists from Polom and Lonjina on the Drina river contain substantial amounts of chlorite. In the schist from Polom, chlorite completely displaces its precursor mineral – amphibole. The schist from Lonjina contains only a minor amount of chlorite which has green and pale yellow pleochroic colours. The chlorite schists from Vilenica near Travnik contain susbtantial amounts of feldspar and chlorite. Chlorite has a pale green colour, pleochroism and birefringence are weak. It was formed probably by alteration of amphibole. Kišpatić determined chlorite microscopically in chlorite-bearing phyllites

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and schists from Fojnica, Čemernica, Kiseljak and Kreševo, and in the porphyrric diabases from Sinjakovo.

In a more recent investigation of the lithostratigraphy of Paleozoic-age rocks in NW Bosnia, Podubsky (1968) determined several lithologic horizons containing chlorite minerals as essential constituents. Such is the case of the early Paleozoic-age argillaceous schists which are green in colour from the chlorite. Chlorite is also a prominent mineral in metasandstones, and similar rocks outcropping in the Sana river valley (Marić and Crnković 1961).

Likewise, chlorite is usually present in altered basic and neutral igneous rocks from the Ljubija area (Podubsky 1968, Podubsky and Pamić 1969), also in the Paleozoic-age rocks of eastern Bosnia (Podubsky 1970). In cases when the amount of chlorite is substantial, then this id reflected in the name of the rock i.e. chlorite schists, sericite-chlorite schists etc.).

Paleozoic-age rocks, and the chlorites in them have not been up to now investigated in any great detail. In the schist mountains of central Bosnia, chlorite is often associated with various ore parageneses (Jurković 1954, 1956, 1962; Simić 1956). Most of the information on these chlorites is in the PhD thesis of I. Jurković, published in 1956. Accoriding to Jurković, chlorite is a meso-epithermal mineral in the ore bodies at Busovača, Šćitovo, Brestovsko, Travnik, Berberuša, Travnik etc.

Chlorite commonly occurs in the quartz veins and metamorphic magnetite deposits at Zagrlski potok near Busovača. The chlorite occuring in quartz veins is green in colour, like the one from the magnetite deposit. Simić (1956) identified also a chrome-bearing variety of chlorite.

4. Chlorite in other rocks

Chlorite has also been identified in carbonates and clastic sediments and bauxite. Gaković and Gaković (1973) identified chlorite in the insoluble residue of some carbonate rocks from the outer Dinarides belt. Ilić (1953) found chlorite in weathered and altered granites from Mt. Motajica. The following authors have also determined chlorites in various rocks: Magdalenić and Šćavničar (1973) – in sandstones from Kulen Vakuf; Ristić et al. (1968) – in sands from the Tuzla basin; Sijerčić (1972) – in the Eocene-age flysch deposits of Mt. Majevica; Simić (1968) – in sediments from the Sarajevo area; Šćavničar and Jović (1962) – in clastic sediments of the Kreka coal basin; Varićak (1955) – in the red granite from Mt. Maglaj; Vasiljević (1969) – in sedimentary quartzites from Podrašnica – Mrkonjić Grad.

Some recent investigations and determinations by powder diffraction showed that chlorites are fairly common constituents of bauxites – Ćatović et al. (1976),

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Sijarić (1975), Sijarić and Trubelja (1974, 1974a), Sijarić et al. (1976), Šćavničar et al. (1968), Šinkovec and Babić (1973), Trubelja (1970). Sijarić (1975) and Sijarić et al. (1976) determined chlorite in bauxite from Mt. Grmeč in NW Bosnia and found the chlorite to be the Al-bearing sudoite. Material from the following localities was determined – Borik, Vranjsko, Mijačica, Oštrelj, Grič, Kravljak and Karanovići. The sudoite content in the sample from Grič is 15.5% and 17.4%, while the Kravljak sample contains 12.0% of sudoite. Samples from Drljače, Guskarica and Leovača also contain some Fe-chlorite.

Šinkovec and Babić (1973) also determined chlorite in the bauxite from the Oštrelj deposit. The three analyzed samples contained 5.59, 3.79 and 6.53% chlorite which is largely cryptocrystalline. Some chlorite flakes up to 10 μm in length were identified.

Ćatović et al. (1976), Sijarić and Trubelja (1974, 1974a) identified chlorite in the bauxite from Mt. Srnetica near Ključ – the chlorite is daphnite (bawalite) and sudoite. The bauxite samples from Studnac contained between 6.0 and 13.3% sudoite. Samples from Jezerine, Pijetlov Vrh, Kladovača, Ravni Lom and Studenac also contain ca. 1-3% of the Fe-bearing chlorite daphnite (bawalite). The bauxite from Ravni Lom contains up to 7.6% daphnite.

Trubelja (1970) determined chlorite in the disapore-type bauxite and bauxite clays from Ljuša near donji Vakuf. The boehmite-gibbsite bauxite from Korenduša – Vinjani (near Posušje) contains small amounts of chlorite (chamosite).

Grafenauer (1975) identified kaemmererite in the chromium ore (chromite) at Krivaja near Duboštica. It occurs in small veins or associated with the ore. It probably formed as a result of the interaction of hydrothermal fluids and the chromite ore.

KAOLINITEAl4 [Si4O10] (OH)8

Crystal system and class: Triclinic, pinacoidal class.Lattice ratio: a : b : c = 0.576 : 1 : 0.830 α = 91° 48’ β = 95° 30’ γ = 90°Cell parameters: ao = 5.14, bo = 8.93, co = 7.37 Z = 1Properties: kaolinite usually occurs in the form of earthy aggregates, less often as pseudohexagonal crystals visible with the aid of a microscope. Cleavage along {001} is good, but usually not macroscopically visible due to the small size of the crystals. Hardness is 2, the specific gravity = 2.6. Colour and streak are white. Lustre can be pearly but is usually earthy.

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X-ray data: d 7.13 (100) 3.566 (66) 4.36 (50) 4.158 (46) 3.839 (33) 1.487 (11)IR-spectrum: 435 475 542 700 760 800 918 940 101 1038 1108 1640 3460 3620 3660 3672 3702 cm-1

A u t h o r s: Bišćević-Muštović, Trubelja and Sijarić (1976, 1976a), Burić and Vujnović (1970), Ćatović and Trubelja (1976), Ćatović, Trubelja and Sijarić (1976), Čičić (1975), Dangić (1971), Đorđević and Mijatović (1966), Ilić (1953), Jakšić, Glavaš and Trubelja (1967), Jeremić (1960, 1963, 1963a), Jurković and Sakač (1964), Karšulin, Tomić and Lahodny (1949), Katzer (1924, 1926), Maksimović and Crnković (1968), Mudrinić and Janjić (1969), Mudrinić and Tadić (1969), Pavlović (1889), Pavlović, Ristić and Likić (1970), Podubsky (1955, 1970), Ramović (1957a), Ristić, Likić and Stanišić (1968), Sakač (1969), Sijarić (1975), Sijarić and Trubelja (1974, 1974a), Sijarić,Trubelja and Šćavničar (1976), Stangačilović (1956, 1969, 1970), Šćavničar, Trubelja and Sijarić (1968), Šibenik-Studen and Trubelja (1967), Šinkovec and Babić (1973), Tajder (1953), Trubelja (1962a, 1963, 1970, 1971, 1971a, 1972, 1973, 1973a), Trubelja and Pamić (1956, 1965), Trubelja and Sijarić (1976), Trubelja and Vasiljević (1968, 1971b), Varićak (1956, 1966), Walter (1887), Weisse (1948).

Kaolinite is the most common and best known clay mineral, and a typical representative of te group. In Bosnia and Hercegovina kaolinite has not been investigated in great detail and literature data is scarce.

There are two types of kalinite deposits in Bosnia and Hercegovina. The first are the ‘in situ’ kaolinite deposits, where the mineral is in its primary location of origin. Some authors refer in this case to ‘primary kaolinite’ and autochtonous deposits. The other group of deposits are the reworked or allochtonous deposits.

The kaolinite deposits at Mt. Motajica belong to the first group. Here kaolinite formed as an alteration product of various granitic and other rocks. The kaolinite from Srebrenica (Bratunac) formed on dacites.

Allochtonous kaolinite deposits comprise argillaceous sediments where kaolinite occurs either alone or with other clay minerals (illite, montmorillonite). Such deposits are found in the basins of Prijedor and Sarajevo – Zenica.

Kaolinite is a typical secondary mineral, formed as an alteration product of potassium feldspars and plagioclase. Under surface conditions, the process of kaolinization can take place only under the influence of atmospheric water (rain) and/or hydrothermal solutions. Therefore, kaolinite can be expected to occur in association with rocks containing feldspars. Many occurences of this mineral have been described in rather general terms, i.e. as ‘kaolinite minerals’. It needs to be mentioned that kaolinite is ubiquitous in various types of soil.

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1. Kaolinite at Mt. Motajica

In his Geology of Bosnia and Hercegovina, Katzer (1924, 1926) mentioned the alteration process of the granites at the Mt. Motajica complex. The process has advanced to subsurface parts of the granite body resulting in the formation of a sandy material. The surface of the granite body has been transformed into a thick layer of clayey soil.

After Katzer, very little information was available abou the Mt. Motajica kaolinite until the paper by Ilić (1953) dealing with kaolinization of the granite complex in the watershed of the Grebski and Kameni creeks in the area of Bosanski Kobaš. The samples were analyzed microscopically and by powder diffraction. The paper contains two powder diffractograms and the results of chemical analysis of several samples of altered granite. Other minerals present in the rock are albite, muscovite, quartz and chlorite.

Ilić believes that the alteration processes leading to kaolinite formation are the result of hydrothermal activity. An additional argument for this conclusion lies in the fact that the alteration process has advanced to a high degree particularly in the vicinity of quartz veins (which formed in the course of postmagmatic processes).

Another publication dealing with alteration processes of the granite complex of Mt. Motajica was published at the same time by by Stangačilović (1956). This author determined kaolinite in samples from the locality Đidovi, using thermal analysis and the Debye-Scherrer powder diffraction method. The coarser fraction of kaolinite (0-15 μm) contained kaolinite, illite and quartz while the finer fraction (0-5 μm) consisted of almost pure kaolinite. Stangačilović however advanced a different view concerning the formation of kaolinite at Mt. Motajica, believing that hydrothermal processes have not caused the alteration of the granite. He maintains that the alteration of the granite, particularly in the area of Kobaš and Brusnik, took place during the Tertiary-age transgressions of the sea, since there is evidence for such a scenario in the area. After the sea-level subsided, further alteration took place in marshes and lacustrine environments, in areas with appropriate orography. The activity and infiltration of surface waters was particularly extensive along fissures which formed around the contact of the quartz veins and the granite host rock. This is why the alteration process is stronger along the quartz veins.

In addition to kaolinite, illite and quartz, the granite contains also orthoclase, plagioclase, sericite, biotite, magnetite and zircon.

Varićak (1966) frequently referrs to kaolinization processes of feldspars and ‘clay minerals’ in his petrologic study of the granites and other rocks of Mt. Motajica.

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2. The kaolinite deposit of Bratunac (Srebrenica)

Tajder (1953) gave the first detailed account of the alteration processes (kaolinization) of the dacites and andesite-dacites in the area of Srebrenica. However, his treatment of the mineral kaolinite is only brief.

Most of the igneous rocks around Srebrenica is comparatively fresh, and alteration processes are present to a limited extent. However, the dacites around Bratunac are almost completely altered (Trubelja 1970a, 1971a, 1972; Dangić 1971). Occurences of kaolinite and altered dacite are located some 2.5 km SW from the village of Bratunac, i.e. some 8 km from Srebrenica. Best outcrops are located at Smoljave and Borići, where exploitation of kaolinite is taking place. Other occurences around Srebrenica are small-scale occurences.

Trubelja identified the kaolinite and other associate minerals by optical microscopy, x-ray diffraction and thermal analysis. The DTA curve of the material consisting of altered dacite shows an endothermic peak at temperatures between 500° and 600°C characteristic for a complete loss of constitutional water. This effect was observed also on the TG curve. The kaolinite content of the material was estimated from the peak area. The kaolinite content is in the range between 28 and 60%, the average being around 35%.

In addition to kaolinite, sanidine, quartz, biotite, marcasite, pyrite, goethite, chlorite, sericite and epidote were identified in the altered dacites. Dickite, sepiolite and nontronite were found in a few samples only.

The altered dacite rocks at Bratunci are significant economically as they are a source of valuable kaolinite. Data from the field and from the laboratory indicate that the alteration process of rocks at Smoljve is more intensive than at Borići and elsewhere. The same is true for the quality of kaolinite as a natural resource. At Borići, the alteration process also led to the formation of sulfide and silicate mineralizations associated with hydrothermal waters. Surface weathering leads to the formation of secondary iron oxides and hydroxides – the cause of the occasional off-colour of kaolinite.

The formation of kaolinite in the case of the Bratunac deposit can be explained in a comparatively simple way. The platelike magmatic (volcanic) body was in extensive contact with hydrothermal solutions during post-magmatic processes (hydrothermal stage). The feldspars contained in the dacite matrix were almost completely altered into kaolinite. However, alteration led also to the formation of chlorite, sericite, marcasite, pyrite and epidote. The original texture of the dacite is maintained to some extent, likewise the presence of sanidine feldspar. It is interesting to note that no plagioclase feldspars were found in the rock, which ma be due to their lower stability with respect to sanidine. Consequently, there is no evidence of plagioclase feldspars in the altered dacite.

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The presence of marcasite which is in intimate contact with kaolinite would imply that the hydrothermal solutions had a low pH and comparatively low temperature. Marcasite is known to crystallize from acidic hydrothermal solutions at temperatures below 400°C, while pyrite forms at higher temperatures.

The hydrothermally altered dacite at Bratunac may be classified as a primary (residual) deposit of kaolinite. Such deposits are rather rare in the world.

3. Kaolinite in bauxite

Kaolinite seems to be regularly associated with bauxites throughout Bosnia and Hercegovina. The kaolinite content is sometimes so high that the rock is classified as kaolinite-bearing bauxitic sediment.

Using modern physical and chemical determinative methods, it was

possible to identify kaolinite in several bauxites in Bosnia and Hercegovina – from Hercegovina, from eastern Bosnia (Vlasenica), from the area of Jajce and Mrkonjić Grad (Baraći), from Mt. Srnetica and Mt. Grmeč.

Bišćević-Muštović et al. (1976, 1976a) determined kaolinite as an essential constituent of bauxitic clays from Prozor and Rama lake. In the available literature, kaolinite is usually described in sections dealing with bauxite, so that more information can be found in sections describing the minerals hematite, gibbsite, diaspore etc.

Jurković and Sakač (1964), Sakač (1969), Sijarić (1975), Sijarić et al. (1976), Šinkovec and Babić (1973) and Trubelja note the presence of kaolinite in bauxites of NW Bosnia. First quantitative data on the kaolinite in bauxite from Oštrelj at Mt. Grmeč are given in the paper by Šinkovec and Babić (1973). The bauxites they studied had a kaolinite content between 26.48 and 57.26%. The material from Mt. Grmeč was also investigated by Sijarić (1975). According to this author, kaolinite was found in bauxite from the localities Bjelaj, Zec, Grbića Brdo, Karanovići, Leskovac, Borik, Gradina, Vranjsko, Trovrh, Mašine Doline, Guskarica, Vranovina, Brezove Poljane, Krnja Jela, Crni Vrh, Oštrelj and Leovača. The Triassic-age bauxite from Bjelaj has a particularly high kaolinite content. More data on the kaolinite content of these bauxite are given in the section on boehmite. Generally, a high content of kaolinite in bauxite makes them less appropriate for alumina production.

Ćatović et al. (1976), Sijarić and Trubelja (1974, 1974a) studied the bauxites from Mt. Srnetica south of the town of Ključ. The bauxites have been classified as high-silica bauxite, due to their kaolinite content. The kaolinite contents are as follows: 21.3-35.6% at Studenac, 28.9% at Jezerine, between 21.3 and 24.8% at Pijetlov Vrh, Krčevine, Kladovača, Ravni Lom.

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Trubelja (1971, 1973) found elevated contents of kaolinite also in the gibbsite-type bauxites from Mrkonjić Grad.

Jakšić et al. (1967), Karšulin et al. (1949), Maksimović (1968), Šćavničar at al. (1968), Trubelja (1973, 1973a), De Weisse (1948) provide data on kaolinite in bauxites from Hercegovina. J.G. de Weisse was the first to estimate kaolinite concentrations in hercegovinian bauxites from Čitluk, Stolac, Domanovići, Zagorje etc). Maksimović (1968) found that theses bauxites contained between 15 and 32% kaolinite. Kaolinite is normally found in the lower parts of the deposit. Ćatović et al. (1976) investigated the kaolinite contents in pyrite-bearing bauxites from Hercegovina. Jeremić (1960a), Mudrinić and Janjić (1969), Mudrinić and Tadić (1969) all identified kaolinite in bauxites from Vlasenica in eastern Bosnia, but information on the content is lacking.

Trubelja and Sijarić (1976) found kaolinite to be an essential constituent of the recently discovered bauxite at Miljevine (eastern Bosnia).

4. Other occurences of kaolinite

Stangačilović (1969, 1970) found kaolinite to be an essential constituent of allochtonous illite-type clays in the basins of Prijedor and Sarajevo – Zenica. Kaolinite contents in these sediments are lower than thos of illite (Pavlović 1975; Tasić 1975).

Jeremić (1963, 1963a) investigated the alteration processes of quartzporphyric rocks from Mračaj in central Bosnia, associated with hydrothermal occurences of barite. Quartztrachyte alterations were mentioned by Walther (1887).

Maksimović and Crnković (1968) determined Cr-bearing kaolinite at Slatina

(near Teslić in the BSZ). Results of the quantitative chemical analysis are given in table 46. The analysis was done by B. Crnković.

Table 46. Quantitative chemical analysis of Cr-kaolinite from Slatina (Teslić)SiO2 46.10 Si 4.02TiO2 0.56 Al 3.78Al2O3 36.85 Cr 0.12Cr2O3 1.72 Ti 0.04Fe2O3 0.28 Fe3+ 0-02MgO 0.48 Mg 0.06CaO 0.32 Ca 0.02Na2O 0.03 Na --H2O

+ 13.42 OH 7.80H2O

- 0.42Total 100.18

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According to Maksimović and Crnković (1968), the chromium-bearing kaolinite formed as a result of hydrothermal alteration of ultrabasic rocks.

A limited amount of information on kaolinite and feldspar alterations can be found in the following publications: Đorđević and Mijatović (1966) – in oligoclase veins near Zavidovići; Podubsky (1955) – from Ljeskovica, between Zavidovići and Žepče; Ristić et al. (1968) – in sediments of the Tuzla basin; Šibenik-Studen and Trubelja (1967) – in igneous rock from the Vrbas river valley; Trubelja and Pamić (1956, 1965) – in dacites from Maglaj; Varićak (1956) – in quartzporhyric rocks from Mt. Prosara. Pavlović et al. (1970) identified kaolinite in the small fraction of the quartz sand in the Tuzla basin. Kaolinite was determined using thermal analysis and XRD.

Use: Kaolinite is one of the most common and ubiquitous clay minerals. It has important industrial applications. The technical term ‘kaoline’ refers to an impure clay material which contains kaolinite as the dominant mineral. Depending on the content of impurities, kaoline is used in its natural form or purified by washing or some other separation and enrichment process. The most important and at the same time the earliest use of kaoline is in the production of ceramics and porcelain. Important in this respect are the plastic properties of kaolinite, and its transformation into a solid and firm material upon heating (ceramics). It is interesting to note the specific properties of kaolinite at different temperatures:

100-150°C loss of pore water, including adsorbed water200-300°C oxidation of organic impurities400-600°C loss of structural OH groups600-950°C loss of CO2 from carbonate-type impurities (carbonate minerals)950-1200°C formation of cristobalite1650-1775°C melting commences – lower melting temperatures may be attained

due to impurities (iron, alkalies, alkaline earths)

Kaolinite is frequently used as a ‘filling’ material in the manufacture of paper. Some typers of paper contain as much as 40% kaolinite.

Kaolinite is mined in Bosnia and Hercegovina at Bratunac and at Mt. Motajica near Bosanski Kobaš. Čičić (1975, p. 41) maintains that the available reserves of kaolinite at both of these localities are around 16 million tons. The kaolinite from Bratunac is mainly used in the production of ceramic tiles.

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DICKITEAl2 [Si2O5] (OH)4

There is very little information on the occurences of dickite in Bosnia and Hercegovina. It has been determined by powder x-ray diffraction in altered (kaolinzed) sanidine dacites near Bratunac and Srebrenica (Trubelja 1971a and 1972). This dickite is of hydrothermal origin.

Pavlović et al. (1976) have identified dickite in the bluish-white matrix of oolitic bauxites of Vlasenica (localities Palež and Krunići).

NACRITEAl2 [Si2O5] (OH)4

As for dickite, data on the occurence of nacrite in Bosnia and Hercegovina are very scarce. Mudrinić and Janjić (1969) are the only authors to mention nacrite in the Vlasenica bauxites in eastern Bosnia, but no further details about this mineral are given.

CHRYSOCOLLA(Cu,Al)2 H2[Si2O5] (OH)4 x nH2O

Chrysocolla is monoclinic with a poorly ordered structure (metacolloidal). Aluminium and iron (III) can substite copper in the lattice, so different formulae can be associated with chrysocolla

(Cu2-xAlx) H2-x[Si2O5] (OH)4 x nH2O

Complete Al substitution results in the formation of halloysite or kaolinite. The name of this mineral dates back to antiquity. It has been used by Teophrastus (ca. 370-285 BC) in his volume Peri Lithon (On stones). The name contains the words chrysos (gold) and colla (glue) since it was used as a soldering material. It is possible that malachite was also known under the name of chrysocolla.

Jurković (1958, p. 230 and 236) idenitifed the mineral in the Trošnik ore body near Fojnica, in associateion with malachite, azurite and limonite. In pure form, chrysocolla is of a darkbrown colour and has a Mohs hardness of 3-4. Associated with limonite it attains a dark-greenish colour. Chemical analysis of this chrysocolla yielded following results: SiO2 = 32.65; Al2O3 = 0.20; Fe2O3 = 3.81; CuO = 42.91; loss-on-ignition = 20.31; MnO – traces; CaO – traces, amounting to a total of 99.98.

The calculated molar ratios of SiO2 : CuO : H2O = 0.54360 : 0.53929 : 1.12834 indicates an iron-containing chrysocolla with traces of manganese impurities. These

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impurities seem to give the characteristic darkbrown and darkgreen colouration to the chrysocolla from Trošnik, this being a secondary mineral within the mentioned ore-body.

According to Đurić and Kubat (1962) chrysocolla occurs in association with copper mineralizations at Mt. Čavka (in the creeks Velika Borovica and Bijelina, and on the flanks of Klis and Otpočivaljka. Chrysocolla occurs here mainly associated with malachite. Kubat (1964) refers to chrysocolla as a typical secondary weathering mineral in the oxidation zone of the ‘Borovica’ mineralization in the central part of the Velika Borovica creek, some 2 km upstream from its confluence with the Velika Ukrina river. Kubat (1964) maintains that the chrysocolla is a product of chalcopyrite weathering in the presence of silica. It has a gel-like texture witha greasy lustre. One other publication by Kubat (1969) mentions chrysocolla in mineralizations around the village of Krnjići, some 15 km south-east of Srebrenica.

When chrysocolla occurs in substantial amounts, it can be used as a copper ore. Such deposits are not known to exist in Bosnia and Hercegovina.

SERPENTINE GROUPMg3 [Si2O5] (OH)4

The serpentine group of minerals comprises several minerals with the same formula Mg3 [Si2O5] (OH)4. The minerals antigorite (clino-antigorite and orho-antigorite), lizardite, chrysotile all belong to this group of minerals. A detialed classification of this group hase been made possible by the application of modern methods of x-ray diffraction analysis, thermal methods and IR-spectroscopy. The minerals antigorite, lizardite, chrysotile, clinochrysotile and garnierite are mentioned in this text.

X-ray data:Antigorite d 3.60 (100) 7.19 (95) 2.527 (30) 2.42 (15) 4.59 (10)Lizardite d 3.63 (100) 7.19 (95) 2.49 (70) 2.45 (60) 4.53 (45)Clinochrysotile d 3.66 (100) 7.25 (85) 2.44 (65) 2.48 (40) 4.57 (25)

IR-spectrum: Antigorite 410 442 585 615 850 1640 cm-1

Chrysotile 411 435 480 545 607 1045 1078 1635 3440 3640 3682 cm-1

A u t h o r s: Čičić (1975a), Džepina (1970), Đorđević (1958), Đorđević (1969a), Đorđević, Buzaljko and Mijatović (1968), Đurić (1968), Golub (1961), Hauer (1884), Ilić (1954), Ilić Miloje (1971), John (1879), Karamata and Petković (1957), Katzer (1924, 1926), Kišpatić (1897, 1900, 1904, 1910), Koch (1908), Majer (1962), Majer and Jurković (1957, 1958), Maksimović and Antić (1962), Marković and Takač

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(1958), Marić (1927, 1969), Mitrović (1955), Mojsisovics, Tietze and Bittner (1880), Pamić (1960a, 1963a, 1969a, 1970, 1972, 1973, 1974), Pamić and Antić (1968), 1974), Pamić and Kapeler (1970), Pamić and Olujić (1974), Pilar (1882), Primics (1881), Radimsky (1889), Ristić, Pamić, Mudrinić and Likić (1967), Schiller (1905), Sijarić and Šćavničar (1972), Stevanović (1903), Sunarić and Olujić (1968), Šćavničar (1965), Šćavničar and Trubelja (1969), Šibenik-Studen (1972/73), Trubelja (1957, 1960, 1961, 1962), Trubelja and Pamić (1965), Tscherne (1892), Tućan (1930, 1957), Vakanjac (1964, 1965, 1967 and 1968/69), Varićak (1966), Walter (1887).

The minerals of the serpentine group belong to the most ubiquitous and wide-spread minerals in Bosnia and Hercegovina. Together with olivine and pyroxenes, the serpentine minerals are the building blocks of serpentinized peridotites – rocks which occur widely within the inner Dinarides in Bosnia. These peridotites and other basic volcanic rocks are spread over an area of more than 2000 sq. km, forming the ‘Bosnian serpentine zone’ (BSZ). This name was given to this formation by Kišpatić (1897, 1900). Many mountain-massifs or parts thereof in Bosnia and Hercegovina are built by these rocks (Mts. Pastirevo, Kozara, Borja, Ljubić, Ozren, Konjuh and the western flanks of Mt. Zlatibor close to Višegrad).

Several older publications dealing mostly with the geology of Bosnia and Hercegovina use the term ‘serpentine’ for these rocks, in fact referring to ultrabasic rocks.

In terms of origin, the serpentine minerals are mostly secondary minerals, formed by weathering processes and alteration of olivine and pyroxenes. The amount of serpentine minerals in these rocks clearly reflects the degree of alteration of the original rocks. Unaltered pyroxenites contain only minor amounts of serpentine minerals. On the other end, serpentinites are largely monomineralic rocks built almost entirely of serpentine minerals.

In ultrabasic rocks the serpentine minerals are contained in veins of various thicknesses, resulting often in fibrous aggregates (serpentine asbestos).

Information on serpentine minerals in rock of the BSZ can be found in numerous publications, both old and recent ones.


Data on serpentine minerals derived from microscopic determinations of these minerals can be retrieved from numerous literature sources (Hauer 1884; John 1879; Mojsisovics et al. 1880; Pilar 1882; Primics 1881; Schiller 1905; Tscherne 1892; Walter 1887). Among these early authors, John was the most prominent author with respect to microscopic investigations.

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In his classic publication under the title „The crystalline rocks of the Bosnian serpentine zone“ Kišpatić (1897, 1900) provides data on numerous microscopic determinations of serpentine minerals in lherzolite rocks, from Bosanski Novi in the north-west to Višegrad in the south-east. This author found that most of the serpentine minerals are alteration products of olivine and rhombic pyroxenes, less often of monoclinic pyroxenes.

The gabbroid rocks of Mt. Kozara carry serpentine minerals in outcrops found around the Bistrica river and Benkovačko jezero (Benkovac lake). The peridoitets from this are contains serpetine which formed by alteration of olivine (Ljučica creek) or olivine and rhombic pyroxene (Kozarac, Benkovačka kosa). Serpentine mienrals can also be found in ultrabasic and basic rocks of Mts. Prisjeka, Skatovica, Uzlomac and Borja.

In a south-east direction, the BSZ rocks (gabbros and peridotites) carry serpentine minerals (i.e. Mts. Ljubić, Ozren, Mahnača and Krivaja). Serpentine containing rocks are also found in the very south-east part of the BSZ, in the area of the township of Višegrad.

Substantial information on serpentine minerals and serpentinization process of rocks around Višegrad can be found in publications by Trubelja (1957, 1960).Serpentine minerals are secondary minerals in harzburgites (Dobrun, Bosanska Jagodina), feldspar-peridotites (Bosanska Jagodina), troctolites (Gornji Dubovik), olivine gabbros (Mirilovići, Velika Gostilja, Banja creek). All mentioned rocks contain serpentine minerals in the form of veinlets forming fine networks. Relicts of olivine crystals can sometimes be observed in thin section. Sometimes the alteration of olivine to serpentine is accompanied with prehnitization of alkaline feldspars in troctolites. In troctolites therefore, a more advanced serpentinization means a more advanced prehnitization. This implies that the alteration of olivine to serpentine is a postmagmatic process. All rocks around Višegrad contain a fibrous variety of serpentine.

A coarse, fibrous variety of serpentine (with almost acicular texture) occurs at the contact of gabbro and peridotite rock in the quarry on the left bank of the Rzav river, close to Bosanska Jagodina. The occurence is a vein with serpentine ‘crystals’ positioned perpendicularly to the rims of the vein. This occurence is considered to be of hydrothermal origin, and we would like to point out that such coarse fibrous aggregates of serpentine minerals seem to be rather common in rocks of the BSZ. Results of chemical analysis of the serpentine from Bosanska Jagodina (Trubelja 1960) are given in table 47 (sample 1).

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SILICATES

Table 47. Chemical composition of serpentine (analysis by F. Trubelja)Sample 1

Bosanska JagodinaSample 2Mt.Ozren

SiO2 41.81 40.46TiO2 --- tracesAl2O3 1.38 2.36Fe2O3 1.66 3.10FeO 1.38 1.17MnO 0.06 0.05MgO 40.08 38.74CaO --- racesH2O

+ 12.73 12.80H2O

- 0.90 1.35Total 100.00 100.03

Some coarse fibrous serpentine (forming veins) was found on the northern flanks of Mt. Ozren, close to the village of Kakmuž (Trubelja and Pamić 1965). This serpentine is macroscopically and microscopically very similar to the one found at Bosanska Jagodina. The chemical composition (sample 2, table 47) is also very similar.

The magnesite bearing complex of Miljevica, located near Kladanj and Mt. Konjuh, is closely associated with peridotite-serpentine rocks. Here we will present the results of our detailed investigations of serpentine rocks. The investigations mainly focused on the identification and determination of discrete serpentine minerals with different crystal structures. Mineralogical determinations on serpentine rock samples from the Miljevica area were done by Sijarić and Šćavničar (1972). These data are an important contribution to the understanding of polimineral aggregates found in the investigated rocks, as opposed to the largely monomineralic serpentine asbestos found at Bosansko Petrovo Selo.

The determinations were done by powder x-ray diffraction analysis and thermal methods. Chemical analyses of macroscopically pure serpentine samples were also done. Based on the mentioned determinative methods, the following serpentine minerals were identified in the rocks from the Miljevica area: clinochrysotile, lizardite and antigorite. These minerals were found to have a zonal distribution on both sides of the magnesite veins. Samples taken 6-7 meters away from the vein contain all three mentioned minerals, while more distant samples contain clinochrysotile and lizardite only. Lizardite is the dominant serpentine mineral in samples taken close to the magnesite vein. This zonar arrangement of the serpentine minerls around the vein is certainly the results of hydrothermal activity which caused the inituial deposition of the serpentine minerals in veins within ultrabasic rocks. Hence, the origin of the serpentine minerals in the miljevica area is probably hydrothermal also.

Unit cell dimensions of discrete serpentine minerals were determined from powder XRD data. The data obtained is in good agreement with literature data on clinochrysotile (Brown 1961) and lizardite (Rucklidge and Zussman 1965).

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Clinochrysotilesample P 4.5z sample K 8.0z Reference

a0 5.33 Å 5.31 Å 5.32 Åb0 9.22 Å 9.22 Å 9.20 Åc0 14.70 Å 14.62 Å 14.64 Åβ 92° 18’ 93° 21’ 93° 20’

Lizardite

sample K 0.5p Referencea0 5.31 Å 5.31 Åb0 9.22 Å 9.20 Åc0 7.30 Å 7.31 Å

Data obtained by thermal analysis is given in table 48. Powder XRD data

indicated that the samples are different with respect to clinozoisite and lizardite content, this information could not be obtained by thermal analysis.

Table 48. Thermal analysis dataSample Endothermic peak (min.) °C Exothermic peak (max.) °C

K 15.0 c 668 805K 15.0 z 688 820K 8.0 c 672 820K 8.0 z 700 820K 6.0 c 680 (750) 810K 6.0 z 675 (770) 810K 2.6 u 665 (625) 810K 0.5 u 670 785P 6.5 c 680 812P 6.5 z 700 812P 9.5 690 805P 17.0 c 690 812P 17.0 z 670 812

All samples showed almost identical behaviour upon heating, and small variations in the peak positions do not neccesarily reflect variations in composition, since they can be associated with experimental conditions. Also, dehydroxylation and recrystallization reactions of clinochrysotile and lizardite occur within similar temperature ranges. The endothermic temperatures in the brackets (table 48) refer to carbonate dissociation (750 and 770°C) and dehydroxylation of chlorite (625°C).

In addition to serpentine minerals, the investigated rock samples also contain olivine, enstatite, diopside, amphibole, dolomite, magnesite, chromite, goethite and chlorite.

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SILICATES

The occurences of serpentine asebestos around Bosansko Petrovo Selo have been imvestigated in detail (Ilić 1954; Mitrović 1955; Karamata and Petković 1957; Vakanjac 1964, 1965, 1967 and 1969; Šćavničar 1965; Đorđević et al. 1968). The investigations by S. Šćavničar are important as they provide the first characterization of discrete serpentine minerals.

Ilić (1954) provides a short description of the occurence of serpentine asbestos around Bosansko Petrovo Selo, and considers briefly their origin. The occurences can mainly be found in the watershed area of the Jadrina river, at Delić Brdo, Senikovište, Krajnje Njive, Studen Potok etc. The asbestos occurs here within peridotites and serpentinized peridotites.

The acidic effusive rocks (rhyolite) in the area of Bosansko Petrovo Selo are genetically associated with the serpentine rock formations. The hydrothermal processes linked with the rhyolite complex have influenced the formation of serpentine minerals and asbestos in this area (Ilić 1954, Vakanjac 1964).

Šćavničar (1965) made a detailed investigation of four samples from the Bosansko Petrovo Selo occurence, using microscopy, powder XRD, thermal methods and chemical analysis. Two of the analysed samples are dense, massive, green aggregates of clinochrysotile and lizardite (in different proportions).

Table 49. Powder x-ray diffraction data for serpentine from Bosansko Petrovo Selo (Šćavničar 1965)

Sample # 1 Sample # 2 Sample # 3hkl d(Å) I d(Å) I d(Å) I002 7.30 100 7.27 100 7.28 100

4.56 4.56020 22 18

4.52 4.52 4.47 8b4.40 5 4.41 34.24 7 4.23 44.08 5 4.08 43.89 5 3.89 3

004 3.64 77 3.64 70 3.64 85024 2.87 3 2.87 3130 2.66 5 2.6 5201* 2.58 11b 2.58 5202 2.54 11 2.54 7202* 2.500 38 2.495 6202** 2.450 29 2.449 32 2.449 29006 2.420 11203** 2.333 6203* 2.273 3 2.271 5b 2.272 5204* 2.214 3204** 2.146 8b204 2.087 9 2.087 11 2.094 7

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205 1.964 9008 1.823 4b206* 1.737 6 1.738 9 1.740 6060 1.537 22 1.536 20 1.534 25208** 1.502 8 1.505 50, 0, 10 1.465 5064 1.414 3 1.416 4

Sample 1 – lizardite and clinochrysotileSample 2 – clinochrysotile with lizarditeSample 3 – clinochrysotile asbestos* refers to β = 90°** refers to β = 93° 16’

The third sample has a typical asbestos texture, of tough fibres between 0.2 and 0.8 mm in length. This sample is almost pure chrysotile. The refraction indices were measured by the immersion method (1.542-1.552). The fourth sample is a white aggregate with a fibrous texture, containing rather thick, pliable fibres more than 5 cm long. This sample is a mixture of antigorite and dolomite. Refractive indices are 1.563-1.570.

Table 50. Unit cell parameters for serpentine from Bosansko Petrovo SeloSample # a0 Å b0 Å c0 Å β1 5.31 9.22 14.58 93° 16’2 5.31 9.22 14.58 93° 16’3 5.31 9.02 14.58 93° 16’ClinochrysotileWhittaker and Zussman 1956

5.34 9.2 14.65 93° 16’

Sample 1 – lizardite and clinochrysotileSample 2 – clinochrysotile with lizarditeSample 3 – clinochrysotile asbestos

Data on x-ray structural analysis are given in tables 49 and 50. Table 51 contains data on the thermal analysis of the four samples.

Table 51. Thermal analysis of serpentine from Bosansko Petrovo Selo (Šćavničar 1965)Sample Endothermic peak °C Exothermic peak °C

Characteristic temp. Peak temperature Characteristic temp.

Peak temperature B

1 608 708 766 7802 607 714 770 7863 622 700 771 7874 613 810 760 776

Sample 1 – lizardite and clinochrysotileSample 2 – clinochrysotile with lizardite

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Sample 3 – clinochrysotile asbestosSample 4 – fibrous antigorite

Chemical analyses of two serpentine samples are given in table 52. The analyes were done by Ms. Dragica Sarvan.

Table 52. Chemical analysis of serpentine from Bosansko Petrovo Selo (Šćavničar 1965)

Sample 1 Sample 2SiO2 41.15 38.91Al2O3 1.44 2.34Fe2O3 3.14 4.27FeO 0.36 0.50NiO 0.07 0.10MnO --- 0.04MgO 40.41 39.93H2O

+ 13.16 13.39H2O

- 0.59 0.41Total 100.32 99.89

The structural formulae of the two serpentine sample, based on results of chemical analysis are as follows (based on 18 (O, OH) ions:

Sample 1.O6.072Si3.839Al0.081Fe3+

0.109(H4)0.067O2.024+1.981(OH)1.981(Mg5.624Fe2+0.029Ni0.005Fe3+

0.109Al0.081)- (OH)5.942

Sample 2.O5.924Si3.695Al0.132Fe3+

0.151(H4)0.078O1.975+2.020(OH)2.020- (Mg5.594Fe2+

0.039Ni0.007 Mn0.003Fe3+0.151Al0.132)(OH)6.061

In these structural formulae the iron (III) and aluminium contents have been distributed between their tetrahedral and octahedral coordination sites.

DTA curves of the serpentine samples are shown in Figure 15. The curves are obviously quite similar, implying that identification of discrete serpentine minerals, based solely on thermal analysis, is not possible.

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Figure 15. DTA curves of serpentine from Bosansko Petrovo Selo (Šćavničar 1965)

Đorđević et al. (1968) also provide data on the determination of serpentine asbestos from Bosansko Petrovo Selo, with special emphasis on the Jovanovići – Stepanovići locality. Based on powder XRD, the authors conclude that this serpentine probably belongs to the clinochrysotile variety. Their paper contains 2 chemical analyses: a pure chrysotile asbestos, and a serpentinite. At Jovanovići – Stepanovići the asbestos fibres are usually 1-4 mm long. Rarely their length is up to 12 cm.

These authors also provide an account on other serpentine occurences in Bosnia and Hercegovina. The occurence at Grudići (Olovo) is in the immediate vicinity of the Petrovići train station, located on the narrow-gauge railway line Zavidovići – Han Pijesak. Further occurences have been identified near Zavidovići (at Turčinovići), near Žepče – at the well-known Ruda – Vis locality, some 10 km northwest of Žepče.

Occurences of serpentine asbestos can further be observed in the Banja Luka area (at Čelinac and Bregovi).

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The nickel-bearing serpentine from Duboštica has been described in older literature under the name nickel-gimnite (Hauer 1884). It forms thin green crusts over chromite. According to Hauer, nickel was determined in this mineral by C. John (1879). The name gimnite has been discredited as a mineral name, and is occasionally used to describe a nickel-enriched variety of antigorite.

Đurić (1968) provides data on the cinnabarite mineralization at Mt. Ljubić, and mentions garnierite as a constituent of the green serpentine altered to listvenite. The author gives no further information on this mineral.

Some general information on serpentine minerals in Bosnia and Hercegovina can be found in more recent literature, but none of these publications provide details about individual minerals of the serpentine group.

2. Schist mountains of central Bosnia

The occurence of serpentine within the Palaeozoic-age phyllites near the village of Kupres at Busovača presents somewhat of a geological curiosity. The serpentine occurs in close association with a flaky aggregate of talc (Šćavničar and Trubelja 1969). The talc-chlorite-serpentine vein is shown in Figure 15. The authors have shown that the core of the vein consists of talc surrounded by a layer of cryptocrystalline antigorite. Antigorite was determined by powder XRD, thermal analysis and quantitative chemical analysis. The powder x-ray diffraction data are given in table 53. The three strong diffraction peaks at 7.184, 3.599 and 2.522 Å, as well as the less intense 1.5645 Å signal probably indicate the presence of antigorite. However, we wish to point out that our x-ray diffraction pattern does not correspond exactly to literature data for antigorite (some of the weaker lines characteristic for antigorite did not appear on film even after long exposure times). Therefore, the calculation of the unit cell dimensions (using β = 91.6°) is based only on the strongest diffraction signals, and should be treated as moderately precise only. The thermal analysis data correspond to serpentine minerals.

Chemical analysis of antigorite from Kupres yielded following results:SiO2 = 42.31; TiO2 = traces; Al2O3 = 2.32; Fe2O3 = 5.20; FeO = 2.67; MnO = 0.08; MgO = 35.34; CaO = 0.46; Na2O = 0.36; H2O

+ = 10.89; H2O- = 0.43; P2O5 = 0.01;

Total = 100.31

The structural formula, based on 9 (O,OH) ions is:(Ca0.024Na0.022K0.022)(Mg2.537Fe2+

0.108Fe3+0.188Al0.132Mn0.003)

VI(Si2.039)IVO5.500(OH)3.500

The structural formula is based on the overall chemical analysis, including impurities which could not be excluded from the sample. Therefore, it corresponds

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only to some extent to serpentine. All these data corroborate our finding that the zonal buildup of the described serpentine vein at Kupres is the result of hydrothermal process which occured over several phases. A largely monomineralic species (depending on the composition and temperature of hydrothermal solutions) was deposited in each of these phases. Chlorite was deposited first, followed by antigorite and – finally – the flaky talc aggregate.

Kišpatić (1910) and Majer and Jurković (1957 and 1958) determined serpentine in the olivine gabbros south of Travnik (the Bijela Gromila complex).

Table 53. Powder x-ray diffraction data of serpentine from Kupres (Šćavničar and Trubelja 1969)Nr. hkl d (Å) I1 9.300 2.52 001 7.188 303 6.228 14 5.191 15 020 4.589 66 4.183 3.57 002 3.599 198 3.448 0.59 3.326 0.510 3.100 211 2.655 0.512 2.585 113 16, 0, 1 2.522 2314 2.50 – 2.39 2d15 2.214 116 16, 0, 2 2.155 617 2.101 118 1.835 119 1.804 120 1.780 221 1.725 1b22 1.588 0.523 24, 3, 0 1.5645 724 060 1.5395 725 1.5225 226 061 1.5050 327 1.4754 0.528 1.4407 129 1.4162 130 1.3804 0.531 1.3403 0.532 1.3159 533 1.2981 1.534 1.2660 1

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35 1.2041 136 1.0152 137 1.0006 138 0.9744 139 0.9506 140 0.8965 1

b = broadening of lined = diffuse line

3. Other occurences of serpentine

Marić (1927) microscopically determined serpentine in some gabbro rock varieties around Jablanica. Pamić (1963a) mentions serpentine rocks in the river Rama region in Hercegovina. Katzer (1924, 1926) was the first author to mention serpentine at Mt. Motajica. Varićak (1966) microscopically identified serpentine (antigorite and chrysotile) in rocks in the Osovica river valley.

4. Origin of serpentine

We have already touched upon the origin of serpentine minerals in Bosnia and Hercegovina. In those case where serpentine minerals occur in the form of vein fills within tectonically fractured ultrabasic rocks, we believe that their origin is hydrothermal. This is particularly true for the area of Bosansko Petrovo Selo on the eastern flanks of Mt. Ozren where economically elevant asbestos deposits were formed. The same is true for the serpentines associated with Miljevica magnesite deposits at Mt. Konjuh where hydrothermal process caused both serpentinization and the deposition of magnesite. With respect to the origin of these hydrothermal solutions, we believe that they have been released in the late, mostly acid-to-neutral magmatic events, since evidence of similar processes can also be observed elsewhere in Bosnia and Hercegovina, especially within the Bosnian serpentine zone (BSZ). However, also other processes leading to serpentinization have been observed or inferred, particularly in ultrabasic and basic rock types. One such case is autometamorphosis where the alteration of olivine and pyroxene is caused by water originating in magmatic processes which have caused a more or less contemporal crystallization of the ultrabasic rock itself. We agree with those authors which have investigated such processes in the BSZ that at least some of the serpentine may have originated through autometamorphism.

Use: the numerous industrial and commercial applications of serpentine minerals involve mainly the chrysotile and chrysotile-asbestos variety. More than 90% of asbestos products are based on serpentine minerals, while amphibole asbestos varietes (tremolite-actinolite, crocidolite) account for less than 10%. The

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asbestos cement industry is singled out as by far the largest current global user of chrysotile fibres. Main applications include the production of corrugated sheets, flat sheets and building boards, slates, moulded goods, including low-pressure pipes, and high-pressure water pipes. Chrysotile is also used, in much smaller quantities, in the manufacturing of friction products, gaskets, and asbestos paper. Serpentine rock is often used as dimension rock and for ornamental purposes. Gernierite deposits can be an important source of nickel.Čičić (1975a) estimates that the reserves of „asbestos ore“ at Delić Brdo near Bosansko Petrovo Selo amount to 116 milion tons.Recent research has indicated the hazards for the environment and human health associated with the use of asbestos and asbestos products, including exposure of humans to chrysotile asbestos. It is the recommendation of several international organizations to discontinue the use of crocidolite asbestos.

HALLOYSITE – (METAHALLOYSITE)Al2 [Si2O5] (OH)4

Crystal system and class: Monolinic, domatic class.Cell parameters: ao = 5.15, bo = 8.9, co = 7.9-7.5 X-ray data: d 7.41 (60) 4.432 (100) 1.484 (50)

Synonyms: (note added in translation) – according to newer classifications of the kaolinite-serpentine group of minerals, as adopted by the benchmark publication Fleischer’s Glossary of Mineral Species (Mandarino and Back, 2004), the use of the name metahalloysite has been discontinued. Metahalloysite is nowadays described as halloysite – (7Å), and may also be understood in terms of a dehydrated halloysite – (10Å). In this section of the book, the name metahalloysite has been changed to halloysite, and pertains to halloysite – (7Å).

A u t h o r s: Dangić (1971), Podubsky (1955), Stangačilović (1956a), Šćavničar, Trubelja and Sijarić-Pleho (1968)

There is not much information available on the occurences of halloysite in Bosnia and Hercegovina. It occurs in halloysite-schists at the locality of Bakija. It is also a constituent of Tertiary-age clays from Kobiljača in the Sarajevo basin. Some occurences associated with the bauxite deposits in Hercegovina have been observed.

1. Halloysite-bearing schists in south-eastern Bosnia

Podubsky (1955) determined halloysite-bearing schists near the village of Bakije, in Paleozoic-age formations near Goražde in south-eastern Bosnia. This is in fact the first information about this mineral in Bosnia and Hercegovina. The mineral

238

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was identified by powder XRD. It is associated with quartz, sericite, muscovite and siderite. The paper by Podubsky also contains two DTA curves. Unfortunately, the material used for thermal analysis was previously dried at elevated temperatures, so the DTA curves cannot be used for halloysite determination.

Dangić (1971) suspects the presence of halloysite in the kaolinite deposit at Bratunac near Srebrenica, but was unable to provide conclusive evidence.

2. The Kobiljača occurence near Sarajevo

Stangačilović (1956a) investigated the Tertiary-age clays at Kobiljača near Sarajevo and identified halloysite as a constituent mineral, second in importance only to illite. The determination is based on thermogravimetric measurements, differential-thermal analysis and powder x-ray diffraction. The DTA curves of two samples of illite-halloysite clays feature two prominent endothermic peaks in the 130-150°C temperature interval. These peaks are associated with the loss of interstitial water from the halloysite structure – an effect which has not been observed in the case of illite.

The powder XRD pattern was important for the identification and characterization of halloysite, illite and quartz. The lines corresponding to d values of 7.22 Å and 7.41 Å are specific for hallyosite only (not for illite or quartz).

3. Occurence of halloysite in bauxites from Hercegovina

Šćavničar et al. (1968) used the powder x-ray diffraction method to determine hallyosite in some hercegovinian bauxites – i.e. the boehmite-gibbsite bauxites from Nevesinje; localities Zamršten – Zubača and Mukinja). A further occurence is in the bauxites from Mratnjača in western Hercegovina.

SEPIOLITEMg4 [Si6O15] (OH)2 x 6H2O

Crystal system and class: Orthorhombic, dipyramidal class.Cell parameters: ao = 5.28, bo = 26.8, co = 13.4 Z = 2Properties: earthy to cryptocrystalline texture, white, yellowish or gray in colour. Hardness is 2.0-2.5, the specific gravity = 2. Sepiolite is usually very porous and normally floats on water. X-ray data: see textIR-spectrum: 443 475 500 535 600 640 782 850 890 985 1025 1972 1200

1635 1660 3440 3570 3600 cm-1

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A u t h o r s: Golub (1961), Hantken (1867), Katzer (1909, 1912), Kišpatić (1893, 1895, 1897, 1900), Miladinović (1969), Mojsisovics, Tietze and Bittner (1880), Panić and Ristić (1972), Pavlović (1891), Pilar (1882), Potier (1879), Radimsky (1889), Ristić, Panić and Janjić (1965), Stevanović (1903), Trubelja (1971a), Tscherne (1892), Tućan (1930, 1947, 1957), Walter (1887).

Sepiolite is a comparatively rare mineral in Bosnia and Hercegovina. Only two occurences have been described in the literature. One occurence, discovered more than a century ago, is in the vicinity of Prnjavor at Mt. Ljubić. The occurence, at Miljevica on Mt. Konjuh was discovered only recently. Some sepiolite was also found at Mt. Kozara and near Srebrenica (Bratunac).

1. Sepiolite from Mt. Ljubić

Hantken (1867) provides first data on the sepiolite occurence on the northern flanks of Mt. Ljubić, within serpentinized peridotites near the town of Prnjavor. This sepiolite has been mined for more than hundred years, at Kremna, Branešci and Reljevac. At Branešci, the sepiolite is associated with conglomerates containing serpentine. At Kremna, sepiolite is found together with magnesite veins (the magnesite is sometimes silified).

Several papers dealing with sepiolite occurences near Prnjavor have been published at the beginning of this century, mainly by foreign investigators (Walter 1887 and others). This is an indication that these authors had substantial interest in this comparatively rare mineral, possibly due to its use for the manufacture of smoking pipes. It is interesting to note that these authors considered the material to be magnesite, although they did use the term „bosnian sepiolite“. This situation motivated Kišpatić (1893, p. 99) to comment with some humor that „they were inclined to delete sepiolite from the list of bosnian ore materials“.

Radimsky (1889) provides some data for the sepiolite from Mt. Ljubić, and notes several properties of this material. He thus notes that sepiolite produces a sticky sensation on the tongue, that it readily absorbs water and has a variable density between 0.47 and 0.95 and variable hardness (between 1 and 2.5). It dissolves in acid, releasing gelatinous silicic acid. When wet, sepiolite is easily cut with a knife.

Tscherne (1892) provides some relevant data for the sepiolite from Mt. Ljubić. His paper contains some microscopic measurements and results of several chemical analyses (either of pure sepiolite or a mixture of sepiolite and magnesite, including some impurities). Table 54 contains results of 3 analyses of sepiolite material.

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Table 54. Chemical composition od sepiolite from Mt. LjubićSample 1 Sample 2 Sample 3

CO2 2.30 26.42 ---Loss on ignition 16.96 7.61 11.38Humidity --- --- 9.11Free SiO2 4.42 --- ---Bound SiO2 46.20 30.47 47.23MgO 23.90 34.53 24.55FeO (Fe2O3) 6.13 0.90 7.20Total 99.71 99.93 99.47

Kišpatić (1893, 1895, 1897, 1900) provides. among other data, the results of chemical analysis of a pure sepiolite (table 55, sample 1). Before analysis, this sample was dried at 110°C which caused all hygroscopic water to be released.

Katzer (1909) also gives results of the chemical analysis of one sepiolite sample from the Kremna locality (table 55, sample 2). His sample was also dried at 110°C.

Table 55. Chemical composition of sepiolite from Mt. Ljubić

Sample 1– Kišpatić Sample 2 – KatzerSiO2 61.09 57.80MgO 25.87 27.32Fe2O3 and Al2O3 2.59 3.12Loss on ignition and CO2 10.47 12.58Total 100.02 100.82

2. Sepiolite from Mt. Konjuh

Ristić et al. (1965), Panić and Ristić (1972), Miladinović (1969) and Živanović (1968) provide data on the occurence of sepiolite in magnesite veins at Miljevica and Zeničica (Mt. Konjuh). Here, sepiolite and magnesite occur together in peridotite rocks. The sepiolite has a banded texture, the bands being 5-20 cm thick and several meters long. Sepiolite also forms lenses or crusts over magnesite.

The sepiolite has a bluish-white or greyish-white colour, and displays a conchoidal fracture with a greasy to vitreous lustre. Sepiolite is normally very hygroscopic.

In thin section, the sepiolite has the appearance of bent, fibrous aggregates. The immersion method was applied to measure refractive indices:

Np = 1.517 ± 0.002 Ng = 1.527 ± 0.002 Ng – Np = 0.010

The results of chemical analysis of two samples of sepiolite from the Miljevica locality are given in Table 56. The results indicate that sepiolite regularly

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contains small amounts of carbon dioxide, caused by the presence of magnesite. DTA curves were characteristic for sepiolite. There is an endothermic peak in the 50-150°C temperature range, indicating loss of adsorbed and zeolite-type water. The second endothermic peak between 350 and 450°C pertains to loss of intra-crystalline water (water of crystallization). The endothermic effect between 700 and 830°C is associated with the loss of structurally bound water and the collapse of the sepiolite crystal structure.

Table 56. Chemical composition of sepiolite from Mt. KonjuhSample Miljevica 11 Sample Miljevica 7

SiO2 54.75 52.07Al2O3 0.51 0.36Fe2O3 0.26 0.18FeO --- ---MgO 24.28 26.86Na2O 0.07 0.05K2O 0.03 0.03CO2 0.33 0.85H2O

+ 9.87 9.50H2O

- 9.93 10.02Total 100.01 99.81

The cited authors believe that the genesis of sepiolite and magnesite in the Mt. Konjuh occurences are similar, both probably being of hydrothermal origin. Sepiolite was obviously deposited at low temperatures, during the epithermal or telethermal phases (possibly even at ambiental temperature).

3. Sepiolite in rocks from Mt. Kozara

Golub (1961) performed microscopic determinations of sepiolite in serpentines from the Lubina creek, and lherzolites of Vrelo creek. In the serpentine rock, the sepiolite very much resembles chrysotile, although it is optically uniaxial and negative. The refractive indices are lower than those of Canada balm. The sepiolite contained in the lherzolite rock has a fibrous texture or forms dense aggregates.

4. Other occurences of sepiolite

Trubelja (1971a) identified small amounts of sepiolite in kaolinized dacites from Bratunac, near Srebrenica. According to some early information provided by Potier (1879, p. 36), some sepiolite is apparently mined notheast of Banja Luka, also near Fojnica and Kreševo, but in minor quantities. The location of the Banja Luka occurence is not completely clear so we believe that this sepiolite is to be associated with the ones from Mt. Ljubić.

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Sepiolite is used commercially in the production of fire-resistant materials and in the manufacture of (smoking) pipes.

Table 57. Powder XRD data of sepiolite from Mt. KonjuhMiljevica 8 Miljevica 9 Zeničica 2 – north Zeničica 2 – south

d (Å) I d (Å) I d (Å) I d (Å) I7.50 3 7.46 1 7.57 3 7.63 1-2

12.28 10 12.03 9 12.20 10 12.12 75.05 1 5.09 14.58 5 4.53 1 4.53 4 4.55 14.29 8 4.25 7 4.33 7 4.31 33.75 5 3.74 1 3.77 4 3.74 23.36 9 3.35 10 3.37 2 3.35 1-23.15 3 3.17 1 3.16 1 3.19 1-2

2.579 8 2.56 2 2.573 8 2.567 1-22.456 6 2.456 4 2.456 3 2.411 12.264 7 2.276 4 2.276 2 2.278 22.075 3 2.066 1 2.073 2 2.072 1-21.868 1-2 1.891 1-2 1.849 1-21.701 4 1.728 5 1.709 2 1.701 91.586 1 1.595 21.543 5 1.543 6 1.563 2 1.566 11.517 3 1.520 1 1.518 3 1.513 41.416 1 1.419 1 1.422 1 1.417 11.378 6 1.373 4 1.392 11.299 4 1.292 2 1.303 3

PREHNITECa2AlVI

[Si3O10] (OH)2

Crystal system and class: Orthorhombic, pyramidal class.Lattice ratio: a : b : c = 0.8401 : 1 : 1.1536Cell parameters: ao = 4.61, bo = 5.47, co = 18.48 Z = 2Synonyms: information in the treatise by B. G. Sage (Elements de mineralogie docimastique, 2eme edition, Paris 1777, p. 232) indicates that the author refers to prehnite. Some years later, Rome de l’Isle (Cristallographie ou description des formes propres a tous le corps du regne mineral etc., 2, Paris 1783, p. 275) describes prehnite smples brought by the monk Rochon from the Cape of Good Hope (Africa). Material brought to Germany (also from the Cape of Good Hope) in 1783 by the Dutch Colonel Prehn was investigated by the mineralogist A. G. Werner who gave the new mineral the name prehnite. The name koupholite was used earlier for a variety of prehnite occuring in the micaschists from Adelsfors in Sweden. Other discredited names include jacksonite and chlorastolite.

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Properties: refractive indices are fairly high: Nz = 1.632-1.665, Ny = 1.615-1.642, Nx = 1.611-1.632. Birefringence Nz – Nx = 0.022-0.035. The optic axial angle +2V = 65-69°. Specific gravity is 2.90-2.95, hardness = 6-6.5. Good cleavage on {001}. Lustre is vitreous, sometimes pearly on (001). The colour varies from pale green to yellow, grey or white. Transparent in thin section. Optic anomalies are frequently observed – some samples show a wavy extinction and unusual interference colours. Prehnite has pyroelectric properties.

X-ray data: see textIR-spectrum: 426 475 530 640 675 745 815 868 940 990 1075 1090 1630 3475 3485 cm-1

A u t h o r s: Atanacković, Mudrenović and Gaković (1968), Brajdić (1964), Džepina (1970), Đorđević (1958), Đorđević and Mojičević (1972), Đorđević and Stojanović (1972, 1974), Đurić and Kubat (1962), Golub (1961), Karamata and Pamić (1964), Kubat (1964), Majer (1962), Marić (1927), Pamić (1960, 1960a, 1961a, 1961b, 1962, 1969, 1969a, 1971, 1972a, 1972d, 1973), Pamić and Kapeler (1970), Pamić and Papeš (1969), Pamić, Šćavničar and Medjimorec (1973), Pamić and Tojerkauf (1970), Petković (1962/62), Ristić, Panić, Mudrinić and Likić (1967), Šibenik-Studen and Trubelja (1971), Trubelja (1957, 1960, 1961, 1966a, 1971b, 1972, 1972/73, 1975), Trubelja and Miladinović (1969), Trubelja and Pamić (1957, 1965), Trubelja and Slišković (1967), Trubelja, Šibenik-Studen and Sijarić (1974, 1975, 1975a), Tućan (1957).

Prehnite is among the more commonly occuring minerals in Bosnia and Hercegovina. It is mostly associated with basic rocks of the Bosnian serpentine zone (BSZ) and the surrounding diabase-chert complex (troctolite, olivine gabbro, diabase, spilite). Prehnite also occurs in amphibolites, and occasionally in granitoid rocks.

Outside of the BSZ prehnite occurs within veins of the gabbros of Jablanica (Marić 1927), and on several other locations in Bosnia and Hercegovina. In the earlier days prehnite was mostly determined by microscopy. Today, modern methods of physico-chemical analysis, including infrared spectroscopy are used.

Occurences of prehnite have also been observed in basic rocks belonging to the Triassic-age magmatic events, since such rocks are widely distributed in the Dinarides of Bosnia and Hercegovina (Trubelja et al. 1975).

1. Prehnite in rocks of the Bosnian serpentine zone (BSZ)

Most determinations of prehnite pertain to basic (but also other) rocks of the Bosnian serpentine zone (BSZ). It occurs around Višegrad, at Mt. Konjuh and Mt. Ozren, in the region between the rivers Bosna and Vrbas, and at Mt. Kozara. Within these rock types prehnite is usually associated with zeolite minerals, forming vein-type parageneses.

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a) Višegrad and surroundings

Trubelja (1957, 1960, 1971b, 1972/73, 1975), Trubelja, Šibenik-Studen and Sijarić (1974, 1975, 1975a) provide more recent accounts on the occurence of prehnite in rocks of the Višegrad area, where prehnite is almost always present in basic magmatic rocks. It occurs in veinlets, either alone or associated with other postmagmatic vein-type minerals. Associations with zeolites are very common, and occasional pseudomorphoses of prehnite over alkaline palgioclase minerals have been determined.

The association of prehnite with alkaline plagioclases is particularly evident in the case of troctolites from Gornji Dubovik. Prehnite is deposited within fractured plagioclase crystals or forms intergrowths. Prehnite grains are usually small but some columnar textures have been observed (the prehnite crystals are elongated parallel to [010]). In thin section the prehnite displays parallel extinction. Birefringence is high, the interference colours vivid. The optic axial angle is +2V = 70°. Acicular and plumose prehnite growths have also been observed.

The prehnitization process of alkaline plagioclase minerals is associated with the alteration of olivine (serpentinization). Based on numerous microscopic measurements, Trubelja (1960) maintains that progressive alteration of basic feldspars i.e. prehnitization usually also means advanced serpentinization.

The troctolites from the village of Lahci (Banja creek valley) contain prehnite in association with zoisite, where both represent alteration prodcuts of plagioclase. Gabbro-pegmatites frequently contain hydrothermal prehnite, sometimes as pseudomorphoses over plagioclases. In such matrices the prehnite grains normally display distinct cleavage along (001). The optic axial angle +2V varies between 68.5° and 70°. In some rocks the 2V angle of prehnite grains can attain even larger values.

At Pavitine (Suha Gora) prehnite forms vein-type associations with hornblende, clinozoisite and chlorite. Altered diabases, outcropping on the road from Višegrad to Dobrun, carry completely altered plagioclases, together with the rare mineral xonotlite (Trubelja 1971b, 1972/73, 1975).

b) Mt. Konjuh

Trubelja (1961) made first determinations of prehnite in postmagmatic, hydrothermal vein-type associations within basic rocks of Mt. Konjuh. Prehnite occurences were found in the feldspar-carrying peridotites on the road between Olovo and Kladanj, in the olivine gabbros near the village of Bjeliš (Stupčanica

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creek) and in porphyrric diabases of Blizanci. Brajdić (1964) made microscopic measurements of prehnite in the gabbro-pegmatites from Bjeliš. Here prehnite is an accessory constituent of 1-2 mm thick veins.

Šibenik-Studen and Trubelja (1971) provide comparatively detailed determinations of prehnite occuring near Kovačići village on the eastern flanks of Mt. Konjuh. Prehnite is associated with thomsonite, in the form of white incrustations or veinlets within diabase-dolerites. These veinlets can be up to 1 cm thick.

A quantitative chemical analysis of prehnite from Kovačići yielded following results:SiO2 = 40.41; Al2O3 = 25.13; Fe2O3 = 1.87; FeO = 0.19; MnO = 0.02; MgO = traces; CaO = 27.69; Na2O = 0.28; H2O = 5.06Total = 100.65

The structural formula, based on 24 (O,OH) ions is:(Ca4.100Na0.083Al3.678Fe3+

0.199Fe2+0.025) (Al0.406Si5.594) O20 (OH)4.665

Trubelja et al. (1974, 1975, 1975a) determined several associations of vein-type minerals in rocks outcropping on the eastern and southeastern flanks of Mt. Konjuh, using powder x-ray diffraction, IR-spectroscopy, thermal and chemical analysis. Their findings complement earlier determinations of prehnite as a very common hydrothermal vein mineral in these rock types (particularly in outcrops on the Olovo – Kladanj road). Associations with laumontite, low-temperature albite, epidote, calcite, tremolite, chlorite and clinozoisite have been observed. Prehnite in rocks of the Mt. Konjuh – Krivaja complex is also mentioned in other publications, but their authors provide no further data on this mineral (Ristić et al. 1967).

Prehnite occurences were also identified in amphibolites of the Mt. Konjuh – Krivaja igneous-metamorphic complex (Pamić and Kapeler 1970; Pamić et al. 1973).

c) Mt. Ozren

Trubelja and Pamić (1965), Pamić (1973), Trubelja et al. (1974, 1975, 1975a) determined prehnite to be a common constituent of veins in basic igneous rocks (mainly diabases and spilites) of Mt. Ozren. Monomineralic veins carrying prehnite were found at Brezici, Gornji Rakovac, Donji Rakovac, Omrklica creek and on the road between Gornji Rakovac and Gornja Bukovica. Associations of prehnite and calcite, albite and chlorite were found at Jadrina creek and on the road between Gornji Rakovac and Gornja Bukovica (here, the paragenesis consists of prehnite, rhipidolite and datolite). The IR-spectra of some of these mineral associations are shown in Figure 16.

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Figure 16. IR-spectra of prehnite from Mt. Ozren (Trubelja et al. 1975a)1. prehnite with a small amount of calcite (Brezici)2. prehnite (Gornji Rakovac)3. prehnite with albite (Jadrina creek)4. prehnite with chlorite (road G. Rakovac – G. Bukovica)5. prehnite (Brezici)

Table 58. Powder XRD data for prehnite from Mt. Ozren (Gornji Rakovac) (Trubelja et al. 1975a)

No. d (Å) I No. d (Å) I1 5.2522 2 26 1.65564 32 4.6082 3 27 1.63453 23 4.1329 1 28 1.59562 14 3.5256 4 29 1.56502 15 3.4636 9 30 1.54225 46 3.2950 6 31 1.53252 37 3.2643 2 32 1.50069 28 3.0623 10 33 1.47834 19 2.8036 4 34 1.45517 110 2.7401 1 35 1.44147 311 2.6232 2 36 1.41389 112 2.5509 10 37 1.40225 313 2.3559 5 38 1.37822 214 2.3060 2 39 1.36973 215 2.2012 1 40 1.34133 116 2.1146 1 41 1.31945 1

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17 2.0668 4 42 1.30994 118 2.04550 1.5 43 1.29022 219 1.98602 1 44 1.23269 120 1.93250 4.5 45 1.20231 1.521 1.84272 3 46 1.17835 222 1.76612 8 47 1.15923 123 1.75226 1.5 48 1.14259 124 1.71331 1 49 1.12238 125 1.69571 2 50 1.08360 2.5

d) The area between the rivers Vrbas and Bosna

Several authors have determined prehnite in basic igneous and metmorphic rocks outcropping in the area between the rivers Vrbas and Bosna – Džepina (1970), Đorđević and Stojanović (1972, 1974), Đurić and Kubat (1962), Kubat (1964), Majer (1962), Pamić (1969a), Trubelja, Šibenik-Studen and Sijarić (1974, 1975, 1975a). Prehnite was likewise determined in granites and syenites (Đorđević and Mojičević 1972; Pamić and Tojerkauf 1970).

Monomineralic prehnite veins occur in diabases (at the edges of the serpentine complex) i.e. in the Usora river valley, on the Doboj – Teslić road. In samples taken from the Lelah – Teslić road prehnite is associated with analcime and calcite (XRD, DTA and IR-spectroscopic determinations). Similar prehnite veins in amphibolites are found in the Vrbanja river valley, near Čelinac (Trubelja et al., 1974, 1975a).

Đorđević and Stojanović (1972) determined amygdaloidal prehnite and natrolite in diabases from Bojići near Banja Luka. Needlelike natrolite crystals often grow on a prehnite substrate. The prehnite is pale-green in colour, with a waxy lustre. The x-ray diffraction lines of this prehnite are: d (Å) 3.07 (100), 2.80 (15), 2.55 (80), 2.47 (2), 2.37 (5) correspond well with published literature data (ASTM-card 7-333).

Džepina (1970) determined prehnite in alkaline metamorphic rocks (some of which are garnet-bearing) on the southern flanks of Mt. Borja. This author believes that the prehnite is an alteration product of alkaline plagioclase, since they both occur in the same parageneses. He notes that veins carrying prehnite and plagioclase cut through all other mineral formations, implying their young age of formation.

e) Mt. Kozara

Golub (1961), Trubelja (1966a), Trubelja et al. (1974, 1975, 1975a) determined prehnite as a common mineral constituent in basic igneous rocks of Mt. Kozara (especially its northern and southern flanks). Prehnite is particularly prominent in altered gabbro-diabases, to be found on the Mrakovica – Kozarac road,

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where it forms monomineralic veins or parageneses with other minerals (analcime and calcite). The IR-spectra of these prehnites are shown in Figure 17.

Figure 17. IR-spectra of prehnites from Mt. Kozara (Mrakovica – Kozarac) road(Trubelja et al. 1975a)

2. Prehnite in products of Triassic-age magmatic events

Basic igneous rock of Triassic age are to be found in several areas in Bosnia and Hercegovina. These rocks often contain prehnite as a common or even important mineral constituent, both in intrusive and extrusive magmatics. Such rocks have important outcrops near Vareš – Atanacković et al. (1968), Đorđević (1958), Karamata and Pamić (1964), Petković (1961/62), Trubelja et al. (1974, 1975a).

Marić (1927), Pamić (1960, 1960a, 1961a, 1961b, 1962, 1969), Pamić and Papeš (1969), Trubelja and Miladinović (1969), Trubelja and Slišković (1967), Trubelja, Šibenik-Studen and Sijarić (1974, 1975, 1975a) provide data on the occurence of prehnite in the areas of Konjic, Jablanica, Prozor, Kupres and within the Ilidža – Kalinovik – Tjentište zone. Marić (1927) made microscopic measurements of prehnite in the gabbro rocks from Jablanica. Here the prehnite is of secondary origin, occuring within veins in the gabbro. Prehnite is associated with calcite, hornblende, chlorite, titanite and quartz. Prehnite grains display complete cleavage along the base. Measured refractive indices are Nz = 1.6482, Ny = 1.62575, Nx = 1.61470 (Na-lamp). Maximum birefringence Nz – Nx = 0.03181. The 2V angle is large.

Pamić (1961a, 1961b) also made microscopic determinations of prehnite in

rocks from the Jablanica and Prozor areas, including basalts and marbles from the contact zone. This author found prehnite to be associated with spilites i.e. with albite phenocrysts. Calcite and sericite often occur together with prehnite. The prehnite associated with spilites has a 2V angle of +64°.

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Table 59. Powder x-ray diffraction data for prehnite from Vareš (Trubelja et al. 1975a)No. d (Å) I No. d (Å) I

1 5.2522 3 27 1.59600 12 4.6177 4 28 1.56405 13 4.1291 1.5 29 1.54271 54 3.5092 5 30 1.53023 45 3.4530 10 31 1.50200 16 3.2903 8 32 1.47707 17 3.2456 3 33 1.45881 18 3.0521 10 34 1.44107 39 2.8002 4 35 1.40299 2.510 2.6173 2.5 36 1.37573 2.511 2.5509 10 37 1.34200 1.512 2.3523 5 38 1.31626 113 2.3094 2 39 1.30838 114 2.1351 1.5 40 1.28872 2.515 2.1118 1.5 41 1.26317 116 2.0632 4 42 1.24025 117 2.04200 1.5 43 1.23321 118 1.98684 1 44 1.20154 1.519 1.92940 5 45 1.17763 320 1.84133 3 46 1.15747 1.521 1.76549 9 47 1.14193 1.522 1.75039 1 48 1.12280 1.523 1.71212 1 49 1.09984 124 1.69745 2 50 1.08286 125 1.65509 3 51 1.06575 3.526 1.63453 2

Đorđević (1958) determined prehnite in gabbro from the Vareš area. Prehnite is associated with other minerals of secondary origin – uralite, chlorite, epidote, zoisite, albite, kaolinite, sericite and serpentine. Trubelja et al. (1974, 1975, 1975a) identified prehnite and pumpellyite in veins within altered melaphyres around Vareš. The prehnite crystals are up to several millimeters in size, and form amygdaloidal structures in the melaphyre. This finding is significant as it indicates the prehnite-pumpellyite metamorhic stage.

Powder XRD and IR-spectroscopy were used to determine prehnite in a basic igneous rock from Mt. Zvijezda. This mineral was also determined in a melaphyre sample obtained from the mineralogical collection of the Country Museum in Sarajevo. Here, prehnite is associated with albite and quartz.

3. Origin of prehnite

We have already described the occurences of prehnite and associated minerals in a variety of rocks belonging to the Bosnian serpentine zone (BSZ) or the Triassic-age igneous complex. Based on our own investigations, as well as data

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obtained from the cited literature references, we may conclude that the prehnite is either associated with the hydrothermal phase, or is the alteration product of alkaline plagioclase minerals. The occurence of prehnite in amphibolites is an indication of its possible origin with regional metamorphic proceses.

Hydrothermal prehnite usually occurs in the form of monomineralic (sometimes associated with other hydrothermal minerals) in veins, filling up older fractures in the host rocks (gabbro, diabase, spilite etc). The prehnite must have been deposited from hydrothermal solutions with high concentrations of Ca, Al and silicic acid.

Formation of prehnite by alteration of alkaline plagioclases often results in prehnite pseudomorphoses of these feldspars. The alteration processes can also be understood in terms of hydrothermal metasomatic reactions.

The occurence of prehnite in amphibolites (representing products of regional metamorphism) also implies its crystallization from Al, Ca, Si-enriched solutions at elevated temperatures.

Generally, the origin of prehnites in Bosnia and Hercegovina is frequently associated with several processes leading to the formation of complex parageneses with secondary minerals like albite, serpentine, chlorite, epidote, clinozoisite, calcite and zeolite minerals.

SEARLESITENaB [Si2O5] (OH)2

Crystal system and class: Monoclinic, sphenoidal class.Lattice ratio: a : b : c = 1.1286 : 1 : 0.6957 β = 93° 56’Cell parameters: ao = 7.97, bo = 7.05, co = 4.90 Z = 1

The formula of searlesite is sometimes written as Na2B2[Si4O10│(OH)4] or NaB[Si2O6] x H2O (Ramdohr and Strunz 1967). The mineral was first determined in a core from Searles Lake, California, taken by John W. Searles, and named after this californian pioneer.

Properties: see text concerning the Lopare deposit. A u t h o r s: Barić (1966, 1966b, 1966c), Barić and Jovanović (1966), Jovanović (1975), Č. Jovanović and O. Jovanović (1966).

Deposits of searlesite occur very rarely. Barić and coauthors investigated the occurrence of this mineral in Bosnia and Hercegovina – Barić (1966, 1966b, 1966c), Barić and Jovanović (1966). At Lopare, 15 km northeast of Tuzla, on the

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northern flanks of Mt. Majevica, searlesite occurs in two deposits. The deposits are not far from each other, but nevertheless separated. The first deposit is located in the creek Duboki Dol. This creek joins the Gnjica river which flows through Lopare. The searlesite occurs here as four 2-4 cm thick layers in a stratified marl. It needs to be said that this deposit was frequently referred to as the Trifunove vode deposit, which is incorrect.

The second searlesite deposit is located south of the Duboki Dol creek. Near the crossing of the road Tuzla – Brčko with the road towards Veselinovci, the searlesite is locate within a complex of argillaceous schists in the Mijajlov Potok creek. The searlesite forms elliptical lenses about 4 x 10 cm in size. Both the marl and argillaceous schist host-rocks are intercalated with layers of tuff and tuff-bearing sandstone. Barić and Jovanović (1966) maintain that these sediments are of Miocene age (Burdigalian – Helvetian).

Some veins and fissures within the host rocks contain small searlesite crystals which grow in a partially free space, with well developed crystal forms on the terminal side. The crystals are elongated along [001] with an overall platelike habit parallel to (100) – see Figure 18. The (100) form shows fine striations parallel to [001]. The crystals are mostly 2-3 mm long, the largest one found was 6 mm long.

Goniometric measurements were done on 26 searlesite crystals (Barić 1966). Even though the crystals were small, measurements on a Goldschmidt type 2-circle reflection goniometer were easily performed. Barić determined the presence of following crystal forms on searlesite from Lopare: c {001}, b {010}, a {100}, i {210}, m {110}, z {120}, e {011}, s {101}, y {201}, q {-201}, p {-101}, f {111}, n {-111}, g {121}, h {331} and l {102} – a total of 16 crystal forms.

Figure 18. Searlesite crystals from Lopare (Barić 1966)

A number of the crystal forms determined on the material from Lopare. Earlier studies on searlesite crystal from USA determined the presence of these crystal forms only: b {010}, a {100}, m {110}, s {101}, y {201}, l {102}. This means that the forms

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c {001}, i {210}, z {120}, e {011}, q {-201}, p {-101}, f {111}, n {-111}, g {121}, h {331} have for the first time been identified on the searlesite from Lopare. The crystal form l {102} has been determined as a cleavage plane in both cases.

The lattice ratio for searlesite was calculated from the polar coordinates of those crystal planes which had the best reflection signals (Barić 1966) a : b : c = 1.1286 : 1 : 0.6957 β = 93° 56’

This ratio is in very good agreement with literature data for searlesite (Fahey and Axelrod 1950). Barić was also able to determine the relationships between geometrical and optical properties (Barić 1966, 1966b). The optic axial plane is in a normal symmetrical position. The principal vibrational direction Z corresponds to the [010] axis. The principal vibrational direction X is inclined with respect to the [001] axis – the inclination angle is 32° 23’. The refractive indices were determined on a thin section, carefully polished perpendicular to the vibrational direction Y. The measurement was done in sodium light (at 18°C) using a Klein-type refractometer

Nz = 1.5351 Ny = 1.5306 Nx = 1.5226

Furthermore, refractive indices were also measured on two cleavage planes parallel to (100) Nz = 1.5350 Nx’ = 1.5246 Nz = 1.5349 Nx’ = 1.5224

Maximum birefringence (and the partial Nz – Nx’ values) were determined on five cleavage planes parallel to (100), using a Berek-type compensator

Nz – Nx = 0.0129 Nz – Nx’ = 0.0106

The optic axial angle was measured on a rotating stage microscope. Somewhat thicker sections were used for this purpose, so that both axes could be measured. The mean value of ten measurements is -2V = 73° 53’. A weak r < v dispersion was determined in white light.

Pure searlesite material was selected for quantitative chemical analysis which yielded following results (analyst Lj. Barić): SiO2 = 58.72; B2O3 = 16.99; Fe2O3 = 0.12; Na2O = 15.16; K2O = ---; CaO = ---; MgO = 0.02; H2O

+105 = 8.92; H2O-105 = 0.08; Total = 100.01

Searlesite is easily soluble in dilute hydrochloric acid. The qualitative test for the borate ion ws positive. The mineral melts under the blow pipe into a vitreous globule. The density of the minerals was determined using the pycnometric method (d = 2.462 g/cm3 at 4°C).

Powder x-ray diffraction was done using a Philips diffractometer, using CuKα radiation. The diffraction pattern of the Lopare searlesite, given in Table 60,

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corresponds well to the searlesite reference ASTM-card No. 6-0037 (which is for searlesite from Wyoming, USA).

At Lopare, the searlesite occurs in association with kalcite, opal, pyrite and trona. Opal is occasionally present in substantial quantities, and can contain radial spherulites (up to 0.5 mm in size) of searlesite. The free terminal ends of individual searlesite crystals are sometimes covered with thin layers of hyalite opal.

Table 60. Powder x-ray diffraction data for searlesite from LopareSearlesite (Lopare) Searlesite ASTM 6-0037

d (Å) I d (Å) I8.02 vvs 8.01 1005.32 w 5.32 104.33 m 4.31 304.05 s 4.06 503.97 vs 3.98 203.68 vw 3.70 103.54 m 3.54 303.48 vs 3.48 403.24 s 3.24 403.20 vs 3.21 302.99 m 2.99 202.92 ms 2.92 302.75 m 2.76 202.65 ms 2.66 302.49 m 2.49 102.46 mw 2.45 202.40 m – broad 2.41 10

2.39 102.26 mw 2.28 102.16 w 2.16 52.13 w 2.12 102.06 vw 2.06 102.02 vw 2.02 5

1.989 m – broad 1.992 101.978 10

1.949 vw 1.945 51.914 m – broad 1.916 10

1.896 101.827 m 1.825 201.765 mw 1.765 101.746 mw 1.746 51.686 vw 1.690 51.669 vvw ---1.647 vvw 1.647 51.631 vvw 1.632 51.617 vvw 1.616 51.605 vw 1.605 51.592 vw 1.592 51.555 m 1.554 20

vvs = very very strong; vs = very strong; vvw = very very weak; w = weak; vw = very weak; m = medium; ms = medium strong; mw = medium weak

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The dark colour of the host rocks (marls and argillaceous schists) is caused by the presence of organic matter. The organic matter can cause a yellow or brown surface colouration of searlesite. The same effect has been observed for the searlesite from the Green-River formation in Wyoming, USA.

The origin of searlesite at Lopare can be explained by the action of boron-enriched hydrothermal waters on silicic acid contained in the volcanic tuffs. A similar explanation was provided for the origin of searlesite from Esmeralda County, Nevada, USA (Foshag 1934). The present opal and hyalite is a strong indication that ‘free’ silicic acid was available in the depositional environment.

Jovanović (1975) mentions briefly an occurrence of searlesite in the halite deposit at Tuzla.

Use: the searlesite deposit in the Green-River formation in USA has commercial significance. Searlesite crystals up to 15 cm long were found in this deposit. The material is used for production of borax and other perborate formulations for industrial and medicinal use.

NEPHELINEKNa3[AlSiO4]4

The only information on nepheline in Bosnia and Hercegovina was provided by Primics (1881). This author mentions two deposits – one at Duboštica near Vareš (where nepheline occurs in garnet-bearing amphibole schists), and the other one in the Žepče – Maglaj area, on the left bank of the Bosna river. Here, nepheline occurs as small crystals in biotite-quartz trachytes.

ANALCIMENa [AlSi2O6] x H2O

Crystal system and class: Cubic, hexaoctahedral class.X-ray data: d 3.43 (100) 5.61 (80) 2.94 (70)IR-spectrum: 415 450 620 746 775 862 1040 1115 1635 3620 cm-1

A u t h o r s: Đorđević and Stojanović (1972, 1974), Sijerčić, Pamić, Jovanović and Šljukić (1974), Trubelja (1962), Trubelja, Šibenik-Studen and Sijarić (1974, 1975, 1975a and 1976).

There is not much information on the occurrence of analcime in Bosnia and Hercegovina. According to available literature data, analcime has been determined in basic igneous rocks of the Bosnian serpentine zone (BSZ) and in sediments of the salt deposit at Tuzla.

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Trubelja (1962) made the first microscopic determination of analcime in biotite-spilites from Torić creek, near Bosanski Novi. Here, small amygdaloids are filled with analcime and calcite. In thin section the analcime displays a low birefringence and grey interference colours. The refractive index of analcime is lower than that of both calcite or Canada balsam (observation is based on the Becke line movements).

The origin of analcime in these rocks is linked to postmagmatic hydrothermal processes which caused the albitization of plagioclases and the spilitization of basic rocks. Analcime is also found to form pseudomorphs over plagioclase.

Đorđević and Stojanović (1972) mention analcime occurrences in rocks

within the BSZ. Unfortunately, the authors do not give locations of these occurrences. In their paper published 2 years later, Đorđević and Stojanović (1974) determined analcime, in association with laumontite and datolite, in diabase rock at Bojići, near Hrvaćani, on the southern flanks of Crni Vrh. The diabases at Višegrad (close to the railway station) also contain some analcime, chlorite and anorthite (powder XRD determination). Analcime was also determined in dacites, andesites and tuffs around Srebrenica, Bratunac and Zvornik.

Trubelja et al. (1974, 1976) investigated the mineralogy of veins in basic rocks of the BSZ finding that analcime frequently occurs within zeolite parageneses. An association of analcime with thomsonite, determined by powder XRD and IR-spectroscopy, was identified in rock from the Karaula locality, on the southeastern flanks of Mt. Konjuh. The diabases at Gradina (Doboj) analcime occurs together with natrolite and calcite. The diabase-dolerites of Mt. Kozara (the Kozarac – Mrakovica sector) contain a paragenesis of analcime, prehnite, calcite and thomsonite.

2. Analcime occurrences in the Tuzla salt deposit

Sijerčić et al. (1974) reported on analcime-bearing aggregates (which they called analcimolites) within the sedimentary series of the Tuzla salt deposit. Analcime was determined by powder x-ray diffraction. In thin section, euhedral analcime crystals were identified. Analcime grains are completely isotropic. An outcrop of this ‘analcimolite’ rock was discovered near Mlič hill.

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SILICATES

SANIDINEK [AlSi3O8]

Crystal system and class: Monoclinic, prismatic class.Lattice ratio: a : b : c = 0.657: 1 : 0.551 β = 115° 59’Cell parameters: ao = 8.56, bo = 13.03, co = 7.175 Z = 4Properties: sanidine is a typical high-temperature alkaline feldspar with a partially ordered arrangement of Al and Si ions. It commonly occurs in young effusive rocks, sometimes as large, distinct phenocrysts. Due to rapid cooling of the host rock, sanidine normally retains high-temperature optical constants. Perfect cleavage parallel to {001}, good parallel to {010}. Hardness = 6. Specific gravity = 2.56. Sandine is normally colourless and transparent. Vitreous lustre. Resistant to acids, except hydrfluoric acid. Refractive indices are lower than those of Canada balsam. Birefringence is low. IR-spectrum: 415 430 546 585 638 728 778 1040 1060 1130 cm-1

A u t h o r s: Barić (1966), Dangić (1971), John (1880), Majer (1961), Pamić (1962, 1969), Pamić, Dimitrov and Zec (1964), Pamić and Papeš (1969), Paul (1879), Ramović (1961, 1962), Simić (1968), Šibenik-Studen and Trubelja (1967), Tajder (1953), Trubelja (1970a, 1971a, 1972), Trubelja and Pamić (1956, 1965), Varićak (1966)

According to available literature references, sanidine has not a very wide distribution in rocks in Bosnia and Hercegovina. It has been determined in Tertiary-age igneous rocks at Srebrenica, as well as in the Bosna river valley and some other localities. Triassic rocks have also been mentioned to contain sanidine. We believe that some data on sanidine will have to be revised, since it has been obtained only by microscopic measurements.

1. Sanidine in Tertiary-age igneous rocks

C. M. Paul (1879) provides the earliest information on the occurrence of sanidine in trachytes of the Maglaj fortress. Sanidine is present as distinct crystals, some of which show twinning according to the Carlsbad law. The same sanidine was investigated also by other authors – John (1880), Pamić, Dimitrov and Zec (1964), Trubelja and Pamić (1956, 1965).

The sanidine-bearing dacites from Brusnička Rijeka contains distinct, idiomorphic sanidine crystals (as phenocrysts), with clearly visible cleavage planes parallel to (010). The sanidine was measured on a rotating-stage microscope. The -2V angle varies in the range 27.5° to 30°. This is evidence for sanidine rather than

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anorthoclase, as could be deduced from the Nikitin diagram. The sanidine crystals have many inclusions, primarily andesine. Sanidine is also present in the matrix of the rock.

Majer (1961) believes that sanidine in present the matrix of the dacitic rocks from the Blatnica creek near Teslić. The authors conclusion is based on chemical analysis of the rock.

Barić (1966) made microscopic determinations of sanidine in tuffs from the Livno area. The grains are completely transparent, and their RI’s are lower than those of Canada balsam. Twinning is according to the Carlsbad law. Birefringence is low (Nz – Nx = 0.0061).

Sanidine in dacites and similar rocks from Srebrenica has been investigated by several researchers – Dangić (1971), John (1880), Ramović (1961, 1962), Tajder (1953), Trubelja (1971a, 1972). The largest amount of information can be found in the publication by M. Tajder (1953). According to this author, sanidine occurs as phenocrysts in dacites from the Kiselica creek, in the biotite-dacite from the village of Ažlice and in the amphibole-dacites from Srebrenica. Based on chemical analyses of these rocks, the author maintains that some sanidine may also be present in the rock matrix. The sanidine from Kiselica creek (grain size 0.5 x 0.7 mm) has a low birefringence, uneven extinction and a very small optic axial angle (2V = -10°) so that it sometimes resembles a uniaxial mineral. Sanidine in other mentioned rocks has similar microphysiographic properties. The amphibole-dacites from Srebrenica contains larger sanidine crystals (5-12 mm), pink in colour and with clearly visible cleavage. It is present in the rock in the form of untwinned, single crystals. The -2V angle lies in the range 10-20°. Sanidine crystals contain numerous inclusions of amphibole, plagioclase, quartz, apatite and calcite.

2. Sanidine in Triassic-age igneous rocks

Pamić (1962, 1969), Pamić and Papeš (1969), Simić (1968), Šibenik-Studen and Trubelja (1967) made microscopic determinations of sanidine in Triassic-age volcanic rocks – in the Ilidža – Kalinovik zone, at Kupre, in the Vrbas river valley and in K-rich effusive rocks near Sarajevo. We wish to point out that microscopic determinations of sanidine in these rock were rather difficult to perform, so that the data should be treated with some caution. Further research, using complementary methods is obviously needed.

3. Sanidine in rhyolite from Mt. Motajica

Varićak (1966) believes that the K-feldspar, contained in the rhyolite from Mt. Motajica, is sanidine. This material is very weathered, and this result must also be regarded with caution.

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SILICATES

ORTHOCLASEK [AlSi3O8]

Crystal system and class: Monoclinic, prismatic class.Lattice ratio: a : b : c = 0.659 : 1 : 0.553 β = 116° 01’Cell parameters: ao = 8.562, bo = 12.996, co = 7.193 Z = 4Properties: orthoclase is a low-temperature feldspar, formed during the process of slow magma cooling. It is a ubiquitous constituent of acidic and neutral igneous rocks (granites, syenites). Other physical properties are similar to those of sanidine. Colour is usually white to pink.X-ray data: d 3.29 (10) 1.81 (9) 4.25 (7)IR-spectrum: 430 (460) 542 586 647 727 763 1040 1150 cm-1

A u t h o r s: Foullon (1893), John (1880), Jovičić (1891), Katzer (1924, 1926), Kišpatić (1897, 1900), Koch (1908), Majer and Jurković (1957, 1958), Marić (1927), Pamić (1957, 1960a), Pilar (1882), Primics (1881), Simić (1964, 1968), Simić, V. (1956), Šćavničar and Jović (1962), Trubelja (1963a), Trubelja and Pamić (1957), Tućan (1930, 1957), Varićak (1955, 1957, 1966), Vujanović (1962).

Up to now, orthoclase has not been very well investigated in rocks from Bosnia and Hercegovina. The available data indicate that this mineral is most common in rocks from Mt. Motajica, where it was first determined by John (1880). Occurrences of orthoclase have also been identified in rocks from Mt. Prosara, as well as in gabbros, diorites and other products of Triassic-age volcanic events. Orthoclase is an important constituent of the ‘red granite’ which occurs in the Maglaj area in the form of pebbles. Some sedimentary rocks also contain orthoclase.

1. Orthoclase in rocks of Mt. Motajica and Mt. Prosara

John (1880) made first microscopic determinations of orthoclase which is an essential mineral in muscovite granites from the Kobaš area at Mt. Motajica. Pilar (1882) provides a description of granites from the menitoned area, agreeing that orthoclase is their essential mineral constituent.

Koch (1908) studied the Mt. Motajica rock-series in detail. According to this author, who made a very significant contribution to microscopic determinations of rock-forming minerals in this area, orthoclase is a prominent mineral in muscovite granites from Vlaknica, near Kobaš, as well as from Brusnik. The Vlaknica granitic pegmatites contain large orthoclase crystals, in association with quartz, mica, microcline and plagioclase. For the orthoclase in the granites from Veliki Kamen (Vlaknica), Koch determined several microphysiographic properties. This orthoclase displays good pinacoidal cleavage and a conspicuous zonar structure. Twins according to the carlsbad law can be frequently be observed. Polysynthetic twinning

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with microcline and plagioclase is also present. Orthoclase decays into kaolinite, muscovite and other alteration products. Orthoclase often contains inclusions of hematite, apatite, biotite, tourmaline, zircon and epidote.

Orthoclase can frequently be found in gneisses. It occurs in biotite-bearing granite-gneisses at Židovski potok, the muscovite gneisses and pegmatites of the Studena Voda creek, and biotite gneisses of Osovica creek near Šeferovac.

Katzer (1924, 1926) notes the presence of orthoclase in rocks of Mt. Motajica, and makes reference to microscopic determinations done by Koch.

Varićak (1966) published a treatise on the petrology of Mt. Motajica, with a substantial number of microscopic determintions of orthoclase. Varićak notes the apparent symmetry change of orthoclase from monoclinic to triclinic, and its transformation to microcline. According to this author, in normal granite orthoclase has a -2V angle = 62° (corresponding to ca. 32% albite). In the so called ‘frozen-edge granite’ orthoclase shows signs of exsolution of albite, kaolinite and sericite. Orthoclase is also present in leucocratic granite, aplite and granite-porphyres (microperthite). In these rocks, the 2V angle of orthoclase shows large variations, within the -62° to -82° range of values (the average ab content is around 35%). Orthoclase in lamprophyres has a -2V angle = 64°. Twinning according to the Carlsbad and Manebach laws is frequent and such crystals have a -2V angle of 60-64° (32% ab). Contactolites of sedimentary origin contain orthoclase which often has an uneven, undulating extinction (2V = -83°).

Igneous rocks from Mt. Prosara, which Katzer (1924, 1926) calles microgranite-porphyres, contain feldspars mainly as orthoclase. More recent investigations have not confirmed the occurrence of orthoclase in these rocks.

2. Orthoclase in Triassic-age igneous rocks

The presence of orthoclase in Triassic-age volcanic rocks has been noted by numerous researchers – Majer and Jurković (1957, 1958), Marić (1927), Pamić (1957, 1960a), Pilar (1882), Simić (1964, 1968), Trubelja (1963a) and Vujanović (1962).

Majer and Jurković (1957, 1958) determined orthoclase to be an essential mineral constituent of diorites from Kopile, south of Travnik (the Bijela Gromila massif). Orthoclase is here usually associated with andesine and labradorite. Orthoclase crystals are usually fresh and single (not twinned), although some grains display relicts of zonar structure. The RI is lower than 1.54, and the -2V angle varies in the range 58-71°.

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Marić (1927) determined orthoclase in some magmatic differentiates of the Jablanica rock series.

Trubelja (1963) identified orthoclase and Na-orthoclase in amphibole-granites from Čajniče by microscopic measurements. The -2V angle varies in the range 63-81°. Some microperthite is present (intergrowths of orthoclase with albite). The orthoclase is generally weathered and altered to kaolinite and sericite.

Pilar (1882) determined orthoclase as an essential constituent of the igneous rocks from the area of Jajce. The orthoclase is usually twinned according to the Carlsbad law, and shows signs of weathering and alteration.

Pamić (1957, 1960a) and M. Simić (1964, 1968) determined orthoclase in rocks associated with the spilite-keratophyre series, near Sarajevo and Kalinovik. Vujanović (1962) mentions orthoclase associated with some manganese minerals (Čevljanovići).

3. Other occurrences of orthoclase

Kišpatić (1897, 1900) identified orthoclase in a pebble (red granite from Maglaj) he retrieved from the Mala Bukovica creek. Orthoclase is an essential constituent of this rock, and displays Carlsbad-law twinning. This rock was also studied by Varićak (1955), who notes the red colour of the orthoclase. In thin section, this orthoclase has a -2V angle between 67-73°. It forms microperthite intergrowths with albite. The crystals are single or twinned, usually strongly weathered and altered (to kaolinite). Orthoclase accounts for 25-30 vol. % of the granite pebble found in Jablanica creek.

It is interesting to note early research of orthoclases, done by John (1880), Jovičić (1891) and Primics (1881). John described orthoclase in amphibolites from Rudo, in liparites from Mt. Vranica and in diorites from Kladanj. Jovičić noted the presence of orthoclase (or oligoclase) in microgranulites from Srebrenica. Primics made microscopic determinations of orthoclase contained in effusive rocks from the Maglaj – Žepče area, as well as in olivine gabbros from the Krivaja river valley and from the area of Duboštica.

Šćavničar and Jović (1962) identified orthoclase and other feldspars in Eocene-age sandstones at Čorbin Han (Tuzla basin).

Foullon (1893) and Katzer (1924, 1926) identified fresh and transparent feldspars (resembling adularia) in quartz-porphyres from the schist mountains of central Bosnia.

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MICROCLINEK [AlSi3O8]

Crystal system and class: Triclinic, pinacoidal class.Lattice ratio: a : b : c = 0.660 : 1 : 0.556 α = 90° 41’, β = 115° 59’, γ = 87° 30’Cell parameters: ao = 8.57, bo = 12.98, co = 7.22 Z = 4Properties: microcline is a low-temperature feldspar, formed during the process of slow magma cooling. Like orthoclase, it is a ubiquitous constituent of acidic and neutral igneous rocks (granites, syenites). Other physical properties are similar to those of sanidine and orthoclase. Granitic pegmatites sometimes contain quite large microcline crystals.X-ray data: d 3.22 (10) 1.80 (8) 4.18 (6)IR-spectrum: 430 467 537 584 607 650 728 772 1018 1052 1085 1140 cm-1

A u t h o r s: Jovanović (1957), Katzer (1924, 1926), Koch (1908), Pamić (1957), Šćavničar and Jović (1962), Trubelja and Pamić (1957), Tućan (1930, 1957), Varićak (1957, 1966).

Microcline is not a very common mineral in rocks of Bosnia and Hercegovina, and not much has been written about this mineral. It occurs as an essential mineral constituent of various rocks from Mt. Motajica and Mt. Prosara. Some authors mention microcline in Triassic volcanic rocks, and in some sediments.

1. Microcline in rocks from Mt. Motajica and Mt. Prosara

F. Koch (1908) provides first data on the occurrence of microcline in granites from Mt. Motajica. In thin section the microcline has a texture characteristic for polysynthetic albite/pericline twinning. The muscovite granite from Brusnik also contains microcline.

Katzer’s Geology of Bosnia and Hercegovina (1924, 1926) mentions only briefly microcline as a constituent of granites and aplites.

Varićak (1966) determined microcline to be an essential mineral constituent of granite-type rocks (normal granite, leucocratic granite, aplite) from Mt. Motajica. Microcline is also contained in other igneous and metamorphic rocks (granite-porphyres, lamprophyres, pegmatites, gneisses) in which a ‘microclinization’ orthoclase is present. Normal granite normally contains microcline with a gridiron (or quadrille) structure, although homogenous grains are also present. It displays good cleavage along (001) and (010), but also along (110) and (1-10). Carlsbad-type

262

SILICATES

twinning is frequently observed. The optic axial angle -2V varies in the range between 75° and 84°. The 2V angle of microcline shows comparatively large variations also in other investigated rocks: -2V = 75-81° (aplites), 76-84° (granite-porphyres), 72-75° (lamprophyres), 69-85° (pegmatites), 78-86° (2-mica gneisses).

Varićak (1957) determined microcline as an essential mineral constituent in gneisses and phyllites from Mt. Prosara.

2. Microcline in Triassic volcanic rocks

Little data is available on the occurrence of microcline in Triassic-age igneous rocks. Pamić (1957) determined microcline in rhyolites from the Ilidža – Kalinovik sector, near Ravne. The -2V angle varies in the range between 75° and 88°. Using the Becke line method, it was determined that the RI of microcline are lower than the RI of Canada balsam. Larger microcline grains show the characteristic gridiron pattern. Microcline was also identified using the Nikitin diagram curves for angles between cleavage systems.

Microcline is usually not a common mineral in acidic effusive igneous rocks. However, it has been identified in the rhyolites from Ravne, so it has probably formed by microclinization of some other feldspar. Jovanović (1957) determined microcline in granites from Mt. Prenj.

3. Microcline in sedimentary rocks

Šćavničar and Jović (1962) determined microcline in Eocene sandstones in the Kreka basin.

ANORTHOCLASE(Na,K) [AlSi3O8]

Anorthoclase is a Na-enriched high-temperature feldspar. It occurs almost exclusively in igneous rocks. According to Strunz (1966), anorthoclase is structurally not well defined. The symmetry is monoclinic or triclinic.

A u t h o r s: Jurković and Majer (1954), Pamić (1957, 1960a), Simić (1968), Trubelja and Pamić (1956), Trubelja and Paškvalin (1962).

Anorthoclase is a crystalline solid solution in the alkali feldspar series, in which the sodium-aluminium silicate member exists in larger proportion. It can also be understood in terms of an alkali feldspar intermediate between low sanidine and high albite. It occurs in sodium-rich effusive rocks.

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There exist very few literature references about anorthoclase in Bosnia and Hercegovina. It has been determined in rhyolites of the central Bosnian schist mountains and in some Tertiary and Triassic igneous rocks.

1. Anorthoclase in rhyolites from the schist mountains of central Bosnia

Jurković and Majer (1954) determined anorthoclase in Paleozoic rhyolites (quartz-porphyres) from Mt. Vranica (Krstac and Rosin localities). Anorthoclase phenocrysts are less abundant than quartz. The largest grains identified are up to 3 x 5 mm in size, and have rounded or corroded rims. They occur as individual crystals or Carlsbad- or Baveno-type twins (sometimes the suture lines are wavy). The crystals display perfect cleavage, and often contain included quartz and biotite. Some grains are fractutred and display uneven extinction. The determination of anorthoclase is based on microscopic measurements (rotating-stage microscope) and the use of a Nikitin-type diagram. The measured -2V angle lies in the range between 52° and 72°. The -2V angle of anorthoclase from the Rosin locality is also highly variable, probably reflecting a change in the chemical composition of anorthoclase phenocrysts. In these rocks, anorthoclase occurs together with albite, quartz and some accessory minerals.

2. Anorthoclase in Tertiary-age effusive rocks

Trubelja and Paškvalin (1962) determined anorthoclase in products of Tertiary-age volcanic events. Anorthoclase is an essential mineral (together with biotite) in the lamprophyre veins from Sasa. In thin section the anorthoclase has the form of elongated or platelike grains. Twinning was not observed. Cleavage along (010) is visible only on some grains. The grains are weathered and show signs of alteration. Inclusions of elongated apatite grains are present in anorthoclase crystals. Microscopic measurements, performed on a rotating-stage microscope, used with a Nikitin diagram confirmed that the feldspar is anorthoclase. The -2V angle lies in the range 41° to 51°. The RI’s of anorthosite are lower than those of Canada balsam (determined by the Becke line method).

Trubelja and Pamić (1956) studied the dacites from the village of Parnice (Brusnička rijeka) and determined the present feldspar to be either anorthoclase or sanidine. The -2V angle lies in the range between 27.5° and 30°.

3. Anorthoclase in Triassic igneous rocks

Pamić (1957, 1960a) mentions anorthoclase in effusive rocks from the Sarajevo area. Within the scope of a study of igneous rocks at Mt. Igman and Mt. Bjelašnica, Pamić identified anorthoclase as an essential mineral constituent of alkaline dolerites (diabases) in the Mojčevići area. In thin section the anorthoclase is

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present as idiomorphic crystals, usually elongated along the [100] axis. Twinning was not observed, and cleavage is parallel to (100). The RI’s of anorthoclase are lower than those of Canada balsam (determined by the Becke line method). Microscopic measurements confirmed the feldspar to be anorthoclase. The -2V angle varies in the range between 41° and 52°. The 2V angle measured on one of the grains was -64°, a value too high for anorthoclase.

In addition to anorthoclase, Pamić (1957) was able to determine albite, chlorite, calcite and magnetite in the paragenesis. In a subsequent publication Pamić (1960a) found anorthoclase to be an important constituent of similar rocks from Kalinovik.

Simić (1968) provides a description of basic potassium-enriched effusive rocks in the area delimited by the geological map – sheet Sarajevo. He does not refer specifically to anorthoclase, but discusses a sanidine-orthoclase feldspar with ca. 20% of albite displaying microintergrowths often seen in anorthoclase. It is interesting to note that this feldspar has a 2V angle similar to the one measured by Pamić on the anorthoclase from Mojčevići.

HYALOPHANE(K, Ba, Na) [Al(Al, Si)Si2O8]

Crystal system and class: Monoclinic, prismatic class.Lattice ratio: a : b : c = 0.6557 : 1 : 0.5516 β = 115° 40’Cell parameters: ao = 8.557, bo = 13.037, co = 14.441 Z = 8 or ao = 8.557, bo = 13.040, co = 14.400 Z = 8

NB the cell parameters as given above are based on measurements of hyalophane crystals from Zagrlski (Zagradski) potok at Busovača – on a 2-circle Goldschmidt-type reflection goniometer (Barić 1969 and 1972). Cell parameters were calculated from x-ray diffraction data of two hyalophane crystals from the same locality. Both samples are kept in the British Museum in London (Gay and Roy 1968). One sample is marked BM 1959, 359 and the other one as No. 195868. The derived lattice ratios are a : b : c = 0.6564 : 1 : 0.5534 β = 115° 41’ a : b : c = 0.6562 : 1 : 0.5522 β = 115° 41’which is in good agreement with the ratio obtained by goniometric measurement.Properties: Hyalophane is an intermediary member of the orthoclase-celsian series, containing potassium and barium. The optical properties show considerable variation, depending on the potassium content. Here we will discuss only the data pertaining to hyalophane from the occurrence in Bosnia and Hercegovina.

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The principal refractive indices show following variations: Nx = 1.5421-1.5463, Ny = 1.5447-1.5489, Nz = 1.5462-1.5503. The optic axial angle -2V varies between 72° 27’ and 73° 51’ with a r<v dispersion. The extinction angle [100] Λ X varies between 24° and 27° (all measurements done in sodium monochromatic light). The specific gravity range is 2.842-2.883 (at 4°C). The lower range of values pertains to hyalophane with 17.02% BaO, the upper range is for a hyalophane with 18.31% BaO. The maximum variation for the -2V angle is 70.3-81° (Barić 1969, 1972). The variation of the optic axial angle obtained by Divljan (1954) is -2V = 78-84°, while Roy (1965) measured this range as -2V = 68.9-76.3°. The extinction angle [100] Λ X is 20.5-28° (Divljan) and 23-24.5° (Roy). Like other feldspars, hyalophane displays perfect cleavage parallel to (001) and good along (010). Hardness is 6-6.5.

A u t h o r s: Arsenijević (1960), Barić (1955, 1957, 1961, 1969, 1971, 1972, 1972a), Divljan (1954), Divljan and Simić (1956, 1956a), Gay and Roy (1968), Jurković (1956), Roy (1965), Simić (1956).

The town of Busovača is located ca. 50 km northwest of Sarajevo. In this area are outcrops of Paleozoic schists, sericite-bearing phyllites, and chlorite- and amphibole-schists. These numerous cracks and fissures in these rocks are often completely filled with quartz. One of these fissures, contains – in addition to quartz – also hyalophane, a barium-rich variety of orthoclase. This occurrence is located about 5 km southwest of Busovača, in the bed of the Zagrlski (Zagradski) creek. The occurrence is sometimes called Crni potok (Black creek), since a creek of this name flows into the Zagrlski (Zagradski) creek upstream from the occurrence.

The schists which hosts the hylophane-bearing fissure have a NE-SW strike, and a dip of 20-30°. The rock hosts also a small and insignificant orebody with magnetite, pyrite and some chalcopyrite. the hyalophane-bearing fissure cuts across both the schist strata and the ore lens. This fissure is nowadays completely covered with earth since a forest communication road has been constructed above it.

First information on this occurrence of hyalophane was published in 1955 (Barić 1955, Divljan 1954). Subsequently Simić studied the ore minerals of this complex (Simić 1956). An overview of available information was provided by Barić (1957) and Jurković (1956, unpublished report). In 1957 Barić lectured on this occurrence in the Austrian Mineralogical Society in Vienna (Barić 1961). Samples of the hyalophane were sent to the British Museum in London, and Roy (1965) published some chemical information (molecular percentages of celsian and orthoclase) in additon to optical measurements and specific gravity. Gay and Roy (1968) calculated cell parameters for the 2 hyalophane samples kept at the British Museum.

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Barić collected several samples of hyalophane, and investigated them in order to complement his earlier results published in 1957. This work reulted in two further papers (Barić 1969, 1972). The paper published in 1972 is a translation into german of his 1969 paper.

In the Busovača occurrence, hyalophane forms beautiful crystals, usually yellowish in colour and semi-transparent (some terminal sections of the hyalophane crystals are quite transparent). Crystals found in this location were up to 10-15 cm in size, most of them twinned by the Baveno and Manebach laws. In addition to twins, multiple twins (i.e. interpenetration fourlings) are sometimes encountered. In such a case the [100] axes of all four individual crystals are synaxial with the fourfold symmetry axis.

Numerous crystals (in the 0.5-3 mm size range) were measured on a Goldschmidt-type two circle reflection goniometer and the following crystal forms were determined: {001}, {010}, {100}, {310}, {110}, {130}, {-203}, {-506}, {-101}, {-201}, {-111} and {-221}. Many of the measured crystal faces were ideally flat resulting in strong, high-quality reflections. Therefore, the lattice ratios could be derived from the measurements:

polar elements: p0 = 0.8413 q0 = 0.4972 μ = 64° 20’linear elements a : b : c = 0.6557 : 1 0.5516 β = 115° 40’

Gay and Roy (1968) provide following information about cell parmeters for two hyalophane samples

Sample Cn wt% a0 b0 c0 βBM 1959, 359 43.3 8.557 13.037 14.441 115° 69’195867 45.3 8.557 13.040 14.400 115° 69’

This data set can be used to calculate the lattice ratios for these two hyalophanes:

Sample a : b : cBM 1959, 359 0.6564 : 1 : 0.5534 β = 115° 41’195867 0.6562 : 1 : 0.5522 β = 115° 41’

There is very good correspondence of these data, obtained by x-ray diffraction, with those obtained by Barić (1969, 1972).

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Figure 19. Hyalophane from Zagrlski (Zagradski) potok near Busovača (Barić 1969)

1. Chemical analysis

A total of five hyalophane samples were subject to chemical analysis. The results are given in Table 61.

Table 61. Chemical analysis of hyalophane from Zagrlski (Zagradski) potok

Analyst1.

I. Janda2.

V. Pavlović3.

J.H. Scoon4.

Lj. Barić5.

Lj. BarićSiO2 49.64 49.42 49.54 49.39 51.04Al2O3 23.54 23.57 24.14 23.43 22.80Fe2O3 0.32 0.11 0.17 0.19BaO 18.97 18.43* 19.01 18.31 17.02CaO traces 0.19 0.30 0.21MgO traces 0.04K2O 5.46 6.23 6.37 6.28 7.38Na2O 1.97 1.67 1.65 1.63 1.42H2O

+ 0.15** 0.17 0.11H2O

- 0.18 0.06 0.08 0.05Total 99.76 99.70 100.05 99.76 100.22

* given as BaO + SrO in the original paper (Divljan 1954)** given as Loss-on-ignition (LOI) in the original paper (Divljan 1954)

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The analysis of sample 1 was done by Ms. I. Janda in Vienna; results of chemical analysis of sample 2 was published by Divljan (1954); results for sample 3 were published by Gay and Roy (1968); samples 4 and 5 were analyzed by Barić and published in 1969 and 1972.

We conclude that the chemical composition of hyalophane from Busovača is not quite constant. A calculation of molecular percentages of celsian (Cn), anorthite (An), orthoclase (Or) and albite (Ab), based on the above chemical analyses give the following range of values:

Cn 35.00-40.78%An 1.08-1.74%Or 38.25-49.39%Ab 14.44-20.97%

Divljan and Simić (1956) maintain that the molecular ratio is 60% Or and 40% Cn.

This variation in chemical composition has an effect on the optical properties, so that a lower percentage of BaO corresponds to a smaller 2V angle, lower refractive indices and smaller [100] Λ X extinction angle in (010). The density also decreases.


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2. Optical properties

First information on the optical properties of hyalophane from Busovača was published by Divljan and Simić (1956). They measured the -2V angle as 78.5°, the extinction angle [100] Λ X = 28.5°. Refractive indices were measured in daylight by the immersion method – Nz = 1.547, Nx = 1.542. According to Divljan (1954), the maximum variation of the optic axial angle -2V is in the range between 78° and 84°. He provides three more measurements of the extinction angle (20.5°, 23.5° and 28°). Two values for the specific gravity were obtained on two samples – 2.849 and 2.868.

Roy (1965) gives further measurements for the samples in the British museum:

Sample Cn % Or % Nz Ny Nx Nz-Nx 2V [100]ΛX DBM 1959, 359

43.3 --- 1.548 1.546 1.543 0.005 -76.3° 23.0° 2.837

195867 45.3 37.7 1.549 1.547 1.544 0.005 -68.9° 24.5° 2.875


Barić (1969, 1972) studied the optical properties of hyalophane from Busovača in considerable detail. He paid particular attention to the dispersion of optical elements, and this set of data is the first one obtained for hyalophane in general. For these investigations Barić used oriented thin sections – a) parallel to the (010) pinacoid, and b) parallel to the (-101) crystal form. The ease-of-vibration

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direction (principal vibrational direction) Z coincides with the perpendicular on the second pinacoid (010) and the axis [010]. This direction is the obtuse bisectrix, meaning that hyalophane is optically negative. The X an Y vibrational directions are located in the plane of the pinacoid (010). The optic axial plane therefore has a normal symmetrical position. The deviation angle of the acute bisectrix X from the perpendicular on (-101) is only 16°.


It was possible to measure the optic axial angle in sections parallel to (010) or (-101), around both the acute and obtuse bisectrices. The sections used were ca. 0.5 mm thick, in order to obtain better accuracy of the measurements. When a proper orientation of these two sections was attained, the r < v dispersion of optic axes was clearly visible around their acute bisectrix. In proper crystallographic orientation, the vibrational direction X has a posterior inclination i.e. within the acute angle β. The vobrational direction Y has an anterior inclination with respect to [001] i.e. towards the observer. These relationships can be visualised in Figure 23 39d which shows the (010) section. The [100]ΛX extinction angle was measured in this section, for different light wavelengths

μm 643.86 578 ± 1 546.07 435.83[100]ΛX 27° 45’ 26° 42’ 26° 12’ 25° 28’

The variation of the optic axial angle -2V (measured on several thin sections of the (010) or (-101) forms) is in the range between 70.3° and 81°.

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Figure 23. The (010) section of hyalophane showing the r<v dispersion of the principal vibrational directions X and Y (dotted lines indicate Xr, Yr and Xv, Yv). The principal

vibrational direction Z = [010] is perpendicular to the plane of the diagram

a) Refractive indices and optic axial angle

Two larger hyalophane crystals, which appeared to be optically homogenous (based on microscopic observations) were subject to chemical analysis (samples 4 and 5 in Table 61) and optical measurements with the aim to establish pertinent relationships between chemical composition and optical properties.

The refractive indices were measured on carefully polished (010) sections, by total reflection method (at 21°C) using a Klein-type refractometer. The 2V angles were measured in the (-101) section. The hyalophane sample no. 4 (see Table 61) with higher BaO content was used to measure optical constants at different light wavelengths. Results are given in Table 62.

Table 62. Optical constants of hyalophane from Zagrlski potok (BaO = 18.31%)Wavelength (μm) 690.75 623.44 589.3 ± 0.3 546.07 435.83Refractive indicesNx 1.5433 1.5450 1.5463 1.5486 1.5567Ny 1.5459 1.5476 1.5489 1.5512 1.5594Nz 1.5472 1.5489 1.5503 1.5527 1.5609BirefringenceNz – Nx 0.0039 0.0039 0.0040 0.0041 0.0042Nz – Ny 0.0013 0.0013 0.0014 0.0015 0.0015Ny – Nx 0.0026 0.0026 0.0026 0.0026 0.00272V angle -73° 17’ -73° 51’ -74° 26’ -75° 59’

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The measured specific gravity of this hyalophane sample is 2.883 gcm-3 (pycnometric method at 4°C).

The same set of measurements was done for sample no. 5 (see Table 61) which had a lower BaO content. Results are given in Table 63.

Table 63. Optical constants of hyalophane from Zagrlski potok (BaO = 17.02%)Wavelength (μm) 690.75 623.44 589.3 ± 0.3 546.07 435.83Refractive indicesNx 1.5392 1.5408 1.5421 1.5443 1.5522Ny 1.5417 1.5433 1.5447 1.5469 1.5549Nz 1.5430 1.5447 1.5462 1.5484 1.5564BirefringenceNz – Nx 0.0038 0.0039 0.0041 0.0041 0.0042Nz – Ny 0.0013 0.0014 0.0015 0.0015 0.0015Ny – Nx 0.0025 0.0025 0.0026 0.0026 0.00272V angle -71° 50’ -72° 27’ -72° 59’ -74° 36’

The accuracy for the determination of refractive indices given in Tables 62 and 63 is ± 0.0002.

The measured specific gravity of this hyalophane sample is 2.842 gcm-3 (pycnometric method at 4°C).

The measurements presented in Tables 62 and 63 show that the dipersion of RI’s is small. This is consistent with the high Abbe number (also called V-number or constringence). For the hyalophane with higher Ba content, the Abbe number for Nz, Ny and Nx is 63, 65 and 66. The refractive indices for the lines C and F – required for the calculation of the Abbe number – were determined from the dispersion curves of these RI’s.

Values of birefringence are also low. The birefringence was additionally measured using a Berek-type compensator. Four measurements on sections (thickness 0.1-0.4 mm) of the high-Ba hyalophane were made: Ny – Nx = 0.0041; 0.0040; 0.0041; 0.0040;

while the partial birefringence values were Nz – Nx = 0.0015 and 0.0014; Ny – Nx = 0.0025 and 0.0025. For the low-Ba hyalophane these values are Nz – Nx = 0.0039, 0.0040 and 0.0040.

These values are reasonably consistent with the values given by Divljan (1955, 1956) and Roy (1965), although they used the immersion method for RI determination – a procedure which is inherently less accurate than the precise optical measurements as done by Barić (1969).

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With respect to the extinction angle [100]ΛX, its value is 27° for the high-Ba hyalophane and 24° for the low-Ba variety. The range of values, measured on numerous hyalophane crystals from this occurrence, is between 23.8° and 31°.

3. Microelement concentrations

The concentration of microelements was done by spectrography, on several hyalophane samples. The analyses were done by Brandenstein and Schroll (Barić 1969, 1972) on completely colourless and transparent hyalophane material. The results obtained (in ppm) are as follows: Rb 250, Sr 200, Pb 70, Ga 20, Tl 10, V 10, Ge 7, Mo 5, B 5, Cu 2, Zn 0.1. The following elements were below the detection limit of the technique: Ag, As, Be, Bi, Cd, Cs, Sb, Sn and Ti.

A similar set of measurements was done by Arsenijević. He determined Al, Si, Ba, K, Na and Sr to be major constituents of the hyalophane. Traces of Ga, Mg, Ca, Ti, Ag, Pb, Mn, Cs, Fe and Ni were also determined (Divlajn 1954). A specific determination of rubidium, thallium and cesium (Arsenijević 1960) in six hylophane samples gave following results (concentrations given in ppm):

Sample 1 2 3 4 5 6Rb 125 110 130 125 110 110Tl --- 4 4 --- 4 ---Cs 10 10 10

In sample no. 3 Arsenijević (1960) also determined Pb = 10, Mn = 21, Sr = 1600, V = 4, Cu = 9 (all values in ppm) as well as traces of Ti, Ca, Mg, Li, Ga, Cr, Ni and Co.The data provided by Arsenijević and Brandenstein and Schroll should be compared with some caution. While Brandenstein and Schroll used perfectly colourless and transparent hyalophane samples for analysis, Arsenijević used a grey variety of hyalophane.

4. Origin and age of hyalophane (Busovača)

At Busovača (Zagrlski or Zagradski potok), hyalophane occurs together with quartz, siderite, pyrite and muscovite. There are two generations of quartz. The first generation is represented by large, columnar, transparent crystals (up to 10 cm long), grey or darkgrey in colour. This quartz usually forms the base for hyalophane growth. As described earlier, the fissure in the Paleozoic schist, which carries the hyalophane, cuts across older structures, indicating that it is younger in age. Therefore, the K-Ar method was used to determine the absolute age of hyalophane. According to the results obtained by Čedžemov (published by Barić 1969, 1972) the age of hyalophane is 59.5 ± 6.4 million years. This indicated that this mineral association crystallized approximately during the Paleocene – Eocene transition.

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The quartz veins at the Busovača locality were mentioned also by Ilić (1954) and Jurković (1956). Ilić believed that the quartz veins in the Paleozoic schists are remnants of older sulphide-ore deposits which have been washed away or eroded. The presence of specularite would indicate that such deposits belong to the oldest metallogenous period (Ilić 1954). However, the comparatively young age of hyalophane is not consistent with the opinion advnced by Ilić. Jurković (1954) described these veins as Alpine-type fissure veins formed during strong radial collisonal-tectonic events.

THE PLAGIOCLASE GROUP

With regard to their chemical composition, the plagioclase group of minerals represents a continuous isomporphic series with albite Na [AlSi3O8] as the Na-rich end-member, and anorthite Ca [Al2Si2O8] the Ca-rich end-member. Like potassium feldspars, plagioclase minerals also have their high-temperature and low-temperature modifications. The plagioclases can thus have high-temperature or low-temperature optical constants. Changes in chemical composition of the individual minerals of the plagioclase group are reflected in variations in optical constants and other physical properties.

Plagioclases display perfect cleavage parallel to {001}. Cleavage is good along {010} and less pronounced along {110}. Hardness is 6 (anorthite) – 6.5 (albite). the colour is usually white (transparent) but reddish, greenish and yellowish varieties are known. Streak is white, lustre vitreous (sometimes pearly on cleavage planes). Plagioclases with high An contents dissolve in hot hydrochloric acid, while hydrofluoric acid attacks all plagioclases.

Plagioclase minerals are triclinic (pinacoidal class). The x-ray diffraction patterns of individual plagioclase minerals are quite similar to each other, and determination based solely on XRD is difficult.

ALBITENa [AlSi3O8]

Lattice ratio: a : b : c = 0.637 : 1 : 0.560 (low albite) α = 94.26° β = 116.58° γ = 87.67°Cell parameters: ao = 8.144, bo = 12.787, co = 7.160 Z = 4X-ray data: (low-albite) d 3.150 (30) 3.188 (100) 4.027 (67) 3.124 (55) 3.658 (37)IR-spectrum: 405 428 463 475 533 590 610 650 723 742 762 786 990 1010 1045 1103 1165 cm-1 (from Moenke 1962). The vibrations at 645 and 529 cm-1 are characteristic for low-temperature albite (Zussman 1967).Synonyms: pericline, tetartine, clevelandite

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A u t h o r s: Atanacković, Mudrenović and Gaković (1968), Barić (1959, 1964, 1969a, 1970, 1970a, 1972b, 1975), Buzaljko (1971), Cissarz (1956), Čelebić (1967), Čutura (1918), Džepina (1970), Đorđević (1958), Đorđević and Mijatović (1966), Đorđević and Stojanović (1964), Golub (1961), Ilić (1953), Jovanović (1957), Jurković (1954, 1956, 1957, 1958, 1958a, 1961a), Jurković and Majer (1954), Karamata (1953/54, 1957), Karamata and Pamić (1960, 1964), Katzer (1924 and 1926), Koch (1908), Majer (1963), Majer and Crnković (1961), Nöth (1956), Pamić (1957, 1960, 1960a, 1961, 1961a, 1961b, 1962, 1963, 1969, 1969b, 1970a, 1971, 1972b, 1974a), Pamić and Buzaljko (1966), Pamić and Đorđević (1974), Pamić and Maksimović (1968), Pamić and Olujić (1969), Pamić and Papeš (1969), Pamić and Tojerkauf (1970), Pamić and Trubelja (1962), Petković (1961/62), Podubsky and Pamić (1969), Simić (1964, 1966, 1968, 1972), Stangačilović (1956), Šćavničar and Jović (1962), Šibenik-Studen and Trubelja (1967), Tajder and Raffaelli (1967), Trubelja (1957, 1960, 1962, 1962a, 1963, 1963a, 1963b, 1963c, 1966a, 1969, 1972a), Trubelja and Barić (1976), Trubelja and Miladinović (1969), Trubelja and Pamić (1957, 1965), Trubelja and Šibenik-Studen (1965), Trubelja, Šibenik-Studen and Sijarić (1974, 1975, 1975a), Varićak (1955, 1956, 1957, 1966), Vujanović (1962).

Albite is one of the most abundant and ubiquitous rock-forming minerals. It is also one of the best researched minerals, as can be seen from the list of authors given above. Albite occurs in acidic, neutral and basic igneous rocks, both in the inner and outer Dinarides. It is very common in the Triassic igneous-sedimentary complex (the spilite-keratophyre series). Special mention deserves the omnipresence of albite in the rocks of the Bosnian serpentine zone (BSZ) and the associated diabase-chert series (albite-bearing granitoids, syenites, diorites, spilites, rhyolites, keratophyres etc.). The gneisses, granites and similar rocks from Mt. Motajica often contain albite. The same is true of the altered basic igneous rocks of Paleozoic age in the areal of the Una and Sana rivers and the schist mountains of central Bosnia. Albite is associated with the iron minerals at the Ljubija iron-ore deposit. Albite is sometimes an essential constituent of some schists.

Apart from some early publications by Koch (1908), Čutura (1918) and Katzer (1924, 1926), all other information on albite in Bosnia and Hercegovina has been published in the period after the II World War.

1. Albite in rock of the Midtriassic spilite-keratophyre series

A variety of albite-containing igneous rocks are to be found in the area of Konjic, Jablanica and Prozor, in the area of Borovica, Vareš and Čevljanovići; in the Vrbas river valley; around the town of Bugojno, Sarajevo, Trnovo, Kalinovik, Čajniče and Tjentište.

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a) The Konjic – Jablanica – Prozor area

Pamić (1960, 1961, 1961a, 1961b), Pamić and Maksimović (1968) and Čelebić (1967) provide a substantial amount of data on the abundance of albite in spilites, keratophyres, quartz-keratophyres, albite diabases, albite granite-porphyres, quartz albitites and some pyroclastic rocks.

According to Pamić, albite-carrying spilites are most abundant in the watershed of the Rama river, near the village of Lug and in the area of Marina Pećina – Gračanica. These rocks contains two generations of albite. The first generation albite crystals are often idiomorphic or hypidiomorphic, with a prominent (001) crystal form and good cleavage along (010). Twins according to the Carlsbad, albite, albite-Carlsbad laws are common. The second generation albite occurs in the form of microlites. In some spilites the albite is completely fresh, while alteration products of albite (prehnite, calcite and sericite) are common in other spilites. Prehnite appears to be the most common weathering product of albite. Some albite crystals contain inclusions of chlorite.

The An content of albites in the Krstac igneous complex was determined by the Fedorov method using a rotating stage microscope. The An content is in the range 4-9.5%, the median being 4.7% An. The optic axial angle is rater large, 2V = +79° to ±90°.

Keratophyres are fairly abundant in the Krstac igneous complex, especially between the townships of Doljani and Vrata on the right bank of the Rama river. These rocks frequently contain albite (together with neutral plagioclases). Twinning according to the Carlsbad and albite laws is common. The phenocrysts are almost always twinned and included with calcite. Their An content is in the range 0-9%. The +2V angle lies in the range 79° to 87° (keratophyres from Gračanica).

The andesine keratophyres from Bukove Ravni near Doljani contain albite within the matrix of the rock. The has been determined based on low RI’s (lower tha Canada balsam, observed by the Becke line method). The quartz-keratophyres also contain two generations of albite. Single crystal, twins and polysynthetic twins have been observed. Twins according to the Carlsbad and albite laws are most common. Most of the crystals are fresh, sometimes included with prehnite. The An content of albites in rocks from Gračac is between 1.5 and 8.5%. The +2V angle is in the range 77.5-87°.

Albite phenocrysts in the quartz-keratophyres from Krstac (village of Lug) have a An content around 2%. The +2V angle is in the range 80-86°. Albite also occurs together with altered alkaline plagioclases in albite diabases. Their An content is 4.8%. The +2V angle is in the range +82° to ±90°.

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Pamić and Maksimović (1968) determined albite in quartz-albite diabases from Bijela (near Konjic). Here the albite surrounds grains of altered plagioclases.

The granite-porphyres from Ravnice (Gračac) contain albite whose An content is 1.3%. The +2V angle is in the range 80-86°. The quartz-albitites from Crima contain albite with 3.8% An.

Albite has been determined in tuffs from the Gračanica river.

b) the Borovica – Vareš – Čevljanovići area

Albite is abundant in igneous rocks originating from Midtriassic magmatic events in Bosnia and Hercegovina, i.e. in the Borovica – Vareš – Čevljanovići area. Pamić (1963), Trubelja (1969, 1972) and Petković (1961/62) have published a substantial amount of data on albite in the rocks of this area. Albite occurs in, and is sometimes an essential constituent of keratophyres, spilites and albite diabases. Vujanović (1962) determined albite in the manganese mineral paragenesis at Čevljanovići. Albite is fresh in some of these rocks, the average An content is 4.8%. The +2V angle is in the range 70-80°. The keratophyre from Kiprovac (Borovica) contains albite with 0-10% An.

c) Area of Kupres – Bugojno – Donji Vakuf – Jajce

Pamić and Papeš (1969) and Trubelja and Šibenik-Studen (1965) have published relevant data on the occurrence of albite in spilites and similar rock types found in the Vrbas river valley, and in the area of Bugojno and Kupres.

Pamić and Papeš (1969) note that albite is abundant in the sodium-rich effusive rocks (keratophyres), diabases (amphibole-albite diabases, ankerite-albite diabases). the authors believe that albite is a primary mineral in all these rocks, i.e. that it crystallized from a „spilite-keratophyre“ magma. No 2V angle measurements of these albites are available, but the authors have determined its positive optical character. Albite has also been determined in some tuffs from Kupres and the Vrbas river area.

d) Area of Ilidža – Trnovo – Mt. Bjelašnica – Kalinovik

Pamić (1957, 1960a, 1962), and Simić (1964, 1966, 1968) provide data on the occurrence of albite-bearing effusive rocks in the area of Sarajevo, Trnovo and Kalinovik. The igneous rock from Mt. Igman contain albite and other feldspars. There is not much information available on the optical properties of these albites, which seem to be somewhat different from albite occurring in other rocks. The optical character of these albites is positive, but the 2V angles are considerably

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smaller. The albite in dolerites (diabase) from Donje Grkarice has a 2V angle = 68°, in the alkaline dolerite from Mojčevići this angle is in the range +64° to +74°.

Albite occurs in spilites in the source area of the Željeznica river near the village of Godinje. The crystals are single or twinned by the Carlsbad law. The An content is 0-9%, the 2V angle is in the range 74° to 80°. The spilites from the Turovo area contain both albite and oligoclase. Simić (1964) determined optically negative albite in basic igneous rocks from the Sarajevo area. The 2V angle = -80°.

e) Eastern and south-eastern Bosnia

Albite is the most abundant, and sometimes the only feldspar in Triassic igneous rocks of south-eastern Bosnia. Trubelja (1962a, 1963) and Pamić and Buzaljko (1966) made detailed microscopic determinations of albite in keratophyres from the Čajniče area. The keratophyres from Janjina Rijeka contain albite as irregular grains, although a transition from phenocrysts to small, matrix-embedded columnar crystals can be observed. Some grains show effects of alteration (into calcite and chlorite). Microscopic measurements on a rotating-stage microscope gave following results: the An content is rather stable in the 0-8% range. The albite is positive, the +2V angle = 82° to 86.5°, twinning is by the Carlsbad or albite law.

Albite has similar properties in other rocks studied in the Čajniče area. In all cases, albite was optically positive and the 2V angle was large. The albite has low-temperature optical properties.

The origin of the albites in rocks from this area is linked to processes of alkaline (sodium) metasomatosis and the crystallization of andesine and labradorite. This metasomatosis process should be understood in terms of spilitization reaction mechanisms. Evidence for the secondary origin of the albite (deposited in the postmagmatic hydrothermal phase) include following:

1. albite is an essential constituent of all investigated rocks, independent of the SiO2 content of the rock;

2. all investigated rock contain albite with visible relicts of an initial zonar plagioclase structure. Pure albite does not have zonar structure;

3. albite phenocrysts almost always contain calcite inclusions. The calcitization process is more pronounced in the center of the grains than towards the edges;

4. the optical constants, measured on a rotating-stage microscope, correspond entirely to low-temperature albite of the ‘spilite’ type (2V = 79-88°);

5. the acidic dacites from the Lim river area contain neutral plagioclases and have a lower sodium oxide content than the basic rocks from the Čajniče area;

6. the rocks from the Čajniče area have been altered by albitization, but also by

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other postmagmatic processes like chloritization, kaolinization, pyritization, sericitization and epidotization;

7. IR-spectroscopic measurements have confirmed that the albites in rocks from the Čajniče area are typical low-temperature albites.

Trubelja and Slišković (1967) and Trubelja and Miladinović (1969) determined albite as a fairly abundant mineral in some Triassic effusive rocks from Tjentište and Sutjeska.

Karamata (1957) found albite to be a prominent constituent of keratophyres from the Zvornik area. The crystals (up to 1.5 x 1 mm in size) are usually altered (sericite, kaolinite). The RI’s are smaller than those of Canada balsam. The 2V angle is in the range +80° to ±90°.

2. Albite in Triassic-age intrusive rocks

Intrusive rocks (with albite) of Triassic age are not very abundant in Bosnia and Hercegovina. There are outcrops around Čajniče, Donji Vakuf, at Mt. Komar and Mt. Prenj. At the contact of the gabbros at Jablanica with surrounding sediments, some occurrences of albite have been observed. Data on albite in these rocks have been published by Cissarz (1956), Čutura (1918), Nöth (1956), Pamić (1961), Jovanović (1957), Trubelja (1963a) and Trubelja and Šibenik-Studen (1965).

Albite is a prominent mineral in granites from the village of Luke, near Čajniče. The +2V angle is in the range 86° to 89°. Twinning of albite and orthoclase (microperthite) has been observed.

Čutura (1918) provides first data about the abundance of albite in granitoid rocks from Mt. Komar (Gornji Vakuf). More recent research (Trubelja and Šibenik-Studen 1965) have confirmed this finding.

Cissarz (1956) observed the occurrence of albite in the contact paragenesis within the gabbro complex at Jablanica (Tovarnica). This albite occurs in fresh and sometimes quite large crystals. The +2V angle is in the range 72° to 84°, the An content is 0-5%. Optical constants of this albite define its low-temperature origin, which is consistent with the formation conditions of the entire paragenesis. Albite crystallized after epidote.

3. Albite in granitoids and other rocks of the Bosnian serpentine zone (BSZ)

Albite is often found to be a prominent or even essential mineral constituent of granitoids and other rocks of the Bosnian serpentine zone (BSZ) and the lateral diabase-chert series. Relevant data on the abundance an optical properties of albite

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has been published by a number of authors – Džepina (1970), Đorđević and Mijatović (1966), Đorđević and Stojanović (1964), Golub (1961), Karamata (1953/54), Karamata and Pamić (1960, 1964), Majer (1963), Pamić (1970a, 1971), Pamić and Buzaljko (1966), Pamić and Đorđević (1974), Pamić and Olujić (1969), Pamić and Tojerkauf (1970), Pamić and Trubelja (1962), Trubelja (1957, 1960, 1962, 1963b, 1963c, 1966a), Trubelja and Barić (1976), Trubelja and Miladinović (1969), Trubelja and Pamić (1957, 1965), Trubelja, Šibenik-Studen and Sijarić (1974, 1975, 1975a).

The basic metamorphic rocks (without garnets) from Mt. Borja contain albite in some albite-bearing actinolite schists (Džepina 1970). The garnet-bearing equivalents of the named rocks usually contain albite as an alteration product of andesine.

Đorđević and Mijatovaić (1966) observed the presence of albite in serpentine rocks from the Zavidovići area, but provide no further information. Golub (1961) determined albite in rocks from Mt. Kozara. The albite has 8-10% An.

Đorđević and Stojanović (1964) determined albite in granites at Selište, on the Žepče-Maglaj road. The albite is an essential constituent if this rock. The An content is 0-6%, the +2V angle variable, in the range between 78° and ±90°. Twinning by the Carlsbad and albite law is common.

Karamata (1953/54) made numerous measurements of albite occurring in albite rhyolites around Bosansko Petrovo Selo (in the vicinity of the asbestos deposit). Albite phenocrysts (3.5 x 2 mm in size) contain 1-10% An (the average is 1-4%). The 2V angles are variable, but always large and positive. Albites with 1-5.5% An have 2V angles between 78° and 82° (less frequetly between 72° and 77°). Albite crystals are often twinned (Carlsbad, albite, Manebach law).

Karamata and Pamić (1960, 1964) determined albite as a prominent mineral in spilites and granitoid rocks from Vareš (Tibija, Vijaka localities). The granite from Duboštica (Vita Kosa) contains albite with a 0-7% An content, and a variable +2V angle in the range 83° to 88°. This albite is a typical low-temperature variety.

Majer (1963) identified zonar plagioclases in pebbles of a conglomerate belonging to the diabase-chert formation (from Prisoj). The central parts of the grains are composed of oligoclase (up to 12.5% An) while the albite rims contain ca. 7.5% An.

Pamić (1970), Pamić and Olujić (1969) determined an abundance of albite in syenites and granites from Mt. Ozren. Albite-bearing granites form outcrops at Mt. Gostilj (774 m asl) near Bosansko Petrovo Selo. The albite grains are hypidiomorphic and are frequently intergrown by polysynthetic twinning. The An content varies between 0.5 and 7%. The +2V angle = 80-86°.

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The spilites of Mt. Ozren sometimes contain significant amounts of albite (Pamić and Trubelja 1962; Trubelja and Pamić 1965). The spilite from Rakovac creek contains albite with 1-10% An, and the +2V angle is 88-90°. The granites at Mt. Borja (on the Doboj – Banja Luka road) contain albite and oligoclase (Pamić and Tojerkauf 1970). Veins within the diabase-spilite rocks often carry a prehnite-albite mineral association. This has also been observed at Mt. Kozara (Trubelja et al. 1974). Infra-red spectroscopy was used to confirm the finding that these albites are low-temperature forms of this mineral. The diabase rocks from Višegrad often contain albite associated with hydrothermal xonotlite, scolezite, stilbite and fassaite. The veins in rocks of Mt. Konjuh carry albite, prehnite and laumontite (locality Karaula, near the Olovo – Kladanj road).

Trubelja (1960) determined albite in gabbro-pegmatites at Višegradska Banja, associated with labradorite, diallage, prehnite, chlorite, epidote and amphibole. Albite is present either as pseudomorphs after labradorite or as veinlets of very clear and transparent albite crystals. The An content is 0-2%, +2V = 84-88° (indicative of low-albite). Trubelja (1963c) determined albite in leucocratic diorites outcropping on the road Višegrad – Dobrun (in the immediate vicinity of Višegrad). The An content is 4-6%, the average +2V = 82.5°. Albite is an important constituent of spilites from Bosanski Novi (outcrops are north of the Blagaj railway station). It was formed by albitization of alkaline plagioclase (Trubelja 1962).

Trubelja (1966a) determined albite in neutral and acidic igneous and pyroclastic rocks from the northern flanks of Mt. Kozara. The An content is 5-8%. Albite in tuffs contain less An. The keratophyres from Mt. Ljubić contain albite as phenocrysts and as small, columnar crystals within the rock matrix (Trubelja 1963b).

4. Albite in rocks from Mt. Motajica

Ilić (1953), Katzer (1924, 1926), Koch (1908), Stangačilović (1956), Varićak (1966) provide data on the abundance of albite in the various rocks from Mt. Motajica. Ilić discusses the optical measurements on albite (in kaolinized granites from Bosanski Kobaš) by Lj. Barić. The An content is 2-6%, the +2V angle 84° and 78.5° (2 measurements). Koch (1908) published first information on albite in gneisses and micaschists from Mt. Motajica. His qualitative microscpic observations were later used by Katzer (1924, 1926) in his description of igneous and other rocks of Mt. Motajica.

Varićak (1966) published a substantial amount of data based on microscopic measurements on albite in various rocks from Mt. Motajica (a treatise on the petrology of Mt. Motajica). Albite in leptinolites had an average An content of 8.5%, and a +2v angle of 76-87°. Twinning by albite and pericline law is frequent. In chlorite-epidote schists albite is often twinned (Carlsbad and albite law). The An content is 0-9% (average value 4%), +2V = 75-87°. The leucocratic granite hosts albite with 5-8%

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An. The measurements on this material included the maximum extinction method on the (010) plane. More information on microscopic measurements can be found in the mentioned treatise.

5. Albite in Paleozoic-age rocks of western Bosnia and the schist mountains of central Bosnia

Albite is an important mineral, and in many cases an essential constituent of numerous rocks of the Paleozoic complex of western Bosnia and the schist mountains of central Bosnia. Since these rocks cover a large area, it is not surprising that numerous authors were involved in research related to these complexes – Barić (1964, 1970a, 1975), Jurković (1951/53, 1956, 1957, 1958, 1958a, 1961a), Jurković and Majer (1954), Majer and Crnković (1961), Nöth (1956), Podubsky and Pamić (1969), Tajder and Raffaelli (1967), Trubelja and Sijarić (1970), Trubelja, Šibenik-Studen and Sijarić (1974, 1975, 1975a), Varićak (1956, 1957).

a) Albite in the Ljubija area

Information on the occurrence of albite in rocks associated with the iron deposit at Ljubija has been published in papers by Barić, Jurković, Marić and Crnković, Nöth, Podubsky and Pamić.

Nöth (1956) was the first to determine albite in the Kozin ore-body (as well as in sandstones in contact with the ore). The origin of albite in these environments is linked to the proximity of igneous rocks which contain significant amounts olf albite (Podubsky and Pamić 1969). Jurković (1961a) mentions albite only in the ore paragenesis of Bjeljevac – Kozin, where it occurs in a finegrained siderite aggregate. Fragments of albite were also observed in a breccia-type siderite mass.

Marić and Crnković (1961) determined the 2V angle of albite as +85°, characteristic for low-temperature albite.

Barić (1964) made a detailed investigation of the albite from Kozin, including numerous microscopic measurements. The albite grains are mostly fresh and completely transparent. An onset of sericitization was observed in some cases only. Measurements using a rotating stage microscope furnished a set of accurate data for the chemical composition of albite and 2V angles. The average value of +2V = 81.25°. The average An content is 1.6%. This albite has low-temperature optical constants.

b) Area of the schist mountains of central Bosnia

Jurković (1954, 1956, 1957, 1958, 1958a) identified albite as a prominent and occasionally essential constituent of ore-body related mineral parageneses in

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the schist mountains of central Bosnia (SMCB). Albite occurs in metamorphic ore formations at Busovača (Zagradski potok) where it is associated with maghemite, chalcopyrite, tourmaline, biotite, chlorite and other minerals. Albite often shows distinct polysynthetic twinning. The crystals are usually fresh, with prominent twinning lamellae. It contains inclusions of rounded ankerite grains, indicating its younger age with respect to ankerite. The albite is obviously of hydrothermal origin (mesoepithermal stage).

At Ščitovo – Vrtlasce, albite is associated with ore formations (pneumatolytic and hydrothermal stages), together with various sulfides and other minerals. Albite grains 0.2 x 1.5 mm i size) display an allotriomorphic shape in thin section. Free-growing albite crystals (in cavities) can attain 3-4 mm in length. Albite contains inclusions of ankerite. Individual crystals, as well as twins and polysynthetic intergrowths can be observed. The lamellae and twinning sutures are of even and sharp outlines. Microscopic (rotating-stage) measurements gave results for +2V = 74-78.5°. The An content is 0-3%. RI = 1.54. Twinning according to the Carlsbad law.

In the area of Brestovsko, albite is associated with barite mineralizations which carry numerous sulfides and silicate minerals (Hrastovo locality). Albite is of pneumatolytic origin (Jurković 1954). Some albite has been found also at the Trošnik locality.

Albite is a common constituent mineral in rhyolites in the schist mountains of central Bosnia (SMCB). Jurković and Majer (1954) determined albite in the albite-bearing rhyolite from Sinjakovo. Albite phenocrysts (0.5-5 mm in size) are usually twinned (individual crystal are rarely found). The grains are usually cracked (fractured) and corroded (rims). Most grains show signs of alteration. Their An content is 0-10%, the +2V angle = 78-86°. These authors have also determined albite among the phenocrysts in rhyolites (quartz-porphyres) from Krstac and Rosin. Barić (1970a) determined albite as an important constituent of the kertophyres from the Trešanica gorge near Bradina in Hercegovina. Albite is present as phenocrysts but also in the rock matrix. The phenocrysts are usually ca. 1-3 mm long. Individual crystals and twins (including) multiple twins have been observed (twinning by Carlsbad, albite, pericline, Manebach laws). The average An content is 3.1%, the average +2V = 82.6°. This albite has low-temperature optical constants. Many of the albite fragments and phyenocrysts are fractured and bent, the fractures being filled with quartz or calcite. Some grains display uneven (wavy) extinction. The low-temperature variety of this albite has been confirmed by IR-spectroscopy (Barić 1975).

Tajder and Raffaelli (1967) made numerous microscopic determinations of albite contained in metamorphosed porphyrite-keratophyres from the schist mountains of central Bosnia. Albite is frequently contained in several types of schist rocks.

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The moderately altered schists from Neretvica creek, defined as an albite-chlorite-muscovite schist (which belongs to the greenschist facies) contains albite mainly in the matrix of the rock. A similar schist from the Željeznica creek contains albite both in the matrix and as phenocrysts (actually porphyroblasts). Albite was probably formed by albitization of alkaline plagioclases. The An content is 0-5% with an average of 2%. Twinning is by Carlsbad and albite laws. Albite of similar features is contined in schists from the source area of the Vrbas river and some other localities. The authors provide no data on the 2V angle.

Trubelja and Sijarić (1970) determined albite in schists from the upper reaches of the Ivanovica creek near Busovača. The albite is a prominent mineral in the albite-chlorite schists, but only of minor importance in the biotite-chlorite-ankerite schist. Some albite is contained in veinlets within these rocks (together with ankerite and quartz), indicating the significance of exsolution processes for the formation of the albite-ankerite paragenesis.

c) Albite in rocks from Mt. Prosara

Varićak (1956, 1957) found albite to be a common and occasionally essential mineral constituent of both igneous and metamorphic rocks. The quartzporphyres from Mt. Prosara contain albite both as phenocrysts and in the rock matrix. The albite is usually twinned by the Carlsbad and albite laws (twinning by the periciline law is rarely encountered). Individual crystals are rare. Mechanical deformation of the albite grains is the cause of substantial optical inhomogenities. The An content of these rocks is 2-10%, the +2V angle = 74-88°. The grains are ca. 0.3 x 1.5 mm in size. Albite is also a constituent of phyllites and limeschists from Mt. Prosara, but no detailed information has yet been made available.

6. Other occurrences of albite

Varićak (1955) established that albite is an important constituent of the so-called ‘Maglaj red granite’ whose primary location has not yet been identified (it has been found only in the form of pebbles in the river Jablanica and smaller creeks in the Maglaj area).

In this red granite, albite is contained as idiomorphic crystal grains. Individual crystals are rare and twinning by the albite or pericline law is common (also polysynthetic twinning). Double twins, by both the Carlsbad and Manebach laws have been identified. The grains are normally up to 2 mm in size, and some display a two-zone structure (the inner zone is usually much more weathered than the outer zone). The measured +2V angle = 71-80°, the average An content is 9.6%. It is interesting to note that Varićak also mentions neoalbite, which seems to have crystallized in an environment of warm alkali-enriched solutions. Such neoalbite is usually fresh and grows next to the ‘old’ albite grains – making them larger.

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Simić (1972) provides information on the occurrence of albite in some clastic rocks in the Sarajevo area. Albite is an important constituent of sandstones, arkoses and quartz-feldspar rocks (outcropping on Mt. Trebević, Mt. Ozren, near Kijevo, Tarčin, Osenik and Ostrožac, and in the Miljacka river valley). The sediments show evidence of alteration processes. The identified mineral associations consist of quartz, albite, muscovite, hydromuscovite, pyrophyllite, K-feldspar and chlorite. Simić gives no further data on albite.

Šćavničar and Jović (1962) determined the presence of albite in sediments of the Kreka coal basin: in Eocene and Miocene clastic sediments and Pliocene sands.

7. Final considerations

All available literature data and results of other resarch indicate that the Triassic igneous rocks, including the spilite-keratophyre series, contain the low-temperature variety of albite. This conclusion is based, among other indicators, on the large and positive 2V angle of albite as well as on IR-spectra. Moreover, in other parts of the world similar rocks always contain low-temperature albite. We wish to place some emphasis on this conclusion because J. Pamić (1969, 1969a, 1972) tried to advance a theory that some of the mentioned rocks hosted albite which had optical properties of the high-temperature variety. A detailed discussion of this issue can be found in the cited publications by Pamić and those of Lj. Barić (1970, 1972b, 1975).

We therefore wish to conclude that albite contained in the rocks and ore formations in Bosnia and Hercegovina is clearly of the low-temperature variety. The only exception to this conclusion could be the albites in basic igneous rocks from the Sarajevo area for which Simić (1964) determined a negative optical character. This is, however, not compatible with literature data.

We have received certain comments implying that the transition from high-temperature albite to low-temperature albite would neccessarily be a very long process. But time does not seem to be a limiting factor in this case, since the discussed rocks belong to the Triassic (i.e. their age is about 200 million years). Moreover, some recent investigations have shown that the concentration of alkaline solutions and their temperature can have a pronounced effect on transitions of albite and K-feldspars (Senderova, Jaskima and Byčkova 1975). This and other research provides sufficient evidence for the fact that the transition from high-temperature to low-temperature albite proceeds at enhanced reaction rates at temperatures around 700°C (Senderov and Ščekina 1976). Hence, the time required for this transition can be estimated to be 1000 years at temperatures of 400°C or 1 million years at temperatures of 300°C.

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OLIGOCLASE(Na, Ca) [AlSi3O8]

An10 – An30 (Ab90 – Ab70)

Lattice ratio: a : b : c = 0.636 : 1 : 0.556 α = 93° 49’ β = 116° 27’ γ = 88° 59’Cell parameters: ao = 8.169, bo = 12.836, co = 7.134 Z = 4IR-spectrum: 405 430 470 538 590 643 729 748 760 788 1010 1040 1105 1160 cm-1.

A u t h o r s: Barić (1966), Đorđević and Mijatović (1966), Golub (1961), John (1880, 1888), Jovanović (1957), Katzer (1924 and 1926), Kišpatić (1897, 1917), Koch (1908), Majer (1963), Marić (1927), Pamić (1961a, 1961b, 1962, 1969, 1969a, 1971, 1971a, 1972d), Pamić and Kapeler (1969), Pamić and Papeš (1969), Pamić, Šćavničar and Međimorec (1973), Pamić and Tojerkauf (1970), Paul (1879), Simić (1964), Stangačilović (1956), Schafarzik (1879), Trubelja (1966a), Trubelja and Pamić (1956), Varićak (1957, 1966), Vujanović (1962).

Oligoclase belongs to the plagioclase group of minerals (acid plagioclases), and is a typical rock-forming mineral. Literature data on the occurrence of oligoclase in Bosnia and Hercegovina is very scarce, particularly with respect to information available for the other members of the plagioclase group. Data on quantitative optical measurements are particularly lacking.

Oligoclase occurs in Bosnia and Hercegovina in igneous and metamorphic rocks of the Bosnian serpentine zone and in Triassic igneous rock series. Very little data is available on the abundance of oligoclase in Tertiary effusive rocks and associated tuffs. Nevertheless, oligoclase has been determined in various rocks of Mt. Motajica and Mt. Prosara, and from other localities.

1. Oligoclase in rocks of the Bosnian serpentine zone (BSZ)

C. von John (1880) published first data on the occurrence of oligoclase in rocks from the BSZ (area of Višegrad). Results of a chemical analysis of oligoclase is as follows: SiO2 = 64.12, Al2O3 = 23.48, CaO = 3.82, MgO = traces, Na2O = 8.49, K2O = 0.90, Total = 100.81

The oligoclase grains are, according to John, up to 3-4 cm long. Golub (1961) determined oligoclase as en essential constituent of the oligoclasites from Kotlovača creek (oligoclase forms an aggregate of a vein within an actinolite gabbro), and basalts from Brnjačin Jarak at Mt. Kozara. The available microscopic measurements (done on a rotating stage microscope) indicate an An content of 19.5% and a negative average -2V angle of 83°. Oligoclase occurs together with andesine in the basalt rock from Mt. Kozara. The An content is 19%, the -2V angle is in the range 84° to 87°.

Pamić and Kapeler (1969) studied the gabbro-dolerites of Kozarački potok, where they determined oligoclase occuring together with other plagiolases.

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Trubelja (1966a) determined oligoclas as an important mineral in the andesite-dacites from the Bukovica creek, and delenites from the Trnova potok on Mt. Kozara. Oligoclase occurs in rocks on Mt. Borja (Pamić and Tojerkauf 1970), and – together with albite – in the granites outcropping in the Teslić – Kotor Varoš region.

Majer (1963) identified zonar plagioclases in pebbles of a conglomerate belonging to the diabase-chert formation (from Prisoj). The central parts of the grains are composed of oligoclase (up to 12.5% An) while the albite rims contain ca. 7.5% An.

Đorđević and Mijatović (1966) determined oligoclase and albite in veins within serpentine rocks in the Zavidovići area. The veins are ca. 3 m thick and about 8 meters long. Oligoclase was determined by microscopic measurements and x-ray diffracton. The average An content is 13%.

Paul (1879) and Schafarzik (1879) studied the diabases rock used in the construction of the Doboj fortress where they found oligoclase. Kišpatić (1897, 1900) also notes the presence of oligoclase and andesine in sandstones from Kostajnice (Doboj) and in pebbles of the ‘red Maglaj granite’.

Pamić (1969a, 1971, 1971a), Pamić et al. (1973) determined the presence of plagioclases, including oligoclase, in the amphibolites from the Bosnian serpentine zone. For instance, oligoclase and andesine are essential constituent of the amphibolites (pyroxene schists) from Mt. Skatavica, and in the Mt. Krivaja – Mt. Konjuh ultrabasic/amphobolite series. The cited authors also found a relationship between the chemical composition of plagioclases and some physical properties of amphiboles. Acid plagioclases (oligoclase, andesine) normally occur together with optically negative amphiboles (green and brown hornblende). This relationship is illustrated in Figure 24.

Figure 24. The relationship between plagioclase composition and optic axial angles of amphiboles in amphibolites of the Bosnian serpentine zone (Pamić et al. 1973).

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2. Oligoclase in Triassic igneous rocks

According to available literature data, oligoclase occurs in rocks of mid-Triassic age outcropping in the area of Konjic, Jablanica, Prozor and Čevljanovići, as well as in the Ilidža – Kalinovik zone – Marić (1927), Pamić (1961a, 1961b, 1962, 1969), Jovanović (1957), Simić (1964), Vujanović (1962).

Marić (1927) determined oligoclase as an essential constituent of some differentiates of the gabbro rocks at Jablanica. Here, the basic plagioclase labradorite is usually surrounded with a layer (rim) of oligoclase (i.e. the rocks from the village of Zlato). Microscopic measurement (the symmetrical extinction procedure) of the oligoclase layer of plagioclase grains, an average An content of 25% was determined. More acid oligoclases (surrounding andesine grains) have also been identified, and these contain ca. 15% An. John (1888) provides results of the chemical analysis of oligoclase from a vein within the gabbro: SiO2 = 62.90, Al2O3 = 22.80, Fe2O3 = 1.05, CaO = 3.55, MgO = 0.40, Na2O = 8.49, K2O = 0.53, Loss-on-ignition = 0.90, Total = 100.81

Pamić (1961a, 1961b) determined oligoclase in spilites, andesine-keratophyres and quartz-keratophyres from the area of Konjic, Jablanica and Prozor. Oligoclase occurs usually in association with albite and contains ca. 13-15% An. Jovanović (1957) noted the presence of oligoclase in granites from Mt. Prenj.

Pamić (1962) identified oligoclase as a prominent mineral in K-Na- spilites from the Turovo area of the Ilidža – Kalinovik zone, near the source of the Željeznica river. The An content of this oligoclase can be as high as 20%.

Simić (1964) studied the basic volcanic rocks from the Rača creek (north of Sarajevo) and found oligoclase (27% An) and andesine plagioclases in them. Andesine is normally surrounded with a rim of oligoclase. Vujanović (1962) determined oligoclase in the manganese mineral paragenesis at Čevljanovići.

3. Oligoclase in rocks from Mt. Motajica and Mt. Prosara

Koch (1908) provides first data on the abundance of oligoclase in rock from Mt. Motajica. It occurs in the granite from Veliki Kamen (Vlaknica), and in the muscovite-bearing granite from Brusnik. Oligoclase is much less abundant than the other plagioclases.

Stangačilović (1956) determined oligoclase as am accessory constituent of altered granites from Mt. Motajica.

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Varićak (1966) published a substantial amount of data based on microscopic measurements of oligoclase in various rocks from Mt. Motajica (a treatise on the petrology of Mt. Motajica). Oligoclase thus occurs in normal granites, „frozen-edge granites“, leucocratic granites, pegmatites and aplites, contactolites, gneisses, kornites, amphibolites and amphibolite-schists. In norml granite, oligoclase has an An content between 10% and 18%, while the 2V angle lies in the range +86° to -86°. The „frozen-edge“ granite contains normally oligoclase with a zonar structure (two zones). The An content is 18-20%. The -2V angle = 83-84°. Twinning according the albite law is common. The leucocratic granite contains oligoclase associated with albite. The An content of this oligoclase is 15%. Oligoclase in other mentioned rocks has similar properties.

Varićak (1957) found that oligoclase and albite are essential constituent of the green metamorphic rocks of Mt. Prosara, but gives no further data on these plagioclases.

4. Oligoclase in Tertiary igneous rocks

John (1880) provides first information on the occurrence of oligoclase in Tertiary-age effusive rocks fro Srebrenica. Subsequent reserach could not confirm this finding.

Trubelja and Pamić (1956) made microscopic determinations of oligoclase (and andesine) in biotite-bearing dacites from the left bank of the Bosna river.

Barić (1966) determined oligoclase in Tertiary volcanic tuffs found in the Livno area. Although most microscopic determinations indicate the presence of andesine, some data correspond to high-temperture oligoclase (28-30% An, 2V = -81.5°).

ANDESINE(Na, Ca) [Al1-2Si2-3O8]

An30 – An50 (Ab70 – Ab50)

Lattice ratio: a : b : c = 0.635 : 1 : 0.552 α = 93° 24’ β = 116° 10’ γ = 90° 24’Cell parameters: ao = 8.176, bo = 12.879, co = 7.107 IR-spectrum: 429 465 537 632 741 1005 1090 1143 cm-1. (for andesine with 33% An, ref. Zussman 1967). 428 471 538 625 678 744 1005 1090 1143 cm-1. (for andesine with 43% An, ref Zussman 1967)

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A u t h o r s: Barić (1966), Buzaljko (1971), Behlilović and Pamić (1963), Čelebić (1967), Džepina (1970), Đorđević (1958), Golub (1961), Jurković (1954a), Katzer (1924 and 1926), Kišpatić (1897, 1900, 1917), Koch (1908), Luković (1957), Majer (1961), Majer and Jurković (1957, 1958), Matić (1927), Pamić (1961a, 1961b, 1969, 1969a, 1971, 1971a, 1972, 1972d), Pamić, Dimitrov and Zec (1964), Pamić and Kapeler (1969), Pamić and Papeš (1969), Pamić, Šćavničar and Medjimorec (1973), Paul (1879), Podubsky and Pamić (1969), Polić (1951), Ramović (1957, 1962), Schafarzik (1879), Simić (1964), Stangačilović (1956), Šćavničar and Jović (1962), Tajder (1951/53, 1953), Trubelja (1960, 1961, 1962a, 1963, 1963b), Trubelja and Pamić (1956, 1957, 1965), Trubelja and Slišković (1967), Varićak (1966).

Andesine occurs in Bosnia and Hercegovina in igneous, sedimentary and metamorphic rocks and is a typical rock-forming mineral. It is fairly abundant in igneous and metamorphic rocks of the Bosnian serpentine zone and the associated diabase-chert series. The Triassic igneous rocks in the Konjic – Jablanica – Prozor area also contain andesine as an essential constituent. The granites and some other rocks at Mt. Motajica contain andesine. The Tertiary-age effusive rocks and tuffs contain andesine together with other plagioclases.

1. Andesine in rocks of the Bosnian serpentine zone (BSZ)

According to available literature reference, andesine occurs in various rocks belonging to the Bosnian serpentine zone. These rocks are found in the area of Višegrad, at Mt. Konjuh, in the watershed of the rivers Bosna and Vrbas (at Mt. Skatovica) as well as on Mt. Kozara.

Trubelja (1960) determined andesine in the basalts from the village of Lahci, near Višegradska Banja. Labradorite is also present in this rock. The andesine grains are mostly idiomorphic and fresh. Occasional fractures are filled with more acidic third-generation plagioclase (albite ?). Their zonar structure is clearly visible under the microscope. The andesine and labradorite grains are frequently pitted and corroded, an effect of their partial resorption. The An content of these andesine grains is around 50%. The +2V angle = 77.5-84.5°. Microscopic measurements were done on twins and multiple andesine twins.

Trubelja (1961) determined andesine and labradorite as essential constituents of the gabbro-diorite vein at the village of Podpaklenik, near Veliki Rastik on Mt. Konjuh. The An content of this andesine is more zhan 45%, while the +2V angle = 78° to 82°. The plagioclases have a zonar structure.

Đorđević (1958) identified extensively altered plagioclase in gabbroid rocks from the Vareš area. Microscopic measurements correspond to an An content of 50%, so the plagioclase can be defined as basic andesine.

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The amphibolites from the Krivaja – Mt. Konjuh area contain andesine, usually associated with optically negative amphiboles (Pamić 1971a, Pamić et al. 1973).

Džepina (1970) determined andesine in the garnet-bearing metamorphic rocks from the southern flanks of Mt. Borja. This andesine has an An content of 42%, and usually occurs in the form of xenoblasts displaying some twinning lamellae. Alteration of plagioclase to prehnite, albite and sericite is more or less extensive. The metamorphic rocks (garnet-diopside schists) from Mt. Skatovica near Banja Luka contain andesine with 41% An (Pamić 1969, Pamić et al. 1973).

Paul (1879) and Schafarzik (1879) studied the diabases rock upon which the Doboj fortress is erected, in which they determined andesine. Kišpatić (1897, 1900) also notes the presence of andesine in sandstones of this area and in pebbles of the ‘red Maglaj granite’ (found at Mala Bukovica).

Barić (unpublished results) made a detailed microscopic study of the diabases from Doboj (fortress). Measurements done using a rotating-stage microscope confirmed that the plagioclase contained in the diabase is a basic andesine (or acid labradorite) with high-temperature optical constants. The variations of anorthite content and 2V angles is as follows:

% An 52-48 44-46 54-51 53-50.5 51-52 51 552V +75-79° -80° +77.5° +75° +78° +73° +75°

One twinned plagioclase crystal had 62-63% An, corresponding to labradorite.

Golub (1961), Trubelja (1966a), Pamić and Kapeler (1969) investigated andesine-bearing rocks of Mt. Kozara. According to Golub, andesine is an essential constituent of diabases from the Kotlovače and Huremovac creeks. The diabase from Kotlovače creek contains columnar andesine grains with 39-46.8% An (+2V = 84-85°). The grains are 0.3-2 mm in size, and often zonar in structure. The material from Huremovac contains prismatic andesine grains. Larger grains are uncommon and display extensive alteration. Microscopic measurements (extinction angle measurements on 8 grains) correspond to 45% An.

Trubelja (1966a) identified andesine of dolerites and diabases on the northern flanks of Mt. Kozara (Trnova creek). The content of An varies in the range 36.3-50%. The 2V angles can be positive or negative.

2. Andesine in Triassic igneous rocks

Andesine is often an essential constituent of intrusive, effusive and vein-type rocks of Triassic age in various regions of Bosnia and Hercegovina (also in associated pyroclastic rocks).

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Pamić (1961a, 1961b) determined andesine in andesites from Vrata near Sovići, in the area of Jablanica and Prozor in Hercegovina. Andesine occurs together with labradorite. The An content is 47-50%, the +2V angle = 83°. The andesine grains have zonar structure and are mostly fresh. Twinning according to the Carlsbad, albite and pericline laws have been observed.

Marić (1927) was able to identify plagioclases in some differentiates of the gabbro series at Jablanica. The composition of these plagioclases corresponds to andesine – labradorite.

Čelebić (1967) studied the andesine-containing keratophyres from Bukove Ravni near Doljani, where andesine is an essential constituent. The andesine occurs as idiomorphic or hipidiomorphic phenocrysts, twinned according to the albite law (less often by the Carlsbad law). Microscopic measurements correspond to 34-48% An, with an average value of 42%, +2V = 77-83°.

Behlilović and Pamić (1963) determined neutral plagioclase (probably andesine) in tuffs from the Drežanka river watershed. Andesine was also determined in the tuffs from Stupari.

The basic and neutral intrusive igneous rocks from Bijela Gromila (Travnik area) contain andesine and labradorite as essential constituents (Majer and Jurković 1957, 1958). Andesine and labradorite also occur in andesites from the village of Orašine in the schist mountains of central Bosnia (Jurković 1954a).

Polić (1951) maintains that andesine and labradorite are essential constituents of andesites from Ljubovički creek, close to the village of Gojevići, near Bakovići. Microscopic measurements were done by V. Nikitin.

Simić (1964) determined the presence of andesine in the complex of basic rocks, located to the north of Sarajevo, near the source of Orački creek. The plagioclase grains are zonar. The central portions contain about 46% An, while the rims consist of oligoclase.

Trubelja (1962a, 1963), Trubelja and Slišković (1967), Buzaljko (1971) studied the igneous rocks and their pyroclastic associates in south-eastern Bosnia. Andesine is often an essential constituent of these rocks. The dacites (quartz-porphyres) from the Lim river valley contain zonar andesite with 45-47% An (+2V = 80°). The rock from the village of Omačine has more than 50% An and a corresponding +2V angle of 85°.

The celadonite-bearing sandstones from Kiprovac and Borovica (near Vareš) contain andesine with 45-48% An. Andesine was determined by microscopic measurements and x-ray diffraction (Ramović 1957, Trubelja 1969).

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Trubelja and Slišković (1967) measured the andesine in andesites from the Tjentište area. The andesine contains 35-44% An.

3. Andesine in Tertiary igneous rocks

The treatise on the petrology of dacites in the Srebrenica area (Tajder 1951/53, 1953) contains numerous microscopic determinations of plagioclases (including andesine) in these rocks. Andesine is an essential constituent of biotite-bearing dacites (Jamno creek, Sase, Divljak), dacites (Kiselica creek, Majdan creek), biotite-bearing dacites (village of Ažlice), amphibole-bearing dacites (Srebrenica) and propilitized dacites (Crvena Rijeka).

The biotite-bearing dacites from Jamno creek contain andesine and labradorite as large, idiomorphic crystals (the largest ones are more than 1 mm long). Twinning on the albite, Carlsbad and combined CA law is common. Some grains are zonar. The An content is in the range 48-50% which correspond to very basic andesine. Alteration into kaolinite can be extensive. The +2V angle = 76-87.5°. The andesine from the dacites of Kiselica creek contain 42-50% An. The idiomorphic/hipidiomorphic crystals are large (the largest one was 1.8 x 2.2 mm in size) and sometimes zoned. Similar twinning as in the previous case.

The biotite-bearing dacites from Ažlice contains andesine with 43-50% An (+2V = 80-89°). Some grains correspond to labradorite composition. The plagioclase grains are mostly idiomorphic, zonar and almost always twinned (albite, Carlsbad laws). Some grains are twinned on the pericline law and display a rhombic twinning plane. Most of the grains are fresh, although some show signs of moderate alteration (to calcite and kaolinite).

The amphibole-bearing dacites from Srebrenica contain andesine of similar microphysiographic properties. The An content is 46-49%, the +2V angle = 80-85°.

The biotite-bearing dacites from the village of Sase contain andesine phenocrysts with an averag An content of 44% (+2V = 80.5°). A similar rock from Divljak carries andesine with 46% An (+2V = 86°).

The treatise on the petrology of the Srebrenica area (Tajder 1953) discusses also the temperature relationships of plagioclase, icluding andesine. Important are spherical coordinates and angles of specific geometric elements with the proncipal vibrational directions X, Y and Z. The cited publication by Tajder contains 37 such measurement (for the [010] axis) of which only 5 datasets correspond reasonably well to the migration curve in the Nikitin diagram (1936). The rest of the data is ‘grouped’ to the ‘southwest’ of the existing curve, in an area where there is no curve in the Nikitin diagram. The first corresponding curves (for high-temperature

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optics) were published in 1958 by Zavarickij et al. This is a strong indication that the andesine contained in the Tertiary effusive rocks of the Srebrenica complex is a high-temperature variety of this plagioclase (Barić 1959).

Trubelja and Pamić (1956) and Pamić et al. (1964) determined andesine as an essential constituent of the andesite-dacite rocks from the Bosna river valley. The biotite-bearing dacite on the left bank of the Bosna river (around Maglaj) contain idiomorphic to hipidiomorphic andesine, which is sometimes extensively altered to kaolinite and calcite. A comparatively small number of microscopic measurement (on a rotating-stage microscope) indicate that the An content is in the range 34-37%.

More data is available for the andesine occurring in amphibole-bearing dacites from the village of Parnice. Andesine phenocrysts are usually zoned and twinned on the Carlsbad, albite or complex Carlsbad-albite law (multiple twins were also observed). Alteration of the andesine grains can be extensive. Their An content is in the range 34-45.5%. The optical character is negative, 2V = -79° to -88°. Some grains only have a positive 2V angle of 80° to 82°.

Majer (1961) determined that the dacitelike rocks from the Blatnica creek near Teslić contain andesine with a 40.5% An content (this is the average value of several measurements). Grains can be up to 3 mm in length, have a zonar structure and show polysynthetic twinning. Some grains show signs of extensive kaolinitization and calcitization. Many have rounded rims due to corrosion.

4. Andesine in sediments and pyroclastic rocks

There is a quite limited amount of data on the presence of andesite in sediments and pyroclastic rocks – Barić (1966), Luković (1957), Šćavničar and Jović (1962).

Barić (1966) made numerous microscopic determinations of plagioclases contained in tuffs from the Livno area, and found that most of the grains are andesine. Their An content is 30-39.5% and the 2V angles are negative, with a few exceptions. This andesine has high-temperature optical constants. Luković (1957) determined andesine as an essential constituent of Neogene tuffs from Tuzla. Šćavničar and Jović (1962) determined andesine in Pliocene-age sands from the Kreka coal basin.

5. Andesine in rocks from Mt. Motajica

Koch (1908), Katzer (1924, 1926), Stangačilović (1956) and Varićak (1966) provide data on the abundance of andesine in the various rocks from Mt. Motajica.

According to Varićak (1966), andesine occurs in amphibole-bearing gneisses, hornblendites, amphibolites, amphibole schists and granite porphyres. Stangačilović notes the presence of andesine in kaolinized granites, but only as an accessory

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constituent. Granite porphyres contain less andesine than albite and oligoclase. The amphibole-bearing gneisses contain andesine as a prominent mineral, together with oligoclase. Andesine crystals and grains are usually twinned on the pericline law so that it displays a lamellar texture. Manebach-type twins are rare. The An content is 34-38.5% (+2V = 85-87°).

LABRADORITE(Ca, Na) [Al1-2Si2-3O8]

An50 – An70 (Ab50 – Ab30)

Lattice ratio: a : b : c = 0.635 : 1 : 2 x 0.552 α = 93° 34’ β = 116° 06’ γ = 89° 47’Cell parameters: ao = 8.16, bo = 12.86, co = 2 x 7.10 Z = 8 IR-spectrum: 427 465 538 622 674 744 992 1089 cm-1. (for labradorite with 52% An, ref. Zussman 1967). 427 465 538 619 679 747 992 1093 1139 cm-1. (for labradorite with 67% An, ref Zussman 1967) The peaks at 538 and 622 cm-1 are diagnostic.

A u t h o r s: Barić (unpublished results), Brajdić (1964), Džepina (1970), Golub (1961), John (1880, 1888), Jurković (1954a), Karamata (1953), Kišpatić (1897, 1900, 1904, 1904a, 1904b, 1910), Majer and Jurković (1957, 1958), Marić (1927), Pamić (1960a, 1961a, 1961b, 1969a, 1971, 1971a, 1972, 1972d), Pamić and Antić (1964), Pamić and Kapeler (1969), Pamić, Šćavničar and Medjimorec (1973), Polić (1951), Ramović (1957, 1962), Ristić, Panić, Mudrinić and Likić (1967), Sijerčić (1972a), Šibenik-Studen and Trubelja (1971), Tajder (1953), Trubelja (1957, 1960, 1961, 1966a), Trubelja and Pamić (1957, 1965), Trubelja and Slišković (1967), Tućan (1928).

Labradorite is a very common and abundant mineral in the rocks of Bosnia and Hercegovina. It occurs most frequently in basic igneous rocks (gabbro, diabase etc.) and amphibolites of the Bosnian serpentine zone (BSZ).

Labradorite is also an essential constituent of Triassic-age igneous rocks of the volcanogenic-sedimentary series. It is abundant both in basic intrusive rocks as well as effusives, veins and tuffs.

The Tertiary volcanic rocks rocks contain plagioclases, including labradorite, as essential mineral constituents.

1. Labradorite in rocks of the Bosnian serpentine zone (BSZ)

C. von John (1880) published first data on the occurrence of labradorite in rocks from the BSZ. He determined the mineral in the gabbro rocks from Barakovac and troctolites from the Višegrad area.

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The wellknown treatise on the rock of the serpentine zone (Kišpatić 1897, 1900) contains a substantial number of microscopic determinations of plagioclases in various rocks of the BSZ. However, not much information refers specifically to labradorite. Nevertheless, Kišpatić notes that labradorite is an essential constituent of the eclogite pyroxenite from Višegrad as well as basic igneous rocks from the Doboj area. A description of labradorite contained in amphibolite from Mt. Borja has been published in a separate paper (Kišpatić 1904b). This labradorite is usually fresh and transparent, with irregular, polysynthetically twinned grains (twinning on the albite and pericline laws is also common). It contains 66% An. Unpublished results of microscopic investigations of the Gradina diabases from Doboj showed the presence of high-temperature labradorite and andesine (Barić, unpublished results).

Trubelja (1957, 1960) determined labradorite is abundant in gabbros, diabases, gabbro-pegmatites and gabbro-peridotites from Višegrad. The gabbro-peridotites from Bosanska Jagodina contain the low-An variety of labradorite with an average An content of 56%. Based on the results of numerous microscopic measurements (on a rotating-stage microscope) the An content varies between 50% and 63.5% (+2V = 74.5-85°). Grains are frequently twinned on the albite and Carlsbad law.

The olivine-bearing gabbros from Rijeka, near Velika Gostilja, contain a high-An labradorite with an average An content of 69.3% (so that grains with bytownite chemistry may be encountered). The abundance of labradorite in this rock is more than 50%. Grains are mostly fresh, and only a few cases of fracturing and alteration have been observed. The An content is comparatively stable, in the range 64.5% to 70% (+2V = 80° to 86°). Twinning according to the albite, Carlsbad and comples albite-Carlsbad law is common. The gabbro rock also hosts monomineral labradorite veins. This labradorite has more or less identical properties to the one in the rock matrix. The An content is 69%, so that some of the labradorite may in fact be bytownite.

The gabbros from the village of Pijavice contain labradorite and some bytownite. The An content is 65-70%. The veins in the gabbro-pegmatite from Višegradska Banja are composed largely of labradorite (the grains are of variable size, in the millimeter to centimeter range). Twinning lamellae are often bent due to tectonic forcing. The An content is 57.5-62% (+2V = 84°).

The diabases from Banja Potok contain labradorite with an An content of 58.5% (+2V = 80-82°) and some of the plagioclase is probably andesine. The crystals are prismatic and often twinned. The dolerite outcrops on the Dobrun – Smrijeće road in the river Rzav valley contain some labradorite (68.5% An).

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The basalts found in the Lahci area contain labradorite as an essential constituent, in addition to andesine. The phenocrysts have a zonar structure, are mostly idiomorphic and fresh with occasional evidence of resorptive corrosion. Twinning on the albite and Carlsbad law is common. The An content is variable (53-70%) and the optic axial angle +2V = 74-83°.

Rocks of the Krivaja – Konjuh ultrabasic complex often contain labradorite as their essential constituent. This is true both for the igneous as well as for the metamorphic rocks. This complex has been investigated in detail, and numerous microscopic determinations, chemical and XRD analyses are given in publictions by Trubelja (1961), Brajdić (1964), Pamić (1971, 1971a), Pamić and Antić (1964), Pamić et al. (1973), Šibenik-Studen and Trubelja (1971), Ristić et al. (1967), Pamić and Kapeler (1970).

The dolerites from Blizanci creek are largely composed of labradorite and some bytownite (Trubelja 1961). The crystals are prismatic (up to 1 cm in length) with a zonar and lamellar structure. The zonar structure is in some grains so expressed that the central portion of the grain is dark when observed in polarized light, while the sectors on the rim are not in extinction position. The polysynthetic twinning lamellae are very narrow so microscopic measurements (rotating stage) could be done only with some difficulty. Nevertheless, most of the grains were fresh and the An content was determined as 64.5-70% (+2V = 80-85°).

Brajdić (1964) determined labradorite in the gabbro-pegmatite from Olovo (village of Bjeliš). The labradorite grains were quite dark (grey) due to inclusions of amphibole. Twinning according to the albite law is common, less frequently according to the Carlsbad or pericline law. Based on a number of microscopic rotating-stage measurments, the An content was determined as 50-58% (corresponding to +2V = 74-86°).

Chemical analysis of this labradorite yielded following results (in %):SiO2 = 53.29; TiO2 = 0.13; Al2O3 = 28.19; Fe2O3 = 0.16; FeO = 0.80; MgO = 0.05; CaO = 10.98; Na2O = 5.54; H2O

+ = 1.11; H2O- = 0.98; Total = 100.33%

If the minor amounts of TiO2, Fe2O3, FeO and MgO are disregarded (these probably reflect amphibole chemistry), and the remainder of the composition recalculated into albite and anorthite molecules (so that the entire amount of CaO and N2O are bound to equivalent mount of Al2O3 and SiO2), a plagioclase with 53.62% An content is obtained, corresponding to an acidic labradorite. This result is in accordance with microscopic measurements.

The density of this labradorite, determined by the pycnometric method, is

2.702 at 20°C. Ristić et al. (1967) determined labradorite as an essential constituent of the gabbro rocks from Mt. Konjuh. The average An content of gabbros from

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Katranička Rijeka and Gnjilo Brdo is 55% (+2V varies in the range between 70° at Katranička Rijeka, to 85° at Gnjilo Brdo). These authors provide results of a chemical analysis of labradorite from the source area of the Bukovica riverSiO2 = 51.11; Al2O3 = 22.28; Fe2O3 = 0.34; FeO = 0.88; MgO = 1.12; CaO = 12.06; Na2O = 6.65; H2O

+ = 4.20; H2O- = 0.50;

The results given above indicate that the labradorite is quite contaminated. Pamić and Antić (1964) determined labradorite to be the predominant and sometimes the only present plagioclase in the gabbro complex of Gostovička Rijeka near Zavidovići. The An content of this labradorite is 50-64% (+2V = 76-88°). The grains are mostly fresh, and twinning according to the albite law is common.

Labradorite and other plagioclases are importanst and essential constituents of metamorphic rocks in the Krivaja – Konjuh area. They usually occur in amphibolites and corundum-bearing amphibolites (Pamić and Kapeler 1970; Pamić et al. 1973). Labradorite normally occurrs in association with pargasite-edenite and green hornblende.

Trubelja and Pamić (1965) determined labradorite as an essential constituent of basic rocks at Mt. Ozren. The plagioclases contained in porphyrric amphiboledolerites of the Krivaja creek comprise two generations. The grains of the first generation are quite large and idiomorphic and rather weathered. Their An content is 64-79% corresponding to basic labradorite or acidic bytownite. Plagioclases of the second generation are more acidic than the porphyry labradorite phenocrysts.

The metamorphic series of rocks at Mt. Skatovica frequently contain labradorite and other plagioclases (Pamić 1969, 1972; Pamić et al. 1973), mostly the oligoclase-bytownite members. Even some reaction effects between different plagioclases have been observed. For example, the sample which contains mainly oligoclase (21% An), contains also relicts of labradorite (58% An). This could mean that the rock originally contained basic plagioclases (labradorite through bytownite), but that alteration processes resulted in the formation of more acidic plagioclase (andesine and oligoclase).

Golub (1961), Trubelja (1966a), Pamić and Kapeler (1969) identified labradorite as an important mineral in basic igneous rocks at Mt. Kozara, especially in the gabbro-type differentiates. Golub provides numerous and detailed microscopic measurements (rotating stage microscope) of labradorite in olivine gabbros, gabbros, uralite gabbros and gabbro-pegmatites from the southern flanks of Mt. Kozara. The gabbros from Jovača creek contain labradorite with an An content in the range 57.75-66% (average = 63% An). The average +2V angle = 84.5°. Twinning is according to the albite law. The optical constant of the labradorite contained in the olivine-bearing gabbros from Kozarački creek are almost identical to the ones

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cited above. On the other hand, the gabbros from Kozarački creek contain more acidic labradorite (average is 51% An, +2V angle = 80°). The composition of the labradorite in uralite gabbros is very similar (62.7% An, and 2V = +80°).

The data on the abundance of labradorite in the above mentioned rocks is quite interesting. The olivine gabbro (Jovača creek) contains ca. 35% labradorite, while the olivine gabbro from Kozarački creek contains 70% labradorite. The abundance of labradorite in the gabbro from Kozarački creek is 57.5%, while the uralite gabbro contains 61% labradorite.

The pegmatite veins from Kotlovača creek contains coarse grained labradorite. The crystals are 0.5-8 cm in length. The labradorite contains 55.5% An, the +2V angle is 76°.

Trubelja (1966a) determined labradorite as an essential constituent of diabase-dolerites from the northern flanks of Mt. Kozara. The diabase from the Bukovica creek contains labradorite with 52-55% An and 2V = 84°, almost identical to the labradorite in dolerites form Trnava creek (54.5-56% An, +2V = 78-87°). The plagioclase in diabase porpyrites from Dobrlin are also labradorite (Kišpatić, 1904b).

2. Labradorite in products of Triassic volcanism

Labradorite is the most common and abundant mineral in rocks of the Triassic-age magmatism in various areas of Bosnia and Hercegovina (apart from rocks belonging to the Bosnian serpentine zone). The gabbro-diorites from Bijela Gromila (south of Travnik, schist mountains of central Bosnia) labradorite and other plagioclases (andesine, bytownite) as essential constituents (Majer and Jurković 1957, 1958). The diorite from Kopile contains plagioclase with 66% An, corresponding to labradorite – usually located in the central portions of the grains. The rims of the grains are normally composed of more acidic plagioclase (andesine). Such is the case with the olivine-bearing gabbros from Stajište (Margetići).

Gabbros and its differentiates in the Jablanica complex contain labradorite as an essential constituent (John 1888, Kišpatić 1910, Marić 1927). In his account of gabbros in the Travnik – Bugojno area, Kišpatić (1910) notes the presence of labradorite and bytownite in the gabbros of the Jablanica complex. John isolated a rather clean labradorite from the ‘augite-diorite’ rock outcrops on the southern flanks of the complex and made a chemical analysis of this material:

SiO2 = 53.50; Al2O3 = 29.65; Fe2O3 = 0.20; CaO = 11.55; MgO = 0.28; Na2O = 4.67; K2O = 0.77; Loss-on-ignition = 0.75; Total = 101.37

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SILICATES

Marić (1927) determined that the zonar plagioclase grains of the Jablanica gabbros are composed of labradorite in the core and oligoclase on the rim of such grains (the gabbro from the village of Zlata). In some cases labradorite forms the rim while bytownite the core of grains. The extensively altered gabbros contain labradorite with an An content of 53-58%, 2V = +75° (rim of grain); 61-69% An, 2V = 83-83.5º (core of grain). The chemical composition of the labradorite was derived from the Fediuk curves and correspond to low-temperature plagioclase (Barić, unpublished results).

Jurković (1954a) determined labradorite in the andesites near Orašine, close to Bakovići. Numerous microscopic measurements correspond to labradorite, although some grains were closer to andesine. The grains are quite different in size (0.03 x 0.03 mm to 2.0 x 1.3 mm. Jurković measured the grains using a standard micrometer-eyepiece. The labradorite crystals are mostly prismatic or columnar, only occasionally tabular parallel to (010). Most of the crystals are twinned (Carlsbad, albite and complex law) – polysynthetic twinning is also common. Zonar structure is more pronounced in the case of smaller grains. Crystal grains of the first generation are mostly fresh and display distinct cleavage planes along (001) and (010). Microscopic measurements (using arotating stage) on 3 grains gave following results: 57.5-59.25% An, +2V = 78-80°. The highest An content determined on some grains was 66%.

Polić (1951) maintains that labradorite and andesine are essential constituents of andesites from Ljubovički creek, close to the village of Gojevići, near Bakovići. Microscopic measurements were done by V. Nikitin.

Labradorite is also an important mineral of the spilite-keratophyre rocks found in the areas of Jablanica and Prozor, and elsewhere – Tućan (1928), Karamata (1953), Ramović (1957), Pamić (1960a, 1961a, 1961b). Tućan determined phenocrysts of zonar but completely fresh labradorite and bytownite in the andesites from Vrata in the river Doljanka watershed. Pamić (references as above) identified labradorite in the basalto-andesitic and pyroclastic rocks from Jablanica and Prozor. The An content of this labradorite is quite high (63-70%). The andesites from Vrata and Krstac contain labradorite with 52-54% An (+2V = 77-87°) associated with basic andesine. The labradorite in the tuffs from this are has an average of 62% An (+ 2V = 87°), while the tuff from Stupari contain a slightly more acidic plagioclase. Labradorite is an essential constituent of basalto-andesites from Kalinovik (Pamić 1960a). Karamata (1953) and Ramović (1957) determined labradorite in basic igneous rocks and associated tuffs in the area of Vareš.

Trubelja and Slišković (1967) determined labradorite in basic-to-neutral effusive and vein rocks of Mid-Triassic age. These rock are particularly abundant in the Hrčavka river valley. The labradorite has an An content of 64-67%.

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3. Labradorite in products of Tertiary volcanism

Information on the abundance of labradorite in products of Tertiary volcanism can be found in the papers by Kišpatić (1904, 1904a), Ramović (1962) and Tajder (1953).

Kišpatić determined labradorite – together with bytownite – in the hypersthene-bearing andesite from Potočari and Crveni Potok in the Srebrenica area. This labradorite contains 56% An (Kišpatić 1904a). It is also a constituent of dacites (from Kneževac near Srebrenica, and from Protin Han – on the road between Potočari and Srebrenica). Kišpatić (1904) found labradorite to be an essential constituent of the andesite-type rocks outcropping in the Bosna river valley. The same is the case for the andesitesfrom Maglaj.

Tajder (1953) provides a substantial amount of data on the labradorite contained in the effusive rocks of the Srebrenica area. The dacites from the village of Diminići contain 50-56% An, the biotite-bearing dacite from Jamno creek (between 50% and 52% An), from Ažlice (73% An). Based on the optical constants, the labradorite contained in the effusive rocks from Srebrnica is of the high-temperatures variety, like andesine.

4. Labradorite in chlorite-bearing schists from Mt. Vilenica near Travnik

Kišpatić (1904b) studied the labradorite contained in the chlorite-bearing schists found at Mt. Vilenica near Travnik. The labradorite grains have a vitreous texture and contain inclusions of epidote and chlorite.

BYTOWNITE(Ca, Na) [Al1-2Si2-3O8]

An70 – An90 (Ab30 – Ab10)

Lattice ratio: a : b : c = 0.635 : 1 : 1.102 α = 93° 22’ β = 115° 58’ γ = 90° 31’Cell parameters: ao = 8.171, bo = 12.869, co = 14.181 Z = 8 IR-spectrum: 425 431 480 538 620 680 751 938 987 1093 1134 cm-1. (for bytownite with 85% An, ref. Zussman 1967).

A u t h o r s: Đurić and Kubat (1962), Esih and Natević (1963), Golub (1961), John (1888), Karamata (1953), Katzer (1924, 1926), Kišpatić (1897, 1900, 1904, 1904a, 1910, 1917), Kubat (1964), Majer (1962), Majer and Jurković (1957, 1958), Marić (1927), Marković and Takač (1958), Pamić (1960a, 1961b, 1969, 1969a, 1971, 1971a, 1972, 1972d, 1974), Pamić and Kapeler (1969), Pamić, Šćavničar and

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SILICATES

Medjimorec (1973), Pamić and Trubelja (1962), Ramović (1957), Schiller (1905), Tajder (1953), Trubelja (1957, 1960, 1961), Trubelja and Pamić (1965), Tućan (1928), Varićak (1966).

Bytownite has quite a significant abundance as a rock-forming mineral in Bosnia and Hercegovina. It is a ubiquitous mineral and essential constituent of gabbro-type rocks and igneous rock series of Triassic and Tertiary age. It occurs frequently in metamorphic rocks, typically amphibolites.

Basic igneous rocks (containing bytownite) are most common in the Bosnian serpentine zone. Triassic igneous rocks belong to the schist mountains of central Bosnia, in the Jablanica – Prozor area, in the Borovica – Vareš – Čevljanovići sector, and around Kalinovik. Bytownite is also a common constituent of the Tertiary-age effusive rocks of Mt. Motajica.

1. Bytownite in rocks of the Bosnian serpentine zone

Kišpatić (1897, 1900, 1917) provided initial information on bytownite in rocks of the Bosnian serpentine zone (BSZ). This author made microscopic determinations of this plagioclase contained in the rocks of the Gostovići – Krivaja area, as well as around Višegrad. The diabases around Doboj contain bytownite associated with labradorite.

In the Gostovići – Krivaja area bytownite occurs in troctolites from Ravni Potok, in lherzolites from Gostovići, in amphibolites on the Kopalište – Duboštica road and from Otežna, as well as in the pyroxene amphibolite from Borovnički creek. In the area of Višegrad, bytownite is an essential constituent of several basic igneous and metamorphic (and vein type) rocks. Bytownite is contained in diabases from the Lazački creek, in troctolites from the village of Lahci and the Rzav valley, in olivine gabbros from the Rijeka river valley near Dobrun and from Pijavice, in the actinolite schists and eclogite pyroxenites from Vidakovićev Potok, and in the pyroxene amphibolite from Kruševački Potok and Sokolovići.

Kišpatić (1917) maintains that bytownite is quite abundant in the rocks of the Bosnian serpentine zone, and that almost all plagioclase in gabbros from Bosnia is bytownite (p. 37). The serpentinites and lherzolites also contain small amounts of bytownite. Schiller (1905) wrote about bytownite and anorthite contained in gabbroid rocks from the Višegrad area. These rock were also studied in more recent times by Trubelja (1957, 1960) and Marković and Takač (1958). These authors made numerous microscopic measurments of the plagioclases, using a rotating-stage microscope.

The troctolites from Gornji Dubovik contain bytownite with an An content between 73% and 85% (average 79.5%). It can be optically positive or negative.

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The optic axial angle lies in the range +2V = 85-87.5° or -2V = 86-89.5°. Bytownite grains are sometimes only fresh but commonly cracked. The fissures are often filled with secondary prehnite. More advanced serpentinization of olivine is usually accompanied with more extensive prehnitization of plagioclases. Bytownite grains are often twinned according to the Carlsbad or albite law. Another troctolite sample from the same location (Gornji Dubovik) contained bytownite with an An content above 80% (81% – 88% An). This bytownite is optically negative (-2V = 81-89°). Twinning is frequent (Carlsbad, albite or complex laws).

The olivine gabbros from the village of Mirilovići contain bytownite with an average An content of 82.25% (range is between 79% and 85.5%) and a negative optical character (-2V = 83-89°). Twinning is common (albite and complex law). At Velika Gostilja, the olivine gabbro contains mostly labradorite and some bytownite (acidic bytownite with an average of 73.5% An, +2V = 82-84°).

The troctolite from Lahci village in the Banja Potok valley contains bytownite with more than 80% An (the average is 84.5% An). The negative 2V angle varies between -81° and -89°. The uralite gabbros from the village of Smrijeće contain bytownite as an essential constituent. The grains are usually twinned and have a lamellar texture – many of the grains are fractured. Their An content is in the range 76-88%, the average value is 81%. The -2V angle is in the range -78° to -89°.

The bytownite contained in the almost monomineralic veins within the troctolite host rock near Čige has a very similar composition (average An content of 82%). The gabbros from the village of Pijavice contain both bytownite and labradorite.

Trubelja (1960) provides further data on the abundance of bytownite in the basic effusive and vein rocks near Višegrad. The basic igneous and some metamorphic rocks of the Krivaja – Konjuh area contain variable amounts of bytownite and labradorite (Trubelja, 1961; Pamić 1971, 1971a, 1974; Pamić and Kapeler 1970, Pamić et al. 1973). The lherzolite from Grbovica creek at Mt. Konjuh contain a minor amount of bytwonite and anorthite. Their An content is 84%, the -2V angle = 79° to 81°.

The feldspar-peridotites at Karaula, on the Olovo – Kladanj road, contains a significant amount of bytownite so that it may be regarded as an essential constituent. Some anorthite is also present in the rock. The troctolite from the source area of the Blizanci creek contains bytownite with 71-82.5% An (-2V is between 85.5° and 89°). The dolerite rock from this creek contains more labradorite than bytownite.

The olivine gabbros from Stupčanica creek (village of Bjeliš) contain bytownite with 77.5-89% An. This bytownite is extensively altered to prehnite.

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SILICATES

The amphibolite rocks of the Krivaja – Konjuh complex contain bytownite which is almost always associated with pargasitic and edenitic hornblende. Similar parageneses occur also elsewhere in the Bosnian serpentine zone – i.e. at Mt. Skatavica near Banja Luka. Pamić et al. (1973) provide some more indepth information on the relationships between individual plagioclase minerals in these rocks.

The basic igneous rocks of Mt. Ozren contain substantial amounts of bytownite (Pamić and Trubelja 1962; Trubelja and Pamić 1965). The olivine gabbros from Paklenica contain bytownite with 70-78% An (2V between +85° and -87°). Amphibolites from this area also contain bytownite – i.e. the pyroxene amphibolite from Gornja Bukovica contains quite fresh bytownite grains with 72-82% An and -2V = 87-89°. Bytownite is also quite abundant in amphibolites and basic igneous rocks in the area between the rivers Vrbas and Bosna. The amphibole- and garnet-bearing gabbros and hornblendites contain both bytownite and anorthite (Majer 1962).

The diabases at Mt. Čavka contain bytownite with 76% An (Đurić and Kubat 1962; Kubat 1964). Bytownite is an essential constituent of the amphibolites at Mt. Skatovica near Banja Luka (Pamić 1969; Pamić et al. 1973).

Bytownite is a rather common constituent of gabbros and associated basic igneous rocks from Mt. Kozara and Kozarački creek. Golub (1961) provides detailed microscopic measurements of plagioclases from these rocks. The troctolites from the Jovača creek contain ca. 54% bytownite by volume, as crystals 0.5-2 mm in size, of a columnar habit. Twinning and prehnitization are a common feature of this bytownite. The An content is in the range 74.5-79% (average is 76.7%). The 2V angle varies in the range -82° to -86°.

The actinolite-bearing gabbros from Kotlovača creek contains an acidic

bytownite with 72% An and a -2V angle of 85° to 88°.

2. Bytownite in products of Triassic volcanism

Bytownite has been microscopically determined in several rock types belonging to the spilite-keratophyre series in Hercegovina, around Jablanica and Prozor (John 1888; Kišpatić 1910; Marić 1927; Tućan 1928; Pamić 1961a, 1961b, 1969).

The earliest reference on bytownite in the gabbro from the Jablanica massif is the paper by John (1888). In addition to microscopic measurements, John also provides a chemical analysis of a sample which he claims to be from the central portion of the massif.SiO2 = 46.80; Al2O3 = 33.50; Fe2O3 = 0.90; CaO = 15.85; MgO = 0.56; Na2O = 2.23; K2O = 0.21; Loss-on-ignition = 0.67; Total = 100.72

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Kišpatić (1910) mentions labradorite and bytownite as essential constituents of the gabbro rock from Jablanica, failing to provide further information on bytownite. Marić (1927) determined that zonar grains frequently have bytownite in the center of the grains and labradorite on the rim. Marić reports that rocks containing labradorite can be found on right bank of the Neretva river, and near Bukov Pod.

Bytownite is an essential constituent of many Triassic basic intrusive rocks (gabbros) from the schist mountains of central Bosnia – Bijela Gromila, south of Travnik (Kišpatić 1910; Katzer 1924, 1926; Majer and Jurković 1957, 1958).

Microscopic determinations done by Pamić and Tućan provide evidence for the occurrence of bytownite (and labradorite) in some basalts and andesites in the area of the Rama and Doljanka rivers. The andesites from Vrata, near Sovići, contain fresh phenocrysts of zonar labradorite and bytownite (0.1-2.5 mm in size). Some alteration products (calcite, epidote) can be observed.

Bytownite has been determined as an essential constituent of baslats and silimar rocks of the Triassic-age igneous-sedimentary series of Kalinovik, Rogatica, Draževići and Vareš (Pamić 1960a; Esih and Natević 1963; Ramović 1957, Karamata 1953).

3. Bytownite in products of Tertiary volcanism

According to available literature references, bytownite occurs only in the effusive rocks of the Srebrenica area (Kišpatić 1904a; Tajder 1953). Kišpatić determined bytownite in the hypersthene-bearing andesite from Sikirić, and dacites from Ljubovija and Protin Han. Tajder (1953, based on microscopic measurments) determined bytownite only in the bytownite-dacites from the village of Diminići. The bytownite has 80% An.

4. Bytownite in hornfelses from Mt. Motajica

Varićak (1966) determined bytownite as an essential constituent of pyroxene hornfels at Mt. Motajica. The crystal grains display characteristic lamellar twinning (albite law). The average An content is 78.5%, the -2V angle is in the range 76-80º.

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SILICATES

ANORTHITECa [Al2Si2O8]

Lattice ratio: a : b : c = 0.635 : 1 : 2 x 0.550 α = 93° 10’ β = 115° 51’ γ = 91° 13’Cell parameters: ao = 8.177, bo = 12.877, co = 14.169 Z = 8 X-ray data: d 3.194 (100) 3.180 (100) 3.210 (58) 3.261 (53) 4.035 (52) IR-spectrum: 407 433 470 484 575 603 624 668 700 728 758 950 1020 1085 1160 cm-1.

A u t h o r s: John (1888), Kišpatić (1897, 1900), Majer (1962), Pamić (1971, 1971a, 1972d), Pamić and Kapeler (1970), Pamić, Šćavničar and Medjimorec (1973), Ristić, Panić, Mudrinić and Likić (1967), Schiller (1905), Trubelja (1960, 1961).

The only occurrence of anorthite (as a rock-forming mineral) in Bosnia and Hercegovina are the rocks of the Bosnian serpentine zone, especially in its central and eastern parts. It occurs, sometimes as an essential constituent, in basic intrusive rocks and amphibolites. Some peridotites contain bytownite as an accessory mineral.

1. Anorthite in basic and ultrabasic rocks

The occurrence of anorthite in basic instrusive rocks of the Bosnian serpentine zone was first determined by John (1880). He maintains that anorthite is an essential constituent of troctolites. In thin section, the anorthite grains are mostly fresh showing distinct polysynthetic twinning. The results of chemical analysis are quite close to that of anorthite:

SiO2 = 44.73; Al2O3 = 34.50; CaO = 17.44;

In his research concerning the basic plagioclases contained in gabbros from the Višegrad area, Schiller (1905) determined them as bytownite. However, as stated by this author, some measurements indicate that some present plagioclase could be anorthite (97-98% An).

Kišpatić (1897, 1900) determined anorthite in the troctolite from Vukovac creek in western Bosnia, and near Rakovac (Doboj area). Anorthite is an essential constituent of olivine-bearing gabbros from Gostovići and Ravni Potok near Duboštica. This rock series belongs to the Krivaja – Konjuh ultrabasic complex.

More recent microscopic investigations of the igneous rocks from the

Višegrad area (Trubelja 1960) indicate that the gabbropegmatite from Karaula contains bytownite and anorthite. The An content is 90-100%, the -2V angle = 76° to 83°. Microscopic and x-ray diffraction data also show that anorthite is an important

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mineral of gabbros, gabbro-peridotites and peridotites of the Krivaja – Konjuh metamorphic complex (Trubelja 1961; Ristić et al. 1967; Pamić 1971).

Lherzolites from Mt. Konjuh (Zečji Vrat, 1275 m asl) contain anorthite as an accessory constituent. Anorthite grains are fresh and have an isometric shape with a lamellar texture. Their An content is 90-100% (-2V = 75-86.5°). The lherzolite from the source area of the Grabovica creek also contains minor amounts of bytownite and anorthite. Twinning lamellae have a wedge-like shape (they are broader on one end). The An content is 96-97%.

The gabbro-peridotite outcrops on the Olovo – Kladanj road, southwest from Karaula contain bytownite and anorthite (optically negative) which are more or less extensively altered by prehnitization processes. Anorthite is an essential constituent of this rock. Majer (1962) determined anorthite and bytownite as essential constituents of gabbros, garnet-bearing gabbros and hornblendites belonging to the serpentine zone in the area between the rivers Bosna and Vrbas.

2. Anorthite in metamorphic rocks

The amphibolites and other metamorphic rocks of the Bosnian serpentine zone (BSZ) contain some anorthite, in addition to the other plagioclase minerals (Kišpatić 1897, 1900; Pamić 1971a; Pamić and Kapeler 1970; Pamić et al. 1973).

Kišpatić (1897) determined anorthite in the pyroxene amphibolite from the Rudine and Velika Bukovica creeks at Mt. Ozren. Similar rocks in the area of Višegrad – Kruševački Potok, Vidakovića Potok and Obrenska Rijeka – contain anorthite associated with bytownite.

Pamić et al. (1973) determined the abundance and properties of anorthite and the other plagioclases contained in amphibolites from Vareš (Duboštica, Vijake), Banja Luka and Rudo. The relationship between the chemical composition of the plagioclases and their optical character is shown by Figure 24. For example, the basic anorthite and bytownite are normally associated with amphiboles enriched in the pargasitic and edenitic end-members which have a positive optical character.

Pamić and Kapeler (1970) determined anorthite in the corundum-bearing amphibolites (pargasitic hornblende) from Donje Vijake, near Vareš. The level of prehnitization is low and anorthite grains are mostly fresh. Their An content is 90-96%.

Use: feldspars and plagioclases are important industrial minerals. Pure feldspar material, derived from pegmatites, is used in the production of ceramics and glass. The alkali feldspars are of particular interest in terms of industrial use of feldspars. Basically, the two properties which make feldspars useful for downstream industries are their alkali and alumina content.

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SILICATES

Plagioclase and feldspar in general is an important ingredient in the manufacture of glass and an important raw material as well, because it acts as a fluxing agent, reducing the melting temperature of quartz and helping to control the viscosity of glass. The alkali content in feldspar acts as flux, lowering the glass batch melting temperature and thus reducing production costs.

In the manufacture of ceramics, feldspar is the second most important ingredient after clay. Feldspar does not have a strict melting point, since it melts gradually over a range of temperatures. This greatly facilitates the melting of quartz and clays and, through appropriate mixing, allows modulations of this important step of ceramic making. Feldspars are used as fluxing agents to form a glassy phase at low temperatures and as a source of alkalies and alumina in glazes. They improve the strength, toughness, and durability of the ceramic body, and cement the crystalline phase of other ingredients, softening, melting and wetting other batch constituents.

Feldspars also are used as fillers and extenders in applications such as paints, plastics and rubber. Beneficial properties of feldspars include good dispersability, high chemical inertness, stable pH, high resistance to abrasion, low viscosity at high filler loading, interesting refractive index and resistance to frosting. The products used in such applications are generally fine-milled grades.

LAZURITE(Na,Ca)7-8(AlSi)12(O,S)24[(SO4)(Cl,OH)2]

Evlija Čelebija writes about lazurite – or lapis lazuli – in Bosnia and Hercegovina. In his travel report (see translation by Hazim Šabanović – Evlija Čelebija: Travel reports, published 1954-1973 in Sarajevo) the following information can be found on pages 133 (1954), p. 120 (1967) and p. 120 (1973) – cit. in this area there is orpiment (a depilating agent). There is also lazurite (a blue stone) which, like the european variety, has a play of thousand of colours. No further information on lazurite in Bosnia and Hervegovina can be found in professional references. We therefore believe that this famous turkish traveller probably saw (in the environs of Sarajevo) the blue mineral azurite, which occurs in the schist mountains of central Bosnia.

SCAPOLITE

The term Scapolite actually refers to the series between the sodium chloride rich mineral called marialite Na [AlSi3O8] NaCl, and the calcium carbonate rich mineral meionite Ca3 [Al2Si2O8] CaCO3. It crystallizes in the tetragonal system.

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Scapolites are rare minerals in Bosnia and Hercegovina. Kišpatić (1897, 1900) microscopically determined scapolite contained in the eclogitic amphibolite from Ravanke, Gornje Vijake, near Vareš. This scapolite is associated with amphibole, omphacite, garnet, hypersthene and plagioclase. The scapolit is not dispersed, but forms agglomerations in some parts of the rock complex. The scapolite grains are colourless, with a high birefringence so interference colours in thin section are correspondingly high. Extinction is parallel, the optical character is negative. A dark cross can sometimes be seen in convergent light.

NATROLITENa2 [Al2Si3O10] x 2H2O

IR-spectrum: 417 515 545 600 633 680 980 1067 1090 1640 3240 3330 3550 cm-1.

A u t h o r s: Đorđević and Stojanović (1972, 1974), Trubelja, Šibenik-Studen and Sijarić (1974, 1975, 1976), Trubelja, Šibenik-Studen, Sijarić and Šljukić (1974).

In Bosnia and Hercegovina, natrolite has been identified and investigated only recently (as can be deduced from the cited literature). Ocurrences of natrolite have been identified in the Bosnian serpentine zone and in fissures of the gabbro complex at Jablanica. Đorđević and Stojanović (1972, 1974) determined natrolite (beautiful needle-like crystals) at Bojići (Hrvaćani) near Banja Luka, as well as near the Višegrad railway station.

1. The occurrence at Bojići near Banja Luka

Đorđević and Stojanović (1974) identified the presence of natrolite in the diabases from Bojići-Hrvaćani, on the south-western flanks of Mt. Crni Vrh. Here, natrolite is associated with analcime, laumontite, prehnite, datolite and some other vein minerals forming a hydrothermal paragenesis. The natrolite needles (5-10 mm long) usually grow on prehnite. In thin section natrolite appears as colourless, prismatic grains with almost square-shaped cross-sections. The refractive index of natrolite is lower than that of Canada balsam. Extinction is parallel, with respect to the elongation of the crystal grains. A pure natrolite specimen was analysed by powder x-ray diffraction. The diffraction pattern corresponds to literature data (ASTM-card 19-1185). The diffraction data are given in table 64.

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Table 64. Powder x-ray diffraction data for natrolite, BojićiNatrolite (Bojići) Natrolite (ASTM 19-1185)

d Å I d Å I6.51 100 6.49 1005.88 30 5.90 654.64 80 4.65 404.59 25 4.56 254.37 25 4.37 254.34 20 4.35 304.14 80 4.15 504.09 50 4.10 253.62 3 3.63 43.26 15 3.27 103.19 18 3.20 203.15 20 3.15 253.10 10 3.10 142.93 15 2.945 182.860 70 2.860 452.837 60 2.837 35

2. The occurrences at Mt. Konjuh and Doboj

Trubelja et al. (1976) determined the presence of natrolite in the diabase upon which the fortress of Doboj is erected, and on the Sarajevo – Tuzla road (near Karaula) on Mt. Konjuh. Natrolite was identified using powder x-ray diffraction and infrared spectroscopy.

The diabase at Doboj (Gradina) contains natrolite in association with calcite and analcime. At Mt. Konjuh, natrolite occurs as fillings in veins, either alone or together with thomsonite. The XRD and IR-spectroscopy data can be retrieved from the cited paper.

3. Occurence in the gabbro from Jablanica

Trubelja et al. (1976) identified natrolite in the veins and fissures within the gabbro rock massif of Jablanica (in the quarry of Ploče). Natrolite occurs in the form of very thin, acicular crystals forming aggregates which appear like ‘hairy’ bundles. Based on the x-ray diffraction data, the authors maintain that this a calcium-enriched mixed crystal approaching the composition of mesolite. The slight differences in values of the inter-lattice distances (d) and intesnities (I) between the natrolite from Ploče and the literature refernce, probably reflect the minor differences in the chemical composition of the two natrolites. Some Crystal-structure parameters of the Ploče natrolite have been determined (by M. Šljukić). The parameters, related to literature data, are given in Table 65.

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Table 65. Unit-cell parameters of natrolite from Ploče with respect to literature data (Meier 1960)Natrolite (Ploče) Natrolite (ref. Meier 1960) a0 = 18.368 Å a0 = 18.30 Å b0 = 18.685 Å b0 = 18.63 Å c0 = 6.618 Å c0 = 6.60 Å Dm = 2.268 Å V0 = 2271.20 Å3 V0 = 2250.10 Å3

Z = 8 Z = 8 Dx = 2.220 g/cm3 Dx = 2.245 g/cm3

Orthorhombic Fdd2

Some issues of the origin of natrolite in the rocks of Bosnia and Hercegovina will be discussed in the section on chabasite.

SCOLECITECa [Al2Si3O10] x 3H2O

Crystal system and class: Monoclinic, domatic class.Lattice ratio: a : b : c = 0.976 : 1 : 0.345 β = 90° 45’Cell parameters: ao = 18.48, bo = 18.94, co = 6.4 Z = 8

A u t h o r s: Šibenik-Studen (1972/73), Trubelja, Šibenik-Studen and Sijarić (1974, 1976), Trubelja, Šibenik-Studen, Sijarić and Šljukić (1974).

Up to now, scolecite has been identified at one location only in Bosnia and Hercegovina, in the Ribnica creek near Višegrad (Šibenik-Studen 1972/73). Scolecite occurs in the form of white, sometimes vein-like aggregates in basic gabbro-diabase host rocks. Scolecite is often associated with stilbite.Quantitative chemical analysis yielded following results:SiO2 = 44.67; TiO2 = traces; Al2O3 = 24.98; Fe2O3 = 0.38; CaO = 14.26; MgO = 0.31; Na2O = 0.61; K2O = --; H2O

+ = 14.11; H2O- = 0.72;

Total = 100.04 Atomic and molecular ratios were calculated from the chemical analysis results, based on 20 oxygen atoms, and are as follows:

Si = 5.97 Al = 3.92 Fe3+ = 0.04 Ca = 2.03Mg = 0.06 Na = 0.14 H2O measured = 6.25 H2O calculated = 6.41

The difference between H2O measured and H2O calculated is – 0.16. Based on this calculation, the structural formula of scolecite is given as follows:Ca2.03Na0.14Mg0.06Al3.92Fe3+

0.04Si5.97O20 • 6.25 H2O

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Foster (1965) studied in detail the composition and water content of scolecites from various localities. The structural formulae for all investigated scolecites were calculated on the basis of 20 oxygen atoms. Our calculation (for the Ribnica scolecite) can therefore be directly compared with the cited reference, and it corresponds very well with Foster’s data.

Table 66. Powder XRD data for scolecite from the Ribnica creek (Šibenik-Studen 1972/73)No. d Å I No. d Å I1 6.637 5 29 1.903 12 5.817 8 30 1.876 1.53 4.760 4 31 1.855 1.54 4.598 4 32 1.834 15 4.387 8 33 1.807 36 4.183 3 34 1.766 27 3.642 3 35 1.743 28 3.227 4 36 1.720 1.59 3.153 4 37 1.685 1

10 2.068 5 38 1.674 1.511 2.994 1 39 1.656 1.512 2.936 8 40 1.634 513 2.861 10 41 1.614 414 2.679 1 42 1.597 0.515 2.572 4 43 1.582 0.516 2.474 3 44 1.542 117 2.423 3 45 1.525 118 2.312 3 46 1.491 0.519 2.262 3 47 1.481 0.520 2.246 2 48 1.469 421 2.204 6 49 1.446 0.522 2.168 2 50 1.433 323 2.141 2 51 1.420 124 2.106 1 52 1.383 325 2.069 2 53 1.374 0.526 2.034 5 54 1.357 0.527 1.992 2 55 1.343 128 1.955 4 56 1.327 3

The scolecite from Ribnica was also subjected to powder x-ray diffraction, thermal analysis and infrared spectroscopy. Hand-picked scolecite crystals of ca. 1 cm in length were used for these analyses. The powder diffraction data (Deby-Scherrer metod) is given in table 66.

The IR-absorption spectrum of this scolecite contains absorptions with following wavenumbers: 632 664 707 926 986 1018 1068 1096 and 1389 cm-1. The literature reference for the IR spectrum of scolecite (Moenke 1962) has wavenumbers 410 455 497 536 650 677 695 810 910 933 980 1003 1055 1405 and 3440 cm-1.

The origin of scolecite and other zeolite minerals is decribed in the section on chabasite.

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MESOLITENa2Ca2 [Al2Si3O10]3 • 8H2O

A u t h o r s: Trubelja, Šibenik-Studen and Sijarić (1974, 1976), Trubelja, Šibenik-Studen, Sijarić and Šljukić (1974).

Up to now, mesolite has been identified at one location only in Bosnia and Hercegovina, in the veins within the gabbro host rock at Jablanica. Mesolite occurs in association with natrolite. The mineral, occurring as needle-like crystals, has been identified by powder x-ray diffraction. Unit cell parameters were determined by M. Šljukić as:

a0 = 18.368 Å b0 = 18.685 Å c0 = 6.618 Å β = 90°

V0 = 2271.20 Å3 Dm = 2.268 Å Dx = 2.220 g/cm3 Z = 8

This mesolite is orthorhombic (Fdd2). The data given above is slightly different from the information provided by Taylor et al. (1933).

No more information is available for mesolite from the gabbros at Jablanica. More material will have to be collected in future so that additional analyses can be made, especially chemical analysis.

THOMSONITENaCa2 [Al5Si5O20] • 6H2O

Crystal system and class: Orthorhombic, dipyramidal class.Lattice ratio:a : b : c = 0.998 : 1 : 1.012Cell parameters: ao = 13.07, bo = 13.09, co = 13.25 Z = 4 IR-spectrum: 412 440 595 630 1008 (1100) 1640 3440 3550 cm-1.

A u t h o r s: Šćavničar, Trubelja and Sijarić-Pleho (1968), Šibenik-Studen and Trubelja (1971), Trubelja, Šibenik-Studen and Sijarić (1974, 1975, 1975a, 1976), Trubelja, Šibenik-Studen, Sijarić and Šljukić (1974).

Thomsonite has been determined in Bosnia and Hercegovina only recently. According to available literature, thomsonite occurs in basic igneous rocks on the edges of the Bosnian serpentine zone – at Mt. Kozara, Mt. Ozren and Mt. Konjuh. However, it is interesting to note that thomsonite was first determined in the boehmite-gibbsite bauxites from Posušje, in the Galića Njive – Vinjani area (Šćavničar et al. 1968).

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1. The thomsonite occurrence at Mt. Konjuh

Thomsonite occurs in veins within diabase outcrops, mainly on the Olovo – Kladanj sector of the Sarajevo – Tuzla motorway. It is associated with prehnite (near the village of Kovačići) or analcime (the Karaule locality).

Šibenik-Studen and Trubelja (1971) note that thomsonite occurs (at Kovačići) as radial aggregates of columnar crystals which are transparent and of a vitreous lustre. These aggregates can also occur as thin crusts. Thomsonite fills veins and fissures, either alone or associated with prehnite. In thin section these two minerals can be identified due to differences in grain shape, intereference colours and refractive indices. Thomsonite has a lower RI than Canada balsam and displays parallel extinction (interference colours are yellowish and grey). Quantitative chemical analysis of thomsonite (the material was carefully separated under a binocular loupe) yielded following results:

SiO2 = 39.85; Al2O3 = 28.64; CaO = 14.06; Na2O = 4.84; K2O = traces; H2O = 12.58; Total = 99.97

The structural formula of this thomsonite, based on 80 oxygen atoms is:Na4.983Ca8.017 (Al17.950Si21.272O80) • 24H2O

The chemical analysis and structural formula correspond well to literature data (Deer et al. 1963).

Powder x-ray diffraction data for the thomsonite from Kovačići is given in table 67. The diffraction pattern corresponds well to literature data (ASTM-card 9-490).

Thomsonite occurs also in several places at the locality called Karaule, on the Olovo – Kladanj road. Powder XRD and infrared spectroscopy was used to identify the thomsonite association with natrolite or analcime. Detailed results of these analyses can be found in the paper by Trubelja et al. (1976).

Table 67. X-ray diffraction data for thomsonite from Kovačići (Šibenik-Studen and Trubelja 1971)

No. d Å I No. d Å I1 6.444 s 33 1.57 w2 5.917 s 34 1.56 vw3 5.498 w 35 1.54 m4 4.670 vs 36 1.51 vw5 4.395 s 37 1.47 vs6 4.152 ms 38 1.44 m

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7 3.829 w 39 1.42 vw8 3.504 s 40 1.39 m9 3.189 w 41 1.33 m10 3.114 s 42 1.31 m11 3.084 w 43 1.30 m12 2.967 vvs 44 1.29 m13 2.866 vvs 45 1.28 w14 2.792 vw 46 1.27 w15 2.668 s 47 1.26 w16 2.586 m 48 1.24 vw17 2.432 w 49 1.23 vw18 2.262 m 50 1.22 sm19 2.190 s 51 1.19 m20 2.14 vw 52 1.17 m21 2.08 vw 53 1.15 vw22 2.02 s 54 1.14 m23 1.95 w 55 1.07 w24 1.89 w 56 1.06 sm25 1.82 m 57 1.03 m26 1.76 vw 58 1.01 vw27 1.73 m 59 1.00 w28 1.71 w 60 0.98 w29 1.65 w 61 0.97 w30 1.63 mw 62 0.96 vw31 1.62 mw 63 m32 1.59 w

2. The thomsonite occurrence at Mt. Ozren

Trubelja et al. (1976) determined thomsonite in diabase-spilitic rocks in the Omrklica creek near Megare, and on the road between Gornji Rakovac and Gornja Bukovica (Mt. Ozren). Based on XRD and IR-spectrometry, the authors conlcude thaT homsonite occurs here alone.

3. The thomsonite occurrence at Mt. Kozara

Trubelja et al. (1976) determined thomsonite in association with analcime in numerous samples of vein fillings collected from basic igneous rocks in the Kozarac – Mrakovica area at Mt. Kozara. Analcime is more abundant than thomsonite.

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SILICATES

LAUMONTITECa [AlSi2O6]2 • 4.5H2O

Crystal system and class: Monoclinic, prismatic class.Lattice ratio: a : b : c = 1.131 : 1 : 0.573 β = 111° 30’Cell parameters: ao = 14.90, bo = 13.17, co = 7.55 Z = 4 X-ray data: d 4.18 (100) 6.97 (60) 3.53 (60)IR-spectrum: 410 432 492 525 565 625 765 960 1000 1038 1095 1134 1655 3470 and 3560 cm-1.

A u t h o r s: Đorđević and Stojanović (1972, 1974), Trubelja, Šibenik-Studen and Sijarić (1974, 1975, 1975a, 1976), Trubelja, Šibenik-Studen, Sijarić and Šljukić (1974).

In Bosnia and Hercegovina laumontite has been identified only recently, and only within the Bosnian serpentine zone. It occurs as fillings in fissures in basic igneous rocks at Mt. Kozara and Mt. Konjuh. Đorđević and Stojanović (1974) identified a laumontite occurrence at Bojići, near Banja Luka.

1. The laumontite occurrence at Mt. Kozara

Occurrences of laumontite are quite common on the southern flanks of Mt. Kozara, on the Kozarac-Mrakovica road. It is also found on the northern flanks of the mountain, in the Bukovica and Trnova creeks, where it occurs associated with prehnite or plagioclase.

Laumontite and the associated minerals were all identified using powder x-ray diffraction and infrared spectroscopy. The results were published in several publications – Trubelja et al. (1974, 1975, 1975a, 1976), Trubelja, Šibenik-Studen, Sijarić and Šljukić (1974). We wish to point out that we had some difficulties with the identification of laumontite by IR-spectroscopy, especially when plagioclases were present in the samples. This is due to the fact that diagnostic absorption peaks of plagioclases are located in the low-wavenumber part of the IR spectrum (400-650 cm-1) and overlaps with the absorption which are caused by laumontite and other zeolites are inevitable. Complementary use of infrared spectroscopy and x-ray diffraction helped to eliminate possible biases in the identification procedures. The respective data-sets for the IR-spectra and XRD patterns can be found in the paper by Trubelja et al. (1976).

Đorđević and Stojanović (1974) identified laumontite in the diabase outcrops at Bojići, near Banja Luka. This laumontite is associated with natrolite, analcime and datolite. In thin section, the laumontite has a lower refractive index than Canada balsam, and a higher relief than natrolite. The x-ray diffraction diagram of this laumontite showed following peaks (d) 9.58; 6.98; 4.19; 3.66 and 3.52 Å.

Another occurrence of laumontite, according to these authors, is close to the railway station in Višegrad.

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2. The laumontite occurrence at Mt. Konjuh

Laumontite occurs, together with other vein minerals (prehnite and plagioclases) in the outcrops along the Olovo – Kladanj road, in the area called Karaule. The respective data-sets for the IR-spectra and XRD patterns of this laumontite can be found in the paper by Trubelja et al. (1976).

STILBITE(Ca0.5,K,Na)9[Al9Si27O72] • 28H2O

A u t h o r s: Katzer (1920, 1924, 1926), Kišpatić (1902), Koch (1899), Marić (1927), Šibenik-Studen (1972/73), Trubelja, Šibenik-Studen and Sijarić (1974, 1976), Trubelja, Šibenik-Studen, Sijarić and Šljukić (1974).

Literature references on stilbite in Bosnia and Hercegovina are very scarce. The first short account on the occurrence of stilbite in the pegmatite veins at Mt. Motajica were published by Koch (1899). He noted that crystals of stilbite were quite small and were attached to black quartz. Koch was able to identify four crystallographic forms on these crystals: M (clinopinacoid), T (base pinacoid), N (orthopinacoid) and P (orthodome). This stilbite is colourless or white. The lustre on the clinopinacoid plane is pearly. A sample of this stilbite is located in the Mineralogical-petrographical Museum in Zagreb.

Kišpatić (1902) investigated the same mineral, but called it heulandite. The data provided by Kišpatić are not identical to the information published by Koch, and it will obviously be neccessary to make a critical revision of both data-sets. Stilbite (heulandite) from the same locality was also briefly mentioned by Katzer (1924, 1926).

According to Katzer (1920), desmine (stilbite) occurs associated with chabasite in amygdaloids within melaphyres from the Stavnja river valley near Vareš. Marić (1927) also mentions radial aggregates of stilbite in the gabbros from Jablanica.

More recently, stilbites from Višegrad and Jablanica have been investigated by Šibenik-Studen (1972/73), Trubelja, Šibenik-Studen and Sijarić (1974, 1976), Trubelja, Šibenik-Studen, Sijarić and Šljukić (1974).

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1. The stilbite occurrence at Ribnica near Višegrad

Šibenik-Studen (1974) made a detailed investigation of stilbite from the Ribnica creek, near Višegrad. It occurs as fillings of veins within basic gabbro-type igneous rocks which have penetrated the diabase-dolerite complex. Stilbite usually forms radial aggregates but individual crystals have also been observed. Its colour is white and has pearly lustre. Stilbite aggregates occasionally form thin crusts over greenish-grey fassaite.

Stilbite material was carefully selected for chemical, thermal and x-ray diffraction analyses. Quantitative chemical analysis yielded following results:SiO2 = 54.10; Al2O3 = 16.55; Fe2O3 = 0.61; TiO2 = 0.24; CaO = 9.25;Na2O = 0.87; K2O = 0.29; H2O

+ = 14.88; H2O- = 3.37; Total = 100.16

The structural formula of this stilbite, based on 72 oxygen atoms is:(Ca4.75Na0.81K0.17) (Al9.38Fe0.23Ti0.09Si26.08O72) • 29.33H2O

Compared to five different stilbites reported by Deer et al. (1963), the stilbite from Višegrad can be classified as normal, somewhat Si-depleted stilbite. The powder diffraction pattern of stilbite is given in table 68.

The stilbite from Ribnica was also analysed by thermogravimetry and differential thermal analysis. The TG and DTA curves can be found in the paper (Šibenik-Studen 1974). The results of thermal analysis correcpond very well to literature references (Pecsi-Donath 1962; Njirkov and Kobilev 1962).

Table 68. X-ray diffraction data for stilbite from Ribnica (Šibenik-Studen 1974)No. d Å I No. d Å I1 9.156 vs 17 2.5996 wd2 6.748 jwd 18 2.3382 w3 5.3723 wd 19 2.2095 wd4 4.6707 s 20 2.05343 wd5 4.3744 jw 21 2.02296 wd6 4.2908 m 22 1.88644 wd7 4.0767 vvs 23 1.86466 wd8 3.7385 wd 24 1.82067 w9 3.4930 jw 25 1.76676 w10 3.4089 m 26 1.72046 w11 3.2098 m 27 1.69397 vw12 3.1274 jw 28 1.64748 vw13 3.0079 vs 29 1.63400 vw14 2.8630 vw 30 1.58411 w15 2.7883 w 31 1.54178 m16 2.7352 w 32 1.43279 vw

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The IR spectrum of stilbite features following wavenumbers: 400 439 550 590 720 785 870 1030 1145 1640 3250 and 3400 cm-1. The IR spectrum of the Ribnica stilbite corresponds very well to the spectrum of stilbite from Teigarhorn, Iceland.

2. The occurrence of stilbite in gabbro at Jablanica

Stilbite, associated with other hydrothermal minerals, is often present as fillings of veins within the Jablanica gabbro complex. Such veins are particularly well exposed in the Ploče quarry. Here, stilbite is associated with small amounts of albite, prehnite and chabasite. In one case, stilbite and albite grew on substrate consisting of pumpellyite, chlorite and hornblende, presenting evidence of the succession of postmagmatic activity and the sequence of crystallization of the minerals in the paragenesis.

Trubelja et al. (1976) performed a set of analyses on this stilbite. The chemical composition is as follows: SiO2 = 55.48; Al2O3 = 15.80; CaO = 8.91; Na2O = 1.14; K2O = 0.40;H2O

+ = 16.04; H2O- = 2.91; Total = 100.37

The structural formula of this stilbite, based on 72 oxygen atoms is:(Ca4.61Na1.04K0.29) (Al8.93Si26.61O72) • 30.5H2O

The chemical composition and structural formula of the Jablanica stilbite and the Ribnica stilbite are quite similar. The x-ray powder diffraction pattern and IR-spectrum of this stilbite is given in the cited paper (Trubelja et al. 1976).

X-ray structural analysis on monocrystals of stilbite (done by M. Šljukić) gave following parameters:

a0 = 13.669 Å b0 = 17.699 Å c0 = 11.189 Å β = 127° V0 = 2161.86 Å3 Dm = 2.173 g/cm3 Dx = 2.235 g/cm3 Z = 4

monoclinic system – C2/m

CHABASITE(Ca0.5Na,K)4 [Al4Si8O24]2 • 12H2O

X-ray data: d 2.907 (100) 4.291 (90) 9.31 (80) d 2.95 (100) 4.35 (90) 9.5 (70)IR-spectrum 415 465 517 630 700 1025 1100 1645 and 3440 cm-1.

A u t h o r s: Katzer (1920), Majer (1953), Ramović (1968), Trubelja, Šibenik-Studen and Sijarić (1974, 1976), Trubelja, Šibenik-Studen, Sijarić and Šljukić (1974), Tućan (1957).

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In Bosnia and Hercegovina, chabasite has been found and studied only at Jablanica, where it occurs in veins within the gabbro host rock. According to limited information provided by Katzer (1920), chabasite also occurs in amygdaloides within the melaphyres from the Stavnja river near Vareš.

Tućan (the textbook on special mineralogy, published in 1957) provides first information on the chabasite from Jablanica. Chabasite occurs together with titanite, tourmaline, prehnite, a plagioclase, amphibole, chlorite and colourless quartz. The 2V angle varies from +70.5° to +82° (average of six individual measurments is +78°). Maximum birefringence Nz – Nx = 0.0010 (optical constants determined by Lj. Barić). The chabasite seems to be pseudo-biaxial.

Ramović (1968) also notes the chabasite occurrence at Jablanica. A large specimen of altered gabbro from Jablanica is deposited in the mineralogical collection of the National Museum in Sarajevo. A chabasite aggregate 0.5 cm in diameter is attached to this specimen. The crystals are transparent or white (vitreous lustre) and posess a rhomohedral habit. This material was used for chemical and other analyses. The results of chemical analysis is given in table 69.

Table 69. Chemical analysis of chabasite from Jablanica (Trubelja et al. 1976) and Bor (Majer 1953)

Chabasite (Jablanica) Chabasite(Bor)

SiO2 48.12 48.78TiO2 --- ---Al2O3 18.36 18.04Fe2O3 --- ---MgO --- ---CaO 8.96 9.77Na2O 0.27 0.98K2O 1.75 0.60H2O

+110 17.29 22.04H2O

-110 4.97 ---Fe, Mn --- tracesTotal 99.72 100.21

The structural formula of this chabasite, based on 72 oxygen atoms is:(Ca4.95K1.11Na0.25) (Al11.20Si24.78O72) • 38.18 H2Oand corresponds well to literature data (Coombs et al. 1959). The chemical composition of the chabasite from Jablanica is similar to the compositon of a chabasite from the copper mine in Bor (Serbia), as given in table 69. The potassium and water content are slightly different.

Trubelja et al. (1974) collected further chabasite material from the Jablanica gabbro complex and compared its powder diffraction pattern with that of the

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chabasite from the museum in Sarajevo (tables 70 and 71). Apart from the Debye-Scherrer film technique, instrumental diffraction analysis was also done in view of a better evaluation of the signal intesities.

Table 70. Powder x-ray diffraction data for chabasite (sample from the National Museum in Sarajevo)

No. d Å I No. d Å I1 9.718 8 16 2.6173 22 6.992 2 17 2.5081 23 5.5877 1 18 2.3037 14 5.6229 7 19 2.0941 25 5.0675 7 20 1.81390 26 4.7051 1 21 1.72769 27 4.3532 9 22 1.69513 18 3.8900 3 23 1.68363 19 3.6043 4 24 1.64474 110 3.4662 2 25 1.56069 111 3.2433 1 26 1.52204 112 3.2022 1 27 1.41808 113 2.9402 10 28 1.40861 114 2.9122 1 29 1.34233 115 2.6936 1

Table 71. Powder x-ray diffraction data for chabasite (Ploče quarry, Jablanica)No. d Å I No. d Å I1 9.408 8 23 2.0969 22 6.970 3 24 1.92018 13 6.398 1 25 1.87548 14 5.5737 6 26 1.86108 15 5.0276 6 27 1.80987 46 4.7199 1 28 1.77442 17 4.3448 10 29 1.72769 28 3.9971 1 30 1.69803 19 3.8833 5 31 1.67512 110 3.6129 6 32 1.64908 211 3.4609 5 33 1.56309 212 3.2433 2 34 1.52430 213 3.1865 2 35 1.49114 114 2.9459 10 36 1.45351 115 2.8937 5 37 1.42115 116 2.8488 1 38 1.40974 117 2.7849 1 39 1.36518 118 2.6952 3 40 1.34568 119 2.6187 6 41 1.33077 120 2.5081 5 42 1.28691 121 2.3559 1 43 1.26777 122 2.3094 1

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SILICATES

A comparison of the powder diffraction patterns of the chabasite from Jablanica with literature references for this mineral results in some discrepancies. The diffraction patterns of our chabasite (Jablanica) contains some diffraction peaks (signals) which have not been observed by other authors (Mason and Greenberg 1954; Mikheev 1957). At first we believed that the extra signals were caused by albite, but the IR-spectrum did not reveal the presence of this mineral. Moreover, the Na2O = 0.27% content does not imply the presence of albite in the material used for powder diffraction analysis. Crystal-structure parameters were also measured on monocrystals of chabasite (table 72):

Table 72. Structural parameters of the Jablanica chabasite compared with literature data (Dent and Smith 1958)

1. Chabasite (Ploče quarry, Jablanica) Mt = 530.9155ar = 9.453 Å ax = 13.801 Åα = 94° 24’ cx = 15.028 ÅV = 841.76 Å3 V = 2478.88 Å3

Dm = 2.078 g/cm3 Dm = 2.078 g/cm3

Z = 2 Z = 6Dx = 2.094 g/cm3 Dx = 2.134 g/cm3

Rhombohedral (hexagonal) system – R-3m

2. Chabasite (ref. Dent and Smith 1958) Mt = 552.4514ar = 9.40 Å ah = 13.78 Åα = 94° 18’ ch = 15.01 ÅV = 828.1 Å3 V = 2468.4 Å3

Z = 2 Z = 6Dx = 2.22 g/cm3 Dx = 2.23 g/cm3

Rhombohedral (hexagonal) system – R-3m

Based on the above crystallographic and structural data, the Jablanica chabasite belongs to the rhombohedral system, which corresponds to literature references, as above. However, the difference in optical constants remain. The chabasite from the Ploče quarry is optically biaxial with a large positive 2V angle. The reason for this optical anomaly is unknown. Deer et al. (1963) note that such anomalie have been observed in the case of chabasite, gmelinite and levinite. It is worth noting that the chabasite from Bor was also determined as biaxial.

The origin (genesis) of zeolites

In our description of the occurrences of chabasite, laumontite, natrolite, scolecite, stilbite and thomsonite in Bosnia and Hercegovina, we have made it clear that these minerals occur as fillings of fissures and veins hosted by basic igneous or vein-type rocks in the Bosnian serpentine zone and within the gabbro complex at Jablanica. They form monomineral or polymineral veinlets, the thickness of which is in the range from several millimeters to several centimeters. Therefore, the zeolites in Bosnia and Hercegovina can be described as typical vein-type minerals.

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The host rocks of the zeolite minerals are largely similar. They consist of gabbros, diabases, spilites (or their effusive equivalents which contain plagioclases as essential constituents). The zeolite parageneses are usually simple, but complex associations occur within the Jablanica complex. This implies the influence of late, low-temperature post-magmatic effects on the composition of these parageneses.

The origin of the zeolites can therefore be discussed in terms of two different scenarios. The zeolites may have formed as primary minerals, crystallizing in the final deposition stages from hot solutions which were in contact with igneous bodies. The other possibility for zeolite formation would be their crystallization from hydrothermal solutions enriched in calcium, sodium, aluminum and silica (and other elements) as a consequence of the leaching of surrounding rocks (especially plagioclases contained in them). In such cases, pseudomorphic zeolite growth over plagioclases could be observed.

The composition of some zeolite parageneses occurring within the Jablanica complex or the Bosnian serpentine zone confirms the notion that they may have been formed by either of the described processes (depending on their location). For example, at Mt. Konjuh (Karaula area) the paragenesis is rather complex (zeolites, thomsonite, laumontite, natrolite, prehnite, analcime etc), and it is obvious that natrolite was the last mineral species to crystallize (natrolite can be deposited even from completely cold solutions, percolating through the fissures of basic igneous rocks). At Mt. Kozara, laumontite is oftn associated with plagioclases, occasionally present as a secondary pseudomorphic growth.

The crystallization sequence of zeolite minerals, as established by Kostov (cited in Deer et al. 1963) is based upon the Al:Si ratio and the energy index. A low energy index corresponds to high crystallization temperatures. This author maintains that scolecite is a high-temperature member of the calcium zeolites. This would be in accordance with our findings for the scolecite from Ribnica near Višegrad.

The origin of chabasite and other zeolites in tha gabbro of the Jablanica complex can be related to hydrothermal processes. Both low-temperature and high-temperature zeolite parageneses have been identified in this area. We therefore believe that the solutions carrying Ca, Na, Al and Si (enriched by laterl secretion processes) are linked to surrounding gabbro rocks. Hydrothermal solutions originating at greater depths had considerably higher temperatures, but cooled off as they rose toward the surface. These solutions, therefore, did not have a profound effect on the chemistry of the gabbro rock. Evidence of this are the fresh plagioclases, which are quite abundant in the host rock.

Uses: Zeolite minerals have specific structural properties which enables them to absorb substantial quantities of ‘zeolite water’. This, and some other properties make them important industrial minerals.

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There are three main uses of zeolites in industry: catalysis, gas separation and ion exchange. Zeolites are extremely useful as catalysts for several important reactions involving organic molecules. The most important are cracking, isomerisation and hydrocarbon synthesis. Zeolites can promote a diverse range of catalytic reactions including acid-base and metal induced reactions. Zeolites can also be acid catalysts and can be used as supports for active metals or reagents. Zeolites can be shape-selective catalysts either by transition state selectivity or by exclusion of competing reactants on the basis of molecular diameter. They have also been used as oxidation catalysts. The reactions can take place within the pores of the zeolite, which allows a greater degree of product control. The main industrial application areas are: petroleum refining, synfuels production, and petrochemical production. Synthetic zeolites are the most important catalysts in petrochemical refineries.

Zeolites are used to adsorb a variety of materials. This includes applications in drying, purification, and separation. They can remove water to very low partial pressures and are very effective desiccants, with a capacity of up to more than 25% of their weight in water. They can remove volatile organic chemicals from air streams, separate isomers and mixtures of gases. A widely used property of zeolites is that of gas separation. The porous structure of zeolites can be used to “sieve” molecules having certain dimensions and allow them to enter the pores. This property can be fine tuned by variating the structure by changing the size and number of cations around the pores. Other applications that can take place within the pore include polymerisation of semi conducting materials and conducting polymers to produce materials having unusual physical and electrical attributes.

Hydrated cations within the zeolite pores are bound loosely to the zeolite framework, and can readily exchange with other cations when in aqueous media. Applications of this can be seen in water softening devices, and the use of zeolites in detergents and soaps. The largest volume use for zeolites is in detergent formulations where they have replaced phosphates as water-softening agents. They do this by exchanging the sodium in the zeolite for the calcium and magnesium present in the water. It is even possible to remove radioactive ions from contaminated water.

325


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I General references

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Geol.Soc.America, Memoir 122, Boulder.Brown, G. (1961): The x-ray identification and crystal structures of clay minerals. Min.Soc.

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Fahey, J.J. and Axelrod, J.V. (1950): Searlesite from Green River formation of Wyoming. Am.Mineral., 35, 1014.

Fersman, A.E. (1932): Pegmatites. Volume 1 – granite pegmatites. 2nd edition. Leningrad (in Russian).

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Fiala, F. (1899): Das Flashgräberfeld und die prähistorische Ansiedlung in Sanski Most. Wissenschatf. Mitt. aus Bosnien und Herzegovina, Heft 6, Wien.

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Görgey, R. (1915): Katzer, F. (Sarajevo): Poechit, ein Manganeisenerz von Vareš in Bosnien. Ref. in Zs. Kristallogr. 54, 408.

Group of authors (1966): Cultural history of Bosnia and Hercegovina. Sarajevo (in Bosnian).Jireček, J. (1951): Commercial roads and mines of Medieval Serbia and Bosnia. Svjetlost,

Sarajevo (in Bosnian, translate originally from German).Johnstone, S.J. and Johnstone M.G. (1961): Minerals for the chemical and allied industries.

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Mason, B. and Greenberg, S.S. (1960): Zeolites and associated minerals from southern Brasil. Ark. Mineral. Geol., 1, 519-526.

Meier, V.M. (1960): The crystal structure of natrolite. Zeit. Kristallogr., 113, 430.Miheev, V.I. (1957): Determination of minerals by x-ray diffraction. Gosgeoltehizdat,

Moscow (in Russian).Mikolji, V. (1969): The history of iron and iron manufacture in Bosnia, Zenica (in Bosnian).Moenke, H. (1962): Mineralspektren. Akademie Verlag, Berlin.Mohs, F. (1824): Grundriss der Mineralogie, 2 Bänder, Dresden.Nikitin, W.W. (1936): Die Fedorow-Methode, Bornträger, Berlin.Njirkov, A.A. and Kobilev, A.G. (1962): Thermoanalytical investigations of zeolites.

Academy of Sciences of USSR (in Russian).Pašalić, E. (1975): Collected works. Svjetlost, Sarajevo (in Bosnian).Patsch, K. (1898): Roman archaelogical sites in the Novi area. Journal of the National

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method. Acta Geol., VI, 3-4, Budapest.Petrović, J. (1937): Development of cultures in the Lašva area. Napredak, Sarajevo (in Bosnian).Petruk, W. (1964): Determination of the heavy-atom content in chlorite by means of the x-ray

diffractometer. Am. Mineral., 47, 617.Plinius, the Elder (1873): Naturalis historia, Lib. 33, Berlin.Pljusnina, I.I. (1967): Infrared spectra of silicates. Moscow University Editions (in Russian).Povarennyh, A.S. (1966): Crystallochemical classification of minerals. Kiev (in Russian).Radimsky, V. (1891): On some prehistoric and Roman artefacts in the area of the Sana river

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Schoen, R. (1962): Semi-quantitative analysis of chlorite by x-ray diffraction. Am. Mineral., 47, 1384.

Senderov, J.J., Yaskin, G.M. and Byčkov, A.M. (1975): The influence of alkaline solutions on the Si-Al ordering in potassium feldspar. Geohimija (Geochemistry International), 1816-1826, Moscow (in Russian).

Senderov, J.J. and Ščekina, T.I. (1976): On the stability of the structural forms of albite and condition of their formation in nature. Geohimija (Geochemistry International), 159-175, Moscow (in Russian).

Simić, V. (1951): Historical development of mining in our areas, Belgrade (in Serbian).Skarić, V. (1935): An old Turkish manuscript on mining activities and terminology. SKA

Memorial volume, 79, Belgrade (in Serbian).Skarić, V. (1939): Ancient mining laws and techniques in Serbia and Bosnia. SKA Special

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Spaho, F. (1913): The Turkish mining laws. Journal of the National Museum of Bosnia and Hercegovina, vol. XXV, Sarajevo (in Bosnian).

Strunz, H. (1966): Mineralogische Tabellen. 4. völlig neubearbeitete und erweiterte Auflage (4th edition). Akademische Verlagsgesellschaft, Leipzig.

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Torre de Assuncao, C. and Garrido, J. (1953): Tables pour la determination des mineraux au moyen des rayones X. Lisbonne.

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II References pertaining to the minerals of Bosnia and Hercegovina

Arsenijević, M. (1960): Geochemical investigations of potassium feldspars from pegmatite-pneumatolytic formations (Prilep area). Journal of the Natural History Museum of Serbia, A-13, 69-104, Belgrade (in Serbian).

Arsenijević, M. (1967): Preliminary investigations on the distribution of beryllium, tin, niobium and molybdenum in granitoid minerals as indicators of geochemical areals in the Dinarides and the Carpatho-Balkan arc. Ann. Inst. Geol. Mining and Nucl. Mat. Min. Resources, 3, 83-89, Belgrade (in Serbian).

Atanacković, M., Mudrenović, V. and Gaković, M. (1968): The stratigraphy and tectonics of the Borovica area near Vareš. Geol. gazette, 12, 5-36, Sarajevo (in Bosnian).

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Barić, Lj. (1959): On the neccessity and possibilities of precise microscopic determinations of plagioclases. Journal of the Geological and Geophysical Survey of NR Serbia, 11, 99-113, Belgrade (in Croatian).

Barić, Lj. (1960): Beryl from Mt. Motajica. Acta Geologica, II, 71-82, Yugosl. Acad. Sci. Arts, Zagreb (in Croatian).

Barić, Lj. (1961): Über die Hyalophane von Busovača. Tschermaks Min. Petr. Mitteilungen, dritte Folge, 7 (Mitteilungen der Österreichischen Gesellschaft 1957-1960), 18, 467-502.

Barić, Lj. (1964): Über den Gips und Albit im Eisenerzrevier Ljubija in Nordwestbosnien. Bull. Sci. Cons. Acad. Yougoslavie, tome 9, 1-2, 8, Zagreb.

Barić, Lj. (1966): Searlesite von Lopare in Nordostbosnien. Ber. Deutsch. Ges. geol. Wiss., B Miner. Lagerstätten, 11, 4, 407-421, Berlin.

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Barić, Lj. (1969a): Vorläufige Erwiderung auf die von J.Pamić gegebene Mitteilung über die Feldpäte mit Hochtemperatur-Optik in den Gesteinen der mitteltriassischen Spilit-Keratophyr-Assoziation in Dinariden. Mineralogisch-petrographisches Museum der Universität in Zagreb. Mitteilung 1. Juni 1969, Zagreb.

Barić, Lj. (1970): Do the rocks of the mid-Triassic spilite-keratophyre association in the Dianrides really contain albite with apparently high-temperature optics ? Proceedings of the VII Congress of Yugoslav Geological Societies, 87-88, Zagreb (in Croatian).

Barić, Lj. (1970a): Keratophyre from the Trešanica gorge near Bradina in Hercegovina. Journal of the National Museum of Bosnia and Hercegovina, new series vol. IX, 5-12, Sarajevo (in Croatian).

Barić, Lj. (1971): Hyalophan aus Zagrlski (Zagradski) potok bei Busovača (Zentralbosnien). 2nd International symposium on the mineral deposits of the Alps, Bled, Slovenia, Yugoslavia, 4-8 October 1971, Papers, 7-8, Ljubljana.

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Barić, Lj. (1975): Albite in rocks of the Middle Triassic spilite-keratophyre association of the dinarides is low, well-ordered albite. Geol. gazette, 28, 173-194, Zagreb.

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Barić, Lj. and Trubelja, F. (1971): Hydromuscovite schists from the area of Repovac west of Bradina (Hercegovina). Journal of the National Museum of Bosnia and Hercegovina, new series vol. X, 5-12, Sarajevo (in Croatian).

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Baumgärtel, B. (1904): Das Nebengestein der Chromeisen-Erzlagerstätten bei Duboštica in Bosnien und das Auftreten von sekundär gebildetem Chromit im demselben. Tschermaks Min. und Petr. Mitt., 23, 5, 393-400.

Behlilović, S. and Pamić, J. (1963): Ladinian volcanogenic formations in the river Drežanka valley (Hercegovina). Geol. gazette, 7, 39-44, Sarajevo (in Bosnian).

Biščević-Muštović, F., Trubelja, F. and Sijarić, G. (1976): Gibbsite-kaolinite bauxites from the shores of lake Rama. Presentation at the IV Yugoslav Symposium on the prospecting and exploitation of bauxite, 11-15.10.1976, Herceg Novi (in Bosnian).

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Cissarz, A. (1956): Über ein ungewöhnliches Magnetitvorkommen am Kontakt des Gabbromassivs von Jablanica in der Herzegowina. Journal of the Geological and Geophysical Survey of NR Serbia, 12, 201-221, Belgrade.

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Conrad, A. (1871): Bosnien mit Bezug auf seine Mineralschätze. Mitteilungen der K.K. Geographischen Gesellschaft, Bd. XIII (1870) 219-228, Wien.

Čelebić, Đ. (1963): Sedimentary deposits of iron and manganese ores in the diabase-chert series of north-west Hercegovina. Geol. gazette, 7, 145-159, Sarajevo (in Bosnian).

Čelebić, Đ. (1967): Geological and tectonic setting of the Paleozoic- and Mesozoic-age area between Konjic and Prozor – with special attention to Fe and Mn ores. Geol. gazette, X (special editions), 1-139, Sarajevo (in Bosnian).

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Čičić, S. and Pudar, N. (1973): Geological, explorational, technical and economic features of the clay deposits of Bosnia and Hercegovina. Geol. gazette, 17, 203-260, Sarajevo (in Bosnian).

Čutura, O. (1918): Volcanic rocks in south-west Bosnia. Journal of the National Museum of Bosnia and Hercegovina,XXX, 11-20, Sarajevo (in Bosnian).

Ćatović, F. and Trubelja, F. (1976): Occurrences of pyrite-bearing bauxites in some deposits in Hercegovina. Presentation at the IV Yugoslav Symposium on the prospecting and exploitation of bauxite, 11-15.10.1976, Herceg Novi (in Bosnian).

Ćatović, F., Trubelja, F. and Sijarić, G. (1976): Bauxites of the Srnetica mountain (Bosnia). Travaux du Comite international pour l’etude des bauxites, de l’alumine et d’aluminium (ICSOBA), No. 13, 103-113, Academie Yougoslave des Sciences et des Arts, Zagreb.

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350

SILICATES

351


Index

A

Actinolite 3, 22, 32, 37, 64, 78, 81, 88, 105, 115-118, 136-142, 154, 174, 237, 280, 286, 302, 304Africite 102Albite 5, 44-46, 51, 67, 76, 78-79, 81-82, 84, 89, 96, 106, 120, 123-124, 126, 141, 151, 155, 174-176, 182, 186, 188, 190, 211-213, 219, 245-246, 248-250, 259-264, 268, 274-285, 287-298, 300, 303, 305, 319, 322, 326, 328-329, 331, 334, 337, 340, 346-347Allanite 3, 85-87Almandine 39, 41-43, 45, 47Amphibole 28, 32-33, 37-38, 40-42, 44, 54, 59, 64, 78-79, 88, 90, 110, 113-116, 119-120, 122-123, 127, 136-151, 153-156, 174, 184, 189, 211, 215, 229, 236, 254, 257, 260, 265, 277, 281, 287, 291, 293-295, 297-298, 304, 307, 309, 320, 331, 340Analcime 247-248, 254-255, 309-310, 314-316, 323, 331, 344Anatase 182Andalusite 3, 55-57, 66, 187, 213Andesine 5, 23, 42, 257, 259, 276, 278, 280, 286-301Andradite 39, 42-43, 45-46Anorthite 5, 22, 255, 268, 274, 291, 297, 302-304, 306-307Anorthoclase 257, 262-264Antigorite 225, 228, 231-232, 234-236Apatite 22, 44, 49, 101, 106, 185, 187, 195, 257, 259, 263 Apyre 102Aquamarine 91, 99Augite 3, 22, 37, 53, 82, 89, 111, 116, 121-127, 139-140, 150-151, 190, 209-210, 334Axinite 3, 90

B

Bagrationite 85Baryte 21, 23, 25, 141, 169, 176-177Basalt 38, 111, 115, 125-126, 142, 145, 209-210, 248, 286, 290, 297, 300, 305Beidellite 4, 200, 202-205, 329Beryl 3, 24, 91-97, 99-100, 103, 105, 171, 188, 327-328, 331, 336, 338, 343Biotite 4, 22, 43-44, 50-51, 54, 56-57, 66, 68, 78-80, 86-87, 101, 104, 110, 121-122, 136, 173, 180, 182-191, 195, 197, 203, 206, 209, 211-213, 219-220, 254-255, 257, 259, 263, 283-284, 289, 293-294, 301, 346Bixibiite 91Bodenite 85Braunite 3, 60-63Bronzite 3, 128-129, 133-134Bytownite 5, 136, 184, 296-307

C

Calcite 22-23, 28, 45-46, 61, 67, 70. 76-77, 80, 82, 84, 90, 107, 125, 159, 162, 165, 182, 195, 198, 200, 203, 209-211, 245-248, 250, 255, 257, 264, 276, 278, 283, 293-294, 305, 310Celladonite 181Chabasite 311, 313, 317, 319-320, 323, 325-326Chalcedony 23Chalcopyrite 23-25, 46, 170, 225, 265, 283Chamosite 207, 217Chlorite 4, 22, 40, 43-44, 76, 80-84, 90, 106, 118, 120, 122-123, 125-127, 136, 141, 155, 167, 169-170, 174, 177, 179, 185, 187-189, 191, 198, 203, 206-217, 219-220, 229, 234-235, 244-246, 248-250, 255, 264-265, 276, 278, 281, 283-285, 301, 319-320, 326, 345Chloritoid 3, 49, 68-69, 175

352

SILICATES

Chromite 23, 25, 34, 36, 43, 114, 131, 146, 217, 229, 234, 329, 339, 345Chrysocolla 4, 224, 225Chrysotile 23, 171, 225, 231, 233, 236-237, 241, 332, 334, 338, 349Clinochlore 206-207, 211-214Clinozoisite 3, 44, 46, 75, 75-83, 145, 155, 229, 244-245, 250Cordierite 100, 101Corundophyllite 206, 209Crocydolite 155-157Cryptomelane 61

D

Daphnite 206-207, 217Datolite 3, 69-71, 245, 255, 309, 316, 331Diallage 3, 22, 111-112, 115-121, 123-124, 135, 138-139, 143, 150, 209, 281Dickite 4, 220, 224, 342Diopside 3, 24, 42-43, 111-116, 121, 136, 171, 182, 229, 291Disthene 57Dolomite 23, 47, 109, 157, 165, 169, 175, 229, 231, 348

E

Edenite 42, 135, 142, 146, 148-150, 298, 304, 307Emerald 91, 97-99Enstatite 3, 34-36, 128-133, 138, 171, 229Epidote 3, 22, 28, 44-46, 67, 75-85, 88-90, 105, 107, 109-110, 141, 155, 157, 174, 185, 188-189, 198, 213, 220, 145, 249-250, 259, 279, 281, 301, 305

F

Fayalite 30, 35-38

G

Gabbro 6, 22, 28, 31-33, 35-38, 41, 45, 65, 76-77, 79, 82, 89-90, 107, 112-113, 115-121, 123-125, 131, 134-140, 142-143, 145, 149-152, 155, 183-184, 186, 190, 197, 208-212, 227, 235-236, 243-245, 247-250, 258, 260, 279, 281, 286, 288, 290, 292, 295-300, 302-307, 309-311, 313, 317-320, 322-323, 329, 331-332, 334, 336-337, 339-340, 344, 348Galene 21, 25, 27Garnets 3, 22-23, 39-47, 82, 90, 101, 107, 110, 113-114, 128, 135, 151, 155, 157, 160, 173, 182, 187, 195, 203, 209, 211-213, 247, 254, 280, 291, 304, 307, 309Garnierite 225, 234Gibbsite 182, 217, 221-222, 238, 313Glauconite 4, 179-182, 347Glaucophane 4, 148, 155-157Gneisse > Gneiss 43-44, 49-50, 52, 54, 56, 66, 78, 80, 86, 87, 102, 104, 154-155, 172-174, 183, 187-188, 212-213, 259, 261-262, 275, 281, 289, 294-295Goethite 26, 199, 205, 220, 229Goshenite 91, 99Grossular 39, 42-43, 45-46

H

Halloysite 4, 194-195, 201, 224, 237-238, 337Harzburgite 24-37, 115, 120, 129-132, 138, 150, 227Hausmannite 61Hedenbergite 111Heliodor 91, 99Hematite 23, 25-26, 62, 101, 110, 118, 121, 221, 259Hemimorphite 3, 71-72Hibschite 48Hornblende 4, 22, 41-44, 78, 83, 113-114,

353


117, 120-121, 124, 135-137, 140-146, 148-155, 174, 182, 211, 213, 244, 248, 287, 294, 298, 304, 307, 319, 332Hornblendite 41, 78, 113, 151, 154, 174, 294, 304, 307Hyalophane 4, 177, 264-274, 330Hydrobiotite 4, 197Hydromica 44, 46, 50, 165, 179, 189, 192, Hydromuscovite 4, 166, 192, 196-197, 285, 329Hypersthene 3, 128-129, 134-136, 138, 153, 301, 305, 309, 336

I

Illite 4, 165, 191-196, 199, 201, 218-219, 222, 238, 344-345Ilmenite 22, 56, 64-66, 101, 145, 155, 195

K

Kaemmererite 206, 217Kalinite 218Kaolinite 4, 165, 171, 194-196, 201, 206, 217-219, 221-224, 237-238, 249, 259-260, 279, 293-294, 329, 337, 342Ksantorite 85Kyanite 3, 7, 57-58, 67, 182, 203

L

Labradorite 5, 22, 33, 42, 79, 190, 259, 278, 281, 288, 290-293, 295-303, 305, 334Lazurite 5, 308Lepidomelane 188Lherzolite 32-36, 112-115, 129-134, 171, 227, 241, 302-303, 307Limonite 23, 25, 50, 71, 110, 165, 167, 194, 224Lizardite 225, 228-231, 326

M

Magnesite 21, 28, 36, 38, 228-229, 236, 239-241, 338, 342-344, 349Magnetite 22-23, 32-33, 35, 37, 43-46, 59, 82-83, 89, 101, 105, 107, 120-121, 125, 136, 141, 151, 157, 177, 185, 190-191, 203, 211, 216, 219, 264-265, 329, 331, 338, 349Marble 45, 76, 174-175, 188, 248Mesolite 5, 310, 313Metahalloysite 201, 237Micaschist 43, 50, 56, 66, 80, 104, 173-174, 183, 187-188, 213, 242, 281Microcline 4, 172, 258-259, 261-262Montmorillonite 4, 165, 171, 192, 194-195, 198-206, 218, 342, 346Morganite 91, 99Muromonite 85Muscovite 4, 22, 43, 50-51, 54, 56, 67, 69, 86-87, 93, 96, 101, 103-104, 165-166, 172-179, 187, 192-193, 195, 203, 219, 238, 258-259, 261, 273, 284-285, 288

N

Nacrite 4, 224Natrolite 5, 70-71, 210, 247, 255, 309-311, 313-314, 316, 322-323, 325-326, 331Nepheline 4, 254Nontronite 4, 203-206, 220

O

Oligoclase 5, 22, 51, 223, 260, 278, 280-281, 286-289, 292, 295, 298, 300, 330Olivine 3, 22, 30-38, 117-120, 129-132, 134-136, 138-140, 143, 145, 150, 155, 167, 171, 186, 190, 206, 226-227, 229, 235-236, 243-245, 260, 296, 298-299, 302-304, 306, 344Omphacite 3, 41, 113, 127-128, 184, 309Orthoclase 4, 22, 80, 104, 171-172, 195,

354

SILICATES

219, 258-261, 264-265, 268, 279Ottrelite 3, 68-69

PPargasite 42, 135, 142, 146, 148-150, 298, 304, 307Pennine 28, 44, 206-207, 211, 213Periclase 182Phlogopite 4, 182Pigeonite 3, 111, 119Pistazite 75, 77, 79, 85Plagioclase 5, 32, 37, 41, 43-44, 52, 76-77, 79, 101, 114, 120, 123, 125-126, 135, 138-139, 163, 182, 185-186, 192, 209, 218-220, 244, 247, 250, 255, 257-259, 274, 276-178, 280-281, 284, 286, 300, 302-304, 306-309, 316-317, 320, 323, 325, 327-328, 343Prehnite 4, 28, 43-44, 66, 71, 76-77, 79-80, 83, 90, 114, 124, 145, 161, 163, 211, 227, 242-250, 255, 276, 281, 291, 303-304, 307, 309, 314, 316-317, 319-320, 323, 345, 348Pumpellyite 3, 90, 249, 319Pyrite 23-25, 44-46, 96, 103, 105, 145, 170, 203, 220-222, 225, 253, 265, 273, 279, 330Pyrope 39, 41-43, 45, 47Pyrophyllite 4, 165-166, 175, 194, 198, 285, 329Pyroxene 28, 33, 37-38, 40-41, 44, 64, 78, 110-116, 118, 120-121, 127-129, 131-135, 138-140, 145, 150-151, 167, 171, 208, 211, 213, 226-227, 236, 287, 296, 302, 304-305, 307, 331, 344

Q

Quartz 12, 21-24, 26, 28, 38, 40, 47, 49, 50, 52, 54, 56-58, 61, 66-67, 69, 81-82, 84, 89, 94-96, 99, 101, 103-110, 127, 141, 153-155, 164-165, 169, 173-179, 184-185, 187-196, 198-199, 201-203, 209, 211-213, 216, 219-220, 222-223, 238, 248-249, 254, 257-258, 260, 263, 265, 273-274, 276-277, 283-285,

288, 292, 308, 317, 320, 330, 332, 334, 340, 342, 349

R

Rhipidolite 71, 206-207, 245Rhodochrosite 26-27Rhodonite 4, 164Riebeckite 155-157Romanechite 61Rubelite 102, 108Rutile 41, 43, 49, 64, 67, 106, 110, 182, 192, 203

S

Sanidine 4, 22, 185, 220, 224, 256-258, 261-264, 347Saponite 4, 206Scapolite 5, 308-309Scolecite 5, 311-313, 322-323Searlesite 4, 250-254, 325-326, 328-329Sepiolite 4, 21, 23-25, 33, 134, 220, 238-242, 336, 341, 343, 345Sericite 44, 56-57, 76, 81, 101, 106-107, 110, 165, 172-179, 195-197, 211, 216, 219-220, 238, 248-249, 259-260, 265, 276, 279, 282, 291, 346Serpentine zone 22-23, 30-34, 38, 40-41, 48-49, 51, 56-57, 64, 70-72, 76, 79-80, 89, 112, 114, 116-117, 121-123, 127, 129, 133-134, 137-138, 143, 147, 155, 158, 164, 167, 168, 171, 178, 183, 186, 197, 199, 205, 208, 210, 226-227, 236, 243, 249, 254, 255, 275, 279, 286, 287, 290, 295, 296, 299, 302, 304, 306-307, 309, 313, 316, 322-323, 326-327, 330, 336-337Sheridanite 206-207Shorl 105Siberite 102Spessartine 39, 42, 45, 47

355


Sphalerite 25, 27, 72, 107, 346Sphene 63Sporogelite 183Staurolite 3, 59-60, 203Stilbite 5, 28, 90, 103, 281, 311, 317-319, 322, 345Stilpnomelane 4, 84, 198Sudoite 206-207, 217Suolunite 3, 72-75, 158-159, 345Syenite 51, 53, 210, 247, 258, 261, 275, 280, 331

T

Talc 4, 96, 103, 130, 166-172, 201, 209-210, 214-215, 234-235, 332, 339, 345Tautolite 85Thomsonite 5, 245, 255, 310, 313-315, 322, 323, 345Thorite 3, 53-55, 86Titanite 3, 28, 63-67, 101, 116, 155, 248, 320, 348Tobermorite 4, 73, 75, 158-159, 345Tourmaline 3, 28, 49, 52, 67, 80, 89, 96, 101-110, 182, 189, 195, 203, 259, 283, 320, 330, 334, 337Tremolite 3, 32, 37, 136-139, 142, 237, 245Troctolite 31-33, 35, 37, 79, 112, 117, 119-120, 138, 140, 145, 206, 227, 243-244, 295, 302-303, 306Tschermakite 148-149Tuff 51, 66, 110, 127, 180-181, 184, 186, 191, 199-201, 206, 210, 212, 251, 254-255, 257, 277, 281, 286, 289, 290, 292, 294-295, 300, 328, 337

U

Uvarovite 39, 42-43, 47

V

Vermiculite 4, 206Vesuvianite 3, 90Vorobievite 91, 99

W

Wasite 85Wollastonite 4, 74, 107, 157-158, 161

X

Xonotlite 4, 74, 159-164, 244, 281, 331, 337, 347

Z

Zeolite 66, 70, 76, 105, 163, 241, 244, 250, 255, 313, 316, 322-327, 348Zircon 3, 41, 43, 58-53, 101-102, 106, 108, 182, 195, 203, 219, 259Zoisite 3, 22, 67, 79, 81-82, 84, 87-90, 109, 139, 154, 244, 249

356

SILICATES

This book was published with financial support of:

ZA IZDAVAŠTVOSARAJEVO

EngineeringConsulting

Design Road Directorate of Federation of Bosnia and Herzegovina

Geoinvest d.o.o. Sarajevo, Department for Transport, Faculty of Civil Engineering in Sarajevo, Ministry of Civil Affairs of Bosnia and Herzegovina, Federal Ministry of Physical Planning, Institute for Geology, Faculty of Civil Engineering in Sarajevo, Construction Institute of the Canton Sarajevo, Federal Directorate for Building, Managing and Maintaining Motorways, Federal Institute for Geology, INTRADE energija, Institute for Hidrotechnics, Faculty of Civil Engineering in Sarajevo

Documents

MINERALS - ANUBIH - Naslovna · Herzegovina”, Book IV “Magmatism and Metalogenia” (1978). The Geological – Institute was awarded Veselin Masleša Prize for this book. As a