Rock-forming Minerals - WordPress.com · Rock-forming Minerals Dr. I Wayan Warmada Laboratory of Mineral Resources. About Earth Materials • All Earth materials are composed of atoms

Rock-forming MineralsRock-forming Minerals

Dr. I Wayan WarmadaLaboratory of Mineral Resources

About Earth MaterialsAbout Earth Materials

• All Earth materials are composed of All Earth materials are composed of atoms bound together.atoms bound together.

• Minerals are composed of atoms bonded Minerals are composed of atoms bonded together and are the building blocks of together and are the building blocks of rocks. rocks.

• Rocks are composed of minerals and Rocks are composed of minerals and they record various geologic processes.they record various geologic processes.

Silicate ion (SiO44–)

Oxygen ions(O2–) Silicon ion

(Si4+)

Formation of silicate mineralsFormation of silicate mineralsClasses of Rock-forming MineralsClasses of Rock-forming Minerals


Oxygen ions(O2–)

The silicate ion forms tetrahedra.

Silicon ion(Si4+)



(Si4+)


Quartzstructure



(Si4+)


Quartzstructure

Quartz is a silicate polymorph.



(Si4+)


Quartzstructure

Tetrahedra are the basic building blocks of all silicate minerals. About 95% of Earth’s minerals are silicates.

Types of silicate minerals:Types of silicate minerals:Isolated silica tetrahedraIsolated silica tetrahedraSingle-chain linkagesSingle-chain linkagesDouble-chain linkagesDouble-chain linkagesSheet linkagesSheet linkagesFrameworksFrameworks

Classes of Rock-forming MineralsClasses of Rock-forming Minerals

Mineral Chemical formula

Cleavage planesand number of

cleavage directionsSilicate

structure Specimen

1 plane Isolatedtetrahedra

Olivine (Mg, Fe)2SiO4




structure Specimen


2 planes at 90°Single chains

Olivine

Pyroxene

(Mg, Fe)2SiO4

(Mg, Fe)SiO3




structure Specimen



2 planes at 60°and 120° Double chains

Olivine

Pyroxene

Amphibole

(Mg, Fe)2SiO4

(Mg, Fe)SiO3

Ca2(Mg, Fe)5Si8O22(OH)2




structure Specimen




1 plane Sheets

Olivine

Pyroxene

Amphibole

Micas

(Mg, Fe)2SiO4

(Mg, Fe)SiO3


Muscovite:KAl2(AlSi3O10)(OH)2

Biotite:K(Mg, Fe)3AlSi3O10(OH)2




structure Specimen




1 plane Sheets

Olivine

Pyroxene

Amphibole

Micas

Feldspars

2 planes at 90° Three-dimensionalframework

(Mg, Fe)2SiO4

(Mg, Fe)SiO3


Muscovite:KAl2(AlSi3O10)(OH)2

Biotite:K(Mg, Fe)3AlSi3O10(OH)2

Orthoclase feldspar:KAlSi3O8

Plagioclase feldspar: (Ca, Na) AlSi3O8

What Are Rocks?What Are Rocks?

QuartzQuartz (SiO (SiO22))

• Hardness (7),• Concoidal fracture• Clear to white• Used as a gemstone,

mortar, scientific apparatus, electronic industry

• Important: metamorphic, igneous, and sedimentary.

Feldspar GroupFeldspar Group[(Na,K,Ca)AlSi[(Na,K,Ca)AlSi

22OO

88]]

• Cleavage

• Hardness (6)

• White to pink

• Ceramics, ornamental

• Important: igneous, metamorphic, sedimentary (clastic)

albite

microcline

Amphibole GroupAmphibole Group[Ca[Ca

22(Mg,Fe,Al)(Mg,Fe,Al)

55(Al,Si)(Al,Si)

88OO

2222]]

• Clevage (56° and 124°)• Green to black• Some form are used as

asbestos

• Important: igneous, metamorphic rocks (hornblende most common)

Tremolite

Pyroxene GroupPyroxene Group[(Mg,Fe)[(Mg,Fe)

22SiOSiO

44(Ca,Na)(Mg,Fe,Al)(Al,Si)(Ca,Na)(Mg,Fe,Al)(Al,Si)

22OO

66]]

• Cleavage (87° and 93°)

• Short prisms

• Dark

• Used as specimens, some gemstones

• Important: igneous, metamorphic (augite most common

Aegirin-augite

Mica GroupMica Group[K(Fe,Mg,Al)[K(Fe,Mg,Al)

33AlSiAlSi

33OO

1010(F,OH)(F,OH)

22]]

• Perfect cleavage• Thin sheets flexible• Clear to black color• Used in electrical,

fireproofing, lubricant, wallpaper

• Important: metamorphic, igneous accesory, sedimentary Muscovite

OlivineOlivine[(Mg,Fe)[(Mg,Fe)

22SiOSiO

44]]

• Green in color

• Conchoidal fracture

• Vitreous look

• Some used as a gem, abrassives

• Important: igneous (ultramafic)

Olivine

Calcite – DolomiteCalcite – Dolomite[CaCO[CaCO

33 – CaMg(CO – CaMg(CO

33))22]]

• Rhombohedral crystals

• Effervesces with acid

• Used in manufacture of cement, fertilizer

• Important: sedimentary and metamorphic (also igneous rock, such as carbonatite)

Calcite

Dolomite

Concentrations of Valuable Concentrations of Valuable Mineral ResourcesMineral Resources

Types of ore minerals:Types of ore minerals:

Vein depositsVein deposits

Disseminated depositsDisseminated deposits

Igneous depositsIgneous deposits

Sedimentary depositsSedimentary deposits

Deformedcountry rock Geysers and

hot springs

Plutonicintrusion

Magma

Groundwater

Origin of vein Origin of vein depositsdeposits



hot springs

Plutonicintrusion

Magma

Groundwater

Groundwater dissolves metal oxidesand sulfides. Heated by the magma, it rises, precipitating metal ores in joints.


hot springs

Plutonicintrusion

Magma

Groundwater

Groundwater dissolves metal oxidesand sulfides. Heated by the magma, it rises, precipitating metal ores in joints.

Vein deposit

Typical sulfide minerals from vein depositsTypical sulfide minerals from vein deposits


Open-pit mine for disseminated Open-pit mine for disseminated deposits of copper-bearing minerals.deposits of copper-bearing minerals.


Igneous depositsIgneous deposits

Chromitelayers (dark)in layeredigneous rock


Sedimentary deposits:Sedimentary deposits:

Copper, iron, other metalsCopper, iron, other metals

Gold, diamonds, other Gold, diamonds, other heavy minerals (placers)heavy minerals (placers)


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Rock-forming Minerals - WordPress.com · Rock-forming Minerals Dr. I Wayan Warmada Laboratory of Mineral Resources. About Earth Materials • All Earth materials are composed of atoms