BORATES BO3 triangular groups
Kernite Na2B4O6 (OH)2 . 3H2O
Borax
NaCaB5O6(OH)6 . 8H2O
Ulexite NaCaB5O6(OH)6. 5H2O
Colemanite CaB3O4(OH)3 . H2O
-
evaporation of lakes – arid regions
uses: glass, soap, detergents, neutron absorbers in nuclear reactors
* Ulexite = TV-Stone - optical conductivity along c-axis
SO42-
group (tetrahedrons)
Barite group
Barite
BaSO4 12 coord.
Celestite
SrSO4
Anglesite
PbSO4
Anhydrite CaSO4 8 coord
SULFATES
Hydrous sulfates
Gypsum CaSO4.2H2O
Barite
- common in hydrothermal F, As, Pb, Zn, Cu deposits in limestones
- also in hotsprings
- complete S.S. w/ less common celestite
- use: medical, drilling mud (soft + P)
Anglesite
- supergene mineral in Pb deposits
Anhydrite
- evaporite mineral interbedded w/LS, SH
Gypsum
- same occur as anhydrite, but more common gypsum  anhydrite
- use: dry wall, sheet rock, plaster of Paris, albaster
Others: Antlerite Cu3SO4(OH)4 + Brochantite CuSO4(OH)6
-copper ores in supergene deposits
Alunite - KAl3(SO4)2(OH)6
- sulfuric acid alteration of K-spar
- ore of K and Al
- primary sulfides oxidized to sulfuric acid by ground water
- useful for ore deposit exploration
Chromates: Crocoite PbCrO4
- oxidized zones of lead deposits
- bright hyacinth red! – 1st discovery of Cr!
Tungstates and Molybdates
Covalent WO42- MoO42- w/limited S.S
Flattened tetrahedral
Wo/framite (Fe, Mn)WO4
ferberite(Fe) - huebnerite(Mn)
- pegmatites, high-T veins
w/ scheelite, cassiterite, molybdenite, fluorite
- ore of tungsten (tungsten-carbide steel)
Scheelite Ca WO4 ↔ Powellite Ca MoO4
- pegmatites, skarns (in altered LS) w/granites
- ore of tungsten, fluorescent
Wulfenite PbMoO4
- oxidized zone of lead deposits
- pretty orange-yellow tabular mineral
- use: Mo ore
PHOSPHATES
)3-
Phosphates : (PO4 tetrahedrons
- similar to (VO4)3- and (AsO4)3- the other common cations : Li, U, Al, REEs,Th
- one of the top 12 elements in abundance but does not fit into silicates.
Triphylite – Lithiophilite
- in pegmatites w/beryl + spodumene
Monazite
- source of REEs
- radio active
- in granites , pegs., gneisses
- chief source of Thorium (mantles for gas lanterns)
Apatite Ca5 (PO4) (F,Cl,OH) – most common phosphate
- typically fluorapatite
- also has U, Th, REEs
- occurrence: granite pegmatites, bones + teeth (hydroxy apatite) , sea animals
anorhtosites
- use: phosphate fertilizer
Pyromorphite Pb5 (PO4)Cl --- Mimetite Pb5 (AsO4)Cl
- supergene oxidized zones of Pb deposits
Vanadite
Pb5 (Vo4)Cl
- largest source of V is Bushveld- there is a layer of v-bearing magnetite.
- Ore of V (ferro-alloy), pigment.
Erythrite ___ Co (AsO4)2. 8H2O purple
- ore guide to Co,Ni, Ag
Amblygonite LiAlFPO4
- in pegmatites w/ spodemene, tourmaline, lepidolite ( Beryllonite NaBePO4 and
Brazilianite NaAl3 (PO4)2(OH)4)
- gems.
Lazulite (Mg,Fe) Al2(PO4)2 (OH)2 blue gem.
Wavellite Al3 (PO4) (OH)3 5H2O.
- secondary mineral in low grade Al rocks.
- Abundant in Arkansas
- Ore of Al.
Turquoise --- Cu Al6 (PO4)4(OH)8. 5H2O
- secondary mineral in veins in altered volcanic rock
- gem.
Autuntite Ca (UO2)2 (PO4)2 . 10-12 H2O
- oxidation of uraninite
- ore of U
Carnotite K2 (UO2)2 (VO4)2 .3H2O
- ore of U and V
- from granite source – K
SULPHIDES
Sulphides
- minor minerals in total earth, but are important as ore minerals. S2-, As 2-, Te2- typically opaque minerals.
STRUCTURES: - 5 MAJOR TYPES.
1) NaCl type : (Fig. 8.8, p-341) e.g galena (PbS) pyrite (FeS2)
- octahedral arrangement
2) Sphalerite type --- FCC lattice
- e.g Sphalerite (ZnS) chalcopyrite (CuFeS2) tetrahedrite (Cu12 Sb4 S13),
greenoccite (CdS)
3) Wurtzite type ---- HCP . lattice
- e.g wurtzite (ZnS), greenoccite (CdS)
4) Covellite type : (Fig. 8.7, p-340) CuS
- some Cu is tetrahedrally co ordinated
- S covalently bonded
- Sheets of CuS3 triangles between double layers of CuS4 tetrahedra w/ covalent
sulfur-sulfur bonds linking layers
5) Marcasite --- orthorhombic (Fig. 8.8, p-341)
- Fe- Oct. coord., closely spaced S2 pairs.
- e.g. marcasite, arsenopyrite.
Acanthite Ag2S monoclinic (argentite) = ruby silver
- silver ore in hydrothermal veins
Chalcocite Cu2S monoclinic, wurtzite type ( digenite Cu9S5)
- typically anhedral
- Cu ore (Butte , Motana)
Bornite -- Cu5FeS4 tetragonal
- Sphalerite type-structure
- “peacock” copper ore
- purple tarnish w/py , po, cpy
Galena - PbS NaCl type isometric structure
- major ore of lead; - MVT deposits in dolomite; - high-T veins
- minor Ag as acanthite solid inclusions and in S.S.
Sphalerite- ZnS, sphalerite type structure
- most important Zn ore
- high-T veins w/py, po
- MVT replacement deposits in Limestone w/dol, galena, cpy
Chalcopyrite- CuFeS2, sphalerite- type structure
- porphyry copper deposits- high-T hydrothermal veins
- major ore of Cu
- w/sp, py, po, bn, gn
Pyrrhotite - Fe1-x S
- S in H.C,P.
- @ low T= monoclinic; @ T>250°  hexagonal
- omission solid- solution, Fe deficient , less-Fe= more magnetic
- in S deficient environments : can’t make FeS2
- hydrothermal veins, basic igneous rocks, contact met. Rx., pegmatites
Millerite – NiS hexagonal, needle-like crystals
- low-T mineral, in Keokuk geodes (in Iowa LS)
Pentlandite- (Fe, Ni)9 S8
- assoc. w/ mafic intrusions
- principal Ni ore (Sudbury, Ontario)
Covellite- CuS, hexagonal, sheet-like structure
- typically supergene mineral, alteration of digenite + chalcocite
(Buttle, Montana) - Cu ore
Cinnabar- HgS hexagonal Hg – S – Hg - S chains
- low- T hydrothermal mineral (hotsprings)
- w/stibnite, opal, quartz, chalcedony
- major ore of mercury
Realgar - AsS monoclinic
red- pigment
- hotsprings
- w/ Orpiment As2S3 monoclinic yellow, foliated
Stibnite- Sb2S3 orthrhombic
- low T hydrothermal mineral w/cinnabar
- chief ore of antimony - pigment, glass
Pyrite
- FeS2 isometric NaCl- type structure
- Common accessory mineral in igneous, met, +sed. Rocks
- Alters to goethite
Marcasite
- FeS2 - low T hydrothermal mineral w/Pb- Zn ore S
- Rare ore of S
Molybdenite
- MoS2 hexagonal sheets of Mo, S, S
- High- T hydrothermal mineral in granite, pegmatites, skarns
- Principal ore of molybdenum
Arsenopyrite
- FeAsS monoclinic , marcasite structure typically euhedral
- W/gold ores in veins
- In pegmatites, w/Sn-W ores
- Principal source of arsenic
Skutterudite (Co, Ni)As3
- w/ Cobaltite (Co, Fe)AsS in hydrothermal veins
- w/Ag; Bi; arsenopyrite
- ore of Co, Ni
Sulfosalts
- unoxidized sulfur mineral w/As, Sb, Bi,etc.
Enargite -Cu3AsS4
wurtzite structure
- hydrothermal high-T mineral (isomorph= luzonite)
Pyrargyrite Ag3SbS3
-Proustite Ag3AsS3
“ruby silvers”
- Ag ores
Tetrahedrite Cu12 Sb4S13 -Tennantite Cu12As4S13
(Freibergite up to 18% Ag)
- high-T hydrothermal mineral
Tellurides
- gold-silver veins: calaverite(AuTe2), sylvanite((Au, Ag)Te2), hessite,
empressite, stuetzite
NATIVE ELEMENTS
METALS : Metallic bonding.
Gold Group:
Gold – Au Isometric, FCC lattice, 12 coordinates, 4/m,3bar,2/m (fig 10.1,p-337)
frequently octrahedrans.
- complete S.S w/silver Ag
- Au+Ag each have a 1.44A0 radians.
- Crustal abundance of Au – 0.004 ppm ( 4 ppb) = rare
- Occurs: hydrothermal veins w/ quartz , pyrite, placer deposits ( fossil placers =
gtz pebble conglomerate) , ultimate source = mafic igneous , 2/3 from South
Africa.
Silver – Ag
- > 20 % Ag in gold or >20% Au in silver = electrum
- occur: oxidized zones of ore deposits = secondary
primary Ag: a) w/sulfides, zeolites, CC , barite, fluorite, Qtz
b) w/ arsenides of Co , Ni and native Bi
c) w/uraninite and Co-Ni minerals
- Use; coins , jewelery , photography
Copper – isometric , CCP , 1.28 A0 = limited S.S w/Ag + Au
- Occur: oxidized zones of copper deposits = secondary
Primary = basaltic lavas in which Cu0 deposition results from reaction of
hydrothermal fluids w/iron oxide minerals.
E.g Keweenew Penninsula, Michi , Precamrian basalts, Nonesuch shale , Copper
Harbor Conglomerate.
- assoc. w/ propylitic alteration : Cc, epidote , Qtz zeolites , datolite.
Platinum Group :
Platinum – Pt isometric, CCP
- occur: ultramafic rx , -- e.g Merensky Reef in Bushveld layered complex , South
Africa
Paladium __ Pd
CCP
Platiniridium _ PtIr
HCP
Iridium -- Ir
CCP
Iridosmine IrOs
HCP
- Use ; jewelery , dentistry , electronics , catalysts in auto exhausts
Iron Group :
Iron – Fe , isometric , rare – very reducing envs ., peridotites
Kamacite - Fe-Ni in meteorites + core of earth ____ 5.5 wt% Ni
Taenite - Fe-Ni in meteorites + core of earth ____ 27 – 65 wt % Ni
Widmanstatten pattern of 2 intergrowth phases in meteorites.
NATIVE SEMI – METALS
Native semi metals: -- As , Sb , Bi , Se covalent bonding
- brittle , poor conductors
- not really closest packing , each atom is closer to 3 atoms than to the other 9.
Arsenic – As + Bismuth – Bi + Selenium – Se
- rare minerals in hydrothermal veins w/Ag , Co, Ni sulfides
- hot spring + fumaroles w/ volcanoes
NATIVE NON – METALS
Native nonmetals : sulfur S, diamond C, graphite C
Sulfur – S , orthorhombic 2/m 2/m 2/m
- covalently bonded s8 groups (rings) , loosely bound by vanderwaals bands( fig
10.7 , p343)
-
occur: fumeroles of volcanoes.
Sublimation product of incomplete oxidation of H2S by bacteria ---- salt dome’s
caps w/anh , gyp, cc (Texas + Louisiana)
Use: sulfuric acid, H2S, insecticides, vulcanization of rubber , soaps, paints,
leather , dried fruit, wine.
Diamond – C , isometric 4/m, 3bar, 2/m (fig 10.8a , p344)
- tetrahedral coord.
- Covalent bonding w/4 valence electrons (sp3)
- Occurrence: -- Kimberlites (peridolite) – South Africa
-- placers
- use: gem, abrasive
- synthetic diamonds – 1953 Erik Lundblad 24000K , 76Kb.
Graphite – C , hexagonal , 6/m 2/m 2/m (fig 10.8b , p344)
- 6 – member rings , 3 of the 4 valence electrons are in covalent bonds , the 4th id
free to wander = high electrical conductivity
- vanderwaals bonds between sheets = weak = good cleavage
- occurrence: - metamorphic rocks – marbles, schists , gneisses
- derived from carbonaceous material of organic origin
- meta . coal beds.
- Hydrothermal veins w/qtz , bio + , orhto. , tour , apatite , Py,
sphere ( from hydrocarbons)
- In igneous rocks: basalts , nepheline syenite , pegmatites
- In meteorites
- Use: refractory , pencils , batteries , generator brushes.