Diamonds - Univerzita Karlova · Diamonds George E. Harlow and Rondi M. Davies Guest Editors Inclusions in Sublithospheric Diamonds: Glimpses of Deep Earth Thomas Stachel, Gerhard

March 2005Volume 1, Number 2

ISSN 1811-5209

DiamondsInclusions in Diamonds

The Origin of Diamond

Strange Diamonds: Carbonado and Framesite

Microdiamonds in Metamorphic Rocks

Meteoritic Nanodiamonds

Changing Color of Gem Diamonds

Growing Better Diamonds

DiamondsGeorge E. Harlow and Rondi M. DaviesGuest Editors

Inclusions in Sublithospheric Diamonds: Glimpses of Deep EarthThomas Stachel, Gerhard P. Brey, and Jeffrey W. Harris

Stable Isotopes and the Origin of Diamond Pierre Cartigny

Strange Diamonds: The Mysterious Origins of Carbonado and Framesite Peter J. Heaney, Edward P. Vicenzi, and Subarnarekha De

Microdiamonds in Ultrahigh-PressureMetamorphic Rocks Yoshihide Ogasawara

Meteoritic Nanodiamonds: Messengers from the StarsGary R. Huss

High-Pressure and High-Temperature Treatmentof Gem DiamondsJames E. Shigley

Growing Diamond Crystals by Chemical Vapor DepositionRussell J. Hemley, Yu-Chun Chen, and Chih-Shiue Yan

DepartmentsEditorial . . . . . . . . . . . . . . . . . . . . . . . . . 59Letters to the Editors . . . . . . . . . . . . . . . . . 60Triple Point . . . . . . . . . . . . . . . . . . . . . . . 61Highlight Paul Ribbe . . . . . . . . . . . . . . . . . 62Conference Reports . . . . . . . . . . . . . . . . . . 63Meet the Authors . . . . . . . . . . . . . . . . . . . 71People in the News . . . . . . . . . . . . . . . . . . 90Reviews . . . . . . . . . . . . . . . . . . . . . . . . . 109Society News . . . . . . . . . . . . . . . . . . . . . . 110

European Association for Geochemistry . . . . . . 110International Association of GeoChemistry . . . . . 112The Clay Minerals Society . . . . . . . . . . . . . . 114Mineralogical Association of Canada . . . . . . . . 116Mineralogical Society of Great Britain and Ireland 118Geochemical Society . . . . . . . . . . . . . . . . . 120Mineralogical Society of America . . . . . . . . . . 122

International News . . . . . . . . . . . . . . . . . . 124Advertisers in this Issue . . . . . . . . . . . . . . . 124Mineral Matters . . . . . . . . . . . . . . . . . . . . 125Calendar . . . . . . . . . . . . . . . . . . . . . . . . 126Voilà . . . . . . . . . . . . . . . . . . . . . . . . . . . 127Parting Shot . . . . . . . . . . . . . . . . . . . . . . 128

57

Elements is published jointly by theMineralogical Society of Great Britainand Ireland, the MineralogicalAssociation of Canada, the GeochemicalSociety, The Clay Minerals Society, theEuropean Association for Geochemistry,the International Association ofGeoChemistry, and the MineralogicalSociety of America. It is provided as abenefit to members of these societies.

Elements will be published three moretimes in 2005. Individuals are encour-aged to join any one of the participatingsocieties to receive Elements. Institutionalsubscribers to any of the followingjournals – American Mineralogist, TheCanadian Mineralogist, Clays and ClayMinerals – will also receive Elements aspart of their subscription. Institutionalsubscriptions are available for US$100 ayear. Contact the managing editor forinformation.

Copyright ©2005 by the Mineralogical Society of America

All rights reserved. Reproduction in anyform, including translation to otherlanguages, or by any means – graphic,electronic or mechanical, includingphotocopying or information storageand retrieval systems – without writtenpermission from the copyright holder isstrictly prohibited.

Publications mail agreementno. 40037944

Return undeliverableCanadian addresses to:PO Box 503 RPO West Beaver CreekRichmond Hill ON L4B 4R6

Printed in Canada ISSN 1811-5209www.elementsmagazine.org

Volume 1, Number 2 • March 2005 ABOUT THE COVER:Diamond, the

ultrahard cubic formof carbon, is a

mineral requiring along string of

superlatives todescribe its

properties, itstechnological and

commercialimportance, and its

roots into humanculture and ourphysical world.Pictured is the

Minton diamondoctahedron (7 mm

across) in kimberlitefrom the De BeersMine, Kimberley,

South Africa. PHOTO BY DENIS FINNIN,

COURTESY OF AMERICAN

MUSEUM OF

NATURAL HISTORY.

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-35 -30 -25 -20 -15 -10 -5 0 50

20

40

60

80

100

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2

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10

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δ 13C (‰)

ycneuqerF

ycneuq erF

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framesite

single crystal

Figure 1

85

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The MineralogicalSociety of America iscomposed ofindividuals interestedin mineralogy,crystallography,

petrology, and geochemistry. Foundedin 1919, the Society promotes,through education and research, theunderstanding and application ofmineralogy by industry, universities,government, and the public.Membership benefits include specialsubscription rates for AmericanMineralogist as well as other journals;25% discount for Reviews in Mineralogyand Geochemistry series and Mono-graphs; Elements, reduced registrationfees for MSA meetings and shortcourses; and participation in a societythat supports the many facets ofmineralogy. For additional informa-tion, contact the MSA Business Office.

PRESIDENT: Robert M. Hazen, CarnegieInst. WashingtonPAST-PRESIDENT: Michael A. Carpenter,University of CambridgeVICE PRESIDENT: John W. Valley,University of Wisconsin–MadisonSECRETARY: George Harlow, AmericanMuseum of Natural HistoryTREASURER: John M. Hughes, MiamiUniversity (Ohio)SOCIETY NEWS EDITOR: Andrea Koziol,University of Dayton

Mineralogical Society of America 1015 Eighteenth Street N.W. Suite 601,Washington, D.C. 20036-5212, USATel.: 202-775-4344Fax: [email protected]

The InternationalAssociation of Geo-Chemistry (IAGC) hasbeen a pre-eminentinternationalgeochemical organi-

zation for over 40 years. Its principalobjectives are to foster cooperation in,and advancement of, appliedgeochemistry, by sponsoring specialistscientific symposia, the activitiesorganized by its working groups, andsupporting its journal AppliedGeochemistry. The administration andactivities of IAGC are conducted by itsCouncil, comprising an Executive andten ordinary members. Day-to-dayadministration is performed throughthe IAGC Business Office.

PRESIDENT: John Ludden, FranceVICE PRESIDENT: Russell Harmon, USASECRETARY: Attila Demeny, HungaryTREASURER: Gunter Faure, USA

BUSINESS MANAGER: Mel GascoyneIAGC Business OfficeBox 501Pinawa, Manitoba R0E 1L0 Canada [email protected]

The MineralogicalSociety of GreatBritain and Irelandwas founded in 1876and has the generalobject of advancing

the science of mineralogy and itsapplication to other subjects includingcrystallography, geochemistry,petrology, environmental science, andeconomic geology. The Society

furthers its objects through scientificmeetings and the publication ofscientific journals, books, andmonographs. The Society publishesthree journals, Mineralogical Magazine(print and online), Clay Minerals (printand online) and the e-journal MINABSOnline (launched in January 2004).For full details on how to join theSociety and its events and publicationsconsult the Society’s website atwww.minersoc.org or contact theGeneral Office.

PRESIDENT: G. David Price, UniversityCollege London,VICE-PRESIDENTS: ChristopherHawkesworth, University of Bristol,and Ian Parsons, University of EdinburghTREASURER: Neil J. Fortey, BritishGeological Survey, KeyworthGENERAL SECRETARY: Mark E. Hodson,University of ReadingEXECUTIVE SECRETARY AND NEWS EDITOR:Adrian H. Lloyd-Lawrence

Mineralogical Society41 Queen’s GateLondon SW1 5HRUnited KingdomTel. +44 (0)20 7584 7516Fax +44 (0)7823 [email protected] www.minersoc.org

The EuropeanAssociation forGeochemistry wasfounded in 1985 topromote geochemicalresearch and study in

Europe. It is now recognized as thepremiere geochemical organization inEurope encouraging interactionbetween geochemists and researchersin associated fields, and promotingresearch and teaching in the publicand private sectors.

OfficersPRESIDENT: Bruce Yardley (Leeds,United Kingdom)VICE-PRESIDENT: Alex Halliday (Oxford,United Kingdom)PAST PRESIDENT: Terry Seward (Zurich,Switzerland)TREASURER: Catherine Chauvel(Grenoble, France)SECRETARY: Mark Hodson (Reading,United Kingdom)

Committee MembersStephen Banwart (UK)Philippe Van Cappellen (Netherlands)Christian France-Lanord (France)Jérôme Gaillardet (France)Sigurður Gíslason (Iceland)Alex Halliday (UK)Carsten Muenker (Germany)

Eric Oelkers (France)Graham Pearson (UK)Andrew Putnis (Germany)Susan Stipp (Denmark)Gerhard Wörner (Germany)Membership information:www.eag.eu.com/membership

The MineralogicalAssociation of Cana-da was incorporated in1955 to promote andadvance the knowl-edge of mineralogy

and the related disciplines of crystallo-graphy, petrology, geochemistry, andeconomic geology. Any person engagedor interested in the fields of mineralo-gy, crystallography, petrology, geo-chemistry, and economic geology maybecome a member of the Association.Membership benefits include asubscription to Elements, reduced costfor subscribing to The CanadianMineralogist, a 20% discount on short-course volumes and special publica-tions, and a discount on theregistration fee at our annual meeting.

PRESIDENT: Daniel J. Kontak, NovaScotia Department of NaturalResources, NS PAST PRESIDENT: Norman M. Halden,University of Manitoba, MB VICE PRESIDENT: Kurt Kyser, Queen’sUniversity, ONSECRETARY: Andy McDonald, Laurent-ian University, ONTREASURER: Mati Raudsepp, Universityof British Columbia, BC

Mineralogical Association of CanadaP.O. Box 78087, Meriline Postal Outlet 1460 Merivale Road Ottawa, ON, Canada K2E 1B1Tel. and fax: 613-226-4651canmin.mac.ottawa@sympatico.cawww.mineralogicalassociation.ca

The Clay MineralsSociety (CMS) beganas the Clay MineralsCommittee of the U.S.National Academy ofSciences – National

Research Council in 1952. By 1962,the CMS was incorporated with theprimary purpose of stimulatingresearch and disseminating informa-tion relating to all aspects of clayscience and technology. Themembership includes those interestedin mineralogy, crystallography,geology, geochemistry, physics,chemistry, biology, agronomy, soilsscience, engineering, materialsscience, and industrial science andtechnology. The CMS holds an annualmeeting, workshop, and field trips,and publishes Clays and Clay Minerals

and the CMS Workshop Lectures series.Membership benefits include reducedregistration fees to the annualmeeting, discounts on the CMSWorkshop Lectures, and Elements.

PRESIDENT: Duane M. Moore, Universityof New MexicoPAST PRESIDENT: Kathryn L. Nagy,University of Illinois at Chicago VICE PRESIDENT: Cliff Johnson, PurdueUniversitySECRETARY: Richard W. Berry, San DiegoState UniversityTREASURER: Andrew R. Thomas,Chevron TexacoSOCIETY NEWS EDITOR: Kathryn L. Nagy

The Clay Minerals SocietyLeslie Shivers, ManagerP.O. Box 460130Aurora, CO 80046-0130 USATel.: 303-680-9002Fax: [email protected]. www.clays.org

The GeochemicalSociety is aninternational non-profit organization forscientists involved inthe practice, study,

and teaching of geochemistry. Ourprincipal roles are to provide ourmembers with programs and servicesthat will help them to be bettergeochemists; to enrich the professionaldevelopment and careers of geo-chemists through information,education, relationships, andresources; and to advance the thoughtand application of geochemistry.

Membership includes a subscription toElements, access to the online quarterlynewsletter Geochemical News, as well asan optional subscription to Geochimicaet Cosmochimica Acta (24 issues peryear). Members receive discounts onpublications (GS Special Publications,MSA, Elsevier and Wiley/Jossey-Bass),and on conference registrationsincluding the V.M. Goldschmidtconference, the fall AGU meeting,and the annual GSA meeting. Formore details on our programs orinformation on how to join, pleasevisit our website at: https://gs.wustl.edu

PRESIDENT: James I. Drever, Universityof WyomingVICE PRESIDENT: Susan L. Brantley,Pennsylvania State UniversitySECRETARY: Jeremy B. Fein, Universityof Notre DameTREASURER: Youxue Zhang, Universityof Michigan

BUSINESS MANAGER: Seth DavisWashington University, Earth & PlanetarySciencesOne Brookings Drive, Campus Box #1169St. Louis, MO 63130-4899, USATel.: 314-935-4131Fax: [email protected]://gs.wustl.edu/

58E L E M E N T S MARCH 2005

The Seven Societies

Institutional subscribers to CMS, MAC, MS, and MSA journals are entitled to electronic access as part of their subscriptions.

American Mineralogist Contact the Mineralogical Society of America (MSA)Business Office ([email protected]). Identify your institution and

provide your IP address.The Canadian Mineralogist Contact [email protected] with your IP

address and provide your subscription number.Clays and Clay Minerals Go to the Ingenta web site, which hosts the

electronic journal (www.ingenta.com), or start at The Clay Minerals Society(CMS) website (www.clays.org). You will find further instructions about

registering and requesting access.Mineralogical Magazine and Clay Minerals. Go to the Ingenta web site,

which hosts the electronic journal (www.ingenta.com). You will find further instructions about registering and requesting access.


Editorial

Elements:Getting intothe Swing

With this second issue of Elements, both theeditorial team and you, the readers, will sensethat we are getting into the swing of a newand exciting enterprise. From now on, eachissue will be the responsibility of one of thethree scientific editors and a guest editor. Thisgives me an opportunity to express, I cansafely say on behalf of the entire geochem-istry–petrology–mineralogy community,heartfelt thanks to the two people, Rod Ewingand Pierrette Tremblay, who more than anyothers have been responsible for the guidingvision, look, and feel of our magazine. Ofcourse, we have benefited enormously fromadvice from many sources, but without Rod’sclear vision and quiet persuasion, the wholeconcept would never have moved off theground and attracted the support of thefounding societies. And, as you thumbthrough this issue, consider the complexityof the production of Elements. Thematicarticles, society news, various minor pieces,and advertising have to be integrated into anattractive whole, all within a tightly definedspace and to an exact deadline. Pierrette doesa superb job of piloting the whole shipthrough the sandbanks and narrows of thepublishing business. Thanks too to Alex Speerand the MSA office staff, who took on theconsiderable task of orchestrating the firstmailing of Elements to 6140 individuals in82 countries and to 1258 libraries.

Elements belongs to the members of itssupporting societies, and is connected tothem through an Executive Committee andan Advisory Board. The Executive Committeeis composed of one representative from eachsociety experienced in its workings. Itprovides financial oversight, acts as a channelof communication between the magazine andthe officers and staff of the societies, andapproves the appointment of the principal(i.e. scientific) editors and members of theAdvisory Board. The Advisory Board hasrepresentatives from each society plus someadditional members, all chosen for theirscientific standing and fields of interest. Theirmain roles are to propose potential thematictopics and guest editors for consideration bythe principal editors, to provide informed

advice and comment as need arises, and to actas reviewers. Thematic topics may also besuggested by interested individuals; a form isavailable on our website.

The three principal editors are appointed forstaggered three-year terms, so that Rod Ewingwill serve until the end of 2005, MikeHochella until 2006, and myself until 2007.Replacements are suggested by the ExecutiveCommittee and reviewed by the principaleditors for final approval by the ExecutiveCommittee. The principal editors intend tomeet at least twice a year, and of course weexchange a great deal of e-mail messages.Seeing full-colour pdf files of proofs material-ize on my computer screen when I’m workingfrom my cottage in the Scottish Highlands iswonderful—an e-miracle. Guest editors aretaking on a substantial task, because they areresponsible for getting manuscripts andillustrations up to pre-production standardwith fixed deadlines and space restrictions.All papers are reviewed by an independentexpert referee, the guest editor, and theprincipal editor. This procedure ensuresquality and gives them all-important ‘peer-reviewed’ standing with those ever-watchfulbean-counters.

Principal editors have an important role indefining the style and content of Elements,and in ensuring that articles are pitched atthe right level. Authors will find that this isnot easy. While we do not aspire to beavailable to a mass audience like the excellentScientific American, we want to publish papersaccessible not only to members of thesupporting societies, but also to students,to scientists in adjacent disciplines and topopular science writers and policy makers.Writing for a wider audience means taking offthe comfortable old jacket of jargon, buzz-words, acronyms, and notations that we allwear for our technical writing, and putting onsomething smarter and more outgoing. It’sworth the effort—what you write for Elementsis likely to be read by a far larger audiencethan even your most-cited technical paper.

Ian Parsons

SCIENTIFIC EDITORSRODNEY C. EWING, University of

Michigan ([email protected])MICHAEL F. HOCHELLA JR., Virginia

Tech ([email protected])IAN PARSONS, University of

Edinburgh ([email protected])

ADVISORY BOARD PETER C. BURNS, University of Notre

Dame, USARANDALL T. CYGAN, Sandia National

Laboratories, USA ROBERTO COMPAGNONI, Università

degli Studi di Torino, ItalyADRIAN FINCH, University of

St Andrews, UK BICE FUBINI, Università degli Studi

di Torino, Italy MONICA GRADY, The Natural History

Museum, UK JOHN E. GRAY, US Geological SurveyALAIN MANCEAU, CNRS, Grenoble,

France DOUGLAS K. MCCARTY, Chevron

Texaco, USA KLAUS MEZGER, Universität Münster,

Germany JAMES E. MUNGALL, University

of Toronto, Canada TAKASHI MURAKAMI, University

of Tokyo, Japan HUGH O’NEILL, Australian National

University, Australia NANCY ROSS, Virginia Tech, USA EVERETT SHOCK, Arizona State

University, USA NEIL C. STURCHIO, University

of Illinois at Chicago, USA JOHN W. VALLEY, University

of Wisconsin–Madison, USA DAVID J. VAUGHAN, The University

of Manchester, UK

EXECUTIVE COMMITTEEJEREMY B. FEIN, Geochemical SocietyNORMAN M. HALDEN, Mineralogical

Association of Canada JOHN M. HUGHES, Mineralogical

Society of AmericaKATHRYN L. NAGY, The Clay

Minerals SocietyERIC H. OELKERS, European

Association for GeochemistryRUSSELL S. HARMON, International

Association of GeoChemistryPETER TRELOAR, Mineralogical

Society of Great Britain and Ireland

Managing EditorPIERRETTE [email protected]

EDITORIAL OFFICE INRS-ETE490, de la Couronne Québec (Québec) G1K 9A9 CanadaTel.: 418-654-2606Fax: 418-654-2525

Layout: POULIOT GUAY GRAPHISTES

Printer: CARACTÉRA

The opinions expressed in this maga-zine are those of the authors and donot necessarily reflect the views ofthe publishers.

www.elementsmagazine.org


Letters to the Editors

Thank you very much for theexcellent first issue of Elements. The

choice of theme was excellent, and thearticles were very well done. I felt thelevel of detail was just right for thetarget audiences described in the initaleditorial, “Elements: Building a NewBridge”. The quality of the production and especiallythe graphics were outstanding. The authors and allthe editorial staff are to be congratulated on a firstrate production. If you “will get better and better”,my mouth is watering.

Mark J. Logsdon, Geochimica Inc., USA

I arrived back from AGU to find the first issue ofElements in my mailbox. What a great first issue! The

issue is packed with information, the articles anexciting mix of data, facts, and description of the“state of the field” as it is now. If you go upwards fromhere, and I am sure that you will, Elements will rapidlybecome a seminally important journal. What a great improvementover the much-too-dry society newsletters (and I know whereof Ispeak, having produced some of those dry Geochemical Society Newslet-ters in early 1990s!). To mix all that society information with excitingscience and to make it available to the seven societies is a master-stroke. My congratulations to all involved in this new journal.

Steven B. Shirey, Carnegie Institution of Washington, USA

The inaugural issue of Elements is excellent! My only critique is thatthe four columns per page used in a couple of items was distracting

(and difficult to read because too many rapid eye motions are required).I think two columns per page is best looking and easiest to read.Otherwise, congratulations on a well-designed layout and high-qualitycontent.

Neil Sturchio, University of Illinois at Chicago, USA

It is just great. The color figures are quite nice and helpful for thereaders to understand the papers. All figures should be with color if

possible. The problem here in Japan is that few students are membersof MSA, GS, and so on. They cannot read Elements. Copies should bedelivered to university libraries so that they have a chance to readElements.

Takashi Murakami, University of Tokyo, Japan

Wow, what a fantastic magazine. For the first time in months ifnot years, I can see myself reading a magazine from cover to

cover. Congratulations on a job well done!

Gregory M. Dipple, University of British Columbia, Canada

In general I heartily approve, although I will definitely miss Canadi-an-locality articles like Dan Kontak’s in the recent MAC Newsletter. I

have two suggestions, one positive and one negative; on the positiveside: continue the “2005 Preview” page as a rolling item—lets get themanticipating things. On the negative, discontinue the use of bold textfor initial figure references; it breaks up the flow of the text since oneautomatically goes to look to see what was so important.

Douglas Scott, Timmins, Ontario, Canada

I know you all worked really hard on Elements, from developing theconcept to the final product and it really shows! Really, really good!

If we can keep the momentum, I cannot see why Elements should notbe a sizable force in improving the profile of our fields! Thanks foryour hard work.

Susan L. Svane Stipp, University of Copenhagen, Denmark

I am very impressed! I enjoyed thescientific articles, and I think that

the way you laid it out, with a coupleof pages for each member society’s“news”, works very well. I am lookingforward to subsequent issues! Congratulations on a great new geo-

science magazine! And best wishes for its successfulfuture.

Sandra Barr, President,Geological Association of Canada

I have just received (and read) the first issue ofElements. What a brilliant publication! It really does

illustrate how relevant mineralogy and geochemistryare and in a manner that is completely accessible.Congratulations! I will look forward to the next issueon diamonds.

Philippa Black, University of Auckland, New Zealand

My congratulations to you and the rest of the editorial group.I’m very pleased and excited that the societies have a common

forum for timely technical and society news. I have two suggestions:(1) Include a section on new web pages that include recent URLs forspecial reports, technical summaries, activities etc. I suggest you solicitthese from readers who want to promote their web-based compila-tions, typically submitted by individuals and non-profit organizations.(2) Highlight a special graphic from a society member at the very endof the issue. The graphic choice should be selected on aesthetics andnot necessarily on technical quality… just a pretty picture. It couldinclude photos of real minerals, molecular models of minerals, phasediagrams, TEM, SEM photomicrographs, field images, etc. Label them“Parting Shot”, “Geoimage”, “Last Glimpse” etc.

Randall T. Cygan, Sandia National Laboratories, USA

IN THE NEXT ISSUE, READ ABOUT

Genesis: Rocks, Minerals, and the GeochemicalOrigin of Life

Robert M. Hazen, Guest EditorFew scientific questions so capture the public imagination, or pro-voke such lively debate, as how life on Earth emerged. In the nextissue of Elements, four of the most creative minds in origins researchpresent their original insights on the geochemical origins of life.Each author has studied the field in depth, and each has come toan inescapable conclusion: rocks and minerals must have played apivotal role in the transition from the blasted, prebiotic Earth to theliving world we now inhabit. Rocks and minerals catalyzed the syn-thesis of key biomolecules; they selected, protected and concen-trated those molecules; they jump-started metabolism; and theymay even have acted as life’s first genetic system.

Rocks and minerals as protective environments for life’s originJOSEPH V. SMITH (University of Chicago)

Minerals and the assembly of biopolymers JAMES P. FERRIS (Rensselaer Polytechnic Institute)

The geochemical evolution of metabolism GEORGE D. CODY (Geophysical Laboratory)

Sketches for a mineral genetic materialA. GRAHAM CAIRNS-SMITH (University of Glasgow)

IN SEPTEMBER Toxic Metals: Role of Surfaces

IN DECEMBER Large Igneous Provinces and Environmental Change

CO

MIN

GU

P

The managing editor received realflowers from her fellow editors tocelebrate the launch of Elements atthe GSA meeting. PHOTO BARBARA

DUTROW.

NOTE FROM THE EDITORS: We are happy to share some of the“flowers” we received following the inaugural issue of

Elements. Several suggestions from our readers areimplemented in this issue or will be in future issues.

Science Societies andthe Democratic ProcessPeter J. Heaney1

After Ed Koch was elected mayor of New York Cityin 1978, he used to stop people on the streetand ask, “How am I doing?” This act of populism

charmed even the most cynical New Yorkers, whoreturned him to office for two additional terms.

It’s a lot harder to gauge the happiness of your constituency if you workfor a scientific society. There are no newspapers that editorialize on thelatest initiatives of the Geochemical Society (GS), andcable news completely ignores the adventures of theMineralogical Association of Canada (MAC). Instead,one is left to look at more indirect indicators. Is thetotal membership growing or declining? Do the publi-cations attract cutting-edge articles that are widelycited? Are the scientists engaged in society affairs?

To weigh this last question, we can ask another: Howmany scientists take the 10 minutes required to readthe biographical statements of candidates for societypositions, check the boxes next to the ones they like,and mail in the pre-addressed envelopes? George Will,political commentator for Newsweek, has argued thatelectorate turnout is a most imperfect measure of votersatisfaction; non-voters may be so at ease with the sta-tus quo that their absence should not be construed asdiscontent. On the other hand, I would note that (a)George Will is wrong about most things; and (b) theseare not two-dimensional television personalities whoare running for office but our friends and colleagueswith whom we went to school and whom we meet atconferences.

I wrote to the presidents of five of the societies that sponsor Elementsto find out how their leadership is chosen. All responded immediately,and I learned something that surprised me. Only the MineralogicalSociety of America offers elections that are actually democratic,meaning that there are more candidates than positions to be filled.The other societies are not in constitutional violation. By-laws formost of the societies are available on the web. Of the five societiespolled, MSA alone explicitly requires that its elections shall becontested: “For Councilors there shall be at least twice as manynominees as there are open positions, and there shall be two nomi-nees for Vice President.”

This situation provokes a thought: How much democracy do we reallyneed in our scientific societies? Even though MSA calls for contestedelections, history shows that most of the membership does not takeadvantage of that privilege. Alex Speer, Executive Director of MSA,provided me with a list of voter participation going back to 1925.Over the last 10 years, voting rates have averaged only 27%, with arange of 23 to 29%. Interestingly, these figures are consistent withthose of the 1930s through the 1950s. The late 1960s and early 1970ssaw a surge in the percentage of returned ballots, coincident withslight increases in the levels of membership (in 1971, for example,41% of 2,674 members voted).


Triple Point

What does it mean when only a quarter of eligible voters cast a ballot?Is MSA structured so adeptly to represent its citizenry that theparticulars of the people in the top offices are immaterial? Or does theMSA Council make decisions that are so irrelevant to life’s dailyroutine that the majority of the membership can happily detach fromthe political process? No one involved in the running of MSA isarrogant enough to assume that the former is true, but neither is thelatter. For example, the society is spearheading the development ofGeoScienceWorld, which will permit electronic publishing of AmericanMineralogist and the RiMG volumes as well as allow full-text websearching on any given topic, and this is exactly the kind of contribu-tion that flies completely below the radar of most members (until theyfind themselves using it).

It also seems important to note that the period ofmaximum voter participation coincided with theheady days of the lunar exploration program, whenmineralogy, petrology, and geochemistry had a cachetthat is less evident in this post-Apollo landscape. Onecan only conclude that today’s anemic voter partici-pation reflects a lack of investment in the directionthat MSA is following. That’s too bad, because thesesocieties belong as much to the first-year graduatestudent trying to make sense of Schreinemaker’s ruleas to the latest winner of the Roebling medal.

And what of the other societies that do not offer eventhe committed 25% an opportunity to select amongmultiple candidates for office? Initially, the democratin me responded to this potential for cronyism withoutrage. After all, societies make decisions that canaffect some lives pretty profoundly; they all designatethe organizers and locations of international meetings,and they all present prestigious awards that can makeor cap a career.

But conversations with representatives of those societies havemoderated my indignation. The smaller organizations, with theirlimited membership, sometimes struggle to convince members to addthe burdens of office to their already overloaded schedules. Inaddition, a lack of democracy can paradoxically allow for fairerrepresentation. Though members of MSA are unambiguously commit-ted to gender diversity (no female candidates for office have ever lost),they apparently are more ambivalent regarding international represen-tation (7 of the last 9 foreign candidates for Council have beendefeated, despite the fact that roughly half the MSA membershipand contributors to American Mineralogist are based outside the US).Conversely, MAC explicitly searches for one representative from eachof the geographic regions of Canada (as well as one from the US), andGS requires that at least two of its directors reside outside the US.

These are complicated issues, and the purpose of this column is not tomoralize. But if you’re feeling disenfranchised, you can change that. Ifyou belong to MSA, you can vote. If you belong to the other societies,you can read the by-laws. They may not require multiple candidates,but they don’t prohibit them either. And they all have mechanisms toallow non-council members to put up nominees. What’s beautiful aboutdemocratic science societies is also what’s terrible about them: theyare as successful or as ineffective as the people who participate.

1 Penn State [email protected]

“How much democracydo we really need in

our scientific societies?”

“What’s beautiful aboutdemocratic science

societies is also what’sterrible about them:they are as successfulor as ineffective as the

people who participate.”


Highlight

“Before and after” the Reviews in Mineralogy!On the left, the picture Paul Ribbe submittedto the University of Cambridge as part of hisapplication in 1959. On the right, Paulenjoying well-earned retirement from editingthe RiMG volumes for 30 years.

Alcohol-Soluble Short Course NotesIn the beginning, short courses ofmineralogical interest wereintended to be held in conjunc-tion with the annual meetings ofthe Geological Society of Americaand affiliated societies. Sponsoredby the American GeologicalInstitute’s Council on Educationand directed by Joseph V. Smith,the first short course, Feldspars,was held November 1–3, 1965.Notes were produced for the 90participants by Joe Smith, DavidStewart, and myself using state-of-the-art Ditto-Master technolo-gy. Tragedy struck when a bottleof Scotch being smuggled inDave’s briefcase into dryManhattan, Kansas, broke,smearing or completely dissolv-ing the purple ink from most of

his handouts. A survivingfragrant fragment reads: “Adiscussion of what needs to beknown in comparison with whatmight be determined will begiven at the beginning of thelecture.” Auspicious beginning!

AGI’s Mimeographed NotesIn subsequent years, coursesentitled Pyroxenes and Amphiboles,Sheet Silicates, and ResonanceSpectroscopy were presented.Lecturers expanded their shortcourse notes into longer chapters.These were mimeographed andcompiled in ever-thicker bindersfor circulation by AGI, whichcoincidentally (?) ran out offunding for the project in 1968.

MSA’s Short Course NotesFive years passed before J.V.Smith, President of MSA,surveyed the members about thedesirability of reviving the shortcourse idea. Thus in 1973 theMSA Councilors appointed acommittee to initiate the projectthat continues to this day. Thefirst of 48 “modern” courses washeld the following year withCharlie Prewitt directing. SulfideMineralogy, a 284-page book, withsix authors and six chapters—Short Course Notes, Volume 1—was produced under my editor-ship in time for presentation atthe Miami GSA. (Interestingly,Sulfides went through fourprintings and sold 7600 copies,more than any other singlevolume.) Three more volumesappeared in subsequent years,with increasing difficulty ofscheduling and quality control.Thus, in 1978 Council asked meto assume the role of SeriesEditor.

Reviews in Mineralogy andthe Science Citation IndexIn 1980 two significant eventstook place: MSA changed thename of Short Course Notes toReviews in Mineralogy and theInstitute for Scientific Informa-tion asked for permission toreference RiM papers (chapters)in their Journal of Citation Reports.Listings in JCR and CurrentContents since 1984 have helpedestablish the RiM volumes assignificant players in the scien-tific literature, simultaneouslysatisfying promotion-and-tenure“bean counters” who insist onknowing the number of citationsan author’s papers receive in agiven year. Furthermore, RiM andRiMG have been provided since1987 to all libraries that subscribeto American Mineralogist, makingthem accessible to a worldwideaudience. (Then there were 1300+library subscribers, now there are790.)

Before 1984, all 12 volumes hadbeen typed on an IBM Selectric(5000 pages by one person—Margie Sentelle), pasted up, andsubmitted as camera-readymanuscripts to the printer. EdRoedder’s Fluid Inclusions, ourfirst monograph, moved us intothe era of word processors, atwhich time the average numberof pages per volume jumped from430 to 530. By the late 1990s, sizewas becoming a problem forpaperbound volumes. Theaverage cover-to-cover distancewas 630 pages, with the apogee at1037 pages (Planetary Materials).In 1989, the second edition ofVolume 2, Feldspar Mineralogy,appeared in a Chinese transla-tion, and in 1992 Roedder’s FluidInclusions was published inRussian.

Reviews in Mineralogyand GeochemistryIn the year preceding 2000, MSA,led by Executive Director AlexSpeer, and the GeochemicalSociety, led by President MikeHochella, negotiated a change ofname for the Reviews series: RiMbecame RiMG—Reviews inMineralogy and Geochemistry.Jodi Junta Rosso was appointedSeries Editor for the GeochemicalSociety’s volumes. The new titlebetter reflected what had beenthe case for at least 15 yearsand expanded our horizonssignificantly.

In 2000, Volume 39 Transforma-tion Processes in Minerals becamethe first RiMG book. The accompa-nying short course was convenedin Cambridge, England—the firstoutside the continental USA.That year, 1565 pages (3 vol-umes) were published—not allthat remarkable. In 2001—theyear the Department of Energybegan generous support ofstudent scholarships for selectshort courses—there were 2196pages (4 volumes), and in 2002,3775 (6 volumes!). As editor, Iwas beginning to feel like a full-time employee of the Society,

Paul Ribbe retired from the Series Editor position ofthe Mineralogical Society of America in 2003, afterediting 50 RiMG volumes and five monographs over

the past 30 years. This stunning achievement was recog-nized at the recent meeting of the Geological Society ofAmerica, where a special symposium was held in hishonor. We gladly accepted his offer to write a briefhistory of the Reviews in Mineralogy.

Professor Emeritus of Mineralogy at Virginia Tech, Paul served aspresident of MSA in 1986 and 1987 and was awarded the Distin-guished Public Service Medal by MSA in 1993 for his work with theReviews in Mineralogy. He suspects that he was presented the 1995Mineralogical Society of Great Britain and Ireland Schlumberger Awardfor the same undertaking. Paul retired from Virginia Tech in 1996after 30 years. He and his wife, Elna, live contentedly in Blacksburg,Virginia, where both are heavily involved in Christian ministries.

Paul Ribbe and the Reviews inMineralogy

A BRIEF HISTORY OF MSA’S REVIEWS IN MINERALOGY:

FROM MANHATTANTO THE MOONPaul H. Ribbe

even though Jodi Rosso hadassisted with several volumes andedited 2.5 of the 13. With mywife’s gentle encouragement, Iretired, knowing that Jodi wouldaccept the job of Series Editor forboth GS and MSA beginning withVolume 54.

RiMG in CyberspaceBy 2003 MSA had joined GSW(GeoScience World), an aggregateof Earth science societies bondedtogether to market their electron-ic publications, all of which aredesigned to exploit the searchcapabilities of AGI’s GeoRef.

Although the means of individualaccess to RiMG has not yet beendetermined, the five volumesprinted in 2003 and 2004 arealready online through GSW,thanks to Jodi and Alex. The planis to continue electronic publica-tion of RiMG and in the nearfuture to post volumes datingback to 2000 and earlier.

RiMG in Orbit?The next volume to appear willbe Volume 57 A New View of theMoon to be published in coopera-tion with NASA.

ConclusionIt would be false modesty tounderestimate the impact on thedisciplines of mineralogy, petrol-ogy, and geochemistry of thework of 963 different authors of716 chapters (30,314 pages) in 56volumes. For the curious: theentire series occupies nearly 6 feet(1.8 m) of shelf space and weighs103 pounds (46.8 kg). More than170,000 books have been sold toindividuals over 30 years; about40,000 are in libraries, and morethan 42,000 are in inventory.Now that the number of books inprint has exceeded the numberof miles from Manhattan to theMoon, RiMG would appear tohave a solar if not a stellar future.


Conference News

The session was opened byMichael Carpenter (Cambridge),with a picture of Paul Ribbe(reproduced here) that Paul hadsubmitted as part of his applica-tion to the University of Cam-bridge back in 1959. At Cam-bridge, Paul determined thecrystal structures of severalfeldspars and was the first toshow that the structure of lowalbite had an effectively fullyordered distribution of Al and Siatoms. Throughout Paul’s career,the underlying theme of hisfeldspar research was the connec-tion between the details of thecrystal structures at the atomiclevel and their macroscopicthermodynamic properties andlattice parameters. This wasemphasized in a review by RossAngel (Virginia Tech) of high-pressure crystallographic studiesof feldspars that have been madesince the feldspar RiM volumewas last revised in 1982, and byIan Parsons (Edinburgh) whodiscussed the fascinatingexsolution microtextures inperthites from the Klokkenintrusion, which can only beunderstood in terms of thecoupling between ordering andun-mixing within the feldspars.

The other early volumes in theShort Course Notes series werealso devoted to specific mineralgroups and built on the same“micro to macro” theme that wasto become the subject of a laterRiM volume in its own right.Progress in understandingbonding in sulfides through high-pressure crystallographic studieswas reviewed by Charlie Prewitt(University of Arizona), acontributor to that first sulfides

volume. “Changing Perspectives”was the very apt title chosen byDavid Vaughan (University ofManchester) for his presentationthat emphasized both thedevelopment of studies of theinteractions of sulfide mineralsand the environment over thelast 30 years, and the novelexperimental tools that havebeen developed to enable thosestudies. Having started as criticalreviews of the structures andproperties of specific mineralgroups, the RiM volumes haveevolved over the years toencompass “even petrology”, asnoted by Darrell Henry (LouisianaState) in his talk on Ti in biotite,as well as experimental tech-niques. Robert Bodnar (VirginiaTech) took up his theme inreviewing the progress in fluidinclusion research since thepublication of the only single-authored volume in the RiMseries—volume 12 by EdwinRoedder. Novel computationalmethods have also revolutionizedmineralogy on all scales frombonding in minerals (Jerry Gibbs,Virginia Tech) and molecularinteractions (Jim Kubicki, PennState) to km-scale modeling ofmetamorphism (Barb Dutrow,Louisiana State).

The last part of the sessionreturned to the theme introducedby David Vaughan, that ofmineralogy being an integratedstudy of the interaction ofminerals with their environment.Mickey Gunter (University ofIdaho) discussed the health issuesarising from mineral dusts.Patricia Dove (Virginia Tech),editor of the recent RiMG volumeon biomineralization, reviewed

the incredible structures built byvarious organisms out of calcitethat must reflect some “vital” orbiological effect. Both she and JillPasteris (St. Louis) also empha-sized the importance of quantify-ing such effects so as to be able touse the compositions of biomin-erals as a proxy for the environ-ment in which the organismsoriginally lived. Bob Hazen(Carnegie Institution of Washing-ton) looked back to the origin oflife and the problem of under-standing how life’s essentialmolecules, such as amino acidsand sugars, became handed or“chiral.” He suggested that chiralmineral surfaces may have playeda key role in separating left- fromright-handed molecules or incatalyzing chiral synthesisreactions. And he looked forwardto the exciting new experimentaltechniques, borrowed frombiochemistry, that are startingto be used to characterize theinteractions between mineralsurfaces and biomolecules. BobDowns (University of Arizona)looked even farther forward withhis presentation of a recentlydeveloped hand-held Ramanspectrometer that was straightout of Star Trek!

The breadth of the talks andposters in the session emphasizedthe influence of the RiM volumeson the careers and thinking ofmost mineralogists. Jim Kubicki(Penn State) reflected the feelingsof many in saying that beingasked to edit a RiM volume wasone of the highest honors he hadreceived in his career. Severalspeakers concluded their talkswith either news of forthcomingvolumes in the series or informalproposals for new volumes,clearly demonstrating that theseries Paul Ribbe founded anddeveloped over thirty yearsremains a vital endeavor and avaluable resource for mineralo-gists. While all participants at thesession expressed their thanks invarious ways to Paul Ribbe for hisservice to the mineralogycommunity and for his incrediblepatience with authors andeditors, the last slide of BobHazen’s talk said it best. It simplyread, in large friendly letters,“Thank you Paul”.

Ross Angel and Nancy RossVirginia Tech

Blacksburg, November 2004

Looking Forward to the Past:A Session in Honor ofPaul Ribbe and theReviews in Mineralogyand Geochemistry

Mineralogists young and old from all over the world gathered in

Denver last November, at the annual meeting of the Geological

Society of America, to contribute to a session in honor of Paul Ribbe.

The title of the session reflected the fact that, as reviewed by Michael

Hochella (Virginia Tech), Paul Ribbe’s career as a teacher and

researcher in mineralogy became so intertwined with the development

of the Reviews volumes that it is difficult to separate one from the other.

Attendance is by invitation andis limited to two delegates percountry (though there may beextra observers). The 29th IGCwelcomed delegates fromAustralia, Bahrain, Canada,China, Czech Republic, Germany,Holland, India, Indonesia, Japan,Korea, Russia, Singapore, Spain,Sri Lanka, Switzerland, Taiwan,Thailand, UK, and USA.

Delegates to the conference areexpected to deliver papers ontheir current research. Papersgiven at the 29th session coveredsuch diverse topics as “Study ofCrystal Defects in SyntheticDiamond with SynchrotronRadiation X-ray DiffractionTopography” (Dr. Chen Tao) and“Trace-element geochemistry ofgem corundum from various gemfields of Madagascar” (Dr. T.Thanasuthipitak). Willow Wight,research associate at the Canadi-an Museum of Nature and editorof the Canadian Gemmologist,spoke on her recent work on thenon-nacreous pearls of Placo-pecten magellanicus scallops fromDigby, Nova Scotia, Canada.

Although the conference itselflasts for one week, there are bothpre- and post-conference tours.For the 29th session, the pre-conference tour included theJurong Shi pearl farms and theMa’anshan turquoise mine. Thepost-conference tours coveredthe Changle sapphire deposits,the Mengyin diamond mine,and the Damaping peridot mine.

The Ma’anshan turquoise minelies some 30 km southwest of thecity of Nanjing. Turquoise wasdiscovered here in the 1960s as aresult of examination of irondeposits in a Mesozoic volcanicsequence. The major item ofinterest during our visit was a

single, 20-tonne slab of turquoisethat had just been mined andwas being crated for shipment.

After the conference, we flew toJinan and drove from there toChangle, 150 km to the east.Sapphire occurs in Changlecounty in two types of deposit.Primary sapphires are obtainedas megacrysts in specific layers inalkalic basalts 16–17 million yearsin age; secondary sapphires arerecovered from ancient streambeds buried beneath 10–12 metresof alluvial soil. The sapphire-producing area covers 420 km2,and is basically agricultural.

The Mengyin diamondmine is also some 150 kmfrom Jinan, to the south-east. Diamonds werediscovered here in 1965,and subsequent explo-ration located the kimber-lite (micaceous peridotite)pipes and veins. The age ofthe kimberlite intrusion isestimated at around 80million years, although thediamonds themselves are

probably more than 450 millionyears old.

Mining first took place as anopen-pit operation, but the workwent underground in 2001 andnow reaches a depth of 210metres. The kimberlite “carrot”divided at depth, and reached thesurface as two separate entities,the larger of which is 75 × 45metres, and the smaller 75 × 20metres. The smaller pipe is themore productive of the two. Thekimberlite, apparently controlledin a NE to NW fan by the Tanlufault, also occurs in small veinsthat are generally short (10–100metres) and range in width from0.5 to 2 metres. Other exposuresare known in the area.

The mine produces an average of300 carats per day, for an annualgross of 100,000 carats, 20% of

which are gem quality. On theday of our arrival, they hadalready found 800 carats, muchto the delight of the minemanager, who insisted that wehad brought them luck. The pri-mary habit is octahedral, and thecolours range from black throughbrown and yellow to completelycolourless. A tiny percentage ofvery small crystals are pink, butno blue diamonds have been seento date. The largest diamondrecovered from the area (in 1977)was a 158.79-carat yellowishcrystal. The largest one founddirectly in the pipe was a 119.01-carat rounded octahedron (in1983).

The mine shaft and buildings areat the edge of a small village and,apart from the incredible noise,have a very casual air aboutthem. Ore brought from the shaftfirst goes through a jaw crusher,then a cone crusher, before beingdelivered to the grease belts. Thefines recovered from the greaseare sorted by hand by five or sixvery sharp-eyed young womenwho can spot a diamond ofinfinitesimal size with ease.

In the crushing house, the noiseis deafening, there is watereverywhere, and the entirebuilding vibrates. In fact, it maybe vibrating to pieces: there wereholes in the walls. Interestingly,two-thousand-year-old technolo-gy works well. The crushedmaterial is moved to an upperlevel by a huge Archimedes screw.

The final stop on the tour(besides the Great Wall, which isde rigueur for everyone) followeda flight to Beijing and a 240-kmdrive northwest from there toZhangjiakou. The Damapingperidot mine is a further 30 kmnorth of Zhangjiakou, in a seriesof Miocene alkaline basalt flows.As in Changle, there are alluvialand in situ deposits. One area ofthe hillside on the long climb upto the mine appears to be coveredby fine, green peridot sand.The peridot is essentially 90%forsterite. Development in thearea is slowing because of weakermarkets, but the resources havenot been exhausted.

Quintin WightOttawa, Ontario, Canada


Conference Reports

InternationalGemmological Conference,Wuhan, China

The 29th International Gemmological Conference (IGC) was held at

the China University of Geosciences in Wuhan, China, September

13–17, 2004. The conference, founded in 1951 by Dr. Edouard Gübelin

and a number of his fellows, is designed to bring together professional

research gemmologists worldwide to discuss the latest developments in

gemmological research and other items of gemmological interest. It is

held every two years, in the odd years, and usually alternates between

venues in Europe and the other continents. The 29th conference was

deferred until 2004 because of the SARS scare in China in 2003.

The Mengyin diamond mine, China

Sorting diamonds by hand

Diamond, the ultrahard cubic form of carbon, is a mineralrequiring a long string of superlatives to describe its prop-erties, its technological and commercial importance, andits roots into human culture and our physical world.Diamond is the hardest known substance, a strategic min-eral critical to the market in superabrasives—over 800 mil-lion carats (160 metric tons) and about US$109 annually(Olson 2002), just for abrasive. Diamond, the king of gems,is at the heart of the most lucrative part of the gem indus-try, with an unmatched combination of brilliance, fire,hardness, and value (~US$2 × 1010 annually for stonesalone; Olson 2003). Natural diamonds are probably the old-est and deepest-sourced objects we will ever touch, and pro-vide direct information about the mantle. The superlativecharacter of diamond—linking technology, commerce,glamour, natural science, and material science—providesgreat impetus for ever-advancing scientific investigation.Consequently, when asked if diamond might serve as aninaugural topic for Elements, the answer had to be “yes.”

One of us has plowed the furrows of diamond subjectswhile creating a well-travelled exhibition entitled TheNature of Diamonds, accompanied by a book with the samename (Harlow 1998), while the other has cut her teethstudying inclusions in diamonds. Thus, we are both certi-fied diamond junkies who find irresistible the attraction ofdiamond crystals, science, and personalities. And the activ-ity relating to diamonds is abundant. Diamond is probablyone of the only minerals on which several journals focus:Diamond and Related Materials, Industrial Diamond Review,Industrie Diamanten Rundschau, New York Diamonds. So, wehad to restrain ourselves to invite only seven investigatorsor research groups to write articles on advancements in dia-mond-related science, with a geoscience connection ofcourse, for this issue of Elements. The topics presented,however, do provide a view into the diversity and wealth ofresearch on, and interest in, the densest form of element six.

Diamond is a beautiful substance in many ways. Its simplebut elegant crystal structure (FIG. 1), in which each carbonatom is bonded to four other atoms in a tetrahedral arrange-ment, yields a strong rigid framework. Combining this struc-tural arrangement, which coincides with the hybrid sp3

orbitals of carbon, with the unmatched strength of the C–Cbond, explains most of diamond’s properties, many ofwhich are presented in TABLE 1.

67E L E M E N T S , V O L . 1 , P P . 6 7 – 7 0 MARCH 200567

George E. Harlow and Rondi M. Davies1

1 American Museum of Natural History, New York, NY 10024-5192, USAE-mail: [email protected]; [email protected]

Active research on diamond, a carbon mineral with superlative proper-ties, extends into many realms of natural and material sciences.Extreme hardness and transparency make diamond a valuable gem

and a high-pressure research tool, as well as a superabrasive. Natural forma-tion at high pressure and resistance to weathering make diamonds our mostinformative messengers from Earth’s mantle. A review of diamond’s charac-ter and forms leads into the topics of the articles in this issue of Elements.

KEYWORDS: diamond, gem, high pressure, mantle, carbon

DiamondsDiamonds

Ball and stick models of the diamond structure showing(A) the unit cell with the C–C distance indicated and (B)

a projection with the boundaries of an octahedron, the archetypal“diamond” shape.

FIGURE 1

A

B

Tiffany diamond,287.42 ct, canary,

from Kimberley,South Africa. PHOTO

COURTESY OF TIFFANY &CO. ARCHIVES

Red chromian pyropeand green chromian

diopside inclusions in adiamond octahedron

from the Mir pipe,Sakha Republic, Russia

(each about0.2 mm across).

COURTESY UIGGM,SIBERIAN BRANCH OF

RUSSIAN ACADEMY OF

SCIENCES, NOVOSIBIRSK.PHOTO: GEORGE HARLOW


The rigid bonding leads to great hardness, incompressibility,and extraordinary thermal conductivity. Diamonds are called“ice” because of their ability to conduct heat so well; theyfeel icy cold because they rob heat from your diamond-touched lip. The uniform covalent bonding causes a largeband gap, 5.5 eV, and makes diamond an electrical insula-tor and transparent over a broad portion of the electro-magnetic spectrum. The dense packing of electrons yields ahigh refractive index (the ratio of light’s velocity in a vacu-um to that in the material) of 2.42, quite remarkable for amaterial with such a low average atomic number. The listgoes on, and the significance of these extraordinary prop-erties will become evident in the articles in this issue ofElements.

The high density of diamond (3.51 g cm-3) as compared tothat of graphite (2.20 g cm-3), the other common poly-morph of carbon, is a clear indication that diamond is ahigh-pressure mineral, formed mostly in Earth’s interior.Thus, diamond is a key indicator and recorder of eventsdeep within our planet, in part because its extreme strength

and refractory nature permits it to survive exhumation toEarth’s surface and subsequent weathering (another aspectis the extraordinary volcanic style of kimberlites and lam-proites, which act as express elevators to raise diamondsquickly from depth, but that is a different story). Moreover,inclusions captured in a diamond growing in the mantleare protected by its adamantine embrace, so diamondshave become our “space missions” to inner Earth, provid-ing our most important samples for understanding thechemistry of the deep mantle. By extracting inclusions(yes, diamonds get busted, burned, and ground away) andanalyzing them, researchers have discovered the associa-tion of diamond with peridotite and eclogite assemblagesfrom the roots of ancient cratons. More recently, transi-tion-zone and lower-mantle signature minerals have beenidentified. The contribution by Stachel, Brey, and Harrisreviews the status of these, the deepest samples of Earththat we have at our finger tips. Diamonds, while essential-ly pure carbon, allow us to investigate their carbon sourcethrough isotopic analysis of C and the minor contained N.Cartigny presents the available isotopic data and showshow diamonds reveal the hallmarks of primitive Earth,recycled crustal sources, and crystallization processes.

Two lesser known and understood varieties of diamondare, first, natural polycrystalline diamond—carbonado andframesite—and, second, microdiamonds discovered overthe last 20 years associated with metamorphic rocks. Heaney,Vicenzi, and De review the characteristics of carbonado andframesite and help unravel some of the mystery around theseenigmatic materials. As a high-pressure mineral, diamond isan important indicator for recognizing portions of Earth’scrust that have been buried to ultrahigh-pressure (UHP) con-ditions (for crustal rocks, that is) and, more remarkably,returned to the surface with diamonds intact. Search for UHPterranes by recognizing diamond or coesite (a high-pressureform of SiO2) has become an exciting direction in metamor-phic petrology, with important implications for how theEarth works. However, only recently have studies focused onthe small UHP diamonds themselves. Ogasawara reviews theUHP occurrences of diamond and the ideas behind theprocesses by which they are formed before focusing on theKokchetav Massif, Kazakhstan, where the most varied andabundant microdiamonds have been found.

One of the most remarkable diamond discoveries in thelast decades is that of the nanometer-sized diamonds inmeteorites. Meteoritic diamonds are hardly new, since theywere described in the Canyon Diablo iron meteorite in1891 (Foote 1891). These were later interpreted as the con-version of graphite to diamond by shock metamorphismupon the meteorite’s impact with Earth. On the otherhand, diamonds in the Nova Urei (Ringwood 1960; Carteret al. 1964) and Kenna (Berkley et al. 1976) ureilites formedby shock on the meteorite parent body. Searching for themost primitive materials and reservoirs of noble gases inprimitive meteorites, such as carbonaceous chondrites, ledEd Anders and colleagues to seek the last moieties in mete-orites that could not be dissolved by aggressive acid orbase—diamond, graphite, and silicon carbide. Huss reviewsthe results of research on these “nanodiamonds” and theirpossible origin in supernovae prior to the formation of oursolar system (we really get goose bumps thinking about thepossibility that the carbon in our bodies arrived on Earth asdiamond and later will be recycled by subduction, in awhile of course, to make more diamond).

Diamond science owes much to the fact that it is the mostdesired of gemstones. Its great value has led to some verysecretive research on how to carry out an alchemy reminis-cent of turning lead into gold—turning brown diamondscolorless, and more. Pure diamond is colorless carbon, so

Composition C (carbon)

Crystallographic class Cubic – hexoctahedral (highest of symmetries)

Space group Fd3m a = 3.57 Å (cell edge)

Common crystal forms Octahedron {111}, cube {100}, dodecahedron {and indices} {110}, rounded variations due to etching

Twins Spinel-law common, yielding the flat triangular “macle”

Hardness 10 on Mohs’ scale, 56–115 Knoop hardnessnumber (GPa), 10,000 Brook’s indenter scale, octahedral face hardest, cube face softest

Moduli Bulk modulus: ~500 GPa; Young’s modulus:~1050 GPa

Cleavage Excellent parallel to octahedron face {111}

Density 3.51 g cm-3 (or specific gravity = 3.51)

Luster Adamantine (the definition for this kind of luster)

Colors Colorless, yellow, blue, green, and many others

Refractive index 2.4175 (in the yellow light of a sodium lamp)

Dispersion Large (0.0437 – the difference in index at G and B Fraunhofer wavelengths), leading to rainbow colors on refraction

Optical transmission Transparent over a broad range of the

electromagnetic spectrum; an excellent material for optical windows

Thermal conductivity Superb, 5 to 25 watts centimeter-1 °C-1

(at 300K); 4 times greater than copper; an excellent thermal conductor

Electrical conductivity 0 to ~100 ohm cm-1 (resistivity at 300K);

an insulator

DIAMONDS: VITAL STATISTICS

TABLE 1


0 4000 kilometersMonasteryKimberleyKoffiefonteinJagersfontein

Premier

Venetia

Jwaneng

OrapaJunia(São Luiz)

Poxoréu(Carbonado)

Guaniamo

Kankan

UdachnayaYubileynaya

Mir

Argyle

Orrorroo

Lac de GrasSnap Lake

Akluilâk

New SouthWales

SãoFrancisco

Dabie

Kokchetav

Erzgebirge

Western GneissRegion

Sulawesi

North Qaidam

C.A.R.(Carbonado)

Equator

Archon

Proton

Tecton

color is the product of trace amounts of another element,such as N or B, or defects, or some combination of these.Treatments have been developed to remove color orenhance color, and Shigley provides this story anddescribes the challenge to the gem industry. After all, peo-ple value the color nature has bestowed on a diamond farmore than colors produced in the lab, so the industry muststrive to maintain confidence by developing methods todistinguish the natural from the enhanced.

Our modern technological society owes much to theprowess of diamond as an abrasive and superhard material.In geoscience, the diamond anvil cell (DAC) has permittedexperimentation at pressures above 100 GPa to betterunderstand the interiors of planets and the basic properties

of matter. And, if only diamonds were large and commonenough, we might all have watches with faces that couldnot be scratched, computers with diamond guts to extractthe heat from much smaller and denser electronic microde-vices, and DACs on our lab bench. Hemley, Chen, and Yandescribe advances in growing diamonds by chemical vapordeposition (CVD), so that such possibilities, and more, arenot just a dream.

These are just a few windows into the exciting sciencespanned by diamond research. We hope you will appreci-ate how much more this extraordinary mineral is thanmerely corresponding to 10 on the Mohs scale of hardnessor being the featured bauble in an engagement ring. .

REFERENCESBerkley JL, Brown HG, Keil K, Carter NL,

Mercier J-CC, Huss G (1976) The Kennaureilite - an ultramafic rock withevidence for igneous, metamorphic, andshock origin. Geochimica etCosmochimica Acta 40: 1429-1437

Carter NL, Kennedy, GC (1964) Origin ofdiamonds in the Canyon Diablo andNovo Urei meteorites. Journal ofGeophysical Research 69: 2403-2421

Foote AE (1891) A new locality formeteoric iron with a preliminary noticeof the discovery of diamonds in the iron.American Journal of Science 42: 413-417

Harlow GE (1998) The Nature ofDiamonds. Cambridge University Press,Cambridge, 278 pp

Levinson, AA (1998) Diamond sourcesand their discovery. In: Harlow GE (ed)The nature of diamonds, CambridgeUniversity Press, Cambridge, pp 72-104

Olson DW (2002) Diamonds, Industrial. USGeological Survey Minerals Yearbook(http://minerals.usgs.gov/minerals/pubs/commodity/diamond/diamomyb02.pdf)

Olson DW (2003) Gemstones. USGeological Survey Minerals Yearbook(http://minerals.usgs.gov/minerals/pubs/commodity/gemstones/gemstmyb03.pdf)and based on US representing ~ 60% ofthe world market (Harlow 1998).

Ringwood AE (1960) The Novo Ureimeteorite. Geochimica et CosmochimicaActa 20: 1-2 .

World map showing diamond sources cited in thisissue. Colored areas demark “Archons”–cratons olderthan 2.5 Ga, “Protons”–cratons 1.6-2.5 Ga, and“Tectons”–0.8-1.6 Ga, important in prospecting formantle-derived diamonds (see Stachel et al., this

issue). Black diamond symbols are used for mantle-derived sources and red diamonds for ultrahigh-pressure (UHP) metamorphic sources. (ADAPTED FROM

LEVINSON 1998)


Solid carbon in natureDiamond – is the cubic form of carbon in which every carbon

atom bonds with four other carbon atoms in a rigid tetra-hedral framework. Its high density (3.51 g/cm3) requireshigh pressure for thermodynamic stability (see Fig. 1 inCartigny, this issue, which shows diamond stability in rela-tionship to the conditions interpreted to exist, on average,below old continents and young ocean floor).

Graphite – is the hexagonal form in which each carbon atombonds with three others to form sheets weakly connected byresidual (Van der Vaals) forces.

Lonsdaleite – is a diamond-like structure with hexagonal sym-metry and appears to be metastable.

Amorphous carbon – is non-crystalline carbon as found in soot.Buckey-balls or buckminster-fullerenes are an organized butnon-crystalline (in the traditional sense) form.

Earth structure and mantle rocksLithosphere – the relatively rigid shallow solid Earth, consisting

of the crust and the non-convecting portion of the mantleimmediately beneath.

Asthenosphere – the relatively weak, convecting portion ofEarth’s upper mantle, with low seismic velocities and locat-ed essentially between the lithosphere and the transitionzone.

Transition zone – a layer in the mantle from ~410 to 660 kmdepth, where olivine converts to wadsleyite and ringwood-ite (see below). Below the transition zone, silicate perovskiteplus ferro-periclase replace ringwoodite.

Pyrolite – coined by A.E. Ringwood for a model composition ofEarth’s primitive or “fertile” mantle, originally consisting of1 part basalt (e.g., as from the mid-ocean ridge—MORB)and up to 4 parts anhydrous peridotite. There are many ver-sions depending on whether the composition is used tomodel the seismological or melting properties of the uppermantle. (The term “fertile” and related words are a hot-bedof meanings and interpretations too rich to go into herebeyond the simple sense of permitting the described rock toproduce a melt of desired composition on adiabatic decom-pression).

Eclogite – a rock consisting of roughly equal parts greenomphacitic clinopyroxene [nominally CaNa(Mg,Fe)AlSi4O12]and orange garnet [(Ca,Fe,Mg)3Al2Si3O12]. It is essentiallythe high-pressure metamorphic equivalent of basalt, themajor constituent of the ocean floor.

Peridotite – is the principal rock in Earth’s mantle. It is domi-nated by olivine (the gem variety is peridot), and is oftensubdivided into types containing spinel [(MgFe)(Al,Cr)2O4],indicating a shallower origin, or garnet [red and rich inpyrope (Mg3Al2Si3O12)], indicating deeper origin. The otherimportant constituents are orthopyroxene and clinopyroxene.

Harzburgite – a peridotite essentially free (<5%) of clinopyrox-ene and thus depleted in elements like Na, Ca, and Al rela-tive to pyrolite; it is interpreted to be the residue afterextraction of a melt fraction.

Lherzolite – a peridotite with 2–10% clinopyroxene, consid-ered to be representative of primitive or fertile mantle, sinceno melt has been extracted from it.

Wehrlite – a type of peridotite in which clinopyroxene is moreabundant than orthopyroxene; it is thus thought to be over-ly “fertile,” perhaps because it has been enriched by theaddition of fluid or melt.

Minerals of the mantleOlivine, wadsleyite, and ringwoodite – are (Mg,Fe)2SiO4 phases.

Olivine is the orthosilicate α-form stable in rocks from Earth’ssurface to a depth of ~410 km where wadsleyite (the β-form)a denser di-silicate is stable, and at ~520 km ringwoodite (theγ-form with spinel structure) becomes stable (see Stachelet al.).

Pyroxene – a rock-forming, chain-silicate, mineral family withformula MSiO3 – where M is usually a divalent metal or met-als and Si is in tetrahedral coordination with oxygen.

Clinopyroxenes – have monoclinic symmetry and are generallyrich in Ca + Mg +Fe and/or Na + Al.

Orthopyroxenes – are orthorhombic and have a formula closeto (Mg,Fe)SiO3.

Garnet – a rock-forming, orthosilicate, mineral family withformula M2+

3N3+2Si3O12; M can be Ca, Mg, or Fe2+ and N is

generally Al, Cr, or Fe3+

Majorite – is a form (polymorph) of silicate garnet in which Siresides in the 6-coordinated site (e.g., symbolized as [6]Si) aswell as the tetrahedral site: Mg3

[6](MgSi)[4]Si3O12.

Ferropericlase – (or magnesiowüstite) is (Mg,Fe)O and signifi-cant in the deep mantle as a dense phase formed as a reac-tion product with MgSiO3-perovskite in the reactionMg2SiO4 = MgSiO 3 + MgO. IMA suggests ferroan periclase.

Perovskites – a structure type with potentially diverse compo-sitions and with the same formula as pyroxene but differentcoordination: [12]M[6]XO3. Perovskite itself is CaTiO3 and isstable at low pressures, but silicate perovskites, MgSiO3 andCaSiO3, are the main minerals of the lower mantle.

Isotope ratios and notationsDelta notation – isotope ratios are often reported in “delta

notation”, which gives the deviation of the measured ratiofrom the standard ratio in parts per thousand [δ13C =((13C/12C)meas/(13C/12C)std)-1)×1000] The standard for C isPDB, a fossil belemnite, for which the notation is sometimespresented as δ13CPDB. In the case of oxygen, the formulationis based on 18O/16O with the standard being StandardMean Ocean Water (SMOW); for sulfur it is 34S/32S withstandard Canyon Diablo Troilite (CDT or a synthetic equiva-lent VCDT).

Noble Gases3He/4He ratios – are used to measure the relative contributions

from mantle and crustal sources in the production of a rock.Since 3He is primordial in origin but most 4He is radiogenic,low 3He/4He ratios suggest a strong input from the crust,where radionuclides are concentrated.

Glossary for Diamond Science


Meet theAuthors

Gerhard P. Breyreceived a Diploma inmineralogy at theFriedrich Alexander-Universität of Erlangenin 1973 and a PhD ingeochemistry from theAustralian NationalUniversity (Canberra) in

1976. From 1978 to 1994, he was a researchassistant at the Max-Planck-Institut fürChemie in Mainz in the Division of Cosmo-chemistry. He taught at the TechnischeUniversität Darmstadt where he fulfilled therequirements for the degree of Habilitation in1990. Since 1995, he has been professor ofpetrology at the Johann Wolfgang Goethe-Universität in Frankfurt, where he continueshis experimental work on geothermobarome-try and the application to mantle xenolithsuites and inclusions in diamonds from theupper and lower mantle. In January 2004 hewas elected as Dr. honoris causa by the RussianAcademy of Sciences in Moscow.

Pierre Cartignyobtained his PhD in1997 at the Institut dePhysique du Globe deParis. After two years as apostdoc at the Universityof Göttingen (Germany),he joined the StableIsotope Laboratory of

IPG-Paris as a CNRS researcher. His maininterests focus on the geodynamic cycle ofnitrogen and on the origin of the isotopicvariability within Earth’s mantle.

Yu-Chun Chen is aPhD student in theDepartment of Electricaland Computer Engineer-ing at Auburn Universityand a predoctoral fellowat the Carnegie Institu-tion of Washington. Hisfields of research include

fabrication and microelectronic applicationsof carbon nanotubes, microelectronicsmanufacturing, and CVD single-crystaldiamond. He was born in Chang-Hua,Taiwan. He received his BS degree from theDepartment of Electronics Engineering atFeng-Chia University prior to entering thegraduate program at Auburn in 2001. He hasbeen a graduate research and teachingassistant and was selected as an AuburnUniversity Graduate Research Fellow in 2004.His PhD advisor is Professor Yonhua Tzeng.

Rondi M. Davies is apostdoctoral fellow inthe Department of Earthand Planetary Sciences atthe American Museum ofNatural History. She waseducated in Papua NewGuinea and Australia,where her benchmark

study of the origin of eastern Australiandiamonds earned her the prestigious VoiseyMedal. Rondi also studied the origins of deep-sourced ancient diamonds from the Slavecraton, Canada. She is now researching thenature and history of Earth’s mantle usinghigh-pressure experimental techniques and isinvolved in the Museum’s educational andoutreach programs.

Subarnarekha Deexamined naturalpolycrystalline diamonds(PCD) using transmissionelectron microscopy forher PhD research atPrinceton University. Shehas also performed high-pressure synthesis of

polycrystalline diamonds at the GeophysicalLaboratory, Carnegie Institution ofWashington, and she has contrasted syntheticcompacts to natural PCD using variousmicroscopic techniques. More recently, as anNRC Post-Doctoral Fellow at the NASA AmesResearch Center, De investigated terrestrialcarbonates and compared them to globulesfrom Martian meteorite ALH84001 to shedlight on the “life on Mars” question.

Jeffrey W. Harris,based at the Universityof Glasgow, has playedan outstanding role inthe development ofresearch on diamond,making significantcontributions in thefields of diamond

classification, inclusion identification andgeochemistry, and age-determinationtechniques. He is author or coauthor of 109peer-reviewed papers. He has acted as adiamond consultant to DeBeers ConsolidatedMines Ltd for 29 years and on their behalf,coordinates, facilitates, and participates injoint research projects with other universitiesand research centres throughout the world.Currently this includes over 30 projects inAustralia, Britain and other European centres,Canada, South Africa, and the United States.He is an Associate Editor of the Journal ofGemmology.

George E. Harlow iscurator of minerals andgems in the Departmentof Earth and PlanetarySciences at the AmericanMuseum of NaturalHistory. His researchfocuses on the chemistry

and structure of minerals as tools for under-standing their origin and the record ofgeological processes they contain. Projectsinspired by the museum’s collections includethe origin of jadeite rock (jade) in Guatemalaand elsewhere, and the mineralogy of theMogok Stone Tract, Myanmar, famous forrubies, spinels, and a complex mineralogy.Diamond inclusions led to study of andexperiments on K-rich clinopyroxene and thebehavior of large-ion lithophiles and volatilecomponents in minerals at upper mantleconditions. He has curated the exhibitions It’sGold (1979–80), Tiffany: 150 Years of Gems andJewelry (1988), Global Warming (1992), andThe Nature of Diamonds (1997).

Peter J. Heaneyreceived his PhD fromJohns HopkinsUniversity in 1989. He iscurrently an associateprofessor in theDepartment ofGeosciences and theMaterials Research

Institute at Penn State. Heaney has focusedhis research on mechanisms of mineralgrowth and transformation as revealed byreal-time X-ray and electron diffractiontechniques. His recent areas of interestinclude the origin of naturally occurringpolycrystalline diamonds, the effects thatatomic exchange exerts on mineral phasetransition behavior, and the formationpathways followed by the many varieties ofmicrocrystalline silica.

Russell J. Hemley isa staff scientist at theGeophysical Laboratory,Carnegie Institution ofWashington. Hisresearch explores thebehavior of materialsover a broad range ofthermodynamic

conditions from low to very high pressuresand how this relates to problems in Earth andplanetary science, physics, chemistry,materials science, and biology. He obtaineddegrees in chemistry (Wesleyan University,BA 1977; Harvard University, MA 1980, PhD1983) before joining the Carnegie Institutionin 1984. He is a fellow of the AmericanPhysical Society, the American GeophysicalUnion, and the American Academy of Artsand Sciences, and a member of the NationalAcademy of Sciences.

Gary R. Huss isprofessor at the Hawai’iInstitute of Geophysicsand Planetology at theUniversity of Hawai’i. Hereceived his Bachelor’sdegree in geology at RiceUniversity, his Master’sdegree in geology at the

University of New Mexico, and his PhD ingeology at the University of Minnesota. Hejoined the laboratory of Edward Anders at the

University of Chicago in 1988 to study thenewly discovered nanodiamonds in mete-orites. Since, his research has covered manyaspects of the early solar system, includingnanodiamonds, various types of presolargrains, short-lived radionuclides, the timingof events in the early solar system, and theprocesses that led to the meteorites, asteroids,and planets.

YoshihideOgasawara, Dr. Eng.,is professor of petrologyat the Department ofEarth Sciences, WasedaUniversity, Tokyo. Sincehis doctoral dissertation,he has worked on low-pressure type dolomitic

marbles and carried out related computer-assisted thermodynamic studies. In 1993, hebegan studying ultrahigh-pressure metamor-phic rocks, with a focus on UHP carbonaterocks. Recently he has concentrated on theevolution of deeply subducted carbonaterocks and the formation of diamond in themetamorphic rocks of the Kokchetav Massif,northern Kazakhstan.

James E. Shigley isdirector of research atthe Gemological Instituteof America (GIA) inCarlsbad, California.Prior to joining GIA in1982, Dr. Shigley studiedgeology as an undergrad-uate at the University of

California at Berkeley and later received hisdoctorate in geology from Stanford University.He is the author of various articles on dia-monds and other gemstones and is a well-known speaker on gemological topics to bothprofessional and general audiences. Dr. Shigleydirects GIA’s research activities, which includethe identification of natural, synthetic, andtreated diamonds, colored stones and pearls,and the evaluation of various characterizationtechniques for identifying gems.

Thomas Stachel isprofessor and CanadaResearch Chair inDiamonds at theUniversity of Albertain Edmonton. He com-pleted his PhD in 1991at Würzburg University,Germany, on the

volcanology and petrology of the Ellendalelamproites, Western Australia. A first postdoc-toral research project on the Gross BrukkarosCaldera in Namibia still kept him in the fieldof volcanology. With a Marie Curie Fellowshipof the European Union, he joined Jeff Harrisat the University of Glasgow in 1994, wherehe became involved in research on diamondsand their inclusions. From 1996 to 2001 hewas a lecturer at the Institute for Mineralogyat Frankfurt University where he completedhis “habilitation” on diamond research in1999. In the same year he was awarded the

Victor Moritz Goldschmidt Award of theGerman Mineralogical Society. He joined theUniversity of Alberta in 2001.

Ed Vicenzi is a researchgeochemist and thedirector of the analyticallaboratories in theSmithsonian Institution’sDepartment of MineralSciences. He is activelyinvolved in the applica-tion of electron and ion

microbeam methods to Earth and planetaryresearch. His current interests include mininginformation from combined Time ofFlight–Secondary Ion Mass Spectrometry, X-ray microanalysis, and cathodoluminescencedatasets. Before joining the National Museumof Natural History in 1999, he spent six yearsat the Princeton Materials Institute. Prior tothis, he spent two years as a postdoc atMacquarie University in Australia. He receivedhis PhD from Rensselaer Polytechnic Institute,a Master’s degree from the University ofOregon, and a BSc from McGill University,all in Earth sciences.

Chih-Shiue Yan is aresearch scientist at theGeophysical Laboratory,Carnegie Institution ofWashington. He wasborn and raised inTaiwan. In 1995, hebegan graduate work onCVD diamond under the

direction of Professor Yogesh Vohra(University of Alabama at Birmingham, UAB)and Russell J. Hemley and Ho-kwang Mao(Carnegie Institution). During this period hedeveloped techniques for the fabrication ofsingle-crystal diamond by CVD and receivedhis PhD in physics from UAB in 1999. Hethen became a research fellow and associateat Carnegie before assuming his currentposition in 2004.


The Clay Minerals Society will hold its Annual Meeting in Burlington,Vermont, U.S.A. June 11-15. Burlington is situated on the shores ofLake Champlain, located between the Green Mountains to the east andthe Adirondack Mountains to the west. The meeting’s theme “GreenMountain Clays”, reflects both the ancient tectonic processes responsiblefor forming metamorphic chlorite, serpentine, talc and muscovite indeformed Paleozoic rocks of the Green Mountains, as well as thePleistocene glaciation and deglaciation that led to the deposition of lacus-trine and marine clay-rich deposits in the Champlain Valley.

One of the highlights of the 2005 meeting will be field trips that takeadvantage of these geological resources. One field trip will be tothe Adirondack Mountains to examine glacial till spodosols andtheir associated weathering reactions and clay mineralogy (June11), and the other will be to serpentinized peridotites in the GreenMountains to examine tectonic, mineralogical and environmentalissues (June 15).

The conference will host numerous theme sessions and symposia,covering topics such as soil mineralogy and geochemistry, linksbetween soils and sediments, clays and the environment, ceramicscience, stable isotopes and clays, structural modeling and quanti-tative analysis, clays and climate, and a special session devoted tothe pioneering research of Robert C. Reynolds in the areas of sed-imentary basin analysis, hydrocarbon geology and structural analy-sis of clays.

The CMS Workshop “Characterization of Solid-Water InterfaceReactions of Metals and Actinides on Clays and Clay Minerals” willbe held on June 11 and is being organized by Andreas Bauer ofForschungszentrum Karlsruhe, Institut für Nukleare Entsorgung(INE), Karlsruhe, Germany; [email protected]

Burlington is a small city of 40,000 inhabitants andis home to the University of Vermont, a thrivingpedestrian-friendly downtown, museums and natu-ral areas, and a working agricultural landscaperenowned for world-class cheeses. The meeting willbe held at the Wyndham hotel on the Burlingtonwaterfront, a venue that is ideally-suited for a CMSmeeting. We encourage you to attend, to meet oldcolleagues and friends, to strike up new profession-al relationships, to share knowledge and ideas, andto enjoy early summer on the shores of LakeChamplain.

IMPORTANT DEADLINES

Abstract Submission: APRIL 1, 2005Pre-registration: May 15, 2005Hotel: May 20, 2005For more information, seewww.middlebury.edu/cms,or contact the conferencechairs:

Peter C. RyanGeology DepartmentMiddlebury CollegeMiddlebury, VT [email protected]

Michele HluchyEnvironmental StudiesAlfred UniversityAlfred, NY [email protected]


Inclusions in Sublithospheric Diamonds:Glimpses of Deep Earth

Thomas Stachel1, Gerhard P. Brey2, and Jeffrey W. Harris3

INTRODUCTIONThe vast majority of diamonds mined from primarydeposits in kimberlite and lamproite pipes and from sec-ondary deposits derived through erosion and redepositionoriginated from a narrow depth window between about140 and 200 km, as indicated by calculations of tempera-ture and pressure of formation of their silicate inclusions.The top end of this depth range corresponds to the transi-tion of graphite to diamond at conditions in Earth’s man-tle; the bottom end appears to coincide with the “normal”maximum thickness of lithosphere, the non-convectinguppermost portion of our planet (FIG. 1). Such substantialthicknesses of lithosphere are only achieved beneath theoldest parts of continents, the cratons; this explains theobservation that primary diamond deposits are generallylimited to areas where the last major tectonothermal eventoccurred at least 2.5 billion years ago—this is the essence ofthe so-called “Clifford’s Rule”.

Mineral inclusions in diamonds are overwhelmingly derivedfrom the two principal rock types occurring in the deep lith-osphere, peridotite and eclogite (e.g., Meyer 1987). Althoughperidotitic diamonds dominate, the relative abundance ofeclogitic diamonds generally increases with larger stonesizes, giving them great economic importance. The study oflithospheric diamonds has proven to be a valuable tool com-plementary to similar research on fragments of mantle rocks

(xenoliths) found in volcanic rocksof deep origin. The inclusions aretypically 0.1–0.2 mm in size, rarely0.5 mm, and are found using anoptical microscope. If necessary,they can be identified in situ usingRaman spectroscopy and character-ized structurally using X-ray dif-fraction. For chemical analysis,mineral inclusions are released bycrushing or burning their diamondhosts. The inert nature and pre-sumed old ages of diamonds maketheir inclusions particularly usefulfor studying the origin and evolu-tion of ancient lithosphere.

Important observations over the lasttwo decades have shown that hid-den among the dominant lithos-pheric diamonds are samples

derived from even greater depths, extending to at least 700km. Xenoliths of mantle material from beneath the litho-sphere are extremely rare, and the few examples appear tohave equilibrated to lithospheric conditions (e.g., Sautter et al.1991). Our knowledge of the mineralogy and chemical com-position of the sublithospheric mantle, therefore, is derivedindirectly, using high-pressure experiments, seismic data, andcosmochemical and isotopic constraints. Mineral inclusionsin ultradeep diamonds are the only direct samples from thedeep mantle available for study and allow us to test themodels derived from geophysical and experimental studies.

Discontinuities in the velocity of compressional and shearwaves discovered in seismic studies point to layering inEarth’s mantle. High-pressure experiments by A.E. Ringwoodand coworkers (including W.O. Hibberson, T. Irifune,L. Liu, and A. Major) showed that these seismic discontinu-ities coincide with phase transitions affecting importantmantle minerals. Based on these data, the mantle is subdi-vided into three major layers (see FIGS. 1 AND 2):

1 The upper mantle (<410 km) It is thought to consistpredominantly of olivine and low-Ca pyroxene. In thepresent paper, we use the term “asthenosphere” for theentire convecting upper mantle beneath the lithosphere(see glossary p. 70).

2 The transition zone (410–660 km) The 410-km seismicdiscontinuity coincides with the experimentallyobserved conversion of olivine (α-phase) into spinel-likewadsleyite (β-phase), with roughly an 8% increase inmineral density. A further 100 km down, wadsleyitetransforms to ringwoodite (γ-phase), which has a truespinel structure and is another 2% denser. This latterphase transition has been linked to a mild seismic dis-continuity in the mid-transition zone (at about 520 km).

1 Earth and Atmospheric Sciences, University of Alberta, Edmonton T6G 2E3, Canada

2 Institut für Mineralogie, Universität Frankfurt, 60054 Frankfurt, Germany

3 Division of Earth Sciences, University of Glasgow, Glasgow, G12 8QQ, UK

E-mail: [email protected]

Diamonds originate in the deep roots of ancient continental blocks(cratons) that extend into the diamond stability field beneath about140 km. Over the last two decades, rare diamonds derived from even

greater depths—the deep upper mantle, the transition zone (410–660 km),and the lower mantle—have been recognized. Inclusions in diamonds fromthe deep upper mantle and the transition zone document sources of basalticcomposition, possibly related to subduction of old oceanic crust back intoEarth’s mantle. Diamonds from the lower mantle carry inclusions that largelyconfirm predictions of the composition and mineralogy of the deep mantlebased on a “pyrolite” (primitive peridotitic) composition of silicate Earth. Forsome inclusions, however, the chemical evidence again points to a connectionwith subducting oceanic slabs, possibly ponding at the top of the lower mantle.

Keywords: diamond inclusion, majorite, perovskite, phase transition,

transition zone, lower mantle, subduction, megalith

A 400-micron wideferropericlase inclusionin a diamond from the

São Luiz alluvialdeposits of Brazil. PHOTO

BY JEFFREY W. HARRIS.


3 The lower mantle (660–2900 km) In contrast to theupper mantle, which is made up of silicate mineralsbased on various combinations of SiO4-tetrahedra, sili-con is octahedrally coordinated with oxygen in the lowermantle. The dominant phases are CaSi- and MgSi-per-ovskites, in addition to the oxide phase ferropericlase.The nature of the 660-km discontinuity is still not fullyunderstood, with conflicting experimental, geochemical,and geophysical evidence as to whether it represents animpediment to whole mantle convection or not (cf. Agee1998).

The discovery of ultradeep inclusions in diamonds was nota stepwise recognition of increasingly deeper origins.Rather, it began unexpectedly in 1984 with a small para-graph in a paper by Scott Smith et al. (1984) on kimberlitedikes near Orrorroo in South Australia. These authors notedthat if ferropericlase (see glossary p. 70) inclusions in dia-monds from this occurrence and the Koffiefontein Mine inSouth Africa were indeed syngenetic, then, because of anapparent association with inclusions of orthopyroxenechemistry, they may indicate diamond formation in “deeperlevels of the mantle” (i.e., the lower mantle). Not muchattention was given to this discovery till more compellingevidence for lower-mantle diamonds was found at Rio SãoLuiz in the Juina area of Brazil (reviewed in Harte et al.1999).

The next stage was the recognition of inclusions of majoritegarnet (see glossary p. 70) in diamonds from the Monasterymine, South Africa (Moore and Gurney 1985), which indi-cated formation in the asthenosphere and the transitionzone. The most recent discoveries of ultradeep inclusionscame from Snap Lake (Canada), in the form of subcalcic,high-Cr majoritic garnet (Pokhilenko et al. 2001) and fromYubileynaya (Siberia), where Sobolev et al. (2004) reportwehrlitic, high-Cr majorite garnet.

Although individual inclusions of “ultradeep” origin are bynow quite common, so far only five localities have yieldedmany sublithospheric diamonds. Of these five localities,four have yielded diamonds with majoritic garnet inclu-sions: Monastery, Jagersfontein (both South African), Juina(Rio São Luiz, Brazil), and Kankan (Guinea). The principalsources of diamonds with lower-mantle parageneses are Juina,Kankan, and the Lac de Gras region of Canada. Studies ondiamonds from these five occurrences (for references seeStachel 2001) form the basis of the review given here.

100

200

300

400

500

600

700

24

13

7

2900

5155

MAJORITE

OLIVINE

W ADSLEYITE

GPa

RINGWOODITE

LOWER MANTLE

CORE

UPPER MANTLE

TRANSITION

ZONE

0CRUST

GRAPHITE

DIAMOND S

UC

TI

UB

D

ON

EO

CL

GIT

E

PHASE TRANSITION

PHASE TRANSITIONPEROVSKITE + FERROPERICLASE

?

Liquid

SPINEL

GARNET

km

3.5

ERH EPSO

HTIL

EREP HS

ON

EH

TS

A

GARNET + PYROXENE

Vertical section through Earth’s crust, mantle and core.The upper mantle, underlying the crust (shown in light

yellow) is separated into two main mineralogical layers, spinel facies(green) and garnet facies (pink). The uppermost, non-convecting por-tion of Earth including the crust and part of the upper mantle is calledthe lithosphere, and the underlying convecting part the asthenosphere.Beneath ancient cratons the lithosphere may extend to about 200 kmdepth. In cooler regions of Earth’s mantle the graphite/diamond transi-tion occurs at shallower depth. Beneath cratons, therefore, there is aregion where lithosphere and diamond stability overlap and this is themain source region of diamonds worldwide. Rare ultradeep diamondsmay come from (i) the deep upper mantle, where majorite garnetbecomes stable, (ii) the transition zone, characterized by the stepwiseisochemical conversion of olivine first to wadsleyite and then to ring-woodite, and (iii) the lower mantle. These ultradeep diamonds are theonly direct samples available from the deep interior of our planet.

FIGURE 1

Olivine

Wadsleyite

Ringwoodite

Grt

Cpx

Opx

Majorite-Garnet

Mg-PerovskiteFP

4

8

12

16

20

24700660

500

300

100

410

0.2 0.60.4 0.8

Ca-

P vk

Lithosphere

“Asthenosphere”

Lower Mantle

Transition

Zone

Relative mineral proportions and phase transitions inEarth’s mantle (after Ringwood 1991; Agee 1998; Wood

2000). FP: ferropericlase; Grt: garnet; Cpx: clinopyroxene; Opx: ortho-pyroxene; Mg-perovskite: MgSi-perovskite; Ca-Pvk: CaSi-perovskite.

FIGURE 2


ASTHENOSPHERE AND TRANSITION ZONE

Important Phase TransitionsAll four major minerals occurring in peridotite, the princi-pal rock type in the upper mantle, are affected by phasetransitions and reactions over the depth range in this zone.First, at around 300 km depth, orthopyroxene is eliminatedby a structural conversion to monoclinic low-Ca pyroxene.At similar depths, garnet increasingly dissolves pyroxene asa majorite component to give a garnet-structured, high-pressure form with pyroxene stoichiometry. For a predictedprimitive composition of the Earth’s mantle (“pyrolite” ofRingwood 1962a and 1962b), all pyroxene would be dis-solved in majorite garnet at about 450 km depth (FIG. 2). Atabout 550 km depth, the majorite component of garnetbegins to decrease through exsolution of CaSi-perovskite.Magnesium-rich olivine, the most important constituent ofthe upper mantle, is eliminated at the top of the transitionzone through conversion to wadsleyite, which in turn con-verts to spinel-structured ringwoodite in the middle of thetransition zone. So, in the mid-transition zone, the typicalfour-phase peridotite of the upper mantle will have con-verted to a two-phase rock composed of silicate spinel andmajorite garnet.

The Problem of Retrograde Phase Transitions Based on these phase transitions, it might be expected thatrecognition of inclusions in diamonds from the deepasthenosphere and transition zone would be fairly straight-forward and could be based on phase identification (X-raydiffraction, Raman spectroscopy). In fact, exhumation con-verts these high-pressure minerals to lower-pressure phasesor assemblages. This happens because diamond deformsplastically at the high temperatures of the Earth’s mantle,and thus high internal pressure on inclusions is relaxedduring ascent. Even rapid ascent from the point of dia-mond formation is not sufficient to prevent retrograde con-version of ringwoodite or wadsleyite to olivine and of low-Ca clinopyroxene to orthopyroxene. The only exception isthe retrograde reaction of majorite to “normal” garnet pluspyroxene, as this conversion is not an isochemical phasetransition and leaves the telltale signature of an extra phaseif reequilibration proceeds. The onset of pyroxene exsolu-tion from majorite garnet has been documented for inclu-sions in diamonds from Juina by Wilding (1990).

Because of the polymorphic transitions, chemical finger-printing appears to be the only way to detect former single-phase low-Ca clinopyroxene, wadsleyite, and ringwooditeinclusions. High-pressure experiments on pyrolite compo-sitions show elevated Al contents in wadsleyite and (evenmore so) in ringwoodite relative to olivine (Akaogi andAkimoto 1979). From experiments, wadsleyite in equilibri-um with a primitive mantle contains ≥0.3 wt% Al2O3,which is also true for ringwoodite. As 0.1 wt% is the high-est Al2O3 content for all of the 700 olivine inclusions ana-lyzed from diamonds worldwide, we can exclude wads-leyite or ringwoodite as precursors.

Majorite GarnetThe only samples recognized so far as being from theasthenosphere and transition zone are inclusions ofmajoritic garnet. Experimental studies have found a nearlinear increase in “excess” silicon with increasing pressurefor the pressure range of about 7–15 GPa, thus suggestingthe possibility of using the majorite component in garnetas a geobarometer. Here we provide an interpretation usingthe 1200°C experimental data of Akaogi and Akimoto(1979) and Irifune (1987) for pressure estimates, thoughbulk chemical effects are not accounted for and experi-

mental data sets of other authors would lead to somewhatdifferent results. FIGURE 3 shows the compositional spreadof majorite inclusions in diamonds from worldwidesources. The bulk of the inclusions show majorite contentsthat translate to an asthenospheric depth of origin of about250–350 km. A few majorites, however, come from greaterdepths, probably extending even into the transition zone.For the one inclusion from Jagersfontein showing the high-est majorite component yet observed, even the most con-servative pressure estimates (e.g., Gasparik 2002) imply anorigin beneath the 410-km discontinuity.

Diamond Growth in the Transition ZoneA surprising feature of majoritic garnet inclusions is theirparagenetic association with eclogite as inferred from theirmajor-element composition. Earth’s mantle is generallyassumed to have a chemistry matching primitive peridotite(“pyrolite”) with a very minor component (probably <1%,cf. Schulze 1989) of eclogite, the high-pressure metamor-phic equivalent of basalt. Yet, only 10% of the about 90majoritic garnet inclusions analyzed so far belong to theperidotitic suite. These peridotitic majorites are so high inchromium (up to 14 wt% Cr2O3) that they do not corre-spond chemically to pyrolitic mantle but to non-convect-ing lithospheric mantle with a history of melt extraction(cf. Pokhilenko et al. 2004). The Cr-rich majorites showthat at some stage during Earth’s history, the lithospheremay have locally extended to a depth of about 300 km,which is significantly deeper than what we observe todaybased on the record from mantle xenoliths.

There is considerable compositional overlap between eclo-gitic majorite garnet inclusions and lithospheric eclogiticgarnet inclusions. This suggests that diamonds witheclogitic inclusions from within and beneath the cratoniclithosphere grew in similar source rocks. This compositionaloverlap seems to support the extreme view that the sub-lithospheric upper mantle is composed of eclogite (cf.

6.0 6.5 7.01

2

3

4

lC

[u

A+

ra

f]

Si [afu]

8 10 12 14 16 18 20

P [GPa]Si

8

10

12

14

16

18

20

PP

a[G

]A

rl+

C

Ta

ion

rns

ti

Zone

MonasteryJagersfonteinJuinaKankanother minesperidotitic

Majoritic garnet inclusions in diamonds from worldwidesources. An increasing majorite component with increas-

ing pressure corresponds to increasing Si and decreasing Al+Cr. PSi andPAl+Cr (given in giga-Pascal) are obtained via linear regression of exper-imental data (1200°C) of Akaogi and Akimoto (1979) and Irifune(1987) and are approximate values only. The transition zone, begin-ning at about 410 km (or 13.7 GPa) is indicated in grey. Except forcrosses, which have peridotitic sources, all majorites shown are eclogiticin paragenesis. [afu] is atoms per fomula unit.

FIGURE 3


Gasparik 2002). However, plate tectonics, the standard modelin Earth sciences, provides a mechanism in accord with thepetrological, geochemical, and geophysical constraints onthe composition of Earth’s mantle and the evidence againstthe long-term survival of extreme compositional stratifica-tion. Plate tectonics predicts that old and therefore denseoceanic lithosphere is subducted back into the mantle (Fig. 1)where it sinks through the asthenosphere and transitionzone to the top of the lower mantle and in part even far-ther, to the core–mantle boundary, as seen from seismictomography. The former basaltic oceanic crust in suchsinking slabs could well be the source of eclogitic majoriteinclusions in diamonds.

But why would diamond formation in the asthenosphereand transition zone be restricted to down-going slabs?Carbon is a trace element in a peridotitic mantle (≤0.04 wt%).For the growth of macrodiamonds, a local enrichmentmechanism for carbon is needed. Within the lithosphere,this is probably accomplished by redox fronts, where reduc-ing fluids encounter oxidized rocks or vice versa. The deepasthenosphere and transition zone are expected to be fairlywell mixed and more reduced than the lithospheric mantle,making the presence of redox fronts unlikely. A sinkingoceanic slab, however, will at least locally be oxidizedthrough seawater alteration and provide redox gradientswhere reduced hydrocarbon-bearing fluids may precipitatediamond. In addition, thermally stable carbonates in sub-ducting slabs may become reduced to diamond by virtue ofa crystal chemistry-induced decrease in oxygen fugacitywith increasing pressure. Strong support for a subductionmodel comes from the rare-earth elements in some majoriticgarnets where europium is depleted relative to its neigh-boring rare-earth elements (REEs). Eu (as Eu2+), unlike theother REEs, follows calcium and fractionates into the low-pressure mineral plagioclase. It is removed from the basalticrocks during crystal–melt fractionation prior to being trans-formed into eclogite during subduction.

Carbon isotopic data on diamonds containing majorite gar-net inclusions (FIG. 4) exist for only three occurrences,Jagersfontein, Juina, and Kankan, and appear to supportmultiple origins for ultradeep diamonds: (i) subducted car-bonates (high δ13C, Kankan), (ii) mantle fluids (at about–5‰) combined with minor isotopic fractionation (Juina),and (iii) subducted organic matter or strong isotopic frac-tionation (low δ13C, Jagersfontein) (see glossary p. 70).

LOWER MANTLE

Phase Transitions at the 660-km DiscontinuityThe present understanding of Earth predicts that mantle ofthe deep transition zone should be approximately 60 vol%ringwoodite and 40 vol% majorite. At about 660 km, ring-woodite breaks down to an Al-poor MgSi-perovskite andferropericlase (FIGS. 1 AND 2). Majorite garnet begins toexsolve CaSi-perovskite at a depth of ~550 km, and fromthe 660-km discontinuity down to ~700 km, the garnetgradually reacts to form aluminous MgSi-perovskite andexpels some more CaSi-perovskite. If the lower mantle isricher in iron then assumed by the pyrolite model,stishovite, the high density polymorph of SiO2, would alsobe present.

Diamond Inclusions from the Lower Mantle Ferropericlase: The most prominent lower-mantle inclu-sion mineral in diamond is ferropericlase [(Mg,Fe)O]. It iseasy to recognize by its peacock-like play of colors underthe microscope. Ferropericlase is preserved during exhuma-tion because it is stable over the entire pressure range of themantle. However, when raised above the depths of thelower mantle and in the presence of low-Ca pyroxene, fer-ropericlase should react to form olivine (or wadsleyite orringwoodite). The absence of ferropericlase from “normal”upper mantle rocks, therefore, appears to indicate that allferropericlase inclusions in diamonds are of lower-mantleorigin. However, there is evidence that local regions withinthe upper mantle have low silica abundances; thus, thepresence of single inclusions of ferropericlase in diamondsdoes not automatically prove a lower-mantle origin. It isonly the coexistence in the same diamond of ferropericlasewith non-touching inclusions of perovskite chemistry thatunarguably reveals a lower-mantle origin.

Experimental studies on pyrolite compositions predict thatferropericlase in the lower mantle should have an Mg-number[100Mg/(Mg+Fe)] of 84–85. Ferropericlase inclusions recov-ered from diamonds show a prominent mode in Mg-numberat 85–88, indicating either a slightly more depleted or aslightly hotter source than modelled in experiments.Ferropericlase inclusions from Juina differ significantlyfrom this fairly uniform picture by showing a very largerange in Mg-numbers, from 36 to 87, and a polymodal dis-tribution, with the majority of analyses falling between 60and 82. The ferrous nature of the inclusions from Juina (inthis case, correctly termed magnesiowüstite) led Harte et al.(1999) to speculate about a possible origin from Fe-enriched mantle regions near the core–mantle boundary(2900 km). Alternatively, these inclusions may reflect muchshallower but non-pyrolitic lower-mantle sources, forexample ancient subducted oceanic crust.

Stishovite: This high-pressure SiO2-phase should be stabletogether with ferropericlase in the lower mantle at elevatediron contents (and possibly also in the transition zone atunusually high T); otherwise the two phases would com-bine to form MgSi-perovskite. Harte et al. (1999) con-strained the magnesium-iron ratio for this reaction usingthe compositions of inclusions in diamonds from Juina and

-25 -20 -15 -10 -5 00

1

2

3

4

Juina

Jagersfontein

Kankan

C arbonates

Organic matter

Carbon isotopic composition of diamonds with majoriticinclusions (all mines with less than two analyses were

excluded). Kankan diamonds with majorites show similarities to the car-bon isotopic composition of carbonates, Jagersfontein diamonds(Deines et al. 1991) resemble organic matter. At Juina (Hutchison et al.1999) the carbon isotopic composition extends from the mantle value(about -5‰) to more negative values (i.e. isotopically lighter composi-tions), which may be due to a fractionation process affecting a primor-dial fluid.

FIGURE 4


found that stishovite coexists with ferropericlase and MgSi-perovskite at Mg-numbers as high as 70 for the former and86 for the latter. Compared with high-pressure experi-ments, these ferropericlase and perovskite Mg-numbers arerelatively high. The other four occurrences of stishoviteplus ferropericlase in diamonds worldwide all reflect evenmore magnesian compositions and, therefore, should notexist in equilibrium. Disequilibrium seems the moststraightforward explanation, but considering the relative“abundance” of these samples, some doubts are justified.

TAPP: One of the surprising discoveries made by theEdinburgh-Glasgow group on Juina diamonds was theoccurrence of inclusions with a garnet-like composition buta tetragonal structure, hence called “TAPP” for TetragonalAlmandine–Pyrope Phase. TAPP is chemically distinct from“normal” peridotitic garnet because it is essentially Ca free(≤0.1 wt% CaO) (FIG. 5). Because TAPP is less dense thangarnet at appropriate pressure–temperature conditions, itwas suggested that TAPP represents a retrograde phase, pos-sibly stabilized by high Fe3+/Fe2+ ratios. This explanation issupported by a TAPP sample in a lower-mantle diamondfrom Kankan, which clearly resulted from a reaction thatoccurred during ascent through the mid-transition zone.

MgSi-perovskite: Compositionally, MgSi-perovskite is ahigh-pressure equivalent of orthopyroxene. Crystallographicstudies of inclusions show that presumed perovskitesinverted to pyroxene during exhumation. Nickel content isthe chemical indicator used to determine whether an inclu-sion originally formed as orthopyroxene or MgSi-perovskite.In the lower mantle, all nickel is partitioned into ferro-periclase, and MgSi-perovskite consequently has less than300 ppm NiO, as opposed to typical orthopyroxene fromthe upper mantle which has >1000 ppm NiO.

Seventeen out of 20 MgSi-perovskite inclusions discoveredworldwide have Al2O3 contents below 3 wt%. As discussedabove, experiments indicate that garnet dissolves graduallyinto MgSi-perovskite in the uppermost 50 km of the lowermantle, as the solubility of Al in perovskite increases withpressure. If models for the composition of the lower man-tle are correct, then MgSi-perovskite with such low Al con-tents should occur only in the topmost ~20 km of the lowermantle. Only three MgSi-perovskites from Juina show highAl contents (about 10 wt% Al2O3) and thus may be derivedfrom the deeper lower mantle.

CaSi-perovskite: Being almost pure CaSiO3, CaSi-perov-skite is compositionally distinct from minerals occurring intypical upper-mantle and transition zone rocks. It should

be a high-pressure phase in both peridotitic and eclogiticparageneses. Despite the fact that the perovskite structure isnever preserved—primary CaSi-perovskite inclusions areeither amorphous or converted to the less dense walstro-mite structure—the discovery of CaSiO3 inclusions was acrucial piece of evidence at Juina that established for thefirst time a lower-mantle origin for some diamonds.

CaSi-perovskite is particularly interesting among lower-mantle phases because it acts as a sink for incompatibletrace elements e.g., strontium (0.03–0.73 wt%), zirconium(0.01–0.22 wt%), and total REEs (0.03–0.22 wt%). FIGURE 6is a concentration diagram (normalized to C1-chondriteas a “primitive” reference material) for the REEs in CaSi-perovskites from Juina and Kankan. The analysedperovskites fall into three groups (see different line colors)with contrasting REE distributions. For each of thesegroups, the behaviour of Eu is different, with positive Euanomalies for all perovskites with fairly flat slopes from Lato Sm and negative anomalies for the three perovskiteswith the lowest total REEs. As discussed before, differencesin the behaviour of Eu relative to neighbouring Sm and Gdare interpreted as a response of protolith composition toaddition or extraction of plagioclase (which readily accom-modates Eu2+ compared to the other trivalent REEs, includ-ing Eu3+) at low pressure.

Formation of Lower-Mantle DiamondsFrom the low Al contents of the MgSi-perovskites, it appearsthat the bulk of the lower-mantle diamonds are derivedfrom the topmost ~20 km of the lower mantle. This char-acteristic, combined with the trace-element composition ofCaSi-perovskites (with their positive or negative Eu anom-alies), suggests that the diamonds were not derived fromprimitive mantle but from former oceanic slabs that accu-mulated at the top of the lower mantle (the “megalithmodel” of Ringwood 1991, see FIG. 7). As in the asthenos-phere and transition zone, redox conditions in the lowermantle may generally be too reducing for the formation of

KankanJuina

10

100

1000

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ca

Si-

Pe

rov

sk

ite

C1

-Ch

on

dri

te

The concentrations of rare-earth elements (REEs) in CaSi-perovskite inclusions in diamonds from Juina and Kankan

normalized to C1-chondrite as a “primitive” reference material. CaSi-perovskites generally show high concentrations in light REEs (left sideof figure). Different types of REE patterns may be distinguished (shownas green, red and blue lines). The three groups also differ in the behav-ior of Eu, which shows positive spikes for the “green group”, negativespikes for the “blue group” and normal behavior for the “red group”.Negative Eu-anomalies are usually attributed to feldspar fractionationand positive anomalies to feldspar accumulation, making formeroceanic crust that subsequently became subducted into the lowermantle a likely protolith.

FIGURE 6

150 micron-long green tetragonal-structured garnetknown as TAPP (tetragonal almandine–pyrope phase), in

a diamond from the São Luiz alluvial deposits, Brazil. PHOTO BY JEFFREY W.HARRIS

FIGURE 5


macrodiamonds without the assistance of oxidized slabmaterial or oxidizing fluids emanating from subductedmaterial (FIG. 7) to provide the necessary redox gradients.

In conclusion, inclusions in ultradeep diamonds haveturned out to be an excellent tool for testing mantle mod-els based on high-pressure experiments and geophysicaldata. We have gained glimpses of the fate of subductingslabs passing through the asthenosphere and transitionzone, and overall we observe good consistency with com-positional models for the lower mantle. However, no studiesinvolving radiogenic isotopes have yet been undertaken onultradeep diamonds, and our knowledge of lower-mantlediamonds is largely based on only two occurrences. Thesearch for more ultradeep material is therefore guaranteedto continue.

ACKNOWLEDGMENTSIn order to produce an easy-to-read overview on sublithos-pheric diamonds, the authors have attempted to keepreferences to a reasonable minimum. We would like toacknowledge that the information reviewed here is basedon the efforts of people like Frank Brenker, Rondi Davies,Peter Deines, John Gurney, Ben Harte, Mark Hutchison,Felix Kaminsky, Rory Moore, Nick Sobolev, Ralf Tappert,and Martin Wilding. .

REFERENCESAgee CB (1998) Phase transformations and

seismic structure in the upper mantleand transition zone. Reviews inMineralogy 37: 165-203

Akaogi M, Akimoto S (1979) High-pressurephase equilibria in a garnet lherzolite,with special reference to Mg2+-Fe2+

partitioning among constituent minerals.Physics of the Earth and PlanetaryInteriors 19: 31-51

Deines P, Harris JW, Gurney JJ (1991)The carbon isotopic composition andnitrogen content of lithospheric andasthenospheric diamonds from theJagersfontein and Koffiefonteinkimberlite, South Africa. Geochimicaet Cosmochimica Acta 55: 2615-2625

Gasparik T (2002) Experimental investiga-tion of the origin of majoritic garnetinclusions in diamonds. Physics andChemistry of Minerals 29: 170-180

Gasparik T, Hutchison MT (2000)Experimental evidence for the origin oftwo kinds of inclusions in diamondsfrom the deep mantle. Earth andPlanetary Science Letters 181: 103-114

Harte B, Harris JW, Hutchison MT, WattGR, Wilding MC (1999) Lower mantlemineral associations in diamonds fromSao Luiz, Brazil. In Fei Y, Bertka CM,Mysen BO (eds) Mantle Petrology: FieldObservations and High PressureExperimentation: A tribute to Francis R.(Joe) Boyd, The Geochemical Society,Houston, pp 125-153

Hutchison MT, Cartigny P, Harris, JW(1999) Carbon and nitrogen composi-tions and physical characteristics of

transition zone and lower mantlediamonds from Sao Luiz, Brazil. InGurney JJ, Gurney JL, Pascoe MD,Richardson SH (eds) The J.B. DawsonVolume, Proceedings of the VIIthInternational Kimberlite Conference,Red Roof Design, Cape Town, pp 372-382

Irifune T (1987) An experimentalinvestigation of the pyroxene-garnettransformation in a pyrolite compositionand its bearing on the constitution ofthe mantle. Physics of the Earth andPlanetary Interiors 45: 324-336

Meyer HOA (1987) Inclusions in diamond.In Nixon PH (ed) Mantle xenoliths, JohnWiley & Sons, Chichester, pp 501-522

Moore RO, Gurney, JJ (1985) Pyroxenesolid solution in garnets included indiamonds. Nature 318: 553-555

Pokhilenko NP, Sobolev NV, McDonald JA,Hall AE, Yefimova ES, Zedgenizov DA,Logvinova AM, Reimers LF (2001)Crystalline inclusions in diamonds fromkimberlites of the Snap Lake area (SlaveCraton, Canada): New evidences for theanomalous lithospheric structure.Doklady Earth Sciences, 380: 806-811

Pokhilenko NP, Sobolev NV, Reutsky VN,Hall AE, Taylor LA (2004) Crystallineinclusions and C isotope ratios indiamonds from the Snap Lake/King Lakekimberlite dyke system: evidence ofultradeep and enriched lithosphericmantle. Lithos 77: 57-67

Ringwood AE (1962a) A model for theupper mantle. Journal of GeophysicalResearch 67: 857-866

Ringwood AE (1962b) A model for theupper mantle. 2. Journal of GeophysicalResearch 67: 4473-4477

Ringwood AE (1991) Phase transformationsand their bearing on the constitutionand dynamics of the mantle. Geochimicaet Cosmochimica Acta 55: 2083-2110

Sautter V, Haggerty SE, Field S (1991)Ultradeep (greater than 300 kilometers)ultramafic xenoliths – petrologicalevidence from the transition zone.Science 252: 827-830

Schulze DJ (1989) Constraints on theabundance of eclogite in the uppermantle. Journal of Geophysical Research– Solid Earth and Planets 94: 4205-4212

Scott Smith BH, Danchin RV, Harris JW,Stracke KJ (1984) Kimberlites nearOrroroo, South Australia. In Kornprobst J(ed) Kimberlites I: kimberlites and relatedrocks, Elsevier, Amsterdam, pp 121-142

Sobolev NV, Logvinova AM, Zegenizov DA,Seryotkin YV, Yefimova ES, Floss C,Taylor LA (2004) Mineral inclusions inmicrodiamonds and macrodiamondsfrom kimberlites of Yakutia: a compara-tive study. Lithos 77: 225-242

Stachel T (2001) Diamonds from theasthenosphere and the transition zone.European Journal of Mineralogy 13: 883-892

Wilding MC (1990) PhD thesis. Universityof Edinburgh, UK

Wood BJ (2000) Phase transformations andpartitioning relations in peridotite underlower mantle conditions. Earth andPlanetary Science Letters 174: 341-354 .

410 km discontinuity

660 km discontinuity

Subduction zone

Upper mantle

Lo werman tle

Continent

Partialresorption

Basalticoceaniccrust

Megalith of former basaltic oceanic crust and harzburgitic lithosphere

Transition zone

Oceaniclithosphere

fluid

According to the “megalith model” of Ringwood (1991),subducting oceanic slabs may become buoyant at the

top of the lower mantle. The resulting pile of subducted lithosphere iscalled a “megalith”. The evidence for diamond formation at the top ofthe lower mantle, in combination with crustal signatures in lower-mantlediamonds containing CaSi-perovskite, suggests that megaliths may wellbe the primary source. Oxidizing fluids coming out of the subductedlithosphere may cause diamond formation in highly reducing “normal”lower mantle. The formation of diamonds with inclusions of majoriticgarnet may occur earlier during the subduction process, in the deepupper mantle and transition zone. Exhumation of ultradeep diamondsmay occur through mantle plumes or in the course of normal mantleconvection.

FIGURE 7

79 MARCH 2005E L E M E N T S , V O L . 1 , P P . 7 9 – 8 4

INTRODUCTIONNatural diamonds crystallize only at high pressures andtemperatures. These conditions occur in the upper mantle,at depths exceeding ~150 km and temperatures above950°C (FIG. 1). Diamonds are brought from the mantle tothe surface as xenocrysts (foreign crystals) within volumet-rically rare volcanic rocks called kimberlites and lamproites.These magmas not only form deep enough to pick up dia-mond, but also ascend to the surface fast enough to preventtransformation of diamond to graphite or its dissolution inthe magma. The occurrence of diamond on the Earth’s sur-face is thus both accidental and the result of the uniqueresistance of diamond to dissolution. For Earth scientists,the study of diamond and its impurities not only providesimportant insights into the conditions prevailing in thevery deep mantle, but also helps us to understand the evo-lution of our planet.

Over the last twenty-five years, studies of diamonds fromoccurrences worldwide have yielded an enormous amountof data. It is now generally accepted that most natural dia-monds are old and xenocrystic, and come from ancientlithosphere. In spite of major advances, the remainingquestions about their formation are profound and com-plex. In particular, the source of carbon from which dia-monds formed is still a hotly debated subject. This articlereviews available stable isotopic data on diamonds, with afocus on the potential source(s) of carbon. The currentmodels for the origin of diamonds in Earth’s mantle will bepresented and discussed in the light of stable isotope dataon carbon and nitrogen from diamonds and on sulfur andoxygen from mineral inclusions found in diamonds.

CARBON ISOTOPES IN DIAMONDSCarbon has two stable isotopes, 12C and 13C, with abun-dances of 98.9% and 1.1%, respectively. The 13C/12C ratio ofmost terrestrial samples varies little, from ~0.010956 to

~0.011237. 13C/12C ratios areexpressed in terms of how theydeviate in ‰ (parts per thousand)relative to the Pee Dee Belemnite,an internationally accepted stan-dard (see glossary p. 70).

Carbon isotopic compositions areavailable from more than fourthousand diamonds worldwide.Major sources include Siberia,Canada, Australia, Brazil, andWest, East, and southern Africa(Botswana and South Africa). Dataare also available from (1) impact-diamonds grown at high tempera-

tures over an extremely short time period, (2) metamorphicdiamonds formed within crustal rocks buried at high pres-sure and temperature along subduction/collision zones(Ogasawara this issue), and (3) diamond types that are lesswell understood, e.g., carbonados (Heaney et al. this issue).

Variation in Carbon Isotopes The distribution of δ13C values in diamonds formed inEarth’s mantle (FIG. 2A) can be divided into distinct popu-lations on the basis of the mineralogy and chemistry ofinclusions of silicate minerals. These are usually about200 µm in maximum dimension and define two principalgroups referred to as ‘peridotitic’ or P-type and ‘eclogitic’ orE-type. The P-type reflects the mineral assemblage of aperidotite, a four-phase assemblage of olivine, enstatite,garnet, and clinopyroxene. The E-type is related to eclogite,a rarer rock consisting principally of garnet and clinopy-roxene. Sulfides are also common as inclusions and have P-or E-type affinities. Peridotitic and eclogitic diamonds can

1 Laboratoire de Géochimie des Isotopes Stables, Institut de Physiquedu Globe de Paris, 4 place Jussieu, Paris Cédex 75251, FranceE-mail: [email protected]

Most diamonds form in a relatively narrow depth interval of Earth’ssubcontinental mantle between 150 and 250 km. From carbonisotope analyses of diamond obtained in the 1970s, it was first

proposed that eclogitic diamonds form from crustal carbon recycled into themantle by subduction and that the more abundant peridotitic diamondsformed from mantle carbon. More recent stable isotope studies using nitro-gen, oxygen, and sulfur, as well as carbon, combined with studies of mineralinclusions within diamonds, have strengthened arguments supporting andopposing the early proposal. The conflicting evidence is reconciled if mantlecarbon is introduced via fluid into mantle eclogites and peridotites, some ofwhich represent subducted oceanic crust.

KEYWORDS: diamond, stable isotopes, mantle, metasomatism

Stable Isotopes and the Origin of Diamond Pierre Cartigny 1

P-T phase diagram for elemental carbon. The differentgeotherms illustrate that diamond is stable in continental

settings at pressures of ~45 kbar (corresponding to depths of 150 km)and in oceanic settings at ~60 kbar. In subduction zones, as illustratedhere by a ‘warm’ subduction gradient, diamond is stable at lowerpressures (~35 kbar). With a steeper geothermal gradient (not shown),diamond is stable at pressures of ~30 kbar (i.e., 100 km depth).

FIGURE 1


have diamond overgrowths, and these are usually referredto as fibrous, cubic, or coated diamond. Hereafter, suchovergrowths will be referred to as “coated/fibrous dia-monds”. They may be related to kimberlite magmatism(Boyd et al. 1994) and record the date of kimberlite empla-cement (less than 350 Ma ago), making them geneticallydifferent from their cores, which vary in age from 1 to 3 Ga(Shirey et al. 2002).

While most macrocryst diamonds sampled by kimberlitesand related rocks originate from the base of ancient litho-sphere known as cratons (~100–250 km depth), they canalso form at much greater depths including Earth’s lowermantle (≥660 km depth) (see Stachel et al. this issue). Overthe depth range of 330 to 660 km, macrocryst diamondsbelong mostly to the eclogitic growth environment, as indi-cated by the present eclogite/peridotite abundance ratio ofabout 8 to 1 (Stachel et al. this issue).

Worldwide diamonds have a carbon isotopic composition(δ13C) ranging from –38.5 to +5.0‰ (FIG. 2A). Of these,approximately 72% are contained within a narrow intervalbetween –8 and –2‰, which is within the range of mantlevalues. The distribution is continuous, with a clear decreasein frequency on either side of a peak δ13C value of about –5± 1‰.

The δ13C distributions of the two principal diamond typesare significantly different (Sobolev et al. 1979). P-type dia-monds (FIG. 2B) exhibit a narrower range of δ13C values(from –26.4 to +0.2‰) than E-type (FIG. 2C) (from –38.5 to+2.7‰), while both fibrous/coated (FIG. 2D) and lower-mantle diamonds (FIG. 2E) show narrow ranges of values:–8.1 to –4.9‰ and –8.5 to –0.5‰, respectively. A muchgreater proportion of E-type diamonds than P-type dia-monds (34 and 2%, respectively) have very negative δ13Cvalues (defined here as <–10‰). δ13C values for diamondformed in crustal rocks—represented by microdiamondsformed in subducted metamorphic rocks—range from –30to –3‰ (FIG. 2F). See Fig. 1 in Heaney et al., this issue, forδ13C data from impact-related diamonds (δ13C from –22 to–8‰) and carbonados (δ13C from –32 to –25‰). Sedimen-tary carbon is divided between a concentration near 0‰and a scatter of light values between about –40 and –15‰(average about –25‰, FIG. 2G).

The distributions shown in figures 2a to 2d are based ondiamond analyses from worldwide kimberlites, lamproites,and their placer deposits. A comparison of the carbon iso-tope values from individual localities, using the example ofVenetia, South Africa (FIG. 3A) shows that more than 90%of individual locations have a similar range and distribu-tion of values. However, there are several striking excep-tions. Diamonds from the Guaniamo kimberlites(Venezuela, FIG. 3B), from the Argyle lamproite (westernAustralia, FIG. 3C), and from the New South Wales placerdeposits (eastern Australia, FIG. 3D) show δ13C distributionsfor eclogitic diamonds centered at approximately –15‰,–11‰, and +2‰, respectively. Rare peridotitic diamondsanalyzed so far from these sources show typical mantleδ13C values of about –5‰. In addition, locations such asOrapa (Botswana) and Jagersfontein (South Africa) (FIG. 3E)show a strong E-type, bimodal δ13C distribution with apeak at about –5‰ and another at about –20‰. For bothsources, the δ13C range for P- and E-type diamonds is nearlyidentical.

Intradiamond Variability Intradiamond carbon isotope variability is studied by com-paring results of the combustion of several fragments froma single stone. Such a method detects δ13C zonations onlyon a scale of up to 1 mm and will not detect any oscillato-

ry zonation on a scale of10–100 µm. Althoughlarge δ13C variations ofup to 15‰ have beenmeasured within a sin-gle diamond, moststones show little δ13Cvariability across growthzones, more than 95%of analyses varying byless than 3‰. Whenlarge variations arefound, they usually cor-respond to distinctgrowth episodes such asthe formation of a coatover a pre-existing dia-mond core.

Within the small rangeof internal δ13C varia-tions, no systematictrend of increasing ordecreasing δ13C valuesfrom core to rim isrecorded for either E- orP-type diamonds.Within the coats offibrous/coated dia-monds, a systematictrend of increasing δ13Cvalues (from –8 to –5‰)from core to rim hasbeen detected (Boyd etal. 1994). Sufficientlydetailed data are notavailable from which todetermine the scale ofδ13C variability in dia-monds formed in thelower mantle or otherenvironments (seeabove).

Origin of Carbon Variability Carbon isotope data combined with the study of inclusionsin diamonds have led to the emergence of three main mod-els to explain the variability of carbon isotope compositions.

Model 1 – Distinct carbon sources: Low δ13C valueswithin some eclogitic diamonds led many scientists to sug-gest that such diamonds formed from distinct carbonsources, unlike their peridotitic counterparts (Kirkley et al.1991). This model suggests that eclogitic diamonds arederived from sedimentary carbon recycled into the mantlevia subduction zones, whereas peridotitic diamonds formedfrom mantle-derived carbon. Metasedimentary carbon con-sists of mixtures of organic matter and carbonates with endmember δ13C values averaging –25‰ and 0‰, respectively

Comparative histograms of δ13C values for (A) worldwidediamonds of known and unknown paragenesis, (B) peri-

dotitic diamonds, (C) eclogitic diamonds, (D) fibrous/coated diamonds,(E) diamonds from the lower mantle, (F) metamorphic diamonds, and(G) sedimentary carbon represented by carbonates and organic matter.The mantle range (vertical yellow band) defined by the study of mid-ocean ridge basalts, carbonatites, and kimberlites is also indicated. ForA to C, each diamond locality has been weighted, because more than10% of all published data on eclogitic diamonds are from Argyle, andwithout weighting these data would cause a false second peak at about11‰ in B.

FIGURE 2


(FIG. 2G), values whichhave remained fairlyconstant through geo-logical time. From thepresent data, about 54%of E-type diamondshave δ13C values ofabout –5 ± 3‰. If thesediamonds were theproduct of recycled car-bon, mass-balance con-siderations indicate theneed to recycle a mix-ture composed of 20%organic matter (averageδ13C value of about–25‰) and 80% of car-bonates (average δ13Cvalue of about 0‰)(FIG. 2G). One wouldaccordingly expect amajority of E-type dia-monds with δ13C valuesbetween –5 and 0‰, incontrast to the observa-tion that most eclogiticdiamonds have a δ13Crange between –5 and–25‰ (FIG 2C). Thus theδ13C distribution pro-duced by mixing car-bonate and organicmatter does not matchthat of eclogitic dia-mond. High δ13C values(i.e., 1 ± 2‰) are actual-ly extremely rare amongmacrodiamonds and arelargely restricted to thealluvial diamonds fromNew South Wales.

During subduction, the carbon isotope compositions oforganic matter and carbonates re-equilibrate as temperatureincreases, the fractionation factor for δ13Ccarbonate–δ13Cgraphite

being 4.5 ± 1.5‰ at 700°C (Satish-Kumar et al. 2002). Thusthe isotopic compositions of metasediments will behomogenized if they maintain chemical connectivity, andextreme variability should not be present within the dia-mond stability field. A comparison of true metamorphicdiamonds (formed in crustal rocks) with eclogitic diamonds(cf. Figs. 2c and 2f) shows some general similarities in theirδ13C range, but the δ13C distributions differ principallybecause there is a near-complete absence of δ13C valuesaround –5‰ for metamorphic diamonds.

Model 2 – Primordial isotopic variability: A statisticalanalysis of carbon isotopes in diamond with respect to dia-mond shape, size, color, nitrogen content and speciation,type and chemical composition of the mineral inclusions,and the occurrence of plastic deformation led to the unam-biguous conclusion that a single kimberlite can sample sev-

eral diamond subpopulations (Deines et al. 1993). As thesedistinct diamond subpopulations are not related by any ofthe above criteria, the authors suggested that the observedisotopic heterogeneity was primordial, acquired duringEarth’s accretion and not homogenized by mantle convec-tion. This model would be supported, for instance, by theδ13C range defined by carbon in meteorites, which isindeed broadly similar to that of eclogitic diamonds(Deines 1980).

The preservation of primordial carbon isotope heterogene-ity in Earth’s mantle, however, is not supported by datafrom other fields of mantle isotope geochemistry, whichshow almost no evidence for preservation of primitivemantle compositions. In addition, methods used to identifydiamond subpopulations are not robust. Identification bymorphological features such as shape, color, size, and plas-tic deformation often associates primary and postgrowthdiamond formation features (Harris 1992). Defining dia-mond subpopulations according to the chemical composi-tion (or nature) of mineral inclusion(s) implicitly assumesfixed chemical compositions but fails to account for multi-ple inclusions from a single diamond spanning almost theentire known range of chemical compositions (e.g., Sobolevet al. 1998). Nitrogen contents have been assumed to reflectthe diamond growth environment (high/low nitrogen con-tents within the diamond being derived from nitrogenrich/poor parts of the mantle), although other processes,such as growth rate, may control the incorporation ofnitrogen into the crystal structure.

Model 3 – Fractionation of stable isotopes at mantletemperatures: A unique property of stable isotopes is thatcoexisting compounds in equilibrium will display distinctstable isotopic compositions. This fractionation dependschiefly on temperature and the phases involved. For tem-peratures of 1000°C, the carbon isotope fractionationbetween coexisting C-bearing species is small—less than4‰ (Bottinga 1969). However, the formation of carbon-bearing species in an open system, where minute amountsof material are removed continuously under conditions ofa constant fractionation factor, can lead to very significantδ13C ranges, in some cases in excess of 40‰. For example,the δ13C compositions of carbonates from a peridotitexenolith spanned a range from –5‰ to +24‰ (Deines1968). As the most positive δ13C values are higher thanmetasedimentary carbon in this example, mixing involvingmetasedimentary carbon can be ruled out to explain theisotopically heavy end-member. Such δ13C variations arebest explained by the precipitation of carbonates from CO2.

Although the range of δ13C produced by isotopic fraction-ation in an open system can be large, the mode(s) and theshape(s) of the resulting distribution(s) are not random. Astep towards identifying the composition of the C-bearingphase(s) (e.g., CO2, carbonate, methane, carbide) in the dia-mond growth medium/media is to examine the δ13C distri-bution(s) for diamond (Deines 1980). As an example, FIGURE

4 shows the model δ13C frequency distributions producedby fractionally precipitating diamond from CO2 andmethane. The worldwide diamond δ13C compositions (Fig2a) are actually compatible with such an open-system frac-tionation process in which diamonds grow from differentgaseous species. It has therefore been suggested that botheclogitic and peridotitic diamonds precipitated from man-tle-derived carbon with an initial δ13C value of about –5‰(Javoy et al. 1986; Galimov 1991). The main strength ofthis model is that it accounts for the strong overlap of botheclogitic and peridotitic diamonds in the δ13C range of –8to –2‰.

Comparative histograms of δ13C values for diamondsfrom individual localities. (A) Venetia (South Africa) rep-

resents a typical locality, while (B) Guaniamo (Venezuela), (C) Argyle(Australia), (D) New South Wales (Australia), and (E) Jagersfontein(South Africa) are atypical localities. Vertical axis is number of diamonds.

FIGURE 3


No precise fractionation mecha-nism, however, has been providedto account for the distinct δ13Cdistributions of eclogitic and peri-dotitic diamonds (Javoy et al.1986; Galimov 1991). Moreover,any simple fractionation modelfor carbon isotopes fails toaccount for the bimodal distribu-tion displayed by the diamonds inkimberlites at Orapa orJagersfontein. Furthermore, aunique carbon source with an ini-tial δ13C value of about –5‰ failsto account for distributions cen-tered around –11‰ (Argyle) or–15‰ (Guaniamo).

ADDITIONAL TRACERSBecause the isotopic compositions of mantle-derived andmetasedimentary carbon overlap, carbon isotopes alonewill not resolve the origin of diamond. An alternativeapproach consists of analyzing major and trace elements(Stachel et al. 2004) and radiogenic and stable isotopes ofinclusions in diamond. Radiogenic isotopes have been usedto decipher the history of diamond formation in the man-tle, in particular to demonstrate the Archean to Proterozoicformation age of most peridotitic and eclogitic diamonds(Shirey et al. 2002). The oxygen and sulfur isotopes of sili-cate and sulfide inclusions are described in the present article.

A second approach consists of analyzing the elementstrapped within the diamond matrix. More than 80 ele-ments have been detected in the crystal structure of dia-monds, of which nitrogen, boron, oxygen, and hydrogen(ppm levels) are the most abundant. Nitrogen, the mainimpurity in diamond (Kaiser and Bond 1959), is the onlyelement that has been systematically studied.

Oxygen and Sulfur IsotopesFor both oxygen and sulfur isotopes, Earth’s mantle isassumed to be homogeneous with δ18O values from +5 to+6‰ relative to SMOW and δ34S from –1 to +1‰ relativeto CDT (see glossary p. 70). In contrast, the igneous oceaniccrust, altered by seawater and including accompanying sed-iments, shows values deviating greatly from the mantlerange. Fairly limited oxygen and sulfur isotope data are cur-rently available from silicate (less than 20 analyses) and sul-fide (less than 50 analyses) inclusions in diamond. Theδ18O values (from +4 to +16‰) and δ34S (from –11 to+14‰) (FIG. 5) obtained respectively from silicate and sul-fide eclogitic inclusions clearly fall outside the mantlerange, and such evidence has been taken to support a sub-duction-related origin (Chaussidon et al. 1987; Lowry et al.1999; Taylor and Anand 2004). In addition, the identifica-tion of mass-independent fractionation of sulfur isotopes(δ33S ≠ 0.5 × δ34S) within eclogitic sulfide inclusions in dia-monds (Farquhar et al. 2002) is key evidence that eclogiteand eclogitic inclusions in diamonds are fragments of sub-ducted Archean oceanic crust. This is because, on Earth,mass-independent fractionations were produced only inthe anoxic Archean atmosphere. Thus, oxygen and sulfurisotopes data from inclusions in diamonds link them tosubducted oceanic crust. Whether oxygen and sulfur iso-

tope data can be used to constrainthe source of the carbon fromwhich the diamonds formed reliesheavily on the assumption thatthe carbon in diamond came fromthe same source as the hostingeclogite.

Nitrogen Content andIsotopic CompositionIn diamonds, nitrogen presentwithin the crystal structure substi-tutes for, and is strongly bondedto, carbon atoms. Nitrogen con-centrations in diamonds rangewidely, from traces up to 3500ppm, and average ~200 ppm and ~300 ppm in peridotitic andeclogitic diamonds, respectively(FIGS. 6A AND 6B, Deines et al.1993). In contrast to an early sug-gestion from Dyer et al. (1965)that 98% of all diamonds would benitrogen bearing (i.e., Type I), asurvey of recent publications

shows that, in the investigated size of crystals (~2 to ~4mm, i.e. <0.02 carat), a value of ~70% is more appropriate.Diamonds of different types show distinctly different Ncontents. Fibrous/coated diamonds have, on average, highN contents, while those from the lower mantle (not shownin Fig. 6) include a high proportion of diamonds with lowN contents (Type II; <20 ppm). Metamorphic diamonds(FIG. 6D) are unique in their range of very high N contents.The distributions of nitrogen contents shown in Figures 6aand 6c are representative of diamonds from most kimber-lite occurrences, with only subtle differences in the abun-dance of Type II diamonds and average N contents.

Within a single diamond growth zone, sharp variations oroscillations of more than several hundred ppm of nitrogenare readily identified between layers using Fourier-trans-form infrared or cathodoluminescence mapping(Mendelsohn and Milledge 1995; Harte et al. 1999). Suchabrupt changes or oscillations probably reflect changinggrowth conditions. Their preservation over billions of yearsof storage in the mantle demonstrates that nitrogen cannotdiffuse out of the crystal structure—the observed distanceof diffusion is about 30 µm. Recent experiments by Koga etal. (2003) further support this premise.

Nitrogen has two stable isotopes, 14N and 15N (~99.6% and~0.4%, respectively). Unlike C isotopes, upper mantle-derived samples and (meta)sediments show distinct iso-topic signatures for nitrogen. Nitrogen in sediments is pres-ent as ammonium ions. Because of similarities in chargeand ionic radius, nitrogen follows potassium and enterspotassic minerals such as illite, smectite, and phengite (thefirst two minerals being clays, the last a mica). Most sedi-ments show positive δ15N values, with an average of about+6‰ relative to air. With increasing metamorphism,devolatilization leads to a decrease in N content and rela-tive enrichment in 15N (Haendel et al. 1986). Accordingly,

The δ13C distribution produced by the precipitation ofdiamond from (A) CO2 and (B) methane (modified fromDeines 1980). In both cases, the initial δ13C value was –5‰.

FIGURE 4

Ranges of δ34S and δ18O values measured from sulfideand silicate inclusions in diamonds. The mantle ranges,

as defined by mid-ocean ridge basalts, are indicated for comparison.The range of δ18O values for eclogite and peridotite xenolith nodulesfrom kimberlites are also shown.

FIGURE 5


metasedimentary nitrogen is characterized by δ15N valuesthat are invariably positive (FIG. 7A), from the Archean torecent geological periods.

The isotopic composition of nitrogen in the upper mantlehas been estimated from the study of fibrous/coated dia-monds, mid-ocean ridge basalts, and diamonds associatedwith peridotite (FIGS. 7C TO 7E). The δ15N values for thesesamples are spread over a large range, from –25‰ to +15‰,with most values being negative (~65%) and centeredaround –5 ± 3‰. Because of the relative 15N enrichmentduring subduction, we would expect to find positive δ15Nvalues in eclogitic diamonds if they were formed solelyfrom crustal carbon and nitrogen. In support of this state-ment, metamorphic diamonds show δ15N values from –1.8to +12.4‰ (FIG. 7B). However, δ15N values for eclogitic dia-monds are mostly (~70%) negative (FIG. 7F). Furthermore,about half of the eclogitic diamonds with low δ13C valuesalso show negative δ15N values. While Figure 7 is a compi-lation of worldwide nitrogen isotope data, eclogitic andperidotitic diamonds from a single kimberlite often showstriking similarities in range and distribution of δ15N val-ues. Distinct carbon sources for eclogitic and peridotiticdiamonds are therefore not supported by nitrogen isotopesystematics. On the basis of the average negative δ15Nvalues (FIG. 7F), the carbon comprising most eclogitic and

peridotitic diamonds ismantle-derived ratherthan subduction-related.

In light of the δ13C andδ15N data, a variation toModel 1, above, wouldinvolve mixing of man-tle-derived carbon withs u b d u c t i o n - r e l a t e dorganic carbon (Navon1999). Subducted organ-ic carbon should pro-duce diamond with lowδ13C values, whereasmantle carbon shouldgrow diamond (separate,overgrowth, or via mix-ing) with higher δ13Cvalues, approaching–5‰. Given the highnitrogen contents ofmetamorphic diamonds,an enrichment in nitro-gen with decreasingδ13C might be expected.However, both eclogiticand peridotitic diamondsshow the opposite trendof decreasing N contentswith decreasing δ13Cvalues (not shown). Also,metamorphic diamondsare not as depleted in13C as some eclogiticdiamonds, and thismodel would predictsome overlap. Thus, Cand N isotopes data donot provide evidence ofa connection betweensubduction-related car-bon and E-type dia-monds.

METASOMATIC DIAMOND FORMATIONIN EARTH’S MANTLEThe evidence provided by S and O isotopes, on the onehand, and by C and N isotopes, on the other, can be rec-onciled if diamonds grew from external carbon and nitro-gen introduced into eclogites and peridotites through ametasomatic process—that is, one in which a new mineralgrows from or by reacting with a fluid permeating a miner-al aggregate.

Evidence supporting a metasomatic process includes (1) 3DX-ray tomographic imaging of eclogite nodules (Schulze etal. 1996), showing that diamonds are confined to metaso-matic veins; (2) trace-element analysis of inclusions in dia-monds (Stachel et al. 2004); (3) fluid(s) trapped during

Comparative histograms of nitrogen contents of dia-monds. Lower-mantle diamonds, usually with N contents

less than 50 ppm, are not shown here.

FIGURE 6

Comparative histograms of δ15N values for (A) metased-imentary nitrogen; (B) metamorphic diamonds from

Akluilâk (Canada); the three arrows represent the mean values for meta-morphic diamonds from three different areas in the Kokchetav massif(Kazakhstan) (see Ogasawara this issue); (C) fibrous/coated diamonds;(D) mid-ocean ridge basalts (E) peridotitic diamonds; and (F) eclogiticdiamonds.

FIGURE 7

fibrous/coated diamond growth (Navon 1999); and (4) thepresence of metasomatic inclusions within diamonds(Loest et al. 2003). These studies demonstrate that carbon-ate-bearing melt/fluid(s) are involved in diamond crystal-lization.

With metasomatic growth of diamond, both eclogitic andperidotitic types can be derived from the same carbonsource, which was initially homogenous isotopically (i.e.,no need to call for multiple, isotopically distinct sources)and mantle derived (with δ13C values of about –5‰). Inthe simplest scenario, isotopic fractionation associated withdiamond crystallization is not significant because it cannotbe the main process responsible for the distinct distribu-tions shown in Figures 2b and 2c. The distinct distributionsare produced before diamond formation, diamond being apassive recorder of the event(s). The carbon precursors arelikely to have been carbonates, and as decarbonation reac-tions are known to be restricted to eclogitic mineral assem-blages (Luth 1993), the escape of CO2 enriched in 13C

would leave a 13C-depleted residue from which eclogiticdiamonds can subsequently crystallize (Cartigny et al.1998). In conclusion, the varied isotopic compositions ofcarbon in mantle-derived diamonds may reflect, in part,distinct carbon sources, but mineral–fluid reactions con-trolled by the mineral assemblages of the rocks in whichthe diamonds formed are probably the most important fac-tor involved in producing the observed isotopic variations.

ACKNOWLEDGMENTSThe author would like to acknowledge the numerous uncit-ed contributions and data of Eric Galimov, NickolaiSobolev, Peter Deines, and their co-workers published dur-ing the last twenty-five years. Jeff Harris is greatly thankedfor his unlimited support to the author and for a thoroughreview, and therefore clarification, of the present article.Steve Shirey is thanked for his very constructive review,and Rondi Davies and George Harlow for their editorialhandling of the manuscript. IPGC contribution 2031. .

REFERENCESBottinga Y (1969) Carbon isotope

fractionation between graphite, diamondand carbon dioxide. Earth and PlanetaryScience Letters 5: 301-307

Boyd SR, Pineau F, Javoy M (1994)Modelling the growth of naturaldiamonds. Chemical Geology 116: 29-42

Cartigny P, Harris JW, Javoy M (1998)Eclogitic diamond formation at Jwaneng:no room for a recycled component.Science 280: 1421-1423

Chaussidon M, Albarède F, Sheppard, SMF(1987) Sulfur isotope heterogeneity inthe mantle from ion microprobemeasurements of sulphide inclusions indiamonds. Nature 330: 242-244

Deines P (1968) The carbon and oxygenisotopic composition of carbonates froma mica peridotite dike near Dixonville,Pennsylvania. Geochimica etCosmochimica Acta 32: 613-625

Deines P (1980) The carbon isotopiccompositions of diamonds: relationshipto diamond shape, color, occurrence andvapor composition. Geochimica etCosmochimica Acta 44: 943-961

Deines P, Harris JW, Gurney JJ (1993)Depth-related carbon isotope andnitrogen concentration variability inthe mantle below the Orapa kimberlite,Botswana, Africa. Geochimica etCosmochimica Acta 57: 2781-2796

Dyer HB, Raal FA, Du Preez L, Loubser JHN(1965) Optical absorption featuresassociated with paramagnetic nitrogenin diamond. Philosophical Magazine 11:763-774

Farquhar J, Wing BA, McKeegan KD, HarrisJW, Cartigny P, Thiemens MH (2002)Mass-independent sulfur of inclusions indiamond and sulfur recycling on earlyEarth. Science 298: 2369-2372

Galimov EM (1991) Isotope fractionationrelated to kimberlite magmatism anddiamond formation. Geochimica etCosmochimica Acta 55: 1697-1708

Haendel D, Mühle K, Nitzsche H-M, StiehlG, Wand U (1986) Isotopic variations ofthe fixed nitrogen in metamorphic rocks.Geochimica et Cosmochimica Acta 50:749-758

Harris JW (1992) Diamond geology. In:Field JE (ed) The properties of diamond.Academic Press, London, pp 345-393

Harte B, Fitzsimons ICW, Harris JW, OtterML (1999) Carbon isotope ratios andnitrogen abundances in relation tocathodoluminescence characteristics forsome diamonds from the KaapvaalProvince, South Africa. MineralogicalMagazine 63: 829-856

Javoy M, Pineau F, Delorme H (1986)Carbon and nitrogen isotopes in themantle. Chemical Geology 57: 41-62

Kaiser W, Bond L (1959) Nitrogen, a majorimpurity in common type I diamond.Physical Review 115: 857-863

Kirkley MB, Gurney JJ, Otter ML, Hill SJ,Daniels LR (1991) The application of Cisotope measurements to the identifica-tion of the sources of C in diamonds: areview. Applied Geochemistry 6: 477-494

Koga KT, Van Orman JA, Walter MJ (2003)Diffusive relaxation of carbon andnitrogen isotope heterogeneity indiamond: a new thermochronometer.Physics of the Earth and PlanetaryInteriors 139: 35-43

Loest I, Stachel T., Brey GP, Harris JW,Ryabchikov ID (2003) Diamondformation and source carbonation:mineral associations in diamonds fromNamibia. Contributions to Mineralogyand Petrology 145: 15-24

Lowry D, Mattey DP, Harris JW (1999)Oxygen isotope composition ofsyngenetic inclusions in diamond fromthe Finsch Mine, RSA. Geochimica etCosmochimica Acta 63: 1825-1836

Luth RW (1993) Diamonds, eclogites, andthe oxidation state of the Earth’s mantle,Science 261: 66-68

Mendelssohn MJ, Milledge HJ (1995)Geologically significant informationfrom routine analysis of the mid-infraredspectra of diamonds. InternationalGeology Review 37: 95-110

Navon O (1999) Diamond formation in theEarth’s mantle. In: Gurney JJ, Gurney, JL,Pascoe MD, Richardson SH (eds),Proceedings of the 7th InternationalKimberlite Conference, Red Roof Design,Cape Town, Vol 2, pp 584-604

Satish-Kumar M, Wada H, Santosh M(2002) Constraints on the application ofcarbon isotope thermometry in high- toultrahigh-temperature metamorphicterranes. Journal of MetamorphicGeology 20: 335-350

Schulze DJ, Wiese D, Steude J (1996)Abundance and distribution of diamondsin eclogite revealed by volume visualiza-tion of CT X-Ray scans. Journal ofGeology 104: 109-113

Shirey SB, Harris JW, Richardson SH, FouchMJ, James DE, Cartigny P, Deines P,Viljoen F (2002) Diamond genesis,seismic structure, and evolution of theKaapvaal-Zimbabwe craton. Science 297:1683-1686

Sobolev NV, Galimov EM, Ivanovskaya IN,Yefimova ES (1979) Isotope compositionof carbon in diamonds containingcrystalline inclusions. Doklady AkademyNauk SSSR 249: 1217-1220

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Stachel T, Aulbach S, Brey GP, Harris JW,Loest I, Tappert R, Viljoen KS (2004) Thetrace element composition of silicateinclusions in diamonds: a review. Lithos77: 1-19

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INTRODUCTIONMost people who like diamonds like them large.Nevertheless, a small cadre of geochemists and mineralo-gists has focused its efforts on diamondiferous grunge—theblack multigranular masses of uncertain pedigree that fallbelow even the basest standards of the GemologicalInstitute of America grading scales. Generically called bort,these diamonds have earned some measure of respect notas gems but as the best abrasives for jobs that require super-hardness and supertoughness (Feenstra 1985). Single-crys-tal diamonds cleave so easily that they wear rapidly duringdrilling applications, and inclusions can explode a single-diamond host when heated. In contrast, the high densitiesof grain boundaries in polycrystalline diamonds (PCD)impede fracture propagation, and the porosity in naturalPCD allows for thermal expansion of included mineralgrains without catastrophic failure of the entire compact.

The taxonomy for polycrystalline diamond tends to bebased on qualitative external characteristics, as the namesare of a cultural rather than scientific origin. Consequently,even the modern literature is inconsistent in its applicationof the terminology. In this review, “carbonado” refersspecifically to multigranular diamond aggregates from theCentral African Republic and Brazil with distinctive proper-ties (summarized in TABLE 1 and FIG. 1). “Framesite” is usedmore broadly to describe clusters of randomly oriented

microcrystalline diamonds foundin association with kimberlites allover the world. The unusual phys-ical features observed in carbona-dos and framesites have provokeda wide array of hypotheses regard-ing their origin. This article willfocus on the chemical and struc-tural properties that unite anddivide these two puzzling diamondvarieties.

CARBONADO

MineralogicalCharacteristicsCarbonado nodules typically arepea-sized or greater. Indeed, thelargest known diamond of any

type is the Carbonado of Sergio (Brazil), weighing in at3,167 carats. Named for the Portuguese word for “burned,”carbonados are black polycrystalline masses. As with frame-site, carbonado nodules often exhibit a “microporphyritic”texture in which euhedral crystals measuring hundreds ofmicrons across are cemented by a matrix of micron-sizedgrains (Fettge and Sturges 1932). In contrast to framesites,however, X-ray microtomography reveals pervasive macro-porosity with tunnel sizes in excess of 1 mm (Vicenzi et al.2003).

Haggerty (1999) has described carbonados as “the mostenigmatic of all diamonds,” and the number of scenariosproposed for their formation would seem to support thisclaim. Unlike framesites, carbonados have never beenfound in direct association with kimberlite pipes, raisingthe possibility that the Earth’s mantle was not their ulti-mate source. Although carbonados have been reportedfrom Venezuela (Kerr et al. 1948) and various Russian local-ities (e.g., Gorshkov et al. 1996), carbonados sensu strictoare found in Mid-Proterozoic (1–1.5 Ga) metaconglomer-ates overlying the São Francisco and Congo-Kasai cratonsin Brazil and the Central African Republic, respectively. TheSão Francisco craton contains the oldest rocks in SouthAmerica, at least ~3.2 Ga (Martin et al. 1997; Magee 2001),and the great age of carbonado is part of its fascination.Both bulk and in situ analyses of radiogenic lead isotopecompositions of carbonado diamond and its inclusionsindicate that crystallization occurred between 2.6 and 3.8Ga ago (Ozima and Tatsumoto 1997; Sano et al. 2002).

Carbonados are distinguished from other polycrystallinediamonds by the inclusions that line pore spaces (Trueband Butterman 1969; Trueb and deWys 1969, 1971;Dismukes et al. 1988). The hydrated rare-earth phosphateflorencite is the most abundant of these, but over 30 other

Polycrystalline aggregates of diamond called carbonado and framesitehave excited the attention of scientists because their crystallizationhistories are thought to depart markedly from established modes of

diamond genesis. In contrast to kimberlitic diamonds, the geochemicalsignatures of carbonados are systematically crustal. Since the apparent ageof carbonados is Archean (~3.2 Ga), a number of exotic formation theorieshave been invoked, including metamorphism of the earliest subductedlithosphere, radioactive transformation of mantle hydrocarbon, and mete-orite impact on concentrated biomass. Unlike carbonados, framesites areknown to originate in the mantle. They appear to have crystallized veryrapidly, shortly before the eruption of the kimberlites that brought themto Earth’s surface, suggesting that old cratonic materials can be remobilizedafter long-term storage in the lithosphere.

KEYWORDS: carbonado, framesite, polycrystalline diamond

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Strange Diamonds:The Mysterious Originsof Carbonado and Framesite

1 Department of GeosciencesPenn State UniversityUniversity Park, PA 16802, USAE-mail: [email protected]

2 Department of Mineral SciencesSmithsonian InstitutionWashington, D.C. 20013-7012, USA

3 6338 Nepo DriveSan Jose, CA 95119, USA

Peter J. Heaney1, Edward P. Vicenzi2,and Subarnarekha De3


minerals have been identified, including orthoclase, quartz,and kaolinite. These phases are distinctly crustal, and, con-versely, the mantle-derived inclusions commonly found inkimberlitic diamond (e.g., pyrope-rich garnet, chromianclinopyroxene, pyrrhotite) have never been reported fromcarbonado. The TEM results of Gorshkov et al. (1996) andDe et al. (1998) also have revealed inclusions of native met-als and metal alloys, such as Fe, Fe-Ni, Ni-Pt, Si, Ti, Sn, Ag,Cu, and SiC. These metal phases are nanometers to hun-dreds of microns in size, and they can be either envelopedwithin the diamond itself or present as a coating of thepores. Gorshkov et al. (1999) describe similar metal assem-blages in kimberlitic polycrystalline diamonds from theUdachnaya pipe in Yakutia.

Geochemical Indicators for FormationThe similarities in the inclusion assemblages of carbonadosfrom the Central African Republic and Brazil provide strongevidence that these now geographically distant carbonadosare genetically related. Equally compelling support for acommon origin comes from the tight clustering of carbonisotope compositions of nodules from the two localities,with δ13C values ranging from –21 to –32‰ (Vinogradov etal. 1966; Galimov et al. 1985; Ozima et al. 1991; Kamiokaet al. 1996; Shelkov et al. 1997) (Fig. 1). In situ isotopeanalyses (De et al. 2001) have shown that within individualsamples, δ13C values are very uniform, with a slightbimodality between the larger euhedral crystals (–26‰)and the finer-grained matrix (–24‰). Further confirmationfor a connection between Central African and Brazilian car-bonados is provided by noble gas analyses (Ozima et al.1991; Burgess et al. 1998), which show that carbonadosfrom both provenances contain high concentrations ofimplanted, radiogenic noble gases arising from 238U fission.They also exhibit high contents of tightly trapped atmos-pheric gases.

Evidence that would serve as a “smoking gun” for the ori-gin of carbonado is frustratingly elusive, and the ambiguitysurrounding the role of mantle versus crustal processes inthe forging of carbonados is even more pronounced than in

the case of framesites, as described below. It is possible thatcarbonados are merely composite diamond clusters thatformed in the same way as kimberlitic diamond nodulesbut with enrichment in light isotopes of C and He. If so,carbonados may represent the end member of a chemicalcontinuum in which framesites serve as a bridge to eclogiticdiamonds. In this scenario, the strong crustal signature incarbonados is related to the subduction of cold slabsbeneath continental margins, such that organic matter isimported to the mantle with virtually no mixing of carbonreservoirs (Robinson 1978). This idea could perhaps explainlight rare-earth element (LREE) patterns suggestive of acrustal origin (Shibata et al. 1993; Kamioka et al. 1996), thehigh concentrations of polycyclic aromatic hydrocarbonsin carbonado pores (Kaminsky et al. 1991), and the pres-ence of aggregated N defects (Nadolinny et al. 2003).

If carbonados represent mineralized organic carbon, theirmeasured age of ~3.2 Ga, when added to the time requiredfor plate subduction, suggests that these diamonds arevestiges of some of the oldest biological material known.Nevertheless, it should be noted that mantle xenoliths areoften depleted in 13C, and efforts to model the range ofδ13C values in these samples by simple mixing models ofcarbon from organic and mantle reservoirs have not suc-ceeded (Deines 2002). Deines’ study suggests that poorlyunderstood kinetic fractionation effects may play a role inthe generation of isotopically light diamonds.

The implications of the radiogenic gases in carbonados areespecially controversial. Some authors have proposed thatexposure of carbonados to radionuclides occurred post-eruption, so that the elevated levels of radiogenic gases aresecondary (Kagi et al. 1994; Shelkov et al. 1998; Burgess etal. 1998). On the other hand, the recent observation ofcrustal nucleogenic Ne in framesites indicates that someparts of the mantle may contain significant quantities ofcrustal noble gases (Honda et al. 2004). It is possible that,in this fashion too, carbonados preserve evidence for earlyatmospheric chemistry and plate tectonic activity. Stillanother hypothesis is that the radiogenic gases reflect for-mation of carbonados by the transformation of a carbon-

86

Carbonado Framesite Single-CrystalEclogitic Diamond

Color and Surface Properties Black, dark gray, or brown Light gray or brown Clear to yellow single with smooth exterior with irregular surface crystals are most common

Grain Sizes Euhedral grains Shares bimodal texture Variable, but mm-sized(Typically up to 200 µm) with carbonado but and larger crystals areset in microcrystalline euhedral grains are larger commonmatrix (<0.5–20 µm)

Porosity High (10% void space) Low (1% void space) Zero

Common Inclusions Florencite-goyazite- Pyrope and almandine- Pyrrhotite, omphacite,gorceixite, xenotime, pyrope garnet, almandine-pyrope garnetkaolinite, quartz, Cr-rich clinopyroxene,orthoclase, zircon, chromiteFe, Fe-Ni, SiC, Si, Sn

δ13C Composition –23 to –30‰ with –1 to –24‰ with +3 to –34‰ with modes a mode at –27‰ a mode at –19‰ at –5‰ and –12‰

δ15N Composition –17 to +8‰ –3 to +15‰ –12 to +5‰

COMPARISON OF CARBONADO, FRAMESITE, AND ECLOGITIC SINGLE-CRYSTAL DIAMOND.

TABLE 1


rich matrix to diamond through 238U irradiation(Kaminsky 1987; Ozima et al. 1991; Ozima and Tatsumoto1997). However, since natural examples of radiogenic dia-monds (Daulton and Ozima 1996) do not exceed 500 nmin diameter, it seems that radiosynthesis might have pro-vided, at most, the seeds for carbonado diamond growth.

Evidence for an Impact OriginThe nearly complete absence of a mantle fingerprint in car-bonados has caused some researchers to seek a purely surfi-cial crystallization process—a tricky proposition in light ofthe high pressures needed to stabilize the diamond struc-ture. Smith and Dawson (1985) attacked this issue byinvoking a meteorite impact within what was once a unit-ed landmass. The light δ13C values for carbonado can thenbe attributed to shock metamorphism of organic matter,

and the tightly trapped atmospheric gases, crustal inclu-sions, high polycyclic aromatic hydrocarbon levels, andmagnetic inclusions all are logical results (Girdler et al.1992; Kletetschka et al. 2000). Moreover, pervasive defectlamellae indicative of plastic deformation have beenobserved in TEM studies of both Central African andBrazilian carbonados (De et al. 1998).

Despite their undeniable appeal, however, impact scenariosfor carbonado formation are troublesome. Deformationlamellae have been documented in framesites (DeVries1973) and reproduced experimentally at mantle tempera-tures and pressures (De et al. 2004); thus, they may not beanalogs of planar deformation features in shocked quartz.Unlike the impact-generated variety of PCD known asyakutite (Kaminsky 1991; Titkov et al. 2004), carbonadoshave never been shown to contain the hexagonal C poly-morph known as lonsdaleite or any other high-pressurephase. Shock wave calculations (DeCarli 1998) indicate thatthe maximum size for a diamond formed by impact is~1 cm, and impact-generated diamonds typically are sub-millimeter in dimension (e.g., Hough et al. 1995; Pratesi etal. 2003; Ding and Veblen 2004). As their large size is oneof the hallmarks of carbonados, the impact scenario is dif-ficult to reconcile with the physical attributes of this PCDvariety.

FRAMESITE

Mineralogical CharacteristicsIn contrast to carbonados, there is no doubt that framesitesare derived from kimberlite pipes that sample Earth’s deepinterior. Named for P. Ross Frames, chairman of the DeBeers and Premier companies in the 1920s, framesite is pro-duced from the Premier and Venetia mines in South Africaand the Orapa and Jwaneng mines in Botswana, where itcan represent several weight percent of the total diamondoutput. Framesites from Russian localities (e.g., the Mirpipe) are known as well (Sobolev et al. 1975). A rigorousstudy of the range of diamond crystal sizes in framesite islacking, but nodules comprising black or brown, euhedral,mm-scale diamonds cemented by randomly oriented,micron-sized crystals are not uncommon.

Framesites from different pipes exhibit subtle variations indiamond textures and included assemblages in the poly-crystalline mass, but several studies have revealed evidencefor a mixed eclogitic and peridotitic paragenesis. Two vari-eties of pyrope-rich garnet inclusions typically occur.Orange garnets with low Cr and moderate Ca contentshave chemistries characteristic of eclogites, and pink gar-nets with higher Cr and lower Ca contents are representa-tive of harzburgite (Gurney and Boyd 1982; McCandless etal. 1989; Kirkley et al. 1991). Olivine and eclogitic clinopy-roxene or omphacite are curiously absent, but garnet,orthopyroxene, and peridotitic clinopyroxene commonlyintergrow with the diamond and sometimes envelop dia-mond crystals, suggesting that diamond and silicate crys-tallization were contemporaneous (Kurat and Dobosi2000). Chromite also can be a major accessory phase inframesites, and Cr concentrations in clinopyroxenes associ-ated with framesites from Orapa, Jwaneng, and Mir areextraordinarily high (Sobolev et al. 1975; Gurney and Boyd1982; Kirkley et al. 1991). Where present, magnetiteimparts a strong natural remanent magnetization(Collinson 1998), giving rise to a subvariety of framesitecalled stewartite.

Carbon isotope studies of framesites from the Venetia,Orapa, and Jwaneng pipes (Kirkley et al. 1991; Shelkov et al.1997; Burgess et al. 1998; Jacob et al. 2000) reveal a broaddistribution of δ13C values ranging from –2‰ to –25‰,

-35 -30 -25 -20 -15 -10 -5 0 50

20

40

60

80

100

2

4

6

8

-35 -30 -25 -20 -15 -10 -5 0 5

2

4

6

8

10

12

δ 13C (‰)

ycneuqerF

ycneuq erF

ycn euq erF

A

B

C

carbonado

framesite

single crystal

Figure 1Compilation of published δ13C values for (A) carbonado(avocado – Brazil; burgundy – Central African Republic);

(B) framesite; and (C) monocrystalline diamonds (blue – harzburgitic;red – eclogitic). Insets: (A) carbonado specimen from Mambere River,Haute-Sangha Province, Central African Republic (15.9 mm across); (B)framesite specimen from Jwaneng, Botswana (9.0 mm across); (C)Oppenheimer diamond, Dutoitspan Mine, South Africa (38 mm across).

FIGURE 1


with a major mode at –19‰ (Fig. 1). Moreover, noble gasanalyses of framesite have yielded low 3He/4He ratios, indi-cating little contribution from primordial mantle-derived3He, and they also show high concentrations of crustalnucleogenic Ne (Burgess et al. 1998; Honda et al. 2004).

Theories of FormationSo how did framesites form? Virtually all authors attributethe fine grain size of framesites to rapid crystallization inlocalized areas of the mantle containing high concentra-tions of C and incompatible and volatile elements. Manyscientists invoke subduction of ocean floor and subsequentmixing with upper mantle lithosphere as a mechanism forframesite crystallization (Kirkley et al. 1991; Burgess et al.1998; Honda et al. 2004). This process explains the mixedeclogitic and peridotitic chemical signatures imprinted onmany framesite samples, the unusual noble gas composi-tions measured for framesite diamonds, and possibly thebroad range of 13C/12C ratios. Kirkley et al. (1991) proposethat metamorphism of C from two crustal environments—one that was carbonate-rich and another that containedorganics—could have generated populations of diamondswith distinct C isotope compositions.

Other researchers are less convinced of a crustal role. Kuratand Dobosi (2000) discount the importance of an eclogiticprecursor and argue that framesite assemblages crystallizedfrom upper mantle fluids containing a carbonatitic compo-nent, as suggested by trace-element profiles of garnets andof fluid inclusions in silicates. Jacob et al. (2000) alsoinvoke a carbonatitic melt to explain trace-element, radi-ogenic, and stable isotope variations, but they argue thateclogitic material reacted with the melt. Moreover, theseauthors propose that framesites in the Venetia pipe crystal-

lized very shortly before the kimberlite erupted. If true,framesites provide surprising evidence that remobilizationof material stored for long periods in the cratonic litho-sphere can lead to the formation of relatively young dia-monds, that is, close to the emplacement age of 533 Ma inthe case of Venetia.

SUMMARYPolycrystalline diamond varieties once were regarded aseccentric expressions of the processes that generate kim-berlitic diamonds, but state-of-the-art characterizationstudies have rendered the origins of carbonados and frame-sites more ambiguous. To the extent that these differentvarieties of PCD formed by unrelated mechanisms, theirproper classification becomes an interpretive rather thanmerely a taxonomical exercise. As this review illustrates,widely accepted genetic models for these diamond aggre-gates remain an unfulfilled challenge, particularly withregard to the roles played by mantle and crustal compo-nents. Nevertheless, enough about these diamond varietieshas been discovered to be sure that they will offer somestartling insights about our planet and its history.

ACKNOWLEDGMENTSThe authors would like to dedicate this article to the lateRob Hargraves, who introduced them to the “carbonadoconundrum.” Thanks also to George Harlow, Rondi Davies,and Pat Taylor for their comments on this manuscript, andto Jeff Harris for providing framesite specimens. TheOppenheimer Diamond photograph was taken by ChipClarke. Funding for the authors’ research was provided byNSF Grant EAR-0073862. .

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People in the News

The eighty-fifth annual awards luncheon ofthe Mineralogical Society of America was heldon November 9, 2004, during the 2004Geological Society of America meeting inDenver, Colorado.

KEVIN ROSSO received the MineralogicalSociety of America Award for outstandingresearch early in his research career. Hisresearch interests are the relationshipsbetween the atomic and electronic structureof mineral surfaces and their reactivity andphysical properties. Citationist Michael F.Hochella Jr. (left) and MSA President MichaelCarpenter (right).

The Distinguished Public Service Award waspresented to ROBERT F. MARTIN, editor ofThe Canadian Mineralogist for 26 years. RobertMartin has done research in many areas, butwas recognized this day for his work withThe Canadian Mineralogist, one of the premierjournals in the field. Citationist John M.Hughes (left), and MSA President MichaelCarpenter (right).

FRANCIS R. “JOE” BOYD was awarded(posthumously) the Roebling Medal, theSociety’s highest honor, in recognition oflifetime scientific achievement. With JosephEngland, he designed and developed a high-pressure, high-temperature apparatus, whichhas been central to the work of a generationof experimental petrologists. Boyd’s initialfocus was on high-pressure phase equilibria,and this work provided the basis for contin-ued studies on the composition, structure,and history of the lithosphere and uppermantle. Elected to the National Academy ofScience in 1974, Boyd also served as presidentof the Geochemical Society, the GeologicalSociety of Washington, and the VGP sectionof the American Geophysical Union.Citationist Stephen Haggerty (left), MargueriteJ. Kingston, widow of Francis R. (Joe) Boyd,and MSA President: Michael Carpenter.

Leading Scientists Recognized at the 2004 MSA Awards Luncheon

Prof. YONG-FEI ZHENG, Universityof Science and Technology of China, Hefei,China won a National Natural ScienceAward of China for 2004. These awardsrecognize a series of prominent achievementsin a certain field of natural science and arethe highest awards for achievement inscientific research. Prof. Zheng’s award is forhis work on theoretical calculations andexperimental measurements of oxygenisotope fractionation factors for minerals.

Julie Roberge is finishingher PhD at the Universityof Oregon, under thesupervision of Paul Wallaceand in close collaborationwith Kathy Cashman. Sheis studying volatiles inmagma and, in particular,analyzing basaltic glassfrom the Ontong Javaplateau in order to establishthe subsidence rate of theplateau. She is also study-ing volatiles in melt inclu-sions and the permeability of pumice(from which the crystals containing the meltinclusions come) from the Bishop tuffto characterize the fragmentation/degassingbehavior of volcanoes. At Christmas time,while she was visiting her family in Québec,her boyfriend had contacted the local media

to tell themabout herfascinatingwork. As aresult, threeregionalnewspaperspublishedarticles onthis local girlstudying far-away volcanoesand she madethe first page in

one of them. The headline read “Volcanoestattooed on her heart”, and the article wenton to talk about her unconditional love forvolcanoes. She was also interviewed onseveral radio stations when Mount St. Helensstarted erupting again (she just happened tobe doing field work nearby). Julie has beenunder the spell of volcanoes since she was8 years old, but it was not until she got touniversity that she discovered that you couldstudy them and actually make a living at it.She wants every child to know that fact, sowhenever she gets a chance she does presen-tations in classrooms as well. She has set upher own web page and she gets e-mails fromyoung people all over the world wanting toknow more about volcanoes and how tobecome a volcanologist.

Julie Roberge ascending the Villarica volcano in Chili.

Julie Roberge on the Outreach Path


Microdiamonds inUltrahigh-PressureMetamorphic RocksYoshihide Ogasawara 1

INTRODUCTIONAfter the discovery of coesite in metamorphic rocks fromthe Dora Maira Massif, western Alps (Chopin 1984), andthe Western Gneiss Region, Norway (Smith 1984), manyresearchers were stimulated to look for coesite and otherminerals indicative of extremely high-pressure formationin metamorphic rocks. What is so interesting here? Coesite,a dense form of SiO2, forms at ~3 GPa (900°C), equivalentto a depth of 90 km under a continent, while diamondrequires ~4 GPa (1000°C), or roughly 140 km depth. Theseminerals would be expected in the deep Earth where suffi-cient silica or carbon is present, so there is nothing revolu-tionary in their discovery. However, up to that time it wasnot thought that tectonic processes could send slabs ofcrust down to extreme depths and, more amazingly, bringthem up again quickly enough to preserve these high-pres-sure minerals. As discussed by Stachel et al. in this issue,most diamond found on Earth is carried to the surface bydeep-rooted volcanism. The collision of fragments ofEarth’s crust in the dance of plate tectonics was known toreturn rocks such as eclogites to the surface with mineralsindicating pressures of >2 GPa, but these minerals are typi-cally overprinted by reactions that returned most mineralsto lower-pressure assemblages. Preservation of high-pres-sure coesite and even higher pressure diamond challengedexisting models of Earth processes and required a wholenew paradigm as more discoveries of ultrahigh-pressuremetamorphism (UHPM) were reported. The subject hastaken off in the last 20 years, and many reviews are avail-able (e.g.¸ Rumble et al. 2003; Roselle and Engi 2002). In thepresent article, some of the discoveries and implications

will be reviewed, with attention torecent results from at least oneoccurrence pointing to multiplegenerations of diamond formation.

OCCURRENCES OF UHPMETAMORPHICDIAMOND Although microdiamond was ini-tially reported many years ago byRozen et al. (1972) from theKokchetav Massif, northernKazakhstan, its metamorphic ori-gin was accepted much later fol-lowing a report by Sobolev andShatsky (1990). Since then, addi-tional occurrences have been dis-covered in the Dabie Mountains(Xu et al. 1992) and north Qaidam

(Yang et al. 2003), China; the Western Gneiss Region,Norway (Dobrzhinetskaya et al. 1995; Van Roermund et al.2002); Erzgebirge, Germany (Massonne 1999; Stöckhert etal. 2001); Sulawesi, Indonesia (Parkinson and Katayama1999); and perhaps the Rhodope Massif, Greece (Mposkosand Kostopoulos 2001). The Dabie and north Qaidam rockshave been dated at 230–209 Ma (Ames et al. 1996) and510–485 (Yang et al. 2001), respectively. Peak P–T condi-tions of the Dabie metamorphism are considered to bearound 5–6 GPa and ca. 850°C (Zhang and Liou 1998).More than 10 diamond grains have been reported as inclu-sions in zircon from north Qaidam (Yang et al. 2003).

Several grains of diamond were first described from residuesseparated from Western Gneiss Region gneisses byDobrzhinetskaya et al. (1995) and confirmed in situ by VanRoermund et al. (2002). Peak P–T conditions for theNorwegian rocks were P >2.8 GPa and T >790°C (Carswellet al. 1999), and peak metamorphism occurred at 425–406Ma (Griffin and Brueckner 1985). Metamorphic diamondsare far more abundant in the Erzgebirge than in otherdiamondiferous terranes, except for Kokchetav. Dia-mondiferous gneisses are restricted to a 1 km-long strip,and the diamonds are abundant as inclusions in garnet,kyanite, and zircon (Massonne 2001). Peak P–T conditionswere >4.2 GPa and 900–1000°C (Massonne 2001) andoccurred at 360–333 Ma (Schmadicke et al. 1995). A numberof in situ diamond grains were identified by laser Ramanspectroscopy within quartz pseudomorphs after coesite ingarnet in jadeite quartzite of the Bantimala complex ofSulawesi, Indonesia. These rocks have yielded radiometricages of 130–120 Ma and recrystallized at P >2.7 GPa ataround 750°C (Parkinson et al. 1998).1 Department of Earth Sciences, Waseda University,

1-6-1 Nishiwaseda, Shinjuku-ku, Tokyo 169-8050, JapanE-mail: [email protected]

Since the first report of microdiamonds of metamorphic origin in crustalrocks of the Kokchetav Massif, northern Kazakhstan, diamonds havebeen described from several other ultrahigh-pressure (UHP) metamor-

phic terranes. In situ diamond is the best indicator of ultrahigh-pressureconditions (>4 GPa), and testifies to subduction of continental crust todepths within the diamond stability field followed by relatively rapid exhu-mation. In contrast to other UHP terranes, the Kokchetav Massif containsrocks with unusually abundant diamonds, particularly in the Kumdy-Kol region.Kumdy-Kol diamonds exhibit diverse morphologies, dependent upon the hostrock. Raman and cathodoluminescence spectra and carbon isotope composi-tions differ between core and rim, indicating two distinct growth stages.

KEYWORDS: microdiamond, ultrahigh-pressure metamorphism,

continental collision, Kokchetav


UHP rocks in these regions display some diversity in termsof tectonic setting. However, the commonalities are per-haps more significant—they are all restricted to collisionalorogens and are predominantly of continental parentage.In general the distribution of diamond-grade rocks isrestricted to considerably smaller areas than that of coesite-grade metamorphism, which is regional in extent in manyUHPM terranes. Presumably, diamonds produced by sub-duction of carbon-bearing crust are not an unusual productof Earth processes, but their return to the planet’s surfacewithout an explosive kimberlite elevator requires specialconditions. High-pressure metamorphic rocks are a charac-teristic feature of the “scars” of plate collisions, but UHProcks appear to be limited to collisions of continental frag-ments, either full continent–continent collisions or onesinvolving microcontinental fragments.

Presumably, the considerable momentum of colliding con-tinents and the pull of an attached oceanic lithosphere‘anchor’ buries a continental edge to diamond-producingpressures. Then exhumation lifts the buried rocks some 140km, sufficiently fast that the UHP signature is not erased bythermal relaxation associated with slow ascent.Exhumation by regional uplift and erosion alone is notrapid enough, so several models of tectonic emplacementhave been suggested: wedge extrusion, channel flow, anddiapiric transport. Break-off of the subducting slab duringcollision is argued to cause extrusion of a buoyant narrowwedge of buried UHP material by normal and thrust fault-ing (e.g., Ernst and Liou 1995; Hacker et al. 2000).

Although still somewhat controversial, wedge extrusionappears to have gained widespread acceptance as a generalexhumation model. It can explain the regional nature ofUHP metamorphism (at least for coesite-grade metamor-phism), whereas channel flow and diapiric transport pro-vide models for exhumation of discrete, essentially “exotic”blocks. In channel flow, the subducted rocks are consideredto have sufficiently low viscosity that they can be squeezedback up the subduction channel in a reverse flow (e.g.,Lardeaux et al. 2001). Diapiric emplacement relies on buoy-ancy forces of either low-density continental material orencapsulating hydrated peridotite (serpentinite) (e.g.,Burov et al. 2001) to lift the UHP blocks. Each model has itsown set of criteria to test its validity, and the jockeying ofthe models continues.

Among the recognized microdiamond occurrences, theKokchetav Massif is perhaps best suited to provide suffi-cient data to determine the local processes and environ-ment of formation of metamorphic diamonds because oftheir extremely high concentration and unequivocal in situoccurrence in UHPM rocks. For these reasons, I focus on thediamonds of Kumdy-Kol. Studies of diamonds in thedolomite marble (dominant carbonate is dolomite) thereprovide a keystone for understanding their “metamorphic”origin and help to resolve the debate as to whether UHPMdiamond is produced by a solid-state transformation or bycrystallization from a fluid or a melt.

Photomicrographs (PPL) of (A) diamond-bearing garnet–biotite gneiss and (B) diamond-bearing dolomite marble

at Kumdy-Kol. Qtz: quartz; Grt: garnet; Bt: biotite; Dia: diamond; Zrn:zircon; Di: diopside; Phl: phlogopite; Dol: dolomite.

FIGURE 1 Photomicrographs (PPL) of a representative microdia-mond in a garnet–biotite gneiss at different focus positions

A, B; stepped octahedral faces are visible in (A).

FIGURE 2

A A

BB


MICRODIAMOND IN THE KOKCHETAVUHPM TERRANEDiamond in the Kokchetav Massif is best known from theKumdy-Kol area where it was once mined. It occurs in car-bonate rock, pyroxene–garnet rock, tourmaline-rich rock,and most abundantly in garnet–biotite gneiss (FIG. 1A) anddolomite marble (FIG. 1B) (see Parkinson et al. 2002 for areview). Diamonds are included in garnet and less fre-quently in phlogopite (pseudomorphic after garnet), zircon,tourmaline, and diopside in the silicate and carbonaterocks. All these diamonds are very fine grained, <25 µm.Diamond with an octahedral form in garnet in garnet–biotite gneiss is shown in FIG. 2.

Diamond occurs in greatest abundance in dolomite marble.Small amounts have been found in layers of calcite marble,but, for an as yet unknown reason, Ti-clinohumite-bearingdolomitic marbles (dominant carbonates are Mg-calciteand dolomite) contain no diamonds. Diamond abundancein the dolomite marble has been estimated by Yoshioka etal. (2001) as up to 2700 carat ton -1, and Ishida et al. (2003)counted 4458 grains of diamond in four thin sections (avolume of ~20 x 160 mm by 30 µm in thickness) with grainsizes ranging from 5 to 25 µm. Some garnet grains containunusually high concentrations of diamond, as shown inFIG. 3, but the distribution of diamonds in garnet is hetero-geneous. Polycrystalline aggregates (5 to 30 µm) ofgraphite, probably after diamond, are included in garnet,diopside, phlogopite, and dolomite. Indeed, many microdia-monds are partially surrounded by graphite.

Ishida et al. (2003) classified microdiamonds, according totheir morphology and other characteristics, into threetypes: (1) S-type—“star-shaped” diamond consisting of atranslucent core and transparent, subhedral to euhedral,very fine-grained, polycrystalline rims (FIG. 4); (2) R-type—translucent crystals with “rugged” surfaces; (3) T-type—transparent, very fine-grained crystals. S-type diamondspredominate (85%), the R-type is minor (~10%), and the T-type is rare (<5%). In a given rock, the spatial distributionof these types with respect to one another appears to berandom. The authors proposed a two-stage growth mecha-nism for diamonds in the dolomite marble based on mor-phology and other characteristic features. Micro-Laue dif-fraction using a finely collimated synchrotron X-ray beam(1.6 to 50 µm in diameter) demonstrated that the rims of S-type diamonds have crystallographic orientations that aredifferent from those of the cores, which are single crystals,and that R-type diamonds are single crystals.

Yoshioka and Ogasawara (in press) reported strong broadbands in the cathodoluminescence (CL) spectra at 514 to537 nm from the rims of all S-type diamonds. This band isa green color that is not common among mantle-deriveddiamonds (FIG. 5). The cores also have the same broadband, but its intensity is very weak. Moreover, the main CLband of S-type diamonds is very similar to the 520 nm CLband of carbonado (Magee and Taylor 1999 and see Heaneyet al. in this issue). These data may indicate different geo-chemical environments for the growth of cores and rims ofS-type diamonds and support evidence for two-stage growth.

Imamura et al. (2004) conducted SIMS (ion-probe) carbonisotope analyses of S- and R-type diamonds in a Kokchetavdolomite marble. Rims of S-type diamonds have light iso-topic compositions with δ13C values ranging from –17.2 to–26.9‰, whereas cores have isotopically heavier carbon,with δ13C values ranging from –9.3 to –13.0‰. The δ13Cvalues for two R-type grains fall between –8.3 and –15.3‰and are similar to those for cores of S-type diamond. Thus,R-type grains may form at the same stage of growth andfrom the same carbon source as the cores of S-types. Thesedata also suggest two stages of growth for S-type diamonds.The extremely light carbon isotopic compositions of rimsof S-type diamond may be explained by a light organicsource or fractionation (see Cartigny article in this issue).

CONDITIONS OF DIAMOND GROWTHIN KUMDY-KOL CARBONATE ROCKSThe two-stage growth model of Ishida et al. (2003) isstrongly supported by the morphology of S-type diamonds,the micro-Laue diffraction data, CL interpretations, andcarbon isotope compositions. The first stage corresponds tothe growth of R-type diamond and the cores of S-types. Thesecond stage represents the growth of rims on S-type and ofT-type diamonds. The origin of the microdiamond cores isstill unclear, but one possibility is prograde (i.e., increasingT and P) transformation of graphite. Katayama et al. (2000)interpreted composite graphite–diamond inclusions in zir-con in this way. Whatever the origin, mineral textures indi-cate that first-stage diamond growth was coeval with garnetand diopside crystallization. Because both S-type and T-type diamonds often occur in the same garnet grain, thesecond stage of growth is either not homogeneous, even ona µm scale, or some factor, like fast growth rate, controls thesecond stage, which is microcrystalline. Moreover, second-stage growth for the rims of S-types and T-types involves asource of carbon different from that of the cores, such asa fluid or melt rather than graphite.

Photomicrographs (PPL) of the highest concentrationdomain of microdiamond in Kumdy-Kol dolomite marble.

FIGURE 3

B

A


Recent UHPM research has focused on determining whethermicrodiamonds formed from a fluid or a melt. Diamondhas been synthesized stably from a CO2–H2O fluid (Kumaret al. 2000) and from dolomite + carbon and dolomite +fluid + carbon systems (Sokol et al. 2001). Diamond hasalso been synthesized in the dolomite–Si (or SiC) systemfrom a carbonatitic melt (Kozai et al. 2000). One of the pos-sible media for second-stage growth of microdiamonds isan aqueous fluid. An important question is why dolomitemarble contains diamond while some other types of marbledo not. Ogasawara et al. (2000) argued that the CO2 con-centration (XCO2) in the metamorphic fluid could explainthis distribution. Ogasawara and Aoki (in press) suggestthat in diamond-bearing dolomite marble, 0.01 < XCO2< 0.1, whereas in diamond-free dolomitic marble, XCO2< 0.01.

Numerous observations point to crystallization of microdia-mond from a fluid, but a melt origin has been suggested aswell. Dobrzhinetskaya et al. (2001) concluded that com-posite, nanometer-sized mineral inclusions (Cr2O3, TiO2,MgCO3) and presence of cavities in diamond from aKokchetav felsic gneiss suggested that diamond had crys-tallized from a fluid; also, H2O-bearing fluid inclusions indiamond from a garnet–pyroxene rock were confirmed byFourier-transform infrared spectroscopy (De Corte at al.1998). The study of fluid inclusions in diamond fromdolomite marble indicates that microdiamonds crystallizedin the presence of fluid and possibly from it(Dobrzhinetskaya et al. 2004). Diamond-bearing metal-sul-fide inclusions in garnet in a garnet–clinopyroxene–quartzrock have been interpreted as evidence of diamond growthfrom a fluid (Hwang et al. 2003). Similar composite inclu-

sions (phlogopite, quartz, paragonite, phengite, apatite,and rutile) were also reported in UHP gneiss fromErzgebirge, Germany, and suggest a dense C–O–H fluid richin K, Na, and SiO2 under UHP conditions (Stöckhert et al.2001). Conversely, Massonne (2003) proposed that dia-mond in silicate rocks of the Kokchetav and Erzgebirgecrystallized from a silicate melt, and Herman and Korsakov(2003) and Korsakov and Herman (2004) proposed that dia-mond in Kokchetav dolomite marble crystallized from car-bonate melt, based on textures and trace-element analyses.However, it is difficult to explain the extremely negativeδ13C values (Imamura et al. 2004) by diamond crystalliza-tion from carbonate melt, because strong isotopic fraction-ation is not expected between diamond and carbonate meltat such high temperatures.

Constraining P-T conditions for diamond formation in thedolomite marble is difficult. Two-stage growth, by itself,does not provide such information. If the carbon sourcewas graphite for the first stage, diamond, in principle, mayhave started to crystallize near the minimum pressure fordiamond stability, or slightly above. However, rim growthrequires an additional source of carbon, such as fluid ormelt. The release of H2O by dehydration reactions from sur-rounding rocks may be one of the fluid sources, and growthof rim diamond could be near peak P–T conditions, whichfor the Kokchetav UHP marble are 6 to 9 GPa (Ogasawara etal. 2002) and 980 to 1250°C. (Ogasawara et al. 2000).

Photomicrographs (PPL) of representative S-type microdia-monds in dolomite marble. A: diamond inclusion in

diopside. B, C, D: diamond inclusions in garnet.

FIGURE 4

B

A

D

C

ACKNOWLEDGMENTSThe author thanks Chris Parkinson and George Harlow fortheir reviews, suggestions and great help for improving thispaper. This study was financially supported by the Grantsin Aid of JSPS no. 13640485 and no. 15204050, and WasedaUniversity Grant no. 2001A-533. .


Images and cathodoluminescence (CL) spectra of an S-type microdiamond in dolomite marble (after Yoshioka

and Ogasawara in press). A: Photomicrograph of analyzed grain. B:Secondary electron SEM image of analyzed grain. Small circles are loca-tions from which CL spectra were obtained. C: CL image at the peakwavelength (523 nm) of the strongest CL band. D: CL spectra of coreand rim.

FIGURE 5

B

A C

D

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MARCH 2005E L E M E N T S

97E L E M E N T S , V O L . 1 , P P 9 7 – 1 0 0 MARCH 200597

Meteoritic Nanodiamonds:Messengers from the Stars

Gary R. Huss 1

INTRODUCTIONPrimitive chondritic meteorites date from the earliest timesin solar system history and have survived largely unaltereduntil today. These meteorites preserve the first objects toform in the solar system, such as calcium–aluminum-richinclusions, metal grains, and chondrules—the round, mil-limeter-sized, crystallized melt droplets for which chon-drites are named and whose origin is poorly understood.They also preserve dust from the dense, cold, interstellarmolecular cloud that collapsed to form the solar system.This presolar dust was the raw material from which thesolar system formed. Although scientists had hints in theform of anomalous isotopic compositions in meteoriticcomponents that presolar material was present in chon-drites, it was not until 1987 that the first presolar grainswere recognized. Diamond was recognized first (Lewis et al.1987), followed by silicon carbide and graphite. Becausepresolar diamonds are only a few nanometers in diameter,the term “nanodiamonds” was coined. To date, more thanten different minerals from primitive meteorites have beenidentified as presolar (e.g., Nittler 2003). Most of these con-densed from the ejecta of dying stars that existed longbefore the solar system formed. Presolar minerals permit usto investigate the stellar nucleosynthetic processes that pro-duced the chemical elements, to study processes in inter-stellar space, and to probe the events that occurred duringthe earliest epochs of solar system history.

Nanodiamonds were recognized as presolar because of theisotopically anomalous noble gases that they contain. Ingeneral, an element will have the same isotopic composi-tion (within tight limits) anywhere on Earth and in objectsformed in the solar system. However, starting in the early1960s, scientists noticed that xenon in some meteoriteshad a very strange isotopic composition. It was more thana decade before a group at the University of Chicago deter-mined that the strange xenon was located in a carbonaceous

residue that makes up only a smallportion of the host meteorite(Lewis et al. 1975). It took anotherten years to determine that thecarrier of the strange xenon wasnanodiamond (Lewis et al. 1987).

Nanodiamonds were the firstpresolar component to be recognized, but in many waysthey are the least well understood. This is primarily becauseof their size. Each ~2–3 nm diamond grain contains only afew thousand carbon atoms. No instrument currently avail-able can determine the isotopic composition of a grain thissmall, and even if such an instrument were available, onlycarbon is present with enough atoms to give a meaningfulcomposition. The isotopic and trace-element informationthat we do have comes from samples containing billions ofindividual nanodiamonds. Unlike µm-sized SiC and Al2O3

grains, which provide detailed information about the stararound which each grain formed, nanodiamonds provideonly a general picture of their source(s).

CHARACTERISTICS OF METEORITIC NANODIAMONDSTransmission electron microscopy is necessary to deter-mine the characteristics of individual nanodiamonds (e.g.,Daulton et al. 1996). The crystal structure of most nano-diamonds is cubic, i.e., true diamond structure, but a fewgrains show hexagonal symmetry, indicating the carbonpolymorph lonsdaleite. Most grains exhibit multiple twinsindicative of rapid growth. Meteoritic nanodiamonds havea log-normal size distribution with a median effectivediameter of ~2.7–3.0 nm.

The isotopically strange xenon that led to the discovery ofnanodiamonds is enriched in both Heavy and Light iso-topes compared to “normal” solar system xenon (FIG. 1). Itoccurs in the diamonds as a trapped gas component, calledHL, which also contains isotopically distinct helium, neon,argon, and krypton (Huss and Lewis 1994a). Nano-diamonds also contain two other noble gas components,called P3 and P6 for historical reasons, with isotopic compo-sitions much closer to those of solar system gases. Heatingor oxidizing nanodiamond samples in steps can effectivelyseparate these three components. The P3 component isreleased at low temperatures (FIG. 2A) and has much less

1 Hawai’i Institute of Geophysics and PlanetologyUniversity of Hawai’i at Manoa, USAE-mail: [email protected]

Primitive chondritic meteorites contain up to ~1500 ppm of nanometer-sized diamonds. These nanodiamonds contain isotopically anomalousnoble gases, nitrogen, hydrogen, and other elements. The isotopic

anomalies indicate that meteoritic nanodiamonds probably formed outsideour solar system, prior to the Sun’s formation (they are thus presolar grains),and they carry within them a record of nucleosynthesis in the galaxy. Theircharacteristics also reflect the conditions encountered in interstellar space,in the solar nebula, and in the host meteorites.

KEYWORDS: nanodiamond, chondrite, presolar grains, isotopic anomalies, solar nebula

This spectacular X-rayimage of the

supernova remnantCassiopeia A is the

most detailed imageever made of the

remains of anexploded star. Colors

represent different X-ray wave lengths. The outer green ring, ten light

years in diameter, marks the location of the shock wavegenerated by the supernova explosion. Inside this

shock wave is the ejecta of the supernova, some ofwhich condenses into tiny grains, perhaps including

the nanodiamonds discussed in this article.Scale: Image is 8 arcmin per side.

CREDIT: NASA/CXC/GSFC/U. HWANG ET AL.


helium and neon and more argon, krypton, and xenonthan the HL component. The P6 component is volumetri-cally much smaller and is released at higher temperaturesthan HL (Huss and Lewis 1994a). Although P3 and P6 haveisotope ratios similar to solar system xenon, their isotopiccompositions are distinct and cannot be produced fromsolar system xenon by any known process.

The noble gas content of meteoritic nanodiamonds isextremely high, so high that helium and neon from nano-diamonds dominate the helium and neon in the host mete-orites, and argon, krypton, and xenon make up several per-cent of the total budget. This is true even thoughnanodiamonds comprise only ~0.15% of the fine-grained“matrix” material in primitive chondrites. Yet in spite ofthe high gas content, only about one diamond in a millioncontains a xenon atom and only about one in ten containshelium. (For example, nanodiamonds contain about 1.5 ppbof xenon, about 10,000 times more gas than most terrestri-al rocks). Thus, there is no such thing as an isotopic com-position for the xenon in a single diamond; measured com-positions are for the gas extracted from billions of diamonds.

The mean carbon isotopic composition of these billions ofnanodiamonds (δ13C = –31‰ to –38‰; Russell et al. 1996)is within the range of compositions measured in solar sys-tem materials, but it is quite different from those of mostterrestrial diamonds, which concentrate between –25‰and +5‰. Chondritic nanodiamonds are rich in nitrogen,the isotopic composition of which is highly enriched in14N (δ15N = –348‰; Russell et al. 1996), and their surfaceatoms are bonded to hydrogen that is enriched in deuterium

by ≥280‰ (Virag et al. 1989). The trace elements telluriumand palladium show small excesses of the heaviest isotopes,analogous to, but somewhat smaller than, the anomalies inKr-H and Xe-HL (Mass et al. 2001).

Origin of Meteoritic NanodiamondsThe origin of meteoritic nanodiamonds is still very muchan open issue. A longstanding interpretation of Xe-HL isthat the excess light and heavy isotopes were produced in asupernova and were implanted into the diamonds beforethe solar system formed (e.g., Heymann and Dziczkaniec1979). On the other hand, because the carbon isotopiccomposition of nanodiamonds is within the compositionalrange of solar system materials and because only about onediamond in a million contains a xenon atom, some scien-tists have suggested that most nanodiamonds formed inthe solar system. This view received support from a trans-mission electron microscope study of interplanetary dustparticles (IDPs) (Dai et al. 2002). These authors did notobserve nanodiamonds in IDPs thought to have originatedfrom comets, but they did observe them in IDPs thought tobe asteroid particles. Because comets probably formed farfrom the sun from material that was not heavily processedin the solar system, the near absence of diamonds incometary IDPs suggests that the bulk of the diamonds orig-inated inside, not outside, the solar system.

Although a local origin for meteoritic nanodiamonds is cur-rently popular, I argue that the bulk of the evidence indi-cates that nanodiamonds formed outside the solar system.The compositions of Xe-HL, Kr-H, tellurium, and palladiumshow that at least some of the diamonds came from asource where heavy isotopes were preferentially synthe-sized, probably a supernova. Xe-HL is associated with fourother isotopically distinct noble gases, and when all fivegases are considered, one out of ~10 diamonds contains anoble gas atom that can reasonably be associated with asupernova source (but see below). The P3 component innanodiamonds is isotopically distinct from both the majorheavy noble gas component in chondrites and from solarwind for all five noble gases (Huss and Lewis 1994a). The P3gases were probably trapped after nanodiamonds formed,and their distinctive isotopic compositions indicate thatthey originated outside the solar system. Also, as will be dis-cussed below, the relative abundances of nanodiamondsand other types of presolar grains in chondrites can best beunderstood in terms of solar system thermal processing ofa single mixture; there is no evidence that diamonds aredecoupled from other types of presolar grains. The majorchallenge to this view is the near absence of nanodiamondsin supposed cometary IDPs. However, there is currently noestimate of the abundance of another type of presolar grainin these IDPs to show that other grain types are present atthe expected abundances. Without such data, the possibil-ity that we simply do not understand how and from whatcomets formed cannot be ruled out.

How do nanodiamonds form? We are normally taught thathigh pressures are required to make diamond, but mete-oritic nanodiamonds apparently formed in the low pres-sures of space. One early idea was that nanodiamonds wereproduced by high-pressure shock metamorphism ofgraphite through grain–grain collisions during the passageof interstellar shocks (Tielens et al. 1987). This process isnot expected to be efficient, so the diamonds should beaccompanied by a large amount of graphite, which has notyet been observed. (The word “shock” has two meanings inthis context. An interstellar shock is a discontinuity in gasvelocity, pressure, density, etc. Gas atoms typically do notcross the discontinuity, but dust grains can penetrate theshock and collide with other dust grains at high velocity.

Isotopically anomalous xenon in meteoritic nanodia-monds. A. Histogram of the abundances of xenon iso-

topes in Xe-HL and in solar wind. B. Xenon isotopes in Xe-HL normal-ized to the composition of solar wind (the flat line at 0) and plotted asdeviations from solar wind composition in parts per thousand (per-mil = ‰). Note the large excesses of the light and heavy isotopes thatgive Xe-HL its name.

FIGURE 1

A

B


High-velocity collisions generate pressure waves withinsolid grains, which are also called shock waves. These shockwaves can cause pressure excursions into the diamond sta-bility field and convert graphite to diamond.) In recentyears, diamonds have been produced industrially at lowpressures by a process called chemical vapor deposition

(CVD; see Hemley et al. p. 105). The conditions for opti-mum diamond growth are remarkably similar to those instellar ejecta (e.g., Anders and Zinner 1993 and referencestherein). Industrial CVD synthesis makes use of kinetic fac-tors to stabilize diamond production. However, there maybe a thermodynamic reason to expect diamond to formpreferentially over other carbon allotropes at very smallsizes. Badziag et al. (1990) showed that when the surfacebonds are terminated with hydrogen, diamonds smallerthan ~3 nm in diameter are energetically favored over poly-cyclic aromatic hydrocarbons (the precursors to graphite).Thus, diamond may well be the stable form of carbon inthe nm size range. Other ideas have also been suggested.Graphite grains might be induced to transform to diamondby intense UV irradiation or by intense particle irradiation.However, transmission electron microscope work on mete-oritic nanodiamonds and terrestrial analogues stronglyindicates that nanodiamonds formed by a vapor-depositionprocess (Daulton et al. 1996).

The isotopic anomalies in meteoritic nanodiamonds arehard to explain by a single stellar source. This is not sur-prising, since the measured isotopic compositions representbillions of grains that may have formed in hundreds of dif-ferent sites. For example, Xe-H and Xe-L are produced indifferent zones of a supernova (e.g., Heymann andDziczkaniec 1979), so one might expect that the two com-ponents should be separable in the laboratory. Severalworkers have claimed marginal evidence of separations ofXe-H and Xe-L, but in most cases the effects turned out tobe due to additional noble gas components or other exper-imental artifacts (e.g., Huss and Lewis 1994a). Meshik et al(2001) used a laser and selective optical absorption toextract gases from different populations of nanodiamondsand again found marginal evidence of a separation, butthey were unable to demonstrate clearly that Xe-H and Xe-Lare separable in the laboratory.

The measured Xe-HL and Kr-H compositions are also sig-nificantly less extreme than compositions from nucleosyn-thetic models (Heymann and Dziczkaniec 1979; Clayton1989). This implies that an isotopically “normal” compo-nent is intimately intermixed with the isotopically anom-alous gas. To calculate the supposedly pure end-memberisotopic composition from the stellar source, the “normal”component is typically removed by assuming that all of the130Xe, which is not produced by the processes that gener-ate Xe-H or Xe-L, is in the “normal” component, usuallyassumed to have the composition of solar wind. Severalideas for the production of Xe-H in a supernova settinghave been suggested. An early idea invokes the classical r-process, in which large numbers of neutrons releasedfrom deep in the exploding star are captured by seed nucleion a timescale that is short with respect to their lifetimeagainst β-decay, to produce large excesses of heavy xenonisotopes (Heymann and Dziczkaniec 1979). Clayton (1989)suggested that when a massive star collapses to become atype II supernova, the neutrino burst generated in the corewould release enough neutrons from the helium shell ofthe pre-supernova star to produce large excesses of neutron-rich isotopes. Ott (1996) suggested that classical r-processnucleosynthesis accompanied by separation of xenon fromiodine and tellurium precursors within a few hours aftertermination of the process could produce Xe-H. Each modelhas its problems, and none has been generally accepted.

A recent experimental study in which noble gas ions wereimplanted into nanodiamonds produced a remarkableresult. A single component was implanted, but when thesample was measured by stepped heating, the gases werereleased in two peaks that were almost identical to thebimodal release shown in Fig. 2a (Koscheev et al. 2001).

Histograms showing xenon released from nanodiamondsfrom three primitive meteorites as a function of temper-

ature during stepped heating in the laboratory. The ordinate shows thevolume of 132Xe released from one gram of nanodiamonds at eachtemperature step in units of 10-10 cubic centimeters at standard T and P.The gas volume for each step has been normalized to the width of thestep in °C so that the area under the curve accurately represents the gasvolume. The meteorites: Orgueil is a CI chondrite thought to best rep-resent the composition of the early solar system. Semarkona andBishunpur are LL chondrites, which have matrix compositions very sim-ilar to CI except they have lost siderophile elements. These meteoritehave experienced very little thermal metamorphism with temperaturesincreasing from Orgueil to Semarkona to Bishunpur.

Xenon in Orgueil diamonds (A) is released in two distinct peaks. Xenonin the first peak (the P3 component) has an isotopic composition simi-lar to that of solar system xenon. This low-temperature gas is appar-ently trapped in the surface layer of the diamonds where many of thebonds are C-H, C-O, C-O-O-H, C-N, etc. These bonds break and recom-bine at relatively low temperature releasing the noble gases. The sec-ond peak is dominated by isotopically anomalous Xe-HL. A third com-ponent, Xe-P6, is released on the high-temperature tail of the Xe-HLrelease. Both of these components are sited within the diamond struc-ture and are released when the diamond reacts with the Pt or Ta foil inwhich the sample is wrapped or with surrounding minerals. Note thatthe size of the Xe-P3 peak is lower in Semarkona diamond (B) andlower yet in Bishunpur diamond (C). This reflects heating of the LLchondrites that released some of the low-temperature gases on themeteorite parent body (Huss and Lewis 1994b). The petrologic types ofthe LL chondrites (3.0, 3.1) are derived from measurements of thermo-luminescence sensitivity (e.g., Sears et al. 1991), which give the degreeof heating each meteorite experienced.

FIGURE 2

A

B

C


REFERENCESAnders E, Zinner E (1993) Interstellar

grains in primitive meteorites: Diamond,silicon carbide, and graphite. Meteoritics28: 490-514

Badziag P, Verwoerd WS, Ellis WP, GreinerNR (1990) Nanometre-sized diamonds aremore stable than graphite. Nature 343:244-245

Clayton DD (1989) Origin of heavy xenonin meteoritic diamonds. AstrophysicalJournal 340: 613-619

Dai ZR, Bradley JP, Joswiak DJ, BrownleeDE, Hill HGM, Genge MJ (2002) Possiblein situ formation of meteoritic nanodia-monds in the early solar system. Nature418: 157-159

Daulton TL, Eisenhour DD, Bernatowicz TJ,Lewis RS, Buseck PR (1996) Genesis ofpresolar diamonds: Comparative high-resolution transmission electronmicroscopy study of meteoritic andterrestrial nano-diamonds. Geochimicaet Cosmochimica Acta 60: 4853-4872

Heymann D, Dziczkaniec M (1979) Xenonfrom intermediate zones of supernovae.Proceedings of the 10th Lunar andPlanetary Science Conference: 1943-1959

Huss GR, Lewis RS (1994a) Noble gases inpresolar diamonds I: Three distinctcomponents and their implications fordiamond origins. Meteoritics 29: 791-810

Huss GR, Lewis RS (1994b) Noble gases inpresolar diamonds II: Componentabundances reflect thermal processing.Meteoritics 29: 811-829

Huss GR and Lewis RS (1995) Presolardiamond, SiC, and graphite in primitivechondrites: Abundances as a function ofmeteorite class and petrologic type. Geo-chimica et Cosmochimica Acta 59: 115-160

Huss GR, Ott U, Koscheev AP (2000)Implications of ion-implantationexperiments for understanding noblegases in presolar diamonds. Meteoriticsand Planetary Science 35: A79-A80

Huss GR, Meshik AP, Smith JB, HohenbergCM (2003) Presolar diamond, siliconcarbide, and graphite in carbonaceouschondrites: Implications for thermalprocessing in the solar nebula.Geochimica et Cosmochimica Acta 67:4823-4848

Koscheev AP, Gromov MD, Mohapatra RK,Ott U (2001) History of trace gases inpresolar diamonds inferred from ion-implantation experiments. Nature 412:615-617

Lewis RS, Srinivasan B, Anders E (1975)Host phase of a strange xenon compo-nent in Allende. Science 190: 1251-1262

Lewis RS, Tang M, Wacker JF, Anders E,Steel E (1987) Interstellar diamond inmeteorites. Nature 325: 160-162

Maas R, Loss RD, Rosman K, De Laeter JR,Lewis RS, Huss GR, Lugmair GW (2001)Isotope anomalies in tellurium andpalladium from Allende microdiamonds.Meteoritics and Planetary Science 36:849-858

Meshik AP, Pravdivtseva OV, HohenbergCM (2001) Selective laser extractionof Xe-H from Xe-HL in meteoriticnanodiamonds: real effect or experimen-tal artifact. Lunar and Planetary ScienceXXXII: abstract 2158

Nittler LR (2003) Presolar stardust inmeteorites: recent advances and scientificfrontiers. Earth and Planetary ScienceLetters 209: 259-273

Ott U (1996) Interstellar diamond xenonand timescales of supernova ejecta.Astrophysical Journal 463: 344-348

Russell SS, Arden JW, Pillinger CT (1996)A carbon and nitrogen isotope studyof diamond from primitive chondrites.Meteoritics and Planetary Science 31:343-355

Sears DWG, Hasan FA, Batchelor JD, Lu J(1991) Chemical and physical studiesof type 3 chondrites–XI: Metamorphism,pairing, and brecciation of ordinarychondrites. Proceedings of the 21st Lunarand Planetary Science Conference: 493-512

Tielens A, Seab C, Hollenbach D, McKee C(1987) Shock processing of interstellardust: Diamond in the sky. AstrophysicalJournal 319: L109-L113

Virag A, Zinner E, Lewis RS, Tang M (1989)Isotopic compositions of H, C, and N inCd diamonds from the Allende andMurray carbonaceous chondrites(abstract). Lunar and Planetary Science20: 1158-1159 .

This suggests that the isotopically “normal” componentintimately mixed with the HL component might be P3, andif so, then calculations of the pure Xe-HL composition havebeen done incorrectly in the past. A calculation subtractingP3 gases produces a Xe-HL composition not too differentfrom previous ones but suggests that Kr-H is accompaniedby Kr-L. Direct evidence for Kr-L has not been seen before.This calculation also suggests that the exotic componentwas implanted and then largely outgassed before the P3component was implanted (Huss et al. 2000).

NANODIAMONDS AS PROBES OF SOLAR SYSTEM PROCESSESThe noble gases in nanodiamonds and the abundances ofnanodiamonds and other presolar materials among chon-drites are sensitive probes of thermal processing, both inthe solar nebula and in the meteorite parent bodies (Hussand Lewis 1994b, 1995; Huss et al. 2003). The P3 compo-nent is released at low temperatures, and the release tem-perature seems to be largely independent of the surround-ings in which the diamonds are located. Because of this, theP3 abundances from diamond separates provide a relativelyprecise measure of the temperature to which the meteoriteswere heated during their history (cf. Fig. 2). This P3-based“metamorphic” scale can be calibrated to give a quantita-tive estimate of the maximum temperature experienced bythe diamonds and associated material, and this calibrationseems to be consistent across the chondrite classes. Theabundances of diamonds in chondrite matrices can be reli-ably determined by measuring the amount of Xe-HL inmeteorite residues (Huss and Lewis 1995; Huss et al. 2003).Among presolar materials whose abundances in the hostmeteorite are easily determined (diamond, SiC, andgraphite), nanodiamond is among the most resistant tothermal processing. Within a meteorite class, the relativeand absolute abundances of presolar grains can establishthe relative amount of heating each meteorite experienced

(Huss and Lewis, 1995). Among the essentially unmeta-morphosed members of the various meteorite classes, therelative abundances of presolar materials and the amountof P3 gas in diamonds seem to reflect the nebular thermalprocessing that produced the chemical classes of chondrites(Huss et al. 2003). Thus, nanodiamonds are potentiallypowerful probes of both nebular and parent-body process-es in the early solar system.

FUTURE RESEARCHFuture research on meteoritic nanodiamonds shouldaddress the following questions:

1. How many different kinds of diamonds are present inbulk nanodiamond samples and how can they be recog-nized?

2. Are the diamonds dominantly presolar or were theymostly produced in the solar system?

3. How did the diamonds form?

4. What nucleosynthetic source or sources are reflected inthe isotopically anomalous noble gases and trace ele-ments in the diamonds?

5. Can these sources be identified and characterized effec-tively from the diamond samples?

These are essentially the same questions that scientists havebeen working on since the diamonds were discovered. Butbecause of the small size of individual diamonds, we do notcurrently have the tools to address them effectively.Instrumentation is improving rapidly, however, and detec-tion limits are getting better. So I am confident that even-tually the tools will be developed that will permit us toanswer these basic questions about meteoritic nanodiamonds.

ACKNOWLEDGMENTSThis work was supported by NASA grant NAG5-11543. .

101E L E M E N T S , V O L . 1 , P P . 1 0 1 - 1 0 4 MARCH 2005101

INTRODUCTIONDiamonds are the most important gemstones, and theirsales are the foundation of the international jewelry indus-try. Gem diamonds hold a special fascination, as evidencedby the popularity of, and media interest in, exhibitions andevents featuring them (e.g., King and Shigley 2003). In2003, retail diamond jewelry sales in the United Statesamounted to over US$29 billion. Continued confidence inthe jewelry marketplace depends both on an accurate deter-mination of whether a diamond (or any gemstone) is natu-ral, synthetic, or laboratory-treated and on a full disclosureof this information at the time of sale.

Commercial treatments to improve the color of gem dia-monds have existed since the 1930s (see Nassau 1994, pp.141–151). These processes mostly involve exposure to high-energy radiation, sometimes followed by heating to tem-peratures up to several hundred degrees Celsius or more.Over time, diamond color (as well as clarity) treatmentshave become both more sophisticated and widespread, andnew treatment processes have been developed. In somecases, a gemologist, using just a binocular microscope anda simple spectroscope, can recognize color-treated dia-monds. However, detecting them often requires moresophisticated instruments such as UV–visible or photolu-minescence spectrometers. For some treated diamonds, this

determination still cannot bemade with certainty; this is espe-cially true when the treatmentprocesses (e.g., irradiation) mimicnatural processes that affect dia-monds in the Earth. The fact thatsome natural-color gem diamondssell at prices in excess of US$100,000or more per carat emphasizes theimportance of a correct “origin ofcolor” determination.

This article deals with the mostdifficult current identificationchallenge—the recognition of dia-monds that have had their coloreither removed or changed byannealing at high pressures andtemperatures (referred to as HPHTtreatment).

DIAMOND TYPESAND COLORATIONDiamonds can be divided intocategories, called types, based on

differences in certain physical properties, particularly opti-cal absorption. Initially, diamonds with strong absorptionsof both IR and UV radiation were designated as Type I,whereas those without were labeled Type II (Robertson etal. 1934). These “types” are related to the presence of impu-rities (see TABLE 1). The boundaries between categories aresomewhat arbitrary, and mixed types are possible within asingle diamond.

The structural arrangements of these impurities within thediamond lattice are perhaps more interesting than theirabundances. Nitrogen (and to a lesser extent boron andhydrogen), along with point and extended defects, causeabsorptions in the visible spectrum, which give rise to col-oration (see Table 1).

Certain colors in diamond are due not to trace-elementimpurities, but to absorptions resulting from various opti-cally active defects. In brown and pink diamonds, the“color centers” (which produce a broad region of absorp-tion centered at about 550 nm) are thought to be caused bydislocations and point defects that result from deformationof the diamonds during their extended storage in the Earth.Exposure of diamonds to radiation, either in nature or thelaboratory, creates defects that cause green and some bluecolors (due to the GR center at 741 nm and its associatedsidebands, see Table 1; for further information, see Fritsch1998; Collins 2001).

1 Gemological Institute of America, Research Department, 5345 Armada Drive, Carlsbad, CA 92008-4603, USAE-mail: [email protected]

Annealing of gem-quality diamonds at very high pressures (above5 GPa) and temperatures (above ~1800°C) can produce significantchanges in their color. Treatment under these high-pressure–high-

temperature (HPHT) conditions affects certain optically active defects andtheir absorptions in the visible spectrum. In the jewelry industry, laboratory-treated diamonds are valued much less than those of natural color. Polisheddiamonds are carefully examined at gemological laboratories to determinethe “origin of color” as part of an overall assessment of their quality.Currently, the recognition of HPHT-treated diamonds involves the determina-tion of various visual properties (such as color and features seen undermagnification), as well as characterization by several spectroscopic tech-niques. HPHT-treated diamonds were introduced into the jewelry trade inthe late 1990s, and despite progress in their recognition, their identificationremains a challenge. While some detection methodologies have been estab-lished, the large number of diamonds requiring testing with sophisticatedanalytical instrumentation poses a logistical problem for gemologicallaboratories.

KEYWORDS: diamond, gemstone, color, treatment, HPHT, annealing, identification

High-Pressure–High-Temperature Treatment of Gem Diamonds Three diamonds

(4.11–5.34 carats)decolorized by the

HPHT-annealing processdeveloped by General

Electric. PHOTO BY

ELIZABETH SCHRADER,© GEMOLOGICAL INSTITUTE

OF AMERICA (GIA).

James E. Shigley 1


HPHT-TREATMENT OF DIAMONDSExperimental studies in the 1970s showed that the degreeof aggregation of nitrogen atoms could be increased ordecreased by heating Type I diamonds to very high tem-peratures at high pressures (see Evans and Rainey 1975;Brozel et al. 1978). This was accompanied by either a weak-ening or an intensification of the yellow color. Because ofthe difficulty in achieving these conditions, this procedurewas not commercially viable as a treatment of gem diamonds.

In March 1999, the jewelry industry was taken by surprisewhen the prominent U.S. jewelry firm, Lazare KaplanInternational, announced a new process developed by theGeneral Electric (GE) Company for transforming certainType IIa diamonds from brown to colorless (see p. 101).Initially sold under the name “GE POL” (for PegasusOverseas Ltd., a foreign GE subsidiary), these color-treateddiamonds are currently marketed under the trade name“Bellataire” (e.g., http://www.ge.com/uk/bellataire/). Nodetails of the process were provided by GE at the time(patents have since been published; see Vagarali et al.2004). However, it was subsequently established that thetechnique involved annealing diamonds for brief periods oftime at very high temperatures and pressures (1800 to~2700°C, and at 5 to 9 GPa to prevent transformation tographite). Under such conditions, lattice-scale defects inthe structure that produce brown coloration are annealedout, thereby rendering the diamonds colorless.

This process is carried out with the same equipment typi-cally used for diamond synthesis, including the “belt”,tetrahedral, cubic, and octahedral presses, as well as the

Russian-designed “BARS” units (=bespressovye apparaty tipa razrez-naya sfera, or “split sphere nopress apparatus”). One or morerough or polished diamonds areloaded into a capsule, which isthen placed in the apparatus. Theexact P and T used depend on thetype of diamonds being treated,the color change desired, and theequipment configuration, withannealing times being as short as afew minutes. At the end of a treat-ment run, the diamonds may havea black, graphitized outer surface,which can be removed by heatingto several hundred degrees Celsiusfor a short time in a laboratoryoven. Following treatment, all dia-monds exhibit surface damage inthe form of etching and pitting, soafter processing, a cut diamondrequires repolishing. Polished dia-monds of all sizes (0.01 to morethan 30 ct) have been treated bythe HPHT process.

Annealing of Type IIa brown dia-monds under HPHT conditionsremoves structural defects bymeans of plastic flow (Schmetzer1999; Collins et al. 2000). Thisdecreases the broad absorption inthe visible spectrum that causesthe brown coloration (Fisher andSpits 2000; also see FIGS. 1 AND 2).It is also possible to change certainvery rare brown-pink and gray-blue Type II diamonds by elimi-

nating the brown component of their coloration and there-by enhancing the underlying pink or blue color,respectively (Hall and Moses 2000, 2001). Wang et al.(2003) recently described an intensely colored green-yellowType IIa diamond that had been treated by this method.

Initially this treatment focused on removal of brown colorfrom Type IIa diamonds, but experiments on changing thecolor of Type I diamonds soon followed (De Weerdt andVan Royen 2000; Reinitz et al. 2000; De Weerdt and Collins2003). Brownish-yellow Type Ia diamonds can be trans-formed to yellow, orange-yellow, or green-yellow as annealing

The visible spectrum of a Type IIa brown diamond (lowerspectrum) exhibits absorption extending from the blue

(400 nm) to the red (700 nm). HPHT annealing resulted in a removal ofmuch of this absorption (upper spectrum), so that the diamond nowappears nearly colorless.

FIGURE 1

Type 1 Type II

Natural Abundance* ~98% Ia ~2% IIa~0.1% Ib Extremely rare: IIb

Nitrogen content (ppm) Ia: ~10–3000 IIa: < 10Ib: ~25–50 IIb: none (< 0.1)

Nitrogen distribution Ia: as small aggregates (see below)Ib: individual substituted atoms

Other constituents IIb: boron

* For diamonds larger than 0.1 ct (0.02 g). Type II is more common in microdiamonds than is indicated above.

Color Centers and Nitrogen Aggregates†:

A aggregate: 2 nitrogen atoms in adjacent lattice sites—no color

B aggregate: 4 nitrogen atoms and a vacancy in adjacent lattice sites—no color

C center: single nitrogen atom—strong yellow

GR center: a vacancy (i.e., a carbon atom missing from a site)—green to blue

N-V center: single nitrogen atom and a vacancy in adjacent sites—pink to redor purple

N3 center: 3 nitrogen atoms and a vacancy in adjacent sites—pale yellow

N-V-N (H3, H2) center: a vacancy trapped at an A aggregate—green

H4 center: a vacancy trapped at a B aggregate—yellow, orange, or brown

† Nomenclature mostly comes from labeling of spectroscopic peaks that are used to identify defects andsubstitutions in diamond. Diamond colors typically result from absorption at the zero-phonon line andassociated sidebands at shorter wavelengths (see Fritsch 1998; Collins 2001). Additional colors result fromboron or hydrogen impurities, or from other color centers of uncertain structure.

DIAMOND TYPES AND DEFECTS OR SUBSTITUTIONS

TABLE 1


permits vacancies to migrate and combine with aggregatednitrogen to form nitrogen-vacancy-nitrogen (N-V-N) centersthat give rise to strong green coloration (due to the H3 opti-cal center; Collins et al. 2000; see FIG. 3). At higher T, someA nitrogen centers are also broken up, forming C centers.This is accompanied by H3 changing to H2 centers and theformation of the nitrogen-vacancy (N-V) centers (seeCollins 2001; Zaitsev 2001). Only recently have Type 1adiamonds been reported whose light yellow color is theresult of HPHT treatment.

When the challenge for gemological laboratories focusedon detecting decolorized Type IIa diamonds, the problemwas limited because of their rarity. Now, with the treatmentof Type I diamonds added, the identification problem ismuch greater because the latter are far more abundant andmore variable in gemological properties.

DETECTING HPHT-ANNEALED DIAMONDSHPHT treatment presented significant challenges for thejewelry industry in terms of identification and disclosure.Even though only a relatively small number were initiallyinvolved, HPHT-treated diamonds often exhibited few ifany visual clues for a jeweler or gemologist to detect thisprocess. As an aid to recognition, General Electric inscribedan identification mark easily visible at 10× magnificationon the polished “girdle” surface of each of their treated dia-monds (those sold by other companies may or may nothave similar laser inscriptions). However, these marks canbe removed by repolishing the inscribed surface.

HPHT-treated diamonds canexhibit visual features that arelacking in untreated diamonds,for example, the above-men-tioned surface damage. Theycan also display graphitizedfracture surfaces and inclusions(see Chalain et al. 1999; Moseset al. 1999). Colorless Type IIadiamonds display greater trans-parency to short-wave (265nm) UV radiation than themore abundant Type Ia dia-monds, and this offers a pre-liminary way to separate theformer for further testing(Moses et al. 1999; Chalain etal. 2000).

Since visual features are notalways present in polished dia-

monds, detection of this treatment requires the use of spec-troscopic techniques (Collins 2001). For example, in HPHT-treated Type II diamonds, Chalain et al. (1999, 2000)interpreted the 637 nm absorption peak (due to the neutralN-V center) as a potential distinctive feature (also seeFritsch et al. 2001). Fisher and Spits (2000) described thebroad 270 nm band (due to C nitrogen centers) seen in thespectra of HPHT-treated diamonds with increasing yellowcoloration. Using 514-nm Ar-laser excitation, they alsoreported that the photoluminescence (PL) peaks at 575 and637 nm (due to neutral and negative charge states at N-Vcenters, respectively) have an intensity ratio (637>575) intreated diamonds that differs from that in untreated TypeIIa diamonds (575>637). Other non-destructive analyticaltools, including X-ray topography and cathodoluminescence,have been tried, but further work is needed on a larger pop-ulation of untreated and HPHT-treated diamonds to supporttheir use for detection purposes (e.g., Smith et al. 2000).

In yellow Type Ia diamonds, HPHT treatment produces newabsorption features while again reducing the brown col-oration (Van Royen and Pal’yanov 2002). For example,strong green H3 luminescence, along with the contributionof the sideband of the H2 center, causes the treated dia-monds to be yellow-green to green (Collins et al. 2000;Collins 2001; see Fig. 4). Just as in Type IIa diamonds, isolated

Before HPHT annealing, the visible spectrum of thisType 1a brown diamond displayed sharp absorption

bands at 415 and 503 nm (due to the N3 and H3 optical centers,respectively), as well as a broad region of absorption centered at about520 nm (lower spectrum). Following treatment, the latter broad bandhas been removed, and the H3 absorption band (along with its side-bands between 450 and 500 nm) is increased in intensity. These spec-tral changes produce the transformation of brown to yellow-greencoloration in Type Ia diamonds as in Fig. 3.

FIGURE 4

HPHT annealing of this 1.08-carat, Type Ia crystalchanged the color of the diamond from brown to yellow-green. PHOTOS BY ELIZABETH SCHRADER, © GIA.

FIGURE 3

A 6.60-carat, faceted Type IIa diamond transformed frombrown to colorless by HPHT annealing. PHOTOS BY

ELIZABETH SCHRADER, © GIA.

FIGURE 2


nitrogen (C centers) are formed in Type Ia diamonds byannealing, as can be seen in mid-infrared spectra (Reinitz etal. 2000; De Weerdt and Van Royen 2000). Current gemo-logical research is focused on confirming the use of spectralfeatures in both diamond types and on establishing addi-tional means of treated-diamond identification.

Several potential detection techniques have been devel-oped to quickly check diamonds to see if they have beenHPHT treated. A patent issued to General Electric describesa method using the presence or absence of one or more PLlines for this purpose (Anthony et al. 2002). Researchers atthe De Beers Diamond Trading Company (DTC) ResearchCentre have developed a prototype screening instrumentthat again is based on the detection of spectral features(Welbourn and Williams 2002). At gemological laboratories,separation of natural-color from HPHT-treated diamonds isbased on as many features as possible. Development ofidentification criteria rests on assembling a database ofinformation on large numbers of known untreated andknown treated diamonds. Creation of such a databaserepresents a significant research activity in the majordiamond-testing gemological laboratories.

CONCLUSIONGemologists face continued challenges in recognizing natu-ral, treated, and synthetic gem materials. HPHT-treated dia-monds pose a special difficulty since some colors producedcorrespond to those of high-priced untreated natural dia-monds, and yet they are valued very differently. Their detec-tion often requires the use of sophisticated scientific equip-ment. Treatment experiments undertaken by theGemological Institute of America and other researchers havebeen able to reproduce the kinds of color changes in dia-monds that can be brought about by HPHT annealing.Systematic documentation of the gemological properties of avast number of treated and untreated diamonds has yieldednew identification criteria. Nonetheless, the distinction ofHPHT-annealed diamonds represents a difficult challenge forgem-testing laboratories that receive numerous gems on adaily basis. Despite much progress, the detection of HPHT-treated diamonds will remain a concern for the jewelryindustry as the use of this process becomes more widespread.

.

REFERENCESAnthony TR, Casey JK, Smith AC, Vagarali

SS (2002) Method of detection of naturaldiamonds that have been processed athigh pressure and high temperatures.U.S. Patent 6,377,340 B1, dated 23 April2002

Brozel MR, Evans T, Stephenson RF (1978)Partial dissociation of nitrogen aggregatesin diamond by high-temperature high-pressure treatments. Proceedings RoyalSociety of London A361: 109-127

Chalain J-P, Fritsch E, Hänni H (1999)Détection des diamants GE POL: unepremière étape. Revue de Gemmologiea.f.g. 138/139: 2-11

Chalain J-P, Fritsch E, Hänni H (2000)Identification of GE POL diamonds: asecond step. Journal of Gemmology 27:73-78

Collins AT (2001) The colour of diamondand how it may be changed. Journal ofGemmology 27: 341-359

Collins AT, Kanda H, Kitawaki H (2000)Colour changes produced in naturalbrown diamonds by high-pressure, high-temperature treatment. Diamond andRelated Materials 9: 113-122

De Weerdt F, Van Royen J (2000)Investigation of seven diamonds, HPHTtreated by NovaDiamond. Journal ofGemmology 27: 201-208

De Weerdt F, Collins AT (2003) Theinfluence of pressure on high-pressure,high-temperature annealing of type Iadiamond. Diamond and RelatedMaterials 12: 507-510

Evans T, Rainey P (1975) Changes in thedefect structure of diamond due to hightemperature–high pressure treatment.Diamond Research 1975: 29–34

Fisher D, Spits RA (2000) Spectroscopicevidence of GE POL HPHT-treatednatural type IIa diamonds. Gems &Gemology 36: 42-49

Fritsch E (1998) The nature of color indiamonds. In: Harlow GE (ed) The natureof diamonds, Cambridge UniversityPress, Cambridge, pp 23-77

Fritsch E, Chalain J-P, Hänni H (2001)Identification of GE POLTM diamonds.Australian Gemmologist 21: 172-177

Hall M, Moses TM (2000) Gem Trade LabNotes: Diamond - blue and pink, HPHTannealed. Gems & Gemology 36: 254-255

Hall M, Moses TM (2001) Gem Trade LabNotes: Update on blue and pink HPHT-annealed diamonds. Gems & Gemology37: 215-216

King JM, Shigley JE (2003) An importantexhibit of seven rare gem diamonds.Gems & Gemology 39: 136-143

Moses TM, Shigley JE, McClure SF, KoivulaJI, van Daele M (1999) Observations onGE-processed diamonds: A photographicrecord. Gems & Gemology 35: 14-22

Nassau K (1994) Gemstone enhancement –history, science and state of the art, 2nd

Edition. Butterworth-Heinemann Ltd,Oxford, 252 pp

Reinitz I, Buerki PR, Shigley JE, McClure SF,Moses TM (2000) Identification of HPHT-treated yellow to green diamonds. Gems& Gemology 36: 128-137

Robertson R, Fox JJ, Martin AE (1934)Two types of diamond. PhilosophicalTransactions of the Royal Society ofLondon A232: 463-535

Schmetzer K (1999) Clues to the processused by General Electric to enhance theGE POL diamonds. Gems & Gemology35: 186-190

Smith CP, Bosshart G, Ponahlo J, HammerVMF, Klapper H, Schmetzer K (2000) GEPOL diamonds: Before and after. Gems& Gemology 36: 192-215

Vagarali SS, Webb SW, Jackson WE,Banholzer WF, Anthony TR, Kaplan GR(2004) High pressure/high temperatureproduction of colorless and fancy-coloreddiamonds. U.S. Patent 6,692,714, dated17 February 2004

Van Royen J, Pal’yanov YN (2002) High-pressure–high-temperature treatment ofnatural diamonds. Journal of Physics –Condensed Matter 14: 10953-10956

Wang W, Hall M, Moses TMM (2003) GemTrade Lab Notes: Diamond – Intenselycolored type IIa with substantialnitrogen-related defects. Gems &Gemology 39: 39-41

Welbourn C, Williams R (2002) DTCResearch comes to diamond’s defence.Rapaport Diamond Report 25 (3 May):44-45

Zaitsev AM (2001) Optical properties ofdiamond – a data handbook. Springer-

Verlag, Berlin, 502 pp .

105E L E M E N T S , V O L . 1 , P P 1 0 5 – 1 0 8 MARCH 2005105

Growing Diamond Crystalsby Chemical VaporDepositionRussell J. Hemley, Yu-Chun Chen, and Chih-Shiue Yan1

INTRODUCTIONBy every measure, diamond is a unique material. Thesupreme hardness, singular strength, high thermal conduc-tivity, low thermal expansion, chemical inertness, excellentoptical, infrared, and X-ray transparency, and semiconduc-tor properties of the material continue to attract scientificand technological interest worldwide. However, the lack oflarge, high-quality single crystals of diamond prevents itsuse in many applications. Although the impurity content,strain, and overall quality of diamonds produced by high-pressure/high-temperature techniques (HPHT; e.g., >4.5GPa, ~1200°C) have improved in recent years (Barnard2000; Hazen 1993), these diamonds cannot be produced asperfect single crystals in the range of several tens of carats.Instead, they are limited commercially to up to ~3 carats (or0.6 g, roughly 7 mm across). In addition, diamond crystalsneed to be produced in different shapes for many applica-tions (e.g., as large plates). Indeed, our imagination regard-ing the applications of single-crystal diamond in manyways has been circumscribed by the limited size of availablehigh-quality HPHT diamond crystals, created either bynature or in the laboratory.

One of the most important developments in diamond syn-thesis is Chemical Vapor Deposition (CVD). The firstattempt at creating diamond using this process was reportedby Eversole in 1949 (see Liu and Dandy 1995). This discov-ery launched a significant period of exploration of variousCVD techniques for synthesizing diamond films and coat-ings in the 1980s (Kamo et al. 1983; Spitsyn et al. 1981). In1982, a group at the National Institute for Research in

Inorganic Materials (NIRIM)reported growth rates for diamondfilms of up to 10 µm h-1 (Matsumotoet al. 1982). The production of sin-gle-crystal particles, polycrys-talline films, and epitaxiallygrown films using the CVDmethod started in the late 1980s(Kamo 1990). Most of the thick(greater than 10 µm) polycrys-talline diamond films producedthen were not transparent. In1992, General Electric (GE)demonstrated the technology forproducing thick and transparentpolycrystalline CVD diamondfilms (Anthony and Fleischer1992). During this period, CVDdiamond was grown at low growthrates up to a few µm h-1 at sub-

strate temperatures below 1000°C in hydrogen gas mixtureswith a low concentration of methane (typically 0.1–2%).

Under the auspices of the NSF Center for High PressureResearch, our group at the Carnegie Institution launched aprogram with the University of Alabama–Birmingham (UAB)in the mid-1990s to produce large homoepitaxial single-crys-tal diamonds. This work resulted in the development of thehigh-temperature (>1000°C) and relatively high-pressure(150 torr) processes that led to the growth of single-crystaldiamond at very high growth rates (Yan 1999). During thecurrent decade, developments in this technique have over-come some of the constraints of HPHT methods. The tech-nique can be used to coat diamonds on various materials,control the doping with other elements, and grow diamondsof larger sizes. Single-crystal diamonds can now be producedat very high growth rates of 50–150 µm h-1 (Yan et al. 2002),and the fabrication of these crystals can be tuned to exhibitremarkable mechanical properties (Yan et al. 2004).

CHEMICAL VAPOR DEPOSITIONChemical vapor deposition (CVD) involves a series of gas-phase and surface chemical reactions and the deposition ofreaction products, i.e., diamond, on a solid substrate sur-face. For diamond deposition, a carbon-containing precur-sor is required for diamond nucleation and growth. Manygas-phase carbon sources can be used, and methane is themost common. In 1981, it was found that adding atomichydrogen to the CVD process stabilized the thermodynam-ically metastable diamond surfaces and promoted diamondgrowth, preferentially etching non-diamond carbondeposits and giving growth rates of the order of one µm h-1

(Spitsyn et al. 1981). Unlike HPHT synthesis, which is typi-cally carried out at pressures in excess of 5 GPa, diamond

1 Geophysical Laboratory, Carnegie Institution of Washington,5251 Broad Branch Road, N.W., Washington, D.C. 20015, USAE-mail: [email protected]

The synthesis of large single-crystal diamonds by chemical vapor deposi-tion (CVD) at high growth rate has opened a new era for applicationsof the material. Large and thick single crystals can now be produced

at very high growth rates, and the mechanical properties, chemistry, andoptical and electronic properties of the material can be tuned over a widerange. The single crystals can have extremely high fracture toughness andexceptionally high hardness following high-pressure/high-temperatureannealing. CVD single-crystal diamonds will make possible a new generationof high-pressure–temperature experimentation to study Earth and planetarymaterials and should enable a variety of other new scientific andtechnological applications.

KEYWORDS: Diamond, chemical vapor deposition, carbon,

high pressure, diamond anvil cell


CVD is usually done at a fraction of one atmosphere. Thedeposition is controlled by strongly coupled parameters, allof which have an impact on the final product. In general,the substrate temperature, the concentration of plasmaspecies, and the substrate materials determine the crys-tallinity of the growing material.

CVD techniques are generally applied using various methodsto activate the gases to generate radicals responsible for thedeposition. Electrical discharge CVD, especially microwaveplasma CVD, is now the most widely used technique for dia-mond deposition (FIG. 1). Microwaves dissociate the mole-cules in the gas to generate a plasma containing carbonatoms for deposition onto the substrate surface. The sub-strate is heated by the absorption of microwaves, the bom-bardment by energetic plasma species, and exothermicrecombination of radicals such as atomic hydrogen on thediamond growing surface.

SINGLE-CRYSTAL CVD DIAMONDSingle-crystal, homoepitaxial growth of diamond is beingcarried out by a growing number of research groups(Martineau et al. 2004). Homoepitaxial growth of single-crystal diamonds uses diamond as the substrate material.Several research groups have produced thin homoepitaxiallayers, usually less than 0.1 mm thick. In the 1990s, fabri-cation of thicker layers was reported (Badzian and Badzian1993; Janssen et al. 1990; Linares and Doering 1999; Plano

et al. 1994; Schermer et al. 1994). Most recently, theCarnegie group reported high-quality single crystals withthicknesses of 4.5 mm (Yan et al. 2004).

For bulk single-crystal diamond deposition, single-crystaldiamond substrates are used, since the quality of the dia-mond films is strongly affected by the quality of the sub-strates. Single-crystal CVD diamond deposition on single-crystal HPHT synthetic substrates was accomplished in theearly 1990s by plasma torch CVD (Snail et al. 1991) atgrowth rates of 100–200 µm h-1, but there are significantdifficulties with precise temperature and growth controlwith this technique. Growth by hot filament (Vitton et al.1993) and microwave plasma (Tzeng et al. 1993; Vitton etal. 1993) yields stable growth conditions, but for years thegrowth rates were low (0.1–10 µm h-1), and most platesproduced were only 0.1–1 mm thick. Single-crystal CVDdiamonds have been used by Element Six and Sumitomo inelectronics applications (Isberg et al. 2002; Okushi 2001)and by Apollo Diamond as gems (Wang et al. 2003). Boron,whose presence in diamond transforms it from an electricalinsulator into a p-type semiconductor, can be introducedduring the growth process, and development of boron-doped CVD diamond for electronic applications is inprogress (Kondo et al. 2002). Large-scale industrial produc-tion of single-crystal CVD diamonds has not yet occurredbecause of the high costs when the growth process is slow(such as 0.1–10 µm h-1), the limited size of the substrates(maximum area around 10 × 10 mm), and the poisoning ofsurfaces by twins and polycrystalline structures (Angus etal. 1992; Tamor and Everson 1994). Many of these prob-lems and limitations have recently been overcome.

Working originally with the UAB team, the CarnegieInstitution group has focused on the growth of large, single-crystal CVD diamond for use as anvils in high-pressureresearch. Producing large and durable diamonds at highgrowth rates with high strength, absence of twinning, andoptical transparency are the main goals and challenges.This work led to optimal conditions for enhancing growthrates and producing smooth, twin-free {100} diamond sur-faces (Yan 1999). With high gas pressures of 150 torr,methane concentrations up to 20% in the CH4/H2 gas mix-ture, and the addition of a small amount of nitrogen gas,diamond growth rates of up to 150 µm h-1 were achieved(Yan et al. 2002), much faster than the typical CVD dia-mond growth rate of 1 µm h-1. The growth-rate enhance-ment with the addition of nitrogen is consistent with

A. Schematic diagram of a microwave plasma CVDchamber; B. Photograph of a diamond growing in the

CVD chamber (Model: SEKI AX5400). The substrates can be Si, Mo,or other materials for heteroepitaxial growth, as well as natural orsynthetic diamond plates for homoepitaxy.

FIGURE 1

A

B

Modified, brilliant-cut, single-crystal diamond grown byCVD. The crystal is 2.45 mm high and was grown in one

day. The top 0.5 mm (table) of the crystal is a yellow Type Ib HPHT substrate; thus the yellow tint is due to internal reflection (the CVDdiamond is transparent and colorless) (Yan et al. 2004).

FIGURE 2


observations for polycrystalline diamond films (Muller-Sebert et al. 1996). This microwave plasma CVD methodcan routinely produce one 3 mm-thick, twin-free, gem-quality diamond in approximately one day (FIG. 2).Interestingly, single crystals produced in this way exhibitvery high toughness (Yan et al. 2004).

In addition to controlling the variety of impurities that canbe introduced for electronic applications, challenges forsingle-crystal CVD diamond growth include producinglarge-area plates (>10 × 10 mm) and large-volume crystals(>10 × 10 × 10 mm, >20 carats), as well as improving crys-tal quality (i.e., reducing strain). Microwave plasma CVDpermits growth on a single surface of the diamond sub-strate. Potential solutions for producing larger area CVDdiamonds include use of a mosaic or tile arrangement ofseveral {100}-surfaced diamond seeds (Kobashi et al. 2003),3-dimensional growth on multiple {100} faces, and enlarge-ment of each surface (FIG. 3A).

Diamond produced by the high-growth process is classifiedas Type IIa (nitrogen <20 ppm) and can be made transpar-ent (FIG 3B). On the other hand, yellow material grownunder certain conditions can be subjected to high P-Tannealing to produce transparent material. In fact, brown

single-crystal CVD diamond annealed at 2000°C and 5–7GPa results in color changes (FIG. 3C) (Charles et al. 2004;Yan et al. 2004) (see also Shigley, this issue). In addition,the hardness of the material can be significantly enhanced,beyond that of conventional natural and as-grown syn-thetic diamonds (Yan et al. 2004). The high fracture tough-ness of the material prior to annealing and the enhance-ment of the hardness correlate with changes in the mosaiccharacter of the crystals and transformation of residual car-bon defects present in the as-grown crystals.

APPLICATIONS OF LARGE SINGLE-CRYSTAL CVD DIAMONDA principal goal of the Carnegie effort has been to producelarge, single-crystal diamonds for new classes of high-pressure devices (FIG. 4). These would be used to pressurizesignificantly larger samples at very high pressures and reachmuch higher pressures and temperatures in the laboratory(e.g., 500 GPa, or 5 megabars). For this, we need very large(e.g., many tens of carats), ultrastrong, single-crystal dia-mond material that is simply not available in nature andcannot be produced by current HPHT methods (Hemleyand Mao 2002). Such diamonds will allow a broad range of

A. Photograph of a typical, three-dimensional, as-grownCVD crystal sitting atop a type 1b substrate. The CVD

layer is 1.2 mm thick and was grown in 12 hours. The yellow color isdue to the substrate. B. Left: 5 x 5 x 0.5 mm diamond plate grown inabout 5 hours by CVD. Right: plate produced by De Beers. C. Colorchanges after HPHT annealing: (i) brown, as-grown CVD layer deposit-ed on yellow type Ib HPHT seed; (ii) annealed at 1900°C and 6.5 GPafor 1 hour—CVD layer turned blue; (iii) annealed at 2200°C and 7.0GPa for 10 hours—CVD layer turned colorless while the substratebecame light yellow (from Charles et al. 2004).

FIGURE 3

A

B

C B

C

(i) (ii) (iii)

A. Example of a current ‘panoramic’ cell, shown herewith ‘conventional’ 0.3 carat diamonds. This type of

device can be scaled up in size for anvils in the tens of carat range (cen-timeter dimensions) and is also currently used with other high-strengthgems such as moissanite (single crystal SiC) (Xu et al. 2004). In additionto using large diamond crystals with significantly larger culets, a ‘belt’can be placed around the anvils (B) to provide additional support athigher loads and to increase sample thickness. The anvil tips can beshaped by micromachining techniques to further enhance sample vol-ume. An example is shown in (C), which is the shape to which dia-monds deform at very high loads (Hemley et al. 1997); it is also the pre-formed shape of ‘toroidal anvils’ used in lower pressure devices (seeHemley 1998). The sample volume is enhanced without sacrificing theversatility of conventional diamond anvil cells. This will make possiblenew kinds of experiments at very high pressures, such as NMR, inelas-tic neutron scattering, and in situ petrology studies.

FIGURE 44

A


REFERENCESAngus JC, Sunkara M, Sahaida SR, Glass JT

(1992) Twinning and faceting in earlystates of diamond growth by chemicalvapor deposition. Journal of MaterialsResearch 7 (11): 3001-3009

Anthony TR, Fleischer JF (1992) Trans-parent diamond films and method formaking. United States Patent 5, 110, 579

Badzian A, Badzian T (1993) Diamondhomoepitaxy by chemical vapordeposition. Diamond and RelatedMaterials 2(2-4): 147-157

Barnard AS (2000) The Diamond Formula.Butterworth Heinemann, Oxford

Charles SJ, Butler JE, Feygelson BN,Newton MF, Carroll DL, Steeds JW,Darwish H, Mao HK, Yan CS, Hemley RJ(2004) Characterization of nitrogendoped chemical vapor deposited singlecrystal diamond before and after highpressure, high temperature annealing.Physica Status Solidi (a) 201(11): 2473-2485

Hazen RM (1993) The New Alchemists:Breaking Through the Barriers of HighPressure. Random House, Time Books,New York

Hemley RJ (1998) Ultrahigh-PressureMineralogy: Physics and Chemistryof the Earth’s Deep Interior. Reviews inMineralogy 37, Mineralogical Societyof America, Washington DC

Hemley RJ, Mao HK (2002) New windowson earth and planetary interiors.Mineralogical Magazine 66(5): 791-811

Hemley RJ, Mao HK, Shen G, Badro J,Gillet P, Hanfland M, Häusermann D(1997) X-ray imaging of stress and strainof diamond, iron, and tungsten atmegabar pressures. Science 276(5316):1242-1245

Isberg J, Hammersberg J, Johansson E,Wikstrom T, Twitchen DJ, Whitehead AJ,Coe SE, Scarsbrook GA (2002) Highcarrier mobility in single-crystal plasma-deposited diamond. Science 297(5587):1670-1672

Janssen G, von Enckevort WJP, SchamineeJJD, Vollenberg W, Giling LJ, Seal M(1990) Rapid single crystalline diamondgrowth by acetylene-oxygen flamedeposition. Journal of Crystal Growth104(3): 752-757

Kamo M (1990) Synthesis of diamond fromgas phase and its properties. The RigakuJournal 7(2): 22-27

Kamo M, Sato Y, Matsumoto S, Setaka N(1983) Diamond synthesis from gasphase in microwave plasma. Journal ofCrystal Growth 62(3): 642-644

Kobashi K, Nishibayashi Y, Yokota Y, AndoY, Tachibana T, Kawakami N, Hayashi K,Inoue K, Meguro K, Imai H, Furuta H,Hirao T, Oura K, Gotoh Y, Nakahara H,Tsuji H, Ishikawa J, Koeck FA, NemanichRJ, Sakai T, Sakuma N, Yoshida H (2003)R & D of diamond films in the FrontierCarbon Technology Project and relatedtopics. Diamond and Related Materials12(3-7): 233-240

Kondo T, Einaga Y, Sarada BV, Rao TN,Tryk DA, Fujishima A (2002)Homoepitaxial single-crystal boron-doped diamond electrodes for electro-analysis. Journal of the ElectrochemicalSociety 149(6): E179-184

Linares R, Doering P (1999) Properties oflarge single crystal diamond. Diamondand Related Materials 8(2-5): 909-915

Liu H, Dandy DS (1995) Diamond ChemicalVapor Deposition: Nucleation and EarlyGrowth Stages. Noyes, New Jersey

Mao WL, Mao HK, Yan CS, Shu J, Hu J,Hemley RJ (2003) Generation ofultrahigh pressure using single-crystalchemical-vapor-deposition diamondanvils. Applied Physics Letters 83(25):5190-5192

Martineau PM, Lawson SC, Taylor AJ,Quinn SJ, Evans DJF, Crowder MJ (2004)Identification of synthetic diamondgrown using chemical vapor deposition(CVD). Gems and Gemology 40(1): 2-25

Matsumoto S, Sato Y, Tsutsumi M, SetakaN (1982) Growth of diamond particlesfrom methane-hydrogen gas. Journal ofMaterial Science 17(11): 3106-3112

Müller-Sebert W, Wörner E, Fuchs F, WildC, Koidl P (1996) Nitrogen inducedincrease of growth rate in chemical vapordeposition of diamond. Applied PhysicsLetters 68(6): 759-760

Okushi H (2001) High quality homoepitax-ial CVD diamond for electronic devices.Diamond and Related Materials 10(3-7):281-288

Plano MA, Moyer MD, Moreno MM, BlackD, Burdette H, Robins L, Pan LS, KaniaDR, Banholzer W (1994) Characterizationof a thick homoepitaxial CVD diamondfilm. Materials Research SocietySymposium Proceedings, Diamond, SiC,and Nitride Wide BandgapSemiconductors 399: 307-312

Schermer JJ, von Enckevort WJP, Giling LJ(1994) Flame deposition and characteri-zation of large type IIA diamond singlecrystals. Diamond and Related Materials3(4-6): 408-416

Snail KA, Marks CM, Lu ZP, Heberlein J,Pfender E (1991) High temperature, highrate homoepitaxial synthesis of diamondin a thermal plasma reactor. MaterialsLetters 12(5): 301-305

Spitsyn BV, Bouilov LL, Derjaguin BV(1981) Vapor growth of diamond ondiamond and other surfaces. Journalof Crystal Growth 52(1): 219-226

Tamor MA, Everson MP (1994) On the roleof penetration twins in the morphologi-cal development of vapor-growthdiamond films. Journal of MaterialsResearch 9(7): 1839-1848

Tzeng Y, Wei J, Woo JT, Landford W(1993) Free-standing single-crystallinechemically vapor deposited diamondfilms. Applied Physics Letters 63(16):2216-2218

Vitton JP, Garenne JJ, Truchet S (1993)High quality homoepitaxial growth ofdiamond films. Diamond and RelatedMaterials 2(5-7): 713-717

Wang W, Moses T, Linares RC, Shigley JE,Hall M, Bulter JE (2003) Gem-qualitysynthetic diamonds grown by a chemicalvapor deposition (CVD) method. Gemsand Gemology 39(4): 268-283

Xu J, Mao HK, Hemley RJ, Hines E (2004)Large volume high pressure cell withsupport moissanite anvils. Reviews ofScientific Instruments 75(4): 1034-1038

Yan CS (1999) Multiple twinning andnitrogen defect center in chemical vapordeposited homoepitaxial diamond. In:Ph.D. Dissertation of Department ofPhysics, University of Alabama atBirmingham

Yan CS, Vohra YK, Mao HK, Hemley RJ(2002) Very high growth rate chemicalvapor deposition of single-crystaldiamond. Proceedings of the NationalAcademy of Sciences 99(20): 12523-12525

Yan CS, Mao HK, Li W, Qian J, Zhao Y,Hemley RJ (2004) Ultrahard diamondsingle crystals from chemical vapordeposition. Physica Status Solidi (a)201(4): 25-27 .

experiments that cannot yet be performed under the P-Tconditions that prevail not only within our planet but alsowithin the larger planets in this and other solar systems.Already, the first experiments have been conducted at closeto 200 GPa with CVD-grown diamond anvils (Mao et al. 2003).

There are many other applications of large, single-crystalCVD diamonds that derive from the unique hardness,toughness, electrical properties, and thermal conductivityof diamond. The excellent hardness and toughness of thesingle-crystal CVD diamond grown at high growth rate ispotentially important for high-precision cutting tools.With diamond’s uniquely high thermal conductivity andlow coefficient of thermal expansion, fabrication of mono-lithic heat spreaders or microchannel structures from sin-gle-crystal CVD diamond would perform well beyond thatof thin diamond films in high-power thermal managementapplications. The availability of large, transparent single-

crystal diamonds will greatly extend their use as far-infrared or high-power microwave windows. In each ofthese applications, chemical and thermal shock resistanceis an important feature. Other applications include largeelectron field emission sources, micro-electromechanicalsystems, surface acoustic wave devices, and large semicon-ductor devices. In conclusion, with the rapid progress inthe development of CVD diamond, and especially withadvances in single-crystal diamond growth during the last2–3 years, the full potential of diamond for a broad rangeof applications is being realized.

ACKNOWLEDGMENTSThis work was carried out in collaboration with H. K. Maoand Y. Tzeng. We thank S. Gramsch and M. Phillips forhelp with the manuscript. This work was supported by theNSF-EAR and DOE/NNSA (CDAC). .

109E L E M E N T SMARCH 2005

All scenarios for the 21st century, howeverthey may differ in detail, agree on one thing:the world energy consumption shouldsteadily increase during the next decades, as aresult of both the growth of the globalpopulation and the economic development ofcountries like China, India, and Brazil, whichwill have to satisfy an increasing domesticdemand for consumer goods. It is predictedthat the energy needs should be about18 GTep in 2050 and 23 GTep in 2100,compared to 9.3 GTep in 2000 (GTep: giga-tonnes equivalent petroleum). This massiveincrease in energy production will require thesolution of complex technological andeconomic problems, as no energy source canmeet the demand alone. In addition, thesedevelopments will generate huge amounts ofgaseous, liquid, and solid wastes, which willhave to be properly managed if we are tocontrol and ultimately reduce the environ-mental consequences. The impact of energy-related wastes, whatever the source (petrole-um, nuclear, renewable sources such as wind,sun, tides and biomass), cannot be neglectedanymore, as the fluxes of matter released intothe environment are now large enough todirectly affect (bio)geochemical cycles andbasic self-regulated processes at the Earth’ssurface. For instance, there is now a wideconsensus within the scientific communitythat the continuous injection of hugeamounts of carbon dioxide into the atmos-phere since the begining of the industrialrevolution, essentially due to the consump-tion of fossil fuels, is responsible for globalwarming through the “green house effect”.This will be a major issue for this century,and it will have to be dealt with in ways thatwill take into consideration all the political,ethical, economic, industrial, scientific, andtechnological aspects.

Energy,waste, and the environment are thusstrongly linked terms that provide the title tothis remarkable book, edited by Prof. R. Gieréand P. Stille, with contributions from a panelof world-class experts, and published by theGeological Society Publishing House. Thebook has an original perspective, as it focuseson geochemical approaches to the treatment,confinement, and dispersion of wastesgenerated by energy production and con-sumption. Its greatest merit is that it demon-strates that international research at thehighest level is being carried out on energy-related wastes and, therefore, that thescientific community is dealing with the issue

as seriously aspossible. Indeed,this field hasbecome, in less thanthree decades, amajor area ofinteraction betweenscience and society,in which diverseconsiderations andinterests are inti-mately entangled.Through thirty-sixcontributedchapters, the readeris led to a deepunderstanding ofthe main environ-mental issues andthe techniquesdeveloped to determine the fate of thesewastes when released or disposed of in nature.In particular, emphasis is put on the use ofthe so-called “natural analogues” to buildstrategies for the confinement of toxic andradioactive components in natural systemsover extremely long periods of time, aprocedure that cannot be properly simulatedin the laboratory. Natural analogues arediverse materials and geochemical processes,occurring in a range of geological (or evenarchaeological) sites, that can be investigatedby scientists. Analogues contribute to thedevelopment of waste immobilizationtechniques, the design of disposal concepts,the confirmation of key mechanismsidentified in laboratory experiments, andthe testing of the robustness and credibilityof models. Such a combined approachguarantees, with reasonable confidence, thestability and safe isolation of wastes in theenvironment. In particular, thermodynamicmodeling and kinetic concepts are criticalgeochemical tools in this respect. All theseaspects are described in the book.

The five sections of Energy, Waste and theEnvironment: a Geochemical Perspectivecontain numerous and thought-provokingideas, a few of which I shall highlight. Thefirst section deals with issues related to thenuclear fuel cycle. It is argued that advancedfuel cycles and waste management technolo-gies must be developed if this source ofenergy is to contribute significantly todecreasing the carbon dioxide concentrationin the atmosphere. Due to the very longtime spans over which safety must be

guaranteed for the undergrounddisposal of nuclear wastes, the roleof natural analogues is emphasized.The fossil fuel cycle is discussed inthe second part of the book. Thereduction of carbon dioxideemissions is envisaged throughinjection and trapping in deepgeological formations. In addition,the mineralogical and geochemi-cal characterization of mining andcombustion wastes appearsessential to assess the environ-mental impact of the extensiveuse of coal. Among alternativesources, the exploitation ofgeothermal heat, supposedly anenvironment-friendly technology,is described in part four of thebook as generating huge amountsof waste fluids. The deep under-ground reinjection of these fluidsis explored as a possible way tominimize their environmentalimpact. The fifth part of the bookdeals with the waste-to-energycycle. The interesting idea ofconsidering “wastes” as a possible

source of valuable chemical components andenergy (an idea already defended in the fiftiesbut since forgotten) is discussed. Finally,water-waste interactions, which are the mainways in which toxic and radioactive elementscan be released and dispersed in the environ-ment, are carefully examined in part six.

In conclusion, this timely book demonstratesthat geochemistry is a key science to help ussolve the difficult environmental issues raisedby the world’s economic development.

Jean-Claude PetitService de Chimie Moléculaire

DSM/DRECAMBât. 125 CEA/Saclay

91190 Gif sur Yvette, France

Review

109

Energy, Waste and the Environment: aGeochemical Perspective

R. Gieré and P. Stille (editors) 2004. Energy, Waste and theEnvironment: a Geochemical Perspective. Geological Society ofLondon, Special Publication 236, 688 pp, ISBN 1-86239-167-x,135£

WANTED

The Hudson Institute of Mineralogy, a not-for-profit organization chartered by theBoard of Regents of the State University ofNew York is seeking used analytical equip-ment, thin sections and mineral specimensfor its descriptive mineralogical laboratoryand educational programs. We are dedicatedto classical mineralogical research, preser-vation of mineral specimens, and educationaloutreach to primary and secondary schoolteachers and students. If your institution isupgrading its analytical equipment, we wantyour used, working devices. Further, if youare disposing of minerals, thin sections orsimilar geological artifacts, let us put them togood use; aesthetics are unimportant, labelsare! Please contact:

The Hudson Institute of MineralogyPO Box 2012 • Peekskill, NY 10566-2012

www.hudsonmineralogy.org


Society News

European Association for Geochemistry

FROM THE PRESIDENT

The European Association for Geochemistry (EAG) is delighted to be

joining this great new publishing venture, which I hope heralds a ren-

aissance for learned societies in the fields of geochemistry and mineral-

ogy. I am very pleased to have this opportunity to congratulate the

whole Elements editorial team on an outstanding first issue that has

established a benchmark of quality for the future. This is going to be a

publication that gets opened and read when it arrives! We may be late

to the party, but the EAG is in the process of expanding its range of

activities, and we hope to be able to make valuable contributions to

Elements in the future.

Bruce Yardley, EAG President

EAG NEWS AND ANNOUNCEMENTS

A Few Words about EAGFounded in 1985 to promote geochemical research and study inEurope, EAG is now recognized as the premiere geochemical organiza-tion in Europe encouraging interaction between geochemists and thoseof associated fields, and promoting research and teaching in thepublic and private sectors. Visit our website at www.eag.eu.com

Development of European Web Network DatabaseTowards the integration of geochemistry in Europe, the EAG iscurrently building a web directory of active European geochemistsand geochemistry groups. We encourage you to list your personaland/or group website in this database. To include yourself and/oryour research group in this database, simply send an e-mail [email protected] Include website address, your nameor group name, country, and a SHORT descriptive title. Examplesmight include:

www.aschmidt.xyz,Anne Schmidt, Germany, stable Fe isotopes, or

www.johnsmith.xyz,John Smith, England, molecular dynamics modeling, or

www.unipa.l’enviro.xyz,Environmental Geochemistry Centre, France, weathering processesand the water cycle.

European GeosciencesUnion General Assembly2005, Vienna, Austria,April 24–29The EAG is co-sponsoring threesessions at the 2005 EGU GeneralAssembly (http://www.coperni-cus.org/EGU/ga/egu05)

SESSION GM4: Climatic andtectonic controls on the Earth’sweathering systemConvenor: F. von Blanckenburg;co-convenors: K. Burton and S.Gíslason

Weathering and erosion areamongst the primary processesresponsible for the evolution ofthe landscape and affect thecycles of many elements at theEarth’s surface; both are influ-enced by active tectonics orclimate change. This session aimsto bring together the range ofapproaches used to study thechemical, physical, and biologicalprocesses involved in weatheringand erosion, both today and inthe past. Contributions will dealwith field, experimental, andmodeling studies, including workon catchment areas and deltas,soils, hydrology, vegetation,lithology, and topography.

SESSION VGP24: Application ofnovel geochemical techniquesto problems of cosmochemistryand early Earth evolution Convenor: C. Münker; co-convenors: S. Weyer and T. Elliott

The understanding of processesactive during the first billionyears of the solar system and theEarth strongly relies on geochem-ical criteria because any directrock record is either absent orvery scarce. In the past decade,new techniques such as MC-ICP-MS, high precision TIMS ormicroanalytical developmentshave spurred investigations ofearly solar system materials andold terrestrial rocks. Major break-throughs include the applicationof new extinct nuclide series, nontraditional stable isotopes, andthe search for nucleosyntheticand elemental anomalies in smallparticles. The aim of this sessionis to provide an overview of thecurrent state of knowledge withan emphasis on new geochemicaltechniques and concepts.

SESSION VGP12: Geochemical insand outs of subduction zonesConvener: C. Chauvel; co-convener: W. Sun

This session aims at evaluatingthe geochemical budget of sub-duction zones. Approaches tothis budget can be related to thecomposition of oceanic crust thatwill be subducted, to the compo-sition and variability of the sedi-mentary piles, and to the quan-tification of the subductedmaterial. Geochemical studiescentered on the composition ofvolcanic arcs and of the materialsfound in back-arc and fore-arcbasins are also central keys forthe general budget. Confronta-tion of these different approachesshould help our community todecipher the complex processesoccurring in one of the key envi-ronments of our planet andconsequently to better under-stand its long-term evolution.

The 15th AnnualGoldschmidt Conference: A Voyage of Discovery,Moscow, Idaho, USA,May 20–25The Goldschmidt Conference isthe premier annual meeting ingeochemistry and mineralogy.The 2005 meeting will cover thefull range of geochemistry fromcosmochemistry to the origin oflife. It will be special because2005 is the 50th anniversary ofthe Geochemical Society. Comecelebrate this anniversary in thefoothills of the Rocky Mountains!The conference also takes placeduring the bicentennial of theLewis and Clark expedition—theCorps of Discovery.

Seventh InternationalSymposium on the Geochemistry of the Earth’sSurface (GES-7), Aix-en-Provence, France,August 23–27The principal focus of past meet-ings has been on processes oper-ating at the surface of the Earthrather than on deep crustal geo-chemical processes. The GES-7meeting continues that overalltheme with some greater emphasison the multiscale environmentalbiogeochemistry of the Earth’ssurface and subsurface (www.cerege.fr/GES7). The technicalsessions will consist of invited

UPCOMING EAG-SPONSORED MEETINGS/SESSIONS

oral contributions and postersthat complement the themes ofthe oral presentations. All contri-butions must be accompanied bya four-page abstract. The abstractswill be reviewed and published ina special issue of Journal of Geo-chemical Exploration, a sisterpublication of Chemical Geology.Abstract submission deadline isApril 1, 2005.

The themes of the symposia are:

1. Environmental impact ofwaste management

2. Water cycle and resources:geochemical tracers and con-taminants

3. Biogeochemical processes insoils and ecosystems: frommolecular to landscape scale

4. Weathering: processes, ratesand ages

5. Coastal biogeochemistry: fromland to continental slope

6. Global element cycles andclimate change through Earthhistory

Update on the EuropeanResearch CouncilThe creation of a new EuropeanResearch Council (ERC) is reportedto be gaining support in Brussels.All but two of the EuropeanUnion members officially sup-ported the creation of the ERCduring a November 2004 meetingand have requested the EuropeanCommission to draft a formalproposal. The ERC is to be a newfunding agency that would sup-port basic research in all areas ofscience based solely on scientificquality; this agency would besimilar to the National ScienceFoundation in the United States.The ERC would be created as partof the Seventh Framework Pro-gram and would start in 2007.The estimated ERC budget for theseventh framework (2007–2010)is rumored to be approximately2 billion Euros.

Opening of the new EarthSciences Institute, Toulouse, FranceIn June 2004, the Laboratoiredes Mécanismes et Transferts enGéologie (LMTG) abandoned itsold laboratories in the center of


Society News

Toulouse to move into a newstate-of-the-art research and teach-ing facility near the main campusin Rangueil. The laboratory iscomposed of 72 researchers andacademic staff, 40 administrativeand technical staff, 36 students,and 6 postdoctoral fellows. TheLMTG is devoted to studying theinteractions between water andthe solid Earth, from the mantleto the biosphere. The particularstrength of the LMTG is that itcan master the whole range ofscientific concepts as well as mostof the analytical and experimen-tal methods needed to make asignificant contribution to thischallenging scientific problem.Members of the permanent staffof the LMTG include its director,Bernard Dupré, Jacques Schott,and Eric Oelkers (website:www.lmtg.obs-mip.fr).

Creation of new Schoolof Earth, Atmospheric andEnvironmental Sciencesin Manchester The recent merging of the Uni-versity of Manchester withUMIST in October 2004 has ledto the formation of a new Schoolof Earth, Atmospheric and Envi-ronmental Sciences (website:www.seaes.manchester.ac.uk).Largely comprising staff from theformer Department of EarthSciences at the University ofManchester and the AtmosphericChemistry and Physics Group inthe Physics Department atUMIST, the new school hasresearch strengths in atmosphericphysics and chemistry, physicsand chemistry of minerals andfluids, geochemistry includingenvironmental geochemistry,petroleum geology and basinstudies, isotope geochemistry,geomicrobiology, structural geol-ogy, and experimental rock defor-mation. Facilities include those ofthe Williamson Research Centrefor Molecular EnvironmentalScience and of the Centre forIsotope Geochemistry and

Cosmochemistry. The Head ofSchool is Professor Richard Pat-trick. The Director of Research isProfessor David Vaughan.

European Weathering Systems Science (WSS) InitiativeEuropean scientists, with supportfrom the Worldwide UniversitiesNetwork, convened a round tablediscussion in London on October14, 2004, creating a scientificframework for a joint European–US research program in Weather-ing Systems Science (WSS). ThisLondon meeting established acommitment between Europeanand US researchers to pursue ajointly directed program betweenthe EC and NSF to build an inter-national WSS Consortium con-tributing to the delivery ofEU research on the sustainablemanagement of soils (EU SoilDirective, now being drafted) andsustainable management of water(EU Water Directive, now beingimplemented). At present theEuropean and internationalcommunities are addressingmany of the outlined weatheringand soil issues, but in a fragment-ed manner. The European WWSInitiative proposes to advance, ina holistic way, our knowledge ofthe life cycle of the entire soilsystem by using an integratedmultidisciplinary approach.Contact K.V. Ragnarsdottir [email protected]

Please send any potentialitems for inclusion in futureEUROPEAN GEOCHEMICALNEWS BRIEFS to either Eric Oelkers([email protected])or Mark Hodson ([email protected]).

New Earth Sciences Institute, opened inthe summer of 2004, Toulouse, France.

EUROPEAN GEOCHEMICAL NEWS BRIEFS


Society News

International Associationof GeoChemistry

FROM THE PRESIDENTWe are pleased to join Elements, not only because ofthe timely advent of this publication, but alsobecause of the need to build links between the majorgeochemical and mineralogical societies of theworld.

Many of you will have known the IAGC, now theInternational Association of GeoChemistry, by its

former name, the International Association of Geochemistry and Cos-mochemistry. This subtle change reflects the “new look” of the Associ-ation, which has involved a migration away from the more fundamen-tal fields of geochemistry towards applied research. This is reflected, notonly by IAGC’s association with the journal Applied Geochemistry, butalso by the working groups and special symposia organised by the Asso-ciation, for example in geochemistry and disease, the Water-Rock Inter-action meetings, and geochemistry training in developing countries.We hope to use the magazine to build links with other societies andexpand the knowledge of geochemistry worldwide.

John Ludden, President IAGC

The International IngersonLecture originated from abequest by Earl Ingerson tothe International Associa-tion of Geochemistry andCosmochemistry in 1985 toprovide an award for distin-guished geochemists. Theaward, which includes aframed certificate and a$500 honorarium, is givenevery two to four years. Todistinguish this award fromthe Ingerson Lecture Awardpresented by the GeochemicalSociety (from a similar bequest byEarl Ingerson), the IAGC in 2002designated the award as theInternational Ingerson Lecture. Therecipient is invited to present thelecture at a suitable internationalgeochemical meeting, such as theGoldschmidt Conference, wherethe award is presented.

The International Ingerson Lecturefor 2004 was delivered inFlorence, Italy at the 32nd Inter-national Geological Congress

by Prof. Stephen Moorbath ofOxford University and was enti-tled “Oldest rocks, earliest life,heaviest impacts, and theHadean-Archaean transition”.The full text of Professor Moor-bath’s presentation will be pub-lished shortly in Applied Geochem-istry. Previous recipients of theaward have included A.E. Ring-wood, A.A. Levinson, K.-H.Wedepohl, A. Masuda, D.M.Shaw, U.G. Cordani, and B.F. Jones.

This year has seen some bigevents and changes for the IAGC.First, the Annual Council Meet-ing was held in conjunction withthe International GeologicalCongress (IGC) in Florence, Italy,on August 20. The meeting waswell attended by both councilmembers and chairmen of IAGCworking groups. Two meetingswere held, in fact. The firstincluded a vote by the outgoingcouncil and executive members,who had served for up to the lasteight years, to appoint new offi-cers. In the subsequent meeting,the new statutes were approvedand, more significantly, the nameof the IAGC was changed fromthe International Association ofGeochemistry and Cosmochem-istry to the International Associa-tion of GeoChemistry. Thischange reflects the shift in

emphasis of IAGC members overthe years, away from theoreticalgeochemistry and cosmochemicalresearch, to applied geochem-istry, especially in the biogeo-chemical, medical, and environ-mental fields. This is borne outby the fact that the IAGC’s jour-nal, Applied Geochemistry hasbecome an important andincreasingly read journal in thegeological world.

One of the main aims of theIAGC is to sponsor symposia andinternational meetings on variousaspects of geochemistry, primari-ly through its working groups butalso through a conference grantsprogram. For instance, the IAGCsponsored a thematic sessionentitled “Frontiers in AnalyticalGeochemistry” at the Interna-tional Geological Congress, inFlorence, Italy, last year, and a

collection of papers on this willappear in the near future as aspecial issue of Applied Geochem-istry. In 2005, IAGC will alsosponsor a special session onarchaeological geochemistry atthe April EGU meeting in Vienna,and will join in the sponsorshipof the 15th Goldschmidt Confer-ence in Moscow, Idaho in May(see article next page). IAGC willalso be a general sponsor of theInternational Symposium onApplied Isotope Geochemistryin Prague on September 11–16(AIG-6).

At present IAGC has sevenworking groups: Water-RockInteraction, Global Geo-chemical Baselines, Geo-chemistry of the Earth’sSurface, Applied IsotopeGeochemistry, Thermody-namics of Natural Processes,Geochemical Training in

Developing Countries, and Geo-chemistry of Health and Disease.The activities of each of these willbe featured in upcoming issues ofElements.

The IAGC has recently revised itswebsite, which now containsinformation on the Association,its history, details of sponsoredmeetings, the biannual Newsletter,how to join, and the activities ofthe working groups. The siteaddress is http://www.iagc.ca.

ACTIVITIES OF THE IAGC

THE INTERNATIONAL INGERSON LECTURE

Stephen Moorbath (right) receivingaward from IAGC President John Ludden

Applied Geochemistry is the official journal of the International Associa-tion of GeoChemistry. The journal was launched in 1986 under theeditorship of Brian Hitchon. The early volumes of the journal consist-ed of around 700 pages in six issues. The journal has expanded dra-matically since those early days with 2000 pages being published inthe twelve issues of volume 19 in 2004.

Applied Geochemistry is an international journal devoted to publicationof original research papers, rapid research communications, and select-ed review papers in geochemistry that have some practical applicationto an aspect of human endeavour, such as the preservation of theenvironment, environmental monitoring, agriculture, health, wastedisposal and the search for resources. Topics covered include:

1. Environmental geochemistry(including natural and anthro-pogenic aspects, and protectionand remediation strategies)

2. Hydrogeochemistry, surface andgroundwater

3. Medical geochemistry

4. Agricultural geochemistry

5. The search for energy resources(oil, gas, coal, uranium, andgeothermal energy)

6. The search for mineral deposits(metalliferous and non–metalliferous)

7. Upgrading of energy and mineralresources where there is a direct geochemical application

8. Waste disposal including the specific topic of nuclear waste disposal.

Papers on applications of inorganic, organic, and isotope geochemistryare therefore welcome provided they meet the main criterion. Theexecutive editor is Ron Fuge (Institute of Geography & Earth Studies,University of Wales, Aberystwyth, Ceredigion, Wales SY23 3DB, UK.Fax: +44 (0) 1970 622659, e-mail: [email protected]). IAGC membersbenefit from discounted subscription cost for Applied Geochemistry.

Some of the papers scheduled to be published in the early part of 2005are listed below.

J. Jönsson, P. Persson, S. Sjöberg, and L. Lövgren: Schwertmanniteprecipitated from acid mine drainage: phase transformations,sulphate release and surface properties.

J. E. Gray, D. L. Fey, C. W. Holmes, and B. K. Lasorsa: Historicaldeposition and fluxes of mercury in Narraguinnep Reservoir,southwestern Colorado, USA.

D. N. Castendyk, J. L. Mauk, and J. G. Webster: A mineral quantifi-cation method for wall rocks at open pit mines, and applicationto the Martha Au-Ag mine, Waihi, New Zealand.

B. L. Brown, A. D. Slaughter, and M. E. Schreiber: Controls onroxarsone transport in agricultural watersheds.

G. Jacks, P. Bhattacharya, and V. Chaudhary: Controls on thegenesis of high-fluoride waters in India.

M. A. Glaus, B. Baeyens, M. Lauber, T. Rabung, and L. R. Van Loon:Influence of water-extractable organic matter from OpalinusClay on the sorption and speciation of Ni(II), Eu(II) and Th(IV).

R. L. Seiler, K. G. Stollenwerk, and J. R. Gabarino: Factors control-ling tungsten concentrations in ground water, Carson Desert,Nevada.

Z. Cheng and K. A. Foland: Lead isotopes in tap water: implicationsfor Pb sources within a municipal water supply system.


Society News

For the first time, IAGC is collab-orating with the GeochemicalSociety, the European Associationfor Geochemistry, and the Miner-alogical Society of America tosponsor the 15th annual Gold-schmidt Conference. This pre-mier international geochemistryconference (www.uidaho.edu/gold2005) will be held in Moscow,Idaho (USA) from 20 to 25 May,2005. IAGC will organise thethree symposia described below.Interested geochemists areencouraged to participate in thisspecial conference and, if appro-priate, one of the three IAGC-sponsored sessions.

The geochemistry of mercury –session SS-74Conveners: John Gray([email protected]), U.S. GeologicalSurvey, and Mark Hines([email protected]), Univer-sity of Massachusetts

There is currently abundantresearch involved in the evalua-tion of natural and anthropo-genic mercury contamination ofthe air, land, water, and wildlifeworldwide. Presentations in thissession will discuss the globalmercury cycle, mercury distribu-tion and speciation at contami-nated sites, and mercury cyclingin terrestrial and aquatic systems.

The halogens and their isotopesin marine and terrestrialaqueous systems – session SS-75Conveners: Glen Snyder ([email protected]), RiceUniversity and Jean Moran([email protected]), LLNL

The generally conservative natureof halides in groundwater andmarine systems has led to their

application as tracers in marineand hydrological systems. Overthe past 25 years, the develop-ment of accelerator mass spec-trometry (AMS) techniques fordetermination of I-129 and Cl-36,along with the development ofstable isotope techniques forchlorine, has opened up newavenues for examining halogenmigration and residence times.The goal of this session is toprovide a forum to address anyaspect of the halogens and theirrelation to aqueous systems,including the interactionsbetween ocean, soil, freshwater,and atmospheric reservoirs.

Watershed-scale geochemistry –session SS-81Conveners: Berry Lyons(lyons.142@osu), Ohio StateUniversity, and David Long([email protected]), Michigan StateUniversity

The focus of this session is geo-chemistry at the watershed scale.Of specific interest are the geo-logical, mineralogical, and geo-chemical nature of sources andsinks and their impact on localand global geochemical cycles;the factors determining mineralalterations at the Earth’s surface;geochemical kinetics of miner-al–water interactions during rockweathering; the hydrological,hydrochemical, and biogeochem-ical processes that occur alongfluid pathways and influencethe migration of elementsthrough the landscape; and thegeochemistry of human impactson watersheds.

THE GOLDSCHMIDT CONFERENCE 2005APPLIED GEOCHEMISTRY, THE JOURNAL OF THE IAGC

GORDON RESEARCH CONFERENCE ON INORGANICGEOCHEMISTRY AND ORE DEPOSITS

Metals in ore-forming systems: Sources, transport, and depositionPROCTOR ACADEMY, ANDOVER, NEW HAMPSHIRE, JULY 31 – AUGUST 5, 2005

The Gordon Research Conference on Inorganic Geochemistryaddresses the geochemistry of metal-rich systems. The organizers

are seeking expressions of interest from those who wish to partici-pate. Subsidies for students and junior level participants are antici-pated, particularly for those presenting posters. We also seek the par-ticipation of women and members of minority groups.

A preliminary program and conference details are available atwww.grc.uri.edu/programs/2005/inorgeo.htm. The organizers areJean Cline, Steve Garwin ([email protected]), andChris Heinrich (heinrich@erdw. ethz.ch). Those who wish to partici-pate should contact Britt Meyer by e-mail at [email protected] who wish to present a poster are invited to send a briefabstract together with expression of interest. To apply for funding,contact Jean Cline ([email protected]).

The Clay Minerals SocietyIn Memory of Robert Coltart Reynolds Jr. October 4, 1927–December 12, 2004

Born to Ludmilla and Robert C.Reynolds Sr. on October 4, 1927, inScranton, PA, Robert C. Reynolds Jr.was a 1945 graduate of Dalton (PA)High School. After serving in the ArmyAir Force, he graduated from KeystoneJunior College and Lafayette College.He then earned his doctorate fromWashington University in St. Louis in1955. After working for Pan-Am Petro-leum for five years, he went to Dart-mouth College in 1960 where he roseto the Frederick Hall Professor of Min-eralogy Chair. Prof. Reynolds, a Distin-guished Member of The Clay Minerals

Society and a Brindley Lecturer, was president of the Society in1991–1992. He received the Roebling Medal from the MineralogicalSociety of America, its highest award and recognition. The Clay Miner-als Society has created a Robert C. Reynolds Jr. Research Award andsupports the awarding of the Reynolds Cup at a biannual contest toquantitatively analyze samples of mixtures of clay-size minerals. Heleaves behind, in addition to the inspiration he has given to genera-tions of students, a long list of seminal papers. Perhaps the most influ-ential of these is his 1967 paper in volume 52 of American Mineralogist,“Interstratified clay systems: calculation of the total one-dimensionaldiffraction function”, which is the basis of his computer program,NEWMOD©. In 1994 he added WILDFIRE©, a program for calculatingthe three-dimensional X-ray diffraction tracing of illite polytypes anddegrees of disorder in illite and illite–smectite mixed-layered minerals.It is not an exaggeration to say that these programs have revolution-ized the way in which clay minerals and other layered minerals arestudied.

Professor Reynolds’s journey through life ended on Sunday, December12, 2004. In the course of that journey, he accomplished much andtouched the lives of many. Robert (Bob) C. Reynolds Jr. grew up intiny Dalton, just 12 miles from Scranton. How tiny you ask? Therewere 16 in his 1945 high school graduating class, 14 of whom hadbeen in the first grade with him. While at Lafayette College, he mar-ried Roseann Fabio from Scranton. They had met and become sweet-hearts while in high school. They had three children, Fayette, Jolene,and Bob III. Fate brought Bob and John Hower together at Washing-ton University, where they met standing in line to register for classes.They became lifelong friends in the fullest sense of the word. At Dart-mouth College, Bob became an institution. He was too broad a manfor any one of us to have known him completely. He is rememberedby each person he touched, but each in a different way. The compos-ite of these memories, some of which are expressed below, conveysthe sense of this influential man.


Society News

“Bob was known as an outstanding teacher amongst the geologystudents at Dartmouth. I remember Bob’s teaching style as a mixof clear explanations, organized lecture style, practical lab exer-cises, hands-on review sessions, experiments and field trips, anduse of humorous and illustrative analogies (e.g., in an undergrad-uate mineralogy class, deconstructing the complexity of XRD pat-terns by drawing an elephant on the board and asking us what itwas, then pointing out that these XRD patterns he was showingus were no more than mere representations of mineralogicalstructures, much like his elephant was just a representation of aliving creature). Outside of the classroom, Bob’s humblenesssometimes made it hard for him to understand that he under-stood his field at a level that left him with few peers. This did nottranslate to his classes, which were so well taught, but rather tothe informal conversations that groups of students and facultyhave together. I remember leaving his office with other grad stu-dent colleagues and professors and just marveling, both at Bob’swondrous mind, and also his cluelessness about how smart hereally was. Jim Aronson, Page Chamberlain, Mike Poage, and I went to seeBob and Roseann a couple of years ago. After a while Roseann leftthe room. Bob peered around the corner, said, ‘Is she gone?’ thenpulled out a cigarette and lighter. He was on O2 and had a hissingsupply tank over in the corner of the room. As he flicked thelighter, all four of us flinched, our faces showing fear of explosion.Bob chuckled and said ‘Don’t worry, I’ve done the calculations,there’s not enough free oxygen in the air to cause an explosion.’We all laughed, in part because it was so fun to laugh with Bob,perhaps in part due to nervous release, but it summed up so muchabout Bob—his hell-be-damned attitude and penchant for livingon the edge, his boyish approach to certain things (as if Roseannleaving the room for five minutes would keep her from knowingthat he had just smoked), and his analytical approach to life.

Peter Ryan

When we were students at Dartmouth, we all called him the BigGuy, and thoroughly meant it in scientific stature, love and zestof life, total inspiration, and not just girth.

Dougal McCarty

Bob and Denny (Eberl) taught me how to climb when I first gotto Dartmouth, and I climbed quite a bit with Bob in those days.When I was finishing my Master’s with Bob at Dartmouth, he justsent me to John (Hower) to do a PhD; I never asked what I shoulddo next or about continuing grad studies; Bob just SENT me toJohn. It was like he was giving me to his friend. He was so god-damned strong and energetic as a young man; I guess that’s howhe survived so long with all the alcohol and cigarette smoke hepumped into himself. I’m still coming to terms with his dying.

Gray Thompson

The most distinctive aspect of Bob Reynolds for me is that I havenever run into anybody who had an unkind thing to say abouthim. How can someone who has been such a leader, who has hadto make tough decisions, accomplish this? I don’t have theanswer. Perhaps it was his exercise of tolerance for the views ofeveryone, not just the elite; perhaps it was that such a great sci-entist could be so modest; perhaps it was his finely tuned sense offairness; perhaps it was his great sense of humor. Whatever it was,I hope we as a clay society can find a way to honor him for beingsuch a great scientist and a great person.

Herman Roberson

Bob Reynolds in 1983-1984. PHOTO

FROM DARTMOUTH COLLEGE’S ARCHIVES.

The CMS congratulates the fol-lowing eight students uponreceiving research grant awardsfor 2004:

Michael K. DeSantis, Universityof Cincinnati, “Regional Correla-tion of the Tioga K-bentonitesCluster Using Apatite Trace Ele-ment Fingerprinting”

Cinzia Fissore, Michigan Tech,“Effect of Temperature and ClayMinerals on Long-term Soil Car-bon Stabilization”

Michelle Leigh Foster, The Uni-versity of Montana, “K-Bentonitesin the Belt Supergroup, Montana”

Deb P. Jaisi, Miami University,“Investigation of MicrobiallyMediated Clay Mineral Reaction”

Debra S. Jennings, University ofKansas, “A PaleoenvironmentalAnalysis of Morrison FormationDeposits, Big Horn Basin,Wyoming: A MultivariateApproach”

Pankaj Kulshrestha, SUNY–Buffalo, “Investigating theMolecular Interactions ofOxytetracycline in Clay andOrganic Matter”

Scott Mitchell, Brigham YoungUniversity, “An Improved MUSICModel for Gibbsite

Gayle Anthony Ordway, PortlandState University, “Origin of Ver-miculite in Well-drained Soils ofthe Southern Oregon Coast”


Society News

I know Professor Reynolds as a brilliant scientist, and without anyexaggeration one may state that he is the best-known expert inthe world on X-ray diffraction analysis of finely dispersed layercompounds and, first of all, of clay minerals.

Victor Anatolievitch Drits

Bob always had to do things for himself. He didn’t just use some-one’s equation. He had to derive the whole thing to be sure heunderstood it and that it was correct. He was very “hands on” inthe lab and in everything. When he needed to know the time ofday, he’d build a clock! Fred Mumpton once told me thatReynolds’ papers were just about the only ones submitted thatneeded no editing. They were always perfect. Hower saidReynolds was the smartest person he knew.

David Pevear”

$500$1000

Pankaj Kulshrestha

Deb Jaisi

Debra Jennings

STUDENT RESEARCH GRANTS AWARDED

$2500STUDENT RESEARCH GRANT APPLICATIONS

DUE MARCH 21, 2005

Grant applications for partial financial support of master’s and

doctoral student research in clay science and technology are

due at the Society Office by March 21. Applications will be judged

based on the technical quality of the research proposal, the qualifica-

tions of the applicant, and financial needs of the research project. The

grants in amounts of up to $2500 each will be awarded by Septem-

ber 2005. There is no restriction with regard to nationality, and a stu-

dent does not need to be a member to apply. Application forms and

instructions are available at www.clays.org or from the Society Office

([email protected]). Electronic submission is preferred.

STUDENT TRAVEL GRANT APPLICATIONS

DUE MARCH 21, 2005

Grants in amounts of up to $500 per grant for students travel-

ling within the country or region of the CMS Annual Meeting

and in amounts of up to $1000 per grant for students travelling over-

seas to the meeting are due at the Society Office by March 21. There

is no restriction as to nationality. Students must submit an abstract for

either an oral or poster presentation to the CMS Annual Meeting

(www.middlebury.edu/cms). Application forms and instructions are

available at www.clays.org or from the Society Office

([email protected]). Electronic submission is preferred. Applicants will

be notified within about six weeks, in time to make travel arrange-

ments for the meeting.

Some things you might not have known about Bob Reynolds: The dayhe was awarded the title Distinguished Member of CMS, he came tothe room almost disabled with astonishment. I think his humilityprevented him from anticipating that others saw him in that category.Or, that he really appreciated classical music. His favorite piece wasMahler’s Ninth Symphony. Or, that there was a Mozart piece that heassociated with working with John Hower in Venezuela and, when heheard it, it brought tears to his eyes. Or, that he was a student ofWorld Wars I and II. Or, that he built his own rifle from scratch. Or,that he changed the shock absorbers on his motorcycles every 5000miles whether they were apparently worn or not. Or, that he delightedin the challenge of identifying mushrooms and then testing that iden-tification by eating them. He was full of stories about the awful thingsthe wrong mushrooms would do to you. Or, that if you were interestedin something, he was interested in it.

I loved him; we all loved him.

Dewey Moore


Society News

and several papers illuminate thiswith clarity. Two papers on veingold deposits (Mernagh et al. andBaker and Seccombe) combinefluid inclusion thermometric datawith Raman analysis to character-ize the fluid chemistry and oreformation. Similarly, Carruzzo etal. and Yang et al. integrate fluidinclusion and stable isotope datato examine the nature of fluidsassociated with mineralization ingranitic rocks of Maritime Cana-da. Interestingly, despite similarsettings, the fluid characteristicsare notably different, with thedeep penetration (10–12 km) ofmeteoric water demonstrated forone area. In another magmatic-related environment, Shin et al.described As–Bi-mineralized veinsfrom South Korea and integratefluid inclusion and stable isotopestudies. The features of higherlevel, epithermal settings areaddressed in two papers. Mooreet al. discuss an active geother-mal system in Indonesia, and inparticular, the consequences ofdescending acid-sulfate waters. Incontrast, Kouzmanov et al.describe the genesis of a high-sulfidation assemblage from aBulgarian mineral deposit andapply infrared microscopy to thestudy of the textures and fluidinclusions of opaque phases.

The concluding papers illustratewell the forensic nature of inclu-sion studies. Marshall et al. char-acterize fluid conditions thatfavoured emerald formation innew localities in northern Cana-da. Next, Schandl combines fluidinclusion and mineralogicalstudies to constrain precious- andbase-metal mineralization at anew site in the strongly mineral-ized Sudbury Basin. Buijs et al.describe an unusual and uniquesetting of fluid inclusions, inwhich microborings are preservedas fluid inclusions. Finally, themagmatic evolution within amineralized porphyry setting isdeciphered by Student and Bod-nar by applying melt inclusionstudies.

This issue of The Canadian Miner-alogist presents an excellentsynopsis of exciting work in afield that continues to be limitedonly by one’s imagination. Sitback, scroll through the pages,and see authors turn the remark-able into the possible.

http://pubs.nrc-cnrc.gc.ca/min-eral/MN42-05.html

Executive MeetingMAC’s Executive met in Montrealon October 23 and 24. Our dis-cussions focused mainly on theincoming 50th anniversary cele-brations. President Kontak alsoled a discussion on how we canimprove collaboration with otherCanadian Earth science societiesand how we can broaden ourappeal to the Canadian geochem-ical community.

Montreal 2006 A dynamic local organizing com-mittee is in place to prepare amemorable GAC-MAC annualmeeting, from May 15 to 17,2006, in Montreal. The TechnicalProgram Committee, chaired byAndrew Hynes, is putting thefinishing touches on a programthat will explore many of thethemes of the International Yearof Planet Earth. Montreal is afavourite tourist destination, easyto get to, and should be especial-ly nice in spring.

50th AnniversaryCelebrations Several events are planned forHalifax 2005, May 15–18, 2005,to celebrate MAC’s 50th birthday.A two-day symposium, convenedby Frank Hawthorne, will featureinvited contributions from lead-ers in the mineral sciences inCanada and beyond. The invitedpapers will be published in aspecial issue of The CanadianMineralogist. A plenary talk enti-tled “Minerals are not just chemi-cal compounds” will be given byIan Parsons, President of theInternational Mineralogical Asso-ciation. A public lecture at a localmuseum by André Lalonde onminerals in everyday life and aspecial exhibition of mineralsfrom the Pinch collection of theCanadian Museum of Nature willbe part of the outreach program.And of course, we will have abirthday party with cake and avisual presentation of the high-lights of MAC’s history. Join us!

Mineralogical Associationof Canada

FLUID AND MELT INCLUSIONS Alive and Well Thank You!Daniel J. Kontak

The October issue of The Canadian Mineralogist includes a collectionof papers stemming from the biennial meeting of the Pan-AmericanConference on Research on Fluid Inclusions (PACROFI) held in Halifax,Nova Scotia, in July 2002. These biennial meetings have provided astimulating forum, for both advanced researchers and budding enthu-siasts, on fluid and melt inclusion research over the past two decades.The collected abstracts (available at [email protected]) and recently pub-lished papers cover such diverse topics as experimental techniques,novel analytical methods, P–T–t modeling of liquid petroleum inclu-sions, the assessment of ore deposit environments, culturing ancientmicroorganisms in primary fluid inclusions of halite, the documenta-tion of Lower Paleozoic sea water chemistry, etc. Collectively theabstracts and papers reflect an area of active, vibrant, and excitingresearch. Below is a summary of the published papers.

The issue commences with appli-cations of analytical techniquesand theoretical modeling toextract meaningful data frominclusions. Linnean et al. useFourier infrared spectroscopy oninclusions with varied mixturesof H2O and CO2 to deduce anempirical equation relatingabsorbency to the H2O:CO2 ratio.Bakker addresses the issue ofdetermining salinity and ionratios in inclusions by combiningcryogenic Raman spectrometryand microthermometry in mixedH2O–NaCl–MgCl2 inclusions. Analternative method for determin-ing solute chemistry is presentedby Kontak, who describes theimaging and analysis (EMPA) ofartificially generated evaporatemounds from inclusions. Incontrast, a more rigorous analyti-cal technique to define inclusionchemistry is presented by Gagnonet al., who integrate thermomet-ric measurements with laserablation ICP–MS in a real caseexample. In a novel paper,Elwood Madden et al. report onsimulation of shock-induced re-equilibration of fluid inclusions

to prepare the way for examininginclusions in extraterrestrialobjects and impact sites. Finally,Burnley and Davis use finite-element modeling to examinevolume changes in fluid inclu-sions due to changing P–T condi-tions.

However, it is the application offluid inclusion studies to thenatural environment that is theprime focus of inclusion work,

MAC NEWS

The Canadian Light Sourceis OnThe Canadian Light Source hadits official opening on Thursday,October 21, and it made Canadi-an television history. Indeed,CBC’s The National with hostPeter Mansbridge was broadcastto the country from atop the CLSstorage ring, before a delightedcrowd of CLS staff, guests fromthe University of Saskatchewan,

and their families. It was the firsttime that a national news pro-grams had ever been broadcastedfrom a Canadian science facility.Mr. Mansbridge was joined byscience columnist Bob McDonaldand CLS staff scientist Dr. ColleenChristensen. The CLS was builtin Saskatoon, Saskatchewan, at acost of $173 million and will beused by researchers from18 differ-ent universities across Canada.


Society News

Short course on Exploration for Platinum-

group Element DepositsAugust 6–7, 2005

ORGANIZERS: Dr. James E. Mungall(Department of Geology, University of Toronto) and

Dr. Markku Iljina (Geological Survey of Finland, Rovaniemi)

SPONSORS: IGCP Project 479 “Sustainable use of the PGE inthe 21st century: Risks and opportunities”, the MineralogicalAssociation of Canada, and the Geological Survey of Finland.

Interest in mineral deposits of the platinum-group ele-ments (PGE) is at an all-time high. Demand is growingrapidly for these metals, which are prized as catalysts for

automotive fuel cells or pollution abatement systems. Theshrinking global reserves of the PGE, primarily hosted by onlytwo countries, Russia and South Africa, are prompting a searchfor new deposits. This two-day short course will be held at theRamada Hotel in the city centre of Oulu, Finland. The fee is160 (double occupancy) or 200 (single occupancy) andincludes hotel accommodation for one night, breakfasts,lunches, and dinner. The minimum number of participants is 10.

This course and its accompanying short-course volume areintended to fill a gap between the knowledge and experienceof practising exploration geologists and the academic researchcommunity. The aim is to give non-specialist geologists aseries of tools with which they can identify prospective areas,recognize significant indicators of mineralization, and synthe-size geological, geochemical, and geophysical data to makenew discoveries of PGE mineralization.

The course will begin with reviews of the geochemical controlson the distribution of PGE in igneous, hydrothermal, and sur-ficial environments. The next section will comprise descriptiveore deposit models of the principal PGE producers and mar-ginally economic but large-tonnage deposits. Controversialgenetic models will be presented in a non-partisan way.

The sections on exploration methods will be presented bypractitioners with extensive experience in mineral explo-ration. The emphasis will be on recognition of the signaturesof mineralized bodies using geological, geochemical or geo-physical probes.

For more information and the tentative workshop program:

http://platinumsymposium.oulu.fi/pdfs/Workshop3Program.pdf

$10 000Scholarship

The Mineralogical Association of Canada Foundationannual scholarship for graduate students involved in an MScor PhD thesis program in the fields of :

MINERALOGY • CRYSTALLOGRAPHY • GEOCHEMISTRY • MINERAL DEPOSITS • PETROLOGY

For more information, contact : Roger H. Mitchell, Department ofGeology, Lakehead University, Thunder Bay ON P7B 5E1 E-mail :[email protected]

Terms of reference and application forms at www.mineralogicalassociation.ca

Deadline to apply:May 1, 2005

Mineralogical Society ofGreat Britain and IrelandEnvironmental MineralogyBATH WINTER MEETING GIVES IT THE SPOTLIGHTThe Mineralogical Society’s Winter Meeting was held at the Bath SpaUniversity, Bath from 6 to 7 January 2005. The theme of the meetingwas “Environmental Mineralogy, Geochemistry, and Human Health”.The meeting was split into seven sessions: Biomineralisation, Toxicity ofMicro- and Nano-Particles, Contaminated Environments, Environmen-tal Geochemistry, Arsenic in Groundwater, Radwaste Management, andPlatinum Metals in the Urban Environment. It was convened by ÉvaValsami-Jones, Ed Stephens, Karen Hudson-Edwards, Kevin Taylor, KymJarvis, Kathryn Linge, Dave Polya, Roy Wogelius, Dave Sherman, SimonRedfern, and John Bowles. Sponsorship was provided by the Mineralog-ical Society, CCLRC Daresbury Laboratory, the Society for Environmen-tal Geochemistry and Health, the Applied Mineralogy Group, the Geo-chemistry Group, and the Environmental Mineralogy Group.


Society News

Schlumberger Medal for 2004to Prof. David A.C. Manning(University of Newcastle) for hisoutstanding contribution to theapplication of mineralogy in awide range of environmentalissues.

Max Hey Medals for 2004jointly to Dr. Mark Hodson(Reading University) and Dr.Lidunka Vocadlo (UniversityCollege, London). These medalsare awarded for excellence inresearch carried out by youngresearchers. Mark Hodson hasdone exceptional work on theunderstanding of geochemistryand biogeochemistry of mineralreactions in soils. Lidunka Vocad-lo has carried out pioneeringresearch in the field of computa-tional mineral physics combiningexperimental studies of materialsat high temperatures and pres-sures with computer simulationsand using the results to under-stand the chemistry and behav-iour of the Earth’s core.

Eva Valsami-Jones

OPEN UNIVERSITY HOSTSVMSG ANNUAL MEETING2005The Volcanic and MagmaticStudies Group held its annualmeeting, together with the Geo-chemistry Group, at the OpenUniversity in Milton Keynes on5–7 January 2005. The meetingwas very successful, with over100 participants and a wide vari-ety of talks and posters. Thematicsessions included ‘Boles: alter-ation, erosion and sedimentationin the volcanic environment’;‘Rates and timing of magmatismand volcanism’; ‘Magmatism inVolcanic Arcs’; and ‘VolcanicEdifice instability’. Keynotespeakers were Dave Jolley(Sheffield University), Steve Blake(Open University), Julian Pearce(Cardiff University), and Ben vanWyk de Vries (Université BlaisePascal, Clermont-Ferrand). Theprizes for best student talks wereawarded to Graham Andrews(University of Leicester) and

Eoghan Holohan (Trinity College,Dublin); prizes for the best stu-dent posters went to EleanorDonoghue (Trinity College,Dublin) and Marie-Noelle Guil-baud (Open University).

Katharine Goodenough

BERNARD LEAKEHONOURED BYTHE SOCIETYOn 11 November ProfessorBernard Leake was guest of hon-our at the Society’s President’sLuncheon held at the StrathmoreHotel, South Kensington,London.

At that event the President, Pro-fessor David Price, presentedBernard Leake with a certificate ofHonorary Life Fellowship in theSociety, given for exceptionalservice to the Society and thehighest honour the Societybestows. In his citation, DavidPrice thanked Bernard Leake forhis long and continuing supportto the Society as an associateeditor of Mineralogical Magazine,as an abstractor, and as a manag-ing trustee and astute financialadvisor over the last 40 years.These services to the Society wereset alongside his lifelong contri-bution as a petrologist and lead-ing expert on the amphibolegroup of minerals. He successfullysteered an IMA committeetowards a now established classi-fication of these minerals.

The meeting attracted some 140participants from around theworld, including the USA, SouthAfrica, and several Europeancountries. The 80 contributedpresentations were given in twoparallel oral sessions and a seriesof poster presentations. Thetheme of the meeting allowed fora range of multidisciplinary top-ics to be presented, showing thatmineralogy and geochemistry inthe 21st century can be funda-mental to many other disciplines,such as medicine, biology, mate-rial science, and archaeology. Thehighlight of the event was the

Hallimond Lecture, which wasdelivered this year by ProfessorCatherine Skinner (Yale Universi-ty, USA). In her talk entitled“Biominerals—broadening oppor-tunities”, Professor Skinner gave afascinating overview of the inti-mate relationship between livingforms and the biominerals thatsupport them.

After the first day’s presentations,the delegates celebrated in stylewith pre-dinner drinks in theatmospheric Roman Bath followedby a banquet in the beautifulVictorian Pump Room. Followingthe live piano entertainment, thePresident of the Society, ProfessorDavid Price, awarded the follow-ing Society medals:

The President’s table at the Pump Roombanquet. From left to right: BrianSkinner, Mark Hodson (Max Hey Medal-list), David Manning (SchlumbergerMedallist), Lidunka Vocadlo (Max HeyMedallist), David Price (President of theSociety), and Catherine Skinner (Hal-limond Lecturer)

Catherine Skinner and David Price

Bernard Leake during his acceptancespeech at the luncheon.

Launched inJanuary 2004MINABS Online,launched in Janu-ary 2004, hasalready establisheda cadre of enthusi-astic users withover 10,000 search-es carried out in thefirst nine months ofoperation. This electronic abstracting journalis the successor to the printed journal Miner-alogical Abstracts which it now replaces. LikeMineralogical Abstracts it is a specializedabstracting publication that targets journalsand other publications in the fields of mineral-ogy, crystallography, environmental mineral-ogy, geochemistry, petrology, and relatedbranches of Earth science. The coverage ofabstracts is aimed at a wide range of Earthscientists in theoretical and applied fields, aswell as undergraduate and postgraduate stu-dents. These include specialists in cosmology,physical geography, clay science, mineralsresources, environmental studies, nuclearwaste disposal, and volcanology, as well asmineralogy, petrology and geochemistry.

Initial feedback from users indicates that theyfind MINABS Online easy to use and a worthysuccessor to Mineralogical Abstracts.

Searching CapabilitySearches can be carried out by words in titlesor abstracts, year, abstract number, journal, orcombinations of these, with categories andsubcategories. A useful feature is that abstractscan be selected for downloading as editabletext delivered direct to the user by e-mail.Quick prints of individual abstracts can alsobe obtained by the print screen command(Ctrl P). There is also a popular browse facilitythat allows users to see the latest additions tothe database or review older records accordingto date and/or subject category.

Abstract and Database ContentThe database includes abstracts published inMineralogical Abstracts from 1982 to the pres-ent, and about 500 abstracts are currentlybeing added to the database every monthfrom over 180 journals published in Canada,China, Europe, India, Russia, South America,Japan, Saudi Arabia, Taiwan, Turkey, Ukraine,and the USA (altogether in excess of 115,000abstracts). The archive of data includes aneven wider geographical coverage andincludes abstracts from journals that haveceased publication or only occasionally pub-lish papers within the target areas of MINABSOnline. Recent titles added are from India(Journal of Applied Geochemistry, Indian Societyof Applied Geochemists, Hyderabad) and theUkraine (Mineralogical Journal, Ukrainian Aca-demy of Sciences, Kiev). The editors are seek-ing to expand the coverage of the literatureoutside Western Europe and North America.

Many of the abstracts are from papers writtenin the language of the country of origin butwith English translations of citations andabstracts. Most of the abstracts, althoughusually based on author abstracts, are editedor rewritten to achieve conciseness and toreflect an accurate assessment of the contentof papers with the target readership in mind.Where papers contain significant amounts ofgeochemical data this is identified.

Abstracts are written by a wide range of pro-fessionals in the fields of study covered.Abstracts from journals that contain paperswritten in languages other than English areoften written by abstractors in the countriesof origin but are thoroughly checked by theeditors before publication.

CrossRefA very useful feature of the service is thatlinks are provided via CrossRef to the fullpapers in journals that have electronic edi-tions. This feature will be of increasing value

to users as libraries sign up to bundles ofelectronic geoscience journals such as theGeoScienceWorld package being launchedthis year. The full texts of many papers willtherefore be available and downloadable bythe user.

The Organisation behindMINABS OnlineMINABS Online is a truly international enter-prise, and the database is published by theMineralogical Society of Great Britain andIreland, a registered charity in the UnitedKingdom. This abstracting service is approvedby the International Mineralogical Associa-tion and is run on a not-for-profit basis toprovide support for research and scholarship.Subscriptions from developed nations help tosupport the Society’s plan to make the data-base available at token cost to scientists in less-developed countries. A small core of paid staffis supported by a large band of volunteerabstractors dedicated to the maintenance ofthe highest possible standards.

A Uniquely Valuable Database When preparing our abstracts we consult theconclusions and body of the original paperand as a result often add details that were notincluded in the author abstracts. This is donewith our target users in mind, so it makes ourproduct different from other abstracting jour-nals and metadata sources. It provides addedvalue to researchers, especially those who donot have easy access to the original publica-tion. Our coverage includes titles not coveredby other abstracting services, and it is editorialpolicy to expand coverage in Asia and otherareas outside Western Europe and North Amer-ica. The e-journal aims to provide a servicethat complements and adds further quality tothe other facilities available to researchers andstudents throughout the world. Visit MINABSOnline at www.minabs.com and sign up for afree two-week trial.


Society News

MINABS ONLINE — A NEW ELECTRONIC DATABASE FOR THE MINERAL SCIENCES

Dr J.G. MacDonald,MBE, Principal Editor

The Mineralogical Society, inresponse to demand for hands-ontraining on state-of-the- art tech-niques in the mineral sciences,has launched a series of work-shops, which will take place atvarious research institutes aroundthe UK. The first of these tookplace at the Natural HistoryMuseum, London from 23 to 25February 2005 on the subject ofelectron probe microanalysis. It ishoped that these courses will beof value to postgraduates as partof their ‘skills training’ for theirdegree course and to others aspart of their continuing profes-sional development (CPD). Full-

time Natural EnvironmentResearch Council (NERC) PhDstudents may be able to apply fora bursary from their departmentsto attend these courses. Moredetails on the courses can be foundat: http://www.minersoc.or/pages/education/edu.html. Futurecourses are planned for June (seeadvertisement p. 96) and Novem-ber 2005. The June course will bea repeat of the February course atthe NHM, and in November theSociety is planning a course atBristol University on the charac-terisation of interfaces of (miner-al) materials.

Adrian Lloyd-LawrenceAs News Editor for the Societyreporting to Elements, I welcomenews from members about theirachievements, awards, and hon-ours. Space is limited but whenpossible we will try to includeyour items; photos/digital imagesare also welcome. Please sendyour items to [email protected]

Call for Nominationsfor Council 2006Nominations are being sought fortwo vacancies for Ordinary Mem-bers of Council for 2006 on theretirements of Prof. Chris.

Hawkesworth and Dr. StephenDaly. Nominations are alsosought for the next President ofthe Society to succeed Prof. DavidPrice in January 2006. Nomina-tion forms can be found on thewebsite.

Nominations must be endorsedby four Ordinary Members of theSociety, and nominees must beOrdinary Members or Fellows ofthe Society. Nominations shouldbe sent to the Society Office at 41Queen’s Gate, London SW7 5HR,to arrive by Wednesday 22 June2005 for consideration by Coun-cil at their meeting on 30 June2005.

NEW FROM THE SOCIETY: TRAINING WORKSHOPS MEMBERS’ NEWS FOR ELEMENTS

Geochemical SocietyGOLDSCHMIDT UPDATEScott WoodGoldschmidt Conference Organizer

The 15th Annual V.M. Goldschmidt Conference in Moscow, Idaho, USAon May 20–25, 2005 is shaping up to be an excellent meeting. As of thiswriting, approximately 1,400 abstracts have been submitted, a newrecord for Goldschmidt in North America! Also 16 exhibitors havereserved booths so far. Accommodation and travel bookings are begin-ning to fill fast. And remember, March 20, 2005 is the deadline for dis-counted early registration! Seth Davis

GS Business Manager

z With the creation of Elements,the quarterly Geochemical Newswill continue under the editorialexpertise of Dr. Carla Koretskyand Dr. Johnson Hass as anonline-only newsletter. Currentand past issues are available at:http://gs.wustl.edu/archives.Highlights from the January 2005issue include an article aboutgeochemistry research (past andpresent) in eastern Europeancountries as well as a continua-tion of the series on geochemistryresearch at U.S. National Labora-tories with a look at the OakRidge National Lab.

z The 2005 V.M. GoldschmidtMedal will be presented to E.Bruce Watson. The 2005 F.W.Clarke Medal will be presented toJames A. van Orman. The 2005C.C. Patterson Medal will bepresented to Kenneth Bruland.The 2005 GS/EAG GeochemistryFellows are: Nicholas Arndt,Stein Jacobsen, Stuart Wake-ham, and Lynn Walter. All ofthese awards will be presented atthe 15th annual GoldschmidtConference in Moscow, Idaho.

z Members may already submitnominations to the 2006 AwardCommittees. More informationregarding submission require-ments and procedures is availableon our website at http://gs.wustl.edu/nominations.html

z The GS Business Office is help-ing organize the Yucca Mountainpreconference field trip. This willbe a two-day field trip, with thefirst day devoted to regionalgeology and hydrology, and thesecond day being a visit to theproposed Yucca Mountain Civil-ian High Level Nuclear WasteDisposal Site. Registration islimited to 50 participants. Moreinformation on this and otherfield trips is available underSocials & Field Trips on theGoldschmidt website: www.uidaho.edu/gold2005

z We are continuing the SpecialPublication Tribute Series withthe release of Volume 9, Geochem-ical Investiga-tions in Earthand SpaceScience: ATribute to IsaacR. Kaplan. Anorder form isavailable inGeochemicalNews or on ourwebsite at:http://gs.wustl.edu/publica-tions/#SPS.

z And finally,I welcome any questions or com-ments you may have about theGeochemical Society. I may bereached via e-mail [email protected].


Society News

As of this time, the followingplenary lectures are planned:

GS Presidential Address: James I.Drever, “Silicate weathering:where have we come in 50 years?”

Goldschmidt Medalist Address:E. Bruce Watson, “Crystallizationtemperatures of Hadean zircons:Plate tectonics at 4.35 Ga?”

Dana Medalist Address: WilliamCarlson, “Rates and mechanismsof metamorphic processes fromnatural occurrences”

Clarke Medalist Address: Jamesvan Orman, “Diffusion in mantleand core materials”

Patterson Medalist Address: KenBruland, “The role of iron as amicronutrient influencing phyto-plankton in coastal upwellingregimes”

The conference will start with anice-breaker party in the eveningof May 20. Oral and poster ses-sions will take place May 21, 22,24, and 25. The plenary sessionwill take place on the morning ofMay 23, followed by the HellsGate barbeque and jet boat tour.Finally, don’t miss the gala din-ner-dance in celebration of the50th anniversary of the Geochem-ical Society. This will be held onMay 24 and is included in theconference registration fee forstudents and professionals.

For further information, see theconference website at: www.uida-ho.edu/gold2005

CALL FOR NOMINATIONS: ALFRED TREIBS MEDAL

Nominations must be received by June1, 2005

The Alfred Treibs Medal is awarded by theOrganic Geochemistry Division of the Geo-

chemical Society for career achievements, over aperiod of years, in organic geochemistry. Such achievements consistof pioneering and innovative investigations that have made highlysignificant contributions to the understanding of the origin andfate of organic materials in the geosphere and/or in extraterrestrial environments. Submission requirements and procedures are available on the GSwebsite at: http://gs.wustl.edu/archives/nominations.html#TREIBS

NOTES FROM ST. LOUIS

Short CourseTHERMOCHRONOLOGYOctober 14–15, 2005

Snowbird Resort, Snowbird, Utah, 84092, USACCoonnvveenneerrssPETER W. REINERS, Department of Geology & Geophysics, Yale University

TODD A. EHLERS, Department of Geological Sciences, University of Michigan.

Analytical and modeling advances, combined with rapidly expanding interest inshallow-crustal and Earth- and planetary-surface processes, have led to significantadvances in the techniques, applications, and interpretations of thermochronom-etry. Recent thermochronologic studies have provided unprecedented insightsinto a wide range of geological problems such as the timing and rates of develop-ment of topographic relief, the architecture and dynamics of orogenic wedges,and feedbacks between erosion, uplift, and climate at a variety of scales. Newtechniques and innovative applications of thermochronometry are also rapidlyemerging in a wide variety of subdisciplines, including precise dating of weather-ing episodes, shock metamorphism, wildfires, and extended time-temperaturehistories from single crystals. As the range of geologic problems accessible tothermochronometry has expanded, so has the need for robust theoretical under-standing of the crystal-scale kinetics (e.g., diffusion, annealing) that controlthermochronometric ages, as well as the crustal- or orogen-scale tectonic andgeomorphic processes that influence their spatial-temporal patterns across thelandscape.

This short course will assess the current state of the art in thermochronometryand evaluate progress in analytical and interpretation techniques, future potential,example applications, and outstanding issues in the field that have recentlyemerged or need attention for robust progress. We will focus attention on severalareas, including techniques for measuring data, innovations in interpretive tech-niques at both crystal and regional scales, and exemplary case studies that inte-grate multiple low-temperature thermochronometers or other techniques. Thiscourse will also serve not only to provide state-of-the-art assessments for practi-tioners of thermochronometry, but also as an introduction for Earth scientistsseeking to use thermochronologic constraints in their research.

There will be a software demonstration session the evening of the first day,to introduce participants to forward and inverse models for interpretation ofthermochronologic data, including diffusion/annealing, and tectonotopographic/thermal phenomena on orogen and crustal scales. The short course will be fol-lowed by thermochronology special sessions at the Geological Society of Americameeting in Salt Lake City.

Topics, speakers, and registration information for the short course are on theMSA website (www.minsocam.org) or available from the MSA Business Office,1015 18th St NW Ste 601, Washington, DC, 20036-5212, USA. Tel: 202-775-4344, Fax: 202-775-0018, e-mail: [email protected]. All-inclusive registra-tion fee covers short course sessions, hotel room for two nights (double occu-pancy), meals including refreshments at breaks, and the Reviews in Mineralogyand Geochemistry volume.

The course is sponsored in part by the U.S. Department of Energy, Yale University,University of Michigan, and Apatite to Zircon Inc.

121E L E M E N T S

Society News

Mineralogical Society of America and Geochemical Society


Society News

Mineralogical Societyof AmericaFROM THE PRESIDENT

Diamond as Metaphor A sparkling new year welcomes this, the second issue of Elements. Howappropriate to emphasize diamond—a substance that epitomizes the sci-entific significance, the industrial utility, and the exceptional beauty ofminerals. Once the exclusive baubles of royalty, diamonds now adornhundreds of millions of gem-hungry consumers worldwide, while syn-thetic abrasive diamond is manufactured by the ton. As this issue attests,the mineralogy–petrology–geochemistry community embraces all ofthese varied aspects of diamond, and more.

Nominations SoughtNominations must be received by June 15, 2005

The Roebling Medal is MSA’s highest award and is given foreminence as represented by outstanding published originalresearch in mineralogy.

The Dana Medal recognizes continued outstanding scientificcontributions through original research in the mineralogicalsciences by an individual in the midst of his or her career.

The Mineralogical Society of America Award is given foroutstanding published contribution(s) prior to 35th birthdayor within 7 years of the PhD.

The Distinguished Public Service Medal is awarded fordistinguished contributions to public policy and awarenessabout mineralogical topics.

Society Fellowship is the recognition of a member’s significantscientific contributions. Nomination is undertaken by one mem-ber with two members acting as co-sponsors. Form required;contact committee chair or MSA home page.

Mineralogical Society of America

Submission requirements and procedures are on MSA’s homepage: http://www.minsocam.org

Diamond’s unique qualities haveinspired many metaphors, somemore apt than others. The gemtrade hawks diamonds as symbolsof intrinsic rarity, unrivaledpermanence, and exquisite beau-ty. Such appealing romantic traitstempt the general populace, butevery mineralogist recognizes theinherent flaws in these threemetaphors. Diamonds are, in fact,relatively common compared tothe vast majority of the 4,000-plus known mineral species.Other precious gemstones,including emeralds, rubies, andsapphires, are far scarcer thandiamonds. Diamond’s reputedpermanence is another question-able metaphor, for diamondburns easily to colorless, odorlesscarbon dioxide gas in a hotflame, as the great Frenchchemist Antoine-Laurent Lavoisi-er demonstrated more than twocenturies ago. And what of beau-ty? Without laborious expertcutting and tedious polishing,most diamonds would appear tobe dull, nondescript pebbles,something the average personwould kick aside without a sec-ond thought. Only seductiveadvertising and hype, coupledwith strict market control (andnot a little hoarding), maintainthe steady demand and heftyprices for these treasured stones.

To me diamond more appropri-ately represents something quitedifferent—discovery and progressthrough the unmatched power ofscience to reveal the workings ofour natural world. Two centuriesago, the origin of diamondremained a great mystery. Geo-logical discoveries of in situ dia-monds in South Africa providedessential clues pointing to thedeep, hot genesis and violentsurface delivery of diamonds,while crystallographic researchrevealed the key structural differ-ences between the two carbonpolymorphs.

Decades of effort culminated 50years ago in General Electric’sfirst reproducible synthesis ofdiamond. Until then, no oneknew how to make a diamond.Today, thanks to the cumulativediscoveries of scientists and engi-neers, anyone with a big basementand a few hundred-thousanddollars can do it. The hundredtons of diamond manufacturedannually attest to the reality ofscientific progress.

Diamond metaphors must thusextend beyond the romantic andutilitarian—diamonds now sym-bolize knowledge. In recent yearsdiamonds have taken on a new,powerful role as a tool for publiceducation, especially thanks tothe extraordinary efforts of

George Harlow. George master-minded the blockbuster diamondexhibit at the American Museumof Natural History. He authoredThe Nature of Diamonds, one ofthe finest mineral books of ourtime, and he serves as guesteditor of this issue. His vision hasbrought the art and science ofminerals to millions of people.

George Harlow’s service to miner-alogy extends far beyond hiscontributions to the diamondstory. As Secretary of MSA he hasembraced what is probably theSociety’s most demanding electedoffice. And, in addition to thisunsung labor, George Harlow is,year in and year out, one of themost generous financial contribu-tors to MSA’s operating funds.His commitment to our sharedgoals is inspiring.

Societies, like diamonds, do notachieve their true brilliance andworth without skilled, dedicatedindividuals and countless unseenhours of labor. As you read thisissue of Elements, I hope that you,too, are inspired by the joy of ourscience, and that you feel arenewed sense of commitmentto your society.

Robert M. Hazen, President

ELECTIONS 2005

The slate of candidates for theMSA Council elections is asfollows:

PRESIDENT: John W. Valley

VICE PRESIDENT

(one to be selected): Harry Y. (Hap) McSween Jr., Barbara L. Dutrow

SECRETARY: George E. Harlow

COUNCILLORS

(two to be selected): Jay D. Bass, Roberta L.Rudnick, Edward Stolper,and Simon A.T. Redfern

John M. Hughes continues inoffice as Treasurer. Continuingcouncillors are Mickey E.Gunter, David London, RossJohn Angel, and Robert T.Downs.

Election materials will beavailable to MSA members inApril in time for the votingdeadline of August 1, 2005.


Society News

INVITATION TO REQUEST A 2005-2006MSA DISTINGUISHED LECTURER

Since its inception the Distinguished Lecture Program of the Min-eralogical Society of America has proven to be a great success. The var-ied and interesting lectures presented by MSA Distinguished Lecturershave been appreciated by students and faculty at many colleges and uni-versities worldwide. The Council of the Mineralogical Society is againoffering the program for the 2005-2006 academic year with the arrange-ment that the MSA will pay travel expenses of the lecturers, and the hostinstitutions will be responsible for local expenses, including accommo-dation and meals. The program will include three lecturers, one of whomresides in Europe, and MSA encourages universities to request lecturers.Depending on the response, one or more lecture tours will be arrangedoutside North America.

Names of the 2005-2006 Distinguished Lecturers and their lecturetitles are not yet available, but they will be posted soon on the MSA web-site. If your institution is interested in requesting the visit of a MSA Dis-tinguished Lecturer, check the website for lecturers and titles and e-mailyour request to the Lecture Program Administrator: Dr. Cameron Davidson,Carleton College, Dept of Geology, 1 N College St, Northfield, MN55057-0001, USA, e-mail: [email protected] Tel: (507) 646-7144,Fax: (507) 646-4400. The Lecture Program is designed to run from Sep-tember, 2005, through April, 2006. Lecturer requests received by MMaayy 1122,,22000055 will be given priority. Late applications will be considered on aspace-available basis. In making your request please include (1) airportproximity from, and travel time to, your institution; (2) the name of acontact person at your institution for the months of May and June (whenLecturer schedules will be assembled); (3) contact e-mail addresses andphone numbers; and (4) flexibility on Lecturer preference. (5) Schools outsidethe U.S. should indicate starting and ending dates of academic terms.

Please note that because of travel and schedule constraints it is normallynot possible to satisfy requests for tightly constrained dates such as seminar days.

Due to thegrowth insubmissions,especially inLetters-stylemanuscripts,and with

approval of the MSA council, wewelcome a third editor to our team:Dr. Bryan C. Chakoumakos ofOak Ridge National Laboratory.He will handle all the new Letterssubmissions and join the editorsin other editorial duties.

Dr. Chakoumakos welcomespapers from all areas of Earthscience. He is a Senior Staff Scien-tist in the Center for NeutronScattering at Oak Ridge NationalLaboratory. His research at ORNLover the past 17 years has focusedon the relationships between thecrystal structure and physicalproperties of a wide range of hightechnology and Earth materials.He did a postdoctoral fellowshipat the University of New Mexicowith Rodney C. Ewing studyingradiation damage effects in com-plex oxides and minerals. He

received his PhD from VirginiaTech where he studied mineralo-gy and crystallography under theguidance of Gerry Gibbs. Hisundergraduate training is ingeology from the University ofNew Mexico. His professionalcareer as a scientist grew out of achildhood fascination with min-erals and crystals.

Letters papers, like all submis-sions, are submitted via our web-based system at http://minso-cam.allentrack.net. Letters areto be no more than 15 double-spaced pages long, and each tableor figure counts as a page. Thisworks out to Letters papers beingfour typeset pages in length, agoal that has been missed inrecent times, but one we are alleager to achieve again. Letters arealso intended to be timely papersof significance in Earth sciences.A statement should be includedwhen submitting the paper stat-ing the paper’s timeliness andsignificance (either cut-and-pasteinto the box in the web-basedsystem or include in a cover letter).

AMERICAN MINERALOGIST ADDS A THIRD EDITOR

The Society welcomes the follow-ing exceptional students to theprogram’s honor roll and wishesto thank the sponsors forenabling the MineralogicalSociety of America to join inrecognizing them. MSA’s Ameri-can Mineralogist Undergraduate(AMU) Award is for students whohave shown an outstandinginterest and ability in mineralogy,petrology, crystallography, andgeochemistry. Each student ispresented a certificate at anawards ceremony at his or heruniversity or college and receivesan MSA student membership, aReviews in Mineralogy or Mono-graph volume chosen by thesponsor, student, or both.

The MSA website lists past AMUawardees and instructions onhow MSA members can nominatetheir students for the award.

Bryan AndersonLouisiana State UniversitySponsored by Dr. Barbara L. Dutrow

Aaron S. BellUniversity of OklahomaSponsored by Dr. David London

Jennifer E. CampbellWilliams CollegeSponsored by Dr. Reinhard A. Wobus

Stanley DalbecUniversity of Hawai’i at ManoaSponsored by Dr. Julia E. Hammer

Sarah Lynn DurhamUniversity of CalgarySponsored by Dr. David R. M. Pattison

Emil D. FreemanEastern Michigan UniversitySponsored by Dr. Christine M. Clark

Allison GaleUniversity of MarylandSponsored by Dr. Michael Brown

Brian Anthony MossOklahoma State UniversitySponsored by Dr. Elizabeth Catlos

Stephen F. PoteralaClemson UniversitySponsored by Dr. Richard D. Warner

Ashley E. ShulerRensselaer Polytechnic InstituteSponsored by Dr. Jonathan D. Price

Stanley P. SkotnickiState University of New Yorkat BuffaloSponsored by Dr. Gary S. Solar

Paula Marie ZelankoUniversity of MarylandSponsored by Dr. Michael Brown

OUTSTANDING UNDERGRADUATES RECOGNIZED

sessions at other meetings, suchas the recent InternationalGeological Congress in Florenceand the forthcoming Gold-schmidt Conference in Moscow,Idaho, and many of these lead tospecial publications or thematicjournal issues. IMA has a newwebsite (ima-mineralogy.org),which can connect you to eachof the member organizations.

So, do we need an IMA, and canit do its job more effectively? Wecertainly need an internationalorganization as a focus for theworldwide activities of mineralo-gists. The word ‘international’ inthe title is essential to raise travelfunds in many countries wherescience is less well developed. Butour quadrennial meetings havebeen nothing like as successful asthe annual geochemical Gold-schmidt meetings, which oftenattract more than twice thenumber of delegates, eventhough the scientific territory thetwo organizations cover is acontinuous solid solution. I fearthat one reason for this is thecurrent scientific dominance ofan English-speaking world, whosemembers see the ‘I’ in IMA (or,for that matter, IGC) as implyingthat participants will have to sitthrough large numbers of lecturesdelivered in less than perfectEnglish. If this influences yourchoice of annual big meeting, Ican only suggest that the greatergains for mankind of a trulyinternational scientific communi-ty is a factor you should consider,even if it entails a little extraeffort.

IMA has long suffered from lackof a communications channel.Elements gives us the opportunityto be regularly in the public eye,and we will provide news of theactivities of commissions and of

meetings in which we areinvolved. My personal view (notshared, I should say, by allmembers of Council) is that theIMA is bureaucratic out of allproportion to its modest size. Themembers of commissions arechosen as representatives of thesupporting societies rather thanfor their scientific standing orability to inspire. I think theywould do a better job if com-posed of like-minded experts andenthusiasts in each field, and ifthey were responsible for theirown membership. Commissionswould not be required to involveevery national organization, butwould have the duty to serve thewhole community. Theirmembership would be subject tothe approval of Council, whichwould ensure that the interna-tional community was represent-ed as widely as possible.

Running IMA is not easy. Manyof the problems fall on theshoulders of our hard-workingsecretary, Maryse Ohnenstetter,and dogged treasurer, Kase Klein.It is frequently difficult to getanswers from national represen-tatives and even from chairs ofcommissions. No less than 10 outof 37 member organizations arecurrently behind with paymentof dues for 2004 (some for severalyears). So let me end with arallying call to you, the mineralo-gists who own IMA: it is onlygoing to be as effective as youmake it. Come to the Kobemeeting, support the work of thecommissions and working groups,do your bit for mineralogyinternational!

Ian Parsons, President of IMA, 2002–2006


International News

International Mineralogical Association

FROM THE PRESIDENT

The arrival of Elements on the mineralogy–geochemistry scene presents

IMA with an unprecedented opportunity to reach its members and pro-

vides a means for its members to communicate with each other. Of

course, by no means all members of IMA are members of the current

group of societies supporting Elements, but most will be able to see the

magazine through their institutional subscription to one of the techni-

cal journals produced by the consortium. The editors of Elements hope

that other societies, particularly from countries where English is not the

main language, will join and make use of the opportunities for widen-

ing communication that Elements offers. Like the predominantly Eng-

lish-speaking founding group, they can use Elements as a pointer to

their national, own-language website to provide detailed information

to members.

IMA is supported by small subscriptions, based on membership,from 37 mineralogical organizations, the largest with more than onethousand members, the smallest with less than ten. The oldest ofthese national mineralogical societies were founded in the earlysecond half of the nineteenth century when many of the importantmineral species were being established on the basis of crystal morphol-ogy and physical properties, a time when analytical chemistry wasextremely primitive. The newer science of geochemistry grew up in aworld in which travel and communication were more developed, andmost geochemical organizations had an international character fromthe outset. The IMA was founded to improve contact between itshistorically fragmented members. Its best known activities are itsquadrennial general meetings, the next in Kobe, Japan, in 2006, andthe work of its Commission on New Minerals and Mineral Names. Itscommissions and working groups regularly sponsor or organize

ADVERTISERS IN THIS ISSUE

Environmental Isotope Laboratory 64Excalibur Mineral Corporation 65, 90Gemological Institute of America 66, 104HORIBA Jobin Yvon Inside front coverHudson Institute of Mineralogy 109Meiji America 128Rigaku 65, 121, 127Rockware Inside back cover, back coverSGS Lakefield Research 65Universität Bayreuth 89

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Mineral Matters

batteries. They postulated that ina conventional cell design,triphylite may yield the highestpower density yet developed inrechargeable Li batteries.Furthermore, they speculatedthat the same doping mechanismfor increasing electrical conduc-tivity in triphylite will apply toother olivine-structure phases,such as lithiophilite. Structuralchanges in triphylite due to solidsolutions with iron may havesignificant effects on its solidelectrolyte properties, includingrates of Li diffusion and activa-tion energies. Thus, knowledgeof structural changes that resultfrom solid solutions are impor-tant in the development anddesign of Li-phosphate storagecathodes. In a recent study byLosey et al. (2004), single-crystalX-ray diffraction experimentswere performed on naturallithiophilite–triphylite sampleswith Fe/(Mn+Fe) ratios of 6, 27,50, 79, and 89 (referred to asTrip06, etc.). The atomic arrange-ment of each sample was refinedto elucidate the structural changeswith composition in this series.

The octahedrally coordinatedcations in the lithiophilite–tri-phylite series are completelyordered between the M1 and M2sites. Only Li occupies the M1site, whereas the M2 site isoccupied by divalent Mn, Fe, andin some cases, Mg. The completeordering of cations in theseminerals is in contrast to themajority of olivine-structurephases, in which there is exten-sive disorder among the octahe-drally coordinated cations.Although Mn and Fe occupy onlythe M2 site in the lithiophilite–triphylite series, the solid solutionbetween these two constituentsaffects both the M2 and M1 sites.

The substitution of Fe2+ (r = 0.78Å; Shannon 1976) for Mn2+

(r = 0.83 Å) in the lithiophilite–triphylite series suggests, byVegard’s law, that a concomitantshortening of the octahedronbond lengths should occur.Although the shortening of thebond lengths involving M2 isexpected, the bond-lengthvariations in that polyhedronalso induce variations in the M1polyhedron, occupied solely byLi. The M1-O1 and M1-O2 bondlengths decrease, whereas theM1-O3 bond length increaseswith increasing Fe-for-Mnsubstitution. This change occurswith no substitution of cationsfor Li in the M1 site. Thesestructural changes in thelithiophilite–triphylite solidsolution may have an effect onthe activation energy for Lidiffusion, and thus the rate ofdiffusion. The activation energyof Li diffusion is directly relatedto the energy necessary to breakall the M1-O bonds. Bond-valenceconsiderations indicate that Li ismore underbonded in lithio-philite and thus is less stable inthe M1 site in this end member.Consequently, breaking the sixM1-O bonds will be energeticallyeasier in lithiophilite, which inturn will lead to greater rates of Lidiffusion, making lithiophilite apotentially better storage cathode.

Although members of thelithiophilite–triphylite series arerather rare minerals of restrictedgeological significance, thephysical and chemical propertiesthat make them amenable toapplications in battery manufac-turing, may someday turn out tobe of great societal and economicimportance.

This text is based in part on thearticle published by Losey et al.(2004)

John Rakovan

The minerals of the lithiophilite(LiMnPO4)–triphylite (LiFePO4)series, for which there exists acomplete solid solution in nature,provide our first example.Lithiophilite–triphylite occur inrather restricted environments—evolved granitic pegmatitesenriched in both Li and P—andthus are relatively uncommon.These phases are isostructuralwith olivine and are thereforecommonly referred to as havingan olivine-type structure.

Recently, there has been consider-able interest in the Li-phosphateolivine, triphylite, as a storage

cathode for rechargeable lithiumbatteries (Andersson et al. 2000;Chung et al. 2002; Huang et al.2001; Padhi et al. 1997a, 1997b;Prosini et al. 2001; Yamada et al.2001a, 2001b; Yang et al. 2002).Keys to the use of triphylite inbatteries are its electrical and ion(Li) conductivities. Triphylite, aswell as other phases with anolivine structure, is an electricalinsulator, which is the mainimpediment to its use inbatteries. Chung et al. (2002),however, have shown thatcontrolled cation nonstoichiome-try combined with doping canincrease the electrical conductivi-ty of triphylite by as much as 108

times, well above that of Listorage cathodes currently usedin commercially available

Triphylite in a matrix of microcline,quartz, and muscovite, Chandlers Mills,New Hampshire. PHOTOGRAPH COURTESY OF

SMITHSONIAN INSTITUTION (NMNH SPECIMEN

#R9228), PHOTOGRAPHER KEN LARSEN.

Li-Phosphate Mineralsand Storage Batteries

Examples of the use of minerals in technological applications abound,

and “materials mineralogy” has remained one of many exciting fron-

tiers in the science. A frequent feature of Elements will be discussions

and updates on recent mineralogical studies that focus on or are rele-

vant to the materials applications of minerals.

REFERENCESAndersson AS, Thomas JO, Kalska B,

Haggstrom L (2000) Thermalstability of LiFePO4-based cathodes.Electrochemical and Solid-StateLetters 3: 66-68

Chung SY, Blocking JT and Chiang YT(2002) Electrically conductivephospho-olivines as lithium storageelectrodes. Nature Materials 1: 123-128

Huang H, Yin S-C, Nazar LF (2001)Approaching theoretical capacity ofLiFePO4 at room temperature at highrates. Electrochemical and Solid-State Letters 4: A170-172

Losey A, Rakovan J, Hughes JM,Francis CA, Dyar MD (2004)Structural variation in the lithio-philite-triphylite series and otherolivine-group structures. CanadianMineralogist 42: 1105-1115

Padhi AK, Nanivndaswamy KS,Goodenough JB (1997a) Phospho-olivines as positive-electrodematerials for rechargeable lithiumbatteries. Journal of the Electro-chemical Society 144, 1188-1194

Padhi AK, Nanjundaswamy KS,Masquelier C, Okada, S, Goode-nough JB (1997b) Effect of structureon the Fe3+/Fe2+ redox couple in

iron phosphates. Journal of theElectrochemical Society 144: 1609-1613

Prosini PP, Zane D, Pasquali M (2001)Improved electrochemical perform-ance of a LiFePO4-based compositecathode. Electrochimica Acta 46:3517-3523

Yamada A, Chung S-C (2001) Crystalchemistry of the olivine-typeLi(Mny/Fe1-y)PO4 and (Mny/Fe1-y)PO4as possible 4 V cathode materials forlithium batteries. Journal of theElectrochemical Society 148: A960-967

Yamada A, Chung SC, Hinokuma K.(2001) Optimized LiFePO4 for lithiumbattery cathodes. Journal of theElectrochemical Society 148: A224-229

Yang S, Song Y, Zavalij PY, Whitting-ham (2002) Reactivity, stability, andelectrochemical behavior of lithiumiron phosphates. ElectrochemicalCommunications 4: 239-244.


Calendar

2005

April 3–7 8th International Confer-ence on the Biogeochemistry of TraceElements, Adelaide, Australia. Details:8th ICOBTE Conference Secretariat, Attn:Sandra Wildman, CSIRO Land & Water,Private Bag No. 2, Glen Osmond 5064,South Australia. e-mail: [email protected]; fax: +61-8-8303-8572; webpage: www.clw.csiro.au/conferences/8thicobte/

April 10–13 107th Annual Meeting& Exposition of the American CeramicSociety, Baltimore, MD, USA. Details:Mark Mecklenborg. Tel.: 614-794-5829;e-mail: [email protected];web page: www.ceramics.org/meetings/am2005/default.asp

April 17–21 Third Study of Matterat Extreme Conditions (SMEC), Miami,FL, USA. E-mail: [email protected]; webpage: www.cesmec.fiu.edu/SMEC2005/index.php

April 25–29 European GeosciencesUnion (EGU) Second GeneralAssembly, Vienna, Austria. Details: EGUOffice, Max-Planck-Str. 13, 37191Katlenburg-Lindau, Germany. Tel.: +49-5556-1440; fax: +49-5556-4709; e-mail:[email protected]; web page:www.copernicus.org/EGU/ga/egu05/index.htm

April 25–30 Asia Pacific WinterConference on Plasma Spectrochem-istry, Chiang Mai, Thailand. Details:Ramon Barnes, ICP InformationNewsletter, P.O. Box 666, Hadley, MA01003-0666, USA. Tel.: 413-256-8942;fax: 413-256-3746; e-mail: [email protected]; web page: www.unix.oit.umass.edu/~wc2005

May 5–7 4th International Colloquiumon Magmatism, Metamorphism andAssociated Mineralizations, Agadir,Morocco. Web page:http://3ma.esta.ac.ma

May 15–18 GAC–MAC: Halifax 2005,Halifax, Nova Scotia, Canada. Details:[email protected]; web page:www.halifax2005.ca/

May 20–25 Goldschmidt 2005,Moscow, Idaho, USA. E-mail:[email protected]; web page:www.uidaho.edu/gold2005

May 23–27 AGU Joint Assembly, NewOrleans, Louisiana, USA. Details: AGUMeetings Department, 2000 FloridaAvenue NW, Washington, DC 20009,USA. Tel.: 202-777-7333; fax: 202-328-0566; e-mail: [email protected];web page: www.agu.org/meetings/sm05/

May 28–June 2 American Crystallo-graphic Association (ACA) AnnualMeeting, Walt Disney World, FL, USA.Details: Ed Collins, Program Chair. E-mail:[email protected]; webpage: www.hwi.buffalo.edu/ACA/future-meetings.html

May 31–June 3 Workshop on Oxygenin Asteroids and Meteorites, Flagstaff,AZ USA. Details: Dave Mittlefehldt,NASA Johnson Space Center. Tel.: 281-483-5043; e-mail: [email protected]; web page:www.lpi.usra.edu/meetings/am2005/am2005.1st.html

June 11–15 42nd Annual Meeting ofThe Clay Minerals Society. Burlington,Vermont, USA. Details: Peter C. Ryan,Geology Department, MiddleburyCollege, Middlebury, Vermont 05753,

USA. Tel.: 802-443-2557; e-mail:[email protected]; web page:www.clays.org/home/HomeAn-nualMeeting.html

June 13–17 European Associationof Geoscientists and Engineers, 67th

Annual International Conferenceand Exhibition, Madrid, Spain. Details:Sandra Hermus, Conference Assistant,Standerdmolen 10, 3995 AA Houten orPO Box 59, 3990 DB Houten, TheNetherlands. Fax: + 31 30 6343534;web page: www.eage.nl/conferences/index2.phtml?confid=17

June 19–22 American Association ofPetroleum Geologists and Society forSedimentary Geology Joint AnnualMeeting and Exhibition, Calgary,Alberta, Canada. Details: AAPGConventions Dept., PO Box 979, Tulsa,OK 74119, USA. Tel.: 918-560-2679;fax: 918-560-2684; e-mail: [email protected]; web page: www.aapg.org/cal-gary/globalroundup.cfm

June 19–28 EMU School: MineralBehaviour at Extreme Conditions,Heidelberg, Germany. e-mail:[email protected]; webpage: http://www.univie.ac.at/Mineralo-gie/EMU/emusch_7.htm

July 3–9 7th International EclogiteConference, Seggau, Austria. Details:Alexander Proyer, IEC-7 OrganizingCommittee, Institute of Earth Sciences,Department of Mineralogy and Petrology,University of Graz, Universitaetsplatz 2,A-8010 Graz, Austria. Fax: +43 316 3809865; e-mail: [email protected]; webpage: www.uni-graz.at/IEC-7/

July 6–9 ECROFI XVIII: EuropeanCurrent Research on Fluid Inclusions,Siena, Italy. E-mail: [email protected] [email protected]; web page:www.unisi.it/eventi/ECROFIXVIII

July 11–15 Role of Volatiles andAtmospheres on Martian ImpactCraters, The Johns Hopkins University,Maryland, USA. Details: Nadine Barlow,Northern Arizona University. Tel.: 928-523-5452; e-mail: [email protected]; web page: www.lpi.usra.edu/meet-ings/volatiles2005/volatiles2005.1st.html

July 31–August 3 5th InternationalDyke Conference(IDC-5), Rovaniemi,Finland. Details: Dr. Jouni Vuollo,Geological Survey of Finland, PO Box77, FIN-96101 Rovaniemi, Finland. Tel.:+358 (0)205 504206; fax: +358 (0)2055014; e-mail: [email protected]; webpage: http://idc5.gsf.fi/

July 31–August 5 Gordon ResearchConference on Inorganic Geochem-istry and Ore Deposits, ProctorAcademy, Andover, New Hampshire.Details at www.grc.uri.edu/pro-grams/2005/inorgeo.htm

August 7–11 10th InternationalPlatinum Symposium, Oulu, Finland.Details: Dr. Tuomo Alapieti, Universityof Oulu. Tel.: +358-8-553 1432; mobile:+358-40-504 4599; fax: +358-8-5531484; e-mail: [email protected];web page: http://platinumsymposium.oulu.fi/

August 8–11 Earth System Processes2, Calgary, Alberta, Canada. Details:Chris Beaumont, e-mail: [email protected]; Don Canfield, e-mail:[email protected]; web page:www.geosociety.org/meetings/esp2/

August 18–21 Society for GeologyApplied to Mineral Deposits, 8th

Biennial Meeting, Beijing, China.Details: 8th SGA Biennial Meeting,Dr. Jingwen Mao – Secretary, Institute ofMineral Resources, Chinese Academy ofGeological Sciences, 26 BaiwanzhuangRoad, Beijing 100037, China. Tel.: +8610 68 32 73 33; fax: +86 10 68 33 6358; e-mail: [email protected]; webpage: www.sga2005.com/

August 21–27 Claysphere: Past,Present and Future, 13th InternationalClay Conference, Waseda University,Tokyo, Japan. Details: Prof. T. Sakamoto,Secretary General 13th ICC, Faculty ofScience, Okayama University of Science,1-1, Ridai-cho, Okayama 700-0005,Japan. Tel.: +81-86-252-8922, e-mail:[email protected]; web page:wwwsoc.nii.ac.jp/cssj2/13ICC/

August 23–26 3rd Federation ofEuropean Zeolite Associations (FEZA)Conference, Prague, Czech Republic. E-mail: [email protected]; webpage: www.jh-inst.cas.cz/~feza2005/

August 23–27 7th InternationalSymposium on the Geochemistryof the Earth’s Surface (GES-7), Aix-en-Provence, France. Details: Jean-Dominique Meunier, CEREGE, EuropôleMéditerranéen de l’Arbois – BP 80,13545 Aix-en-Provence cedex 4, France.Tel.: (+33) 442 971 524; fax: (+33) 442971 540; e-mail: [email protected]; webpage: www.cerege.fr/GES7/index.htm

August 23–31 XX Congress ofInternational Union of Crystallography,Florence, Italy. Details: CongressSecretariat, XX Congress and GeneralAssembly of the International Union ofCrystallography, c/o Dipartimento diEnergetica, University of Florence, via S.Marta 3, 50139 Firenze, Italy. Tel.: +39-055-4796209; fax +39-055-4796342; e-mail: [email protected]; web page:www.iucr2005.it

August 28–September 1 AmericanChemical Society 230th meeting,Washington, DC. Details: 2005 ACSMeetings, 1155 – 16th St NW,Washington, DC 20036-489, USA. Tel.: 202-872-4396; fax: 202-872-6128;e-mail: [email protected]

August 29–September 2 Structure,Tectonics and Ore MineralizationProcesses (STOMP), James CookUniversity, Townsville, Australia. E-mail:[email protected] [email protected];Web page: www.es.jcu.edu.au/STOMP/

September 10–11 Symposium onAgate and Other Forms of Cryptocrys-talline Quartz, Colorado School ofMines, Golden, CO, USA. Details: PeterModreski, U.S. Geological Survey. Tel.303-202-4766, e-mail: [email protected]

September 11–16 6th InternationalSymposium on Applied IsotopeGeochemistry (AIG-6), Prague, CzechRepublic. E-mail: [email protected];web page: http://www.aig6.cz

September 12–13 Micro-organismsand Earth Systems: Advances inGeomicrobiology, University of Keele,UK. Details: Society for General Microbiol-ogy, Marlborough House, BasingstokeRoad, Spencers Wood,Reading RG71AG, UK. E-mail: [email protected]; webpage: www.sgm.ac.uk/meetings

September 12–16 68th AnnualMeteoritical Society Meeting,

Gatlinburg, Tennessee, USA. Details:Kimberly Taylor (LPI Meeting Coordina-tor), Program Services Department,Lunar and Planetary Institute, 3600 BayArea Boulevard, Houston, TX 77058-1113, USA. Tel.: 281-486 2151; fax:281-486 2160; e-mail: [email protected] or [email protected]; webpage: http://geoweb.gg.utk.edu/2005/metsoc2005.html

September 12–16 22nd InternationalMeeting on Organic Geochemistry (22IMOG), Seville, Spain. Details: Viajes ElCorte Ingles, Teniente Borges 5, Seville41002, Spain. Tel.: +34 954506605;fax: +34 954223512; e-mail: [email protected]; web page: http://www.imog05.org

September 19–23 From Tropics toTundra: 22nd International Sympo-sium of the Association of ExplorationGeochemists, Perth, Western Australia.Details: Promaco Conventions Pty Ltd,ABN 68 008 784 585, PO Box 890,Canning Bridge, Western Australia 6153.Tel.: + 61 8 9332 2900; fax: + 61 89332 2911; e-mail: [email protected]; web page: www.promaco.com.au/conference/2005/iges

September 25–28 Materials Science& Technology 2005 (MS&T ’05),Pittsburgh, PA, USA. Contact: TMSMeetings Services, 184 Thorn Hill Road,Warrendale, PA 15086. Tel.: 724-776-9000, ext. 243; e-mail:[email protected]

October 16–19 GSA Annual Meeting,Salt Lake City, Utah, USA. Details: GSAMeetings, Box 9140, Boulder, CO80301-9140, USA. Tel.: 303-447-2020,ext. 164; fax: 303-447-1133; e-mail:[email protected]; web page:www.geosociety.org/meetings/index.htm

November 6–11 InternationalGondwana 12 Conference, Mendoza,Argentina. Details: Gondwana 12,Centro de Investigaciones Geológicas,Calle 1 # 644, B1900TAC La Plata,Argentina. Tel./Fax: +54 221 4215677;e-mail: [email protected]; web page: http://cig.museo.unlp.edu.ar/gondwana

November 13–15 Geology Forum 05:Focus on Exploration, Cape Town,South Africa. Details: B. Wills, MineralsEngineering Int., 18 Dracaena Ave.,Falmouth, Cornwall TR11 2EQ, UK. Tel.:44 (0)7768 234 121; e-mail: [email protected]; web page: www.min-eng.com/geologyforum05/index.html.

December 5–9 American GeophysicalUnion Fall Meeting, San Francisco,California, USA. Details: E. Terry, AGUMeetings Department, 2000 FloridaAvenue NW, Washington, DC 20009USA. Tel.: 202-777- 7335; fax: 202-328-0566, e-mail: [email protected] [email protected]; web page:www.agu.org/meetings

2006

March 12–16 The Minerals, Metals& Materials Society Annual Meeting& Exhibition, San Antonio, TX, USA.Contact: TMS Meetings Services, 184Thorn Hill Road, Warrendale, PA 15086,USA. Tel.: 724-776-9000, ext. 243; e-mail: [email protected]; web page:www.tms.org/Meetings/Meetings2006.asp

March 26–30 American ChemicalSociety 231st Annual meeting, Atlanta,GA, USA.

If you sense, from reading Ian Parsons’editorial, that the editorial team works welltogether, you are right. Indeed, we feelpriviledged that we get along so well and thatwe can happily come to a consensus on justabout every issue that comes our way.

DIAMONDS AND GLAMOURWhile working on this issue, I learned a lotabout diamonds and the unique contributiontheir study has made to our understandingof the mantle. Studying diamonds can be aglamorous occupation at times, as this pictureof George Harlow attests. When George sentme the picture for fun, I begged him to allowme to use it.

AND THEN THERE WERE SEVENSo much has happened since I was closing theinaugural issue, in a race against time to havethe issue on hand for the Geological Societyof America meeting. Just as I was putting the

finishing touches to the issue, I received an e-mail message from Terry Seward informing usthat the European Association for Geochem-istry (EAG) Council had voted to join Elements.We were able to add a last-minute news item.During the GSA meeting, we learned that theInternational Association of GeoChemistry(IAGC) Council had also voted to join theElements effort, and members of bothEAG and IAGC did receive the inaugural issue.We welcome these two societies and theirmembers, and you can read their news onpages 110 and 112.

ELEMENTS’ WEBSITEElements now has its own website, whichis also linked to the website of each of theparticipating societies. Take a moment tobrowse through it. We have posted theinaugural issue on the website as a samplecopy. We welcome comments. www.elementsmagazine.org

THANKS Thanks to all who have contributed timeand talent to this issue, to George Harlowand Rondi Davies, guest editors, and all theauthors; to the society news editors SethDavies, Mel Gascoyne, Andrea Koziol, DanielKontak, Adrian Lloyd Lawrence, KathrynNagy, Eric Oelkers; to contributors Ross Angel,Peter J. Heaney, Ian Parsons, Jean-ClaudePetit, John Rakovan, Nancy Ross, Paul Ribbe,Quintin Wight; and to copy editorThomas Clark.

Pierrette Tremblay

127E L E M E N T S

Voilà !

From the Managing Editor

It has been heartwarming to read the positive feedback and the usefulsuggestions many of you have sent. It made all the hard work worth-while. My favorite message was this one: «Wow… Quel magazine! Il esttrès beau maman. Félicitations! J’espère qu’il sera un succès monstre.Beau travail.» It was from my son David, who is doing an MSc in geol-ogy at McGill University.

George Harlow at a dinner held just prior to theopening event for the exhibition The Nature ofDiamonds in October 1997. COURTESY OF THE AMERICAN

MUSEUM OF NATURAL HISTORY

PARTING QUOTE

DON’T WRITE MERELY

TO BE UNDERSTOOD;WRITE SO THAT YOU

CANNOT POSSIBLY BE

MISUNDERSTOOD.

ROBERT LOUIS STEVENSON

May 4–6 Society of EconomicGeologists 2006 Conference,Keystone, Colorado, USA. Webpage: www.segweb.org/meeting.htm

June 3–7 Joint 43rd AnnualMeeting of The Clay MineralsSociety and Annual Meeting ofthe Groupe Français des Argiles(French Clay Group), OléronIsland, France. Details: Sabine Petit,Université de Poitiers, CNRSHydr’ASA, 40 Av. du RecteurPineau, 86022 Poitiers Cédex,France. Tel.: 33-(0)5-49-45-37-56;e-mail: [email protected]; web page: www.clays.org

July 16–23 Zeolite ‘06, Socorro,New Mexico, USA. Details: Dr.Robert Bowman. E-mail: [email protected]; web page: http://cms.lanl.gov/zeo2006.html

July 23–28 19th InternationalMineralogical Association (IMA)Meeting, Kobe, Japan. Details:Prof. T. Yamanaka. E-mail:[email protected]; webpage: www.congre.co.jp/ima2006/

August 26–27 GIA GemologicalResearch Conference, San DiegoCalifornia, USA. Contact information:Dr. James Shigley, [email protected],or Brendan Laurs, [email protected]

August 27–September 116th Annual V.M. GoldschmidtConference. Melbourne, Australia.e-mail: [email protected]; web page: www.gold-schmidt2006.org

August 27–September 1 17th

International Mass SpectrometryConference (IMSC), Prague, CzechRepublic. Web page:www.imsc2006.org/

October 22–25 GeologicalSociety of America AnnualMeeting, Philadelphia, Pennsylva-nia, USA. Details: GSA MeetingsDept., PO Box 9140, Boulder, CO80301-9140, USA. Tel.: 303-447-2020; fax: 303-447-1133; e-mail:[email protected]; webpage: www.geosociety.org/meetings/index.htm

December 11–15 AmericanGeophysical Union Fall Meeting,San Francisco, California, USA.Details: E. Terry, AGU MeetingsDepartment, 2000 Florida AvenueNW, Washington, DC 20009, USA.E-mail: [email protected]; web page:www.agu.org/meetings

To get meeting information listedin the calendar, contact AndreaKoziol ([email protected]).

2006 (cont’d)


Parting Shot

TheBadmintonCabinet: the mostexpensivepiece of furniture…ever!

NOTE FROM THE EDITORS: We

follow up on Randy Cygan’s

suggestion to present an inter-

esting picture to close each

issue. Our first submission is

from Ian Parsons. Readers are

invited to submit interesting

pictures, with a caption, to

the managing editor.

This fabulous cabinet, construct-ed of ebony and gilt-bronze andincorporating lapis lazuli, agate,red and green Sicilian jasper,chalcedony, and amethyst, aswell as a variety of polishedrocks, was sold in December 2004at Christie’s of London for£19,045,250 (US$36,662,106;Eu27,463,250), making it themost expensive nonpictorial work

of art ever. It is 3.86 m high and2.33 m wide. The cabinet, ofunsurpassed richness andsplendour, was commissionedby Henry Somerset, 3rd Duke ofBeaufort, whose family seat wasat Badminton in southwestEngland, when he was onlynineteen. It was made at theGrand Ducal workshops (Ufficiodelle pietre dure) in Florencefrom 1720 to 1732. It remainedin Badminton until 1990 when itwas sold (again for a record price,£8.58 million) to the collectionof the American philanthropistBarbara Piasecka Johnson (of thebaby-powder family, anothermineralogical connection!). Inthe recent auction, the cabinetwas purchased by the Directorof the Liechtenstein Museum inVienna, on behalf of Prinz Hans-Adam II of Liechtenstein. It willbe on permanent display inVienna from spring 2005. I amindebted to Norman Butcher fordrawing my attention to thisspectacular contribution ofmineralogy to the art world.

Ian Parsons

Detail of cabinet construction. PHOTOGRAPHS COPYRIGHT CHRISTIE’S 2005

Documents

Diamonds - Univerzita Karlova · Diamonds George E. Harlow and Rondi M. Davies Guest Editors Inclusions in Sublithospheric Diamonds: Glimpses of Deep Earth Thomas Stachel, Gerhard