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Home , Alabandite, Armalcolite, Bournonite, Chalcocite, Cobaltite, Djurleite

Appendix A.1 Refractive indices of biaxial

Silicates 14 1515416 1 7 18 amphiboles anthophyllite-gedrite tremolite-ferroactinolite the hornblende series glaucophane-riebeckite richterite katophorite -- oxyliornblende kaersutite eckermannite -- arfvedsonite -- Al2SiOs polymorphs andalusite - kyanite - sillimanite - chlorite - clay minerals kaolin - illite f-- montmorillonite cordierite - r-- epidote group clinozoisite - epidote - group

K - } alkali feldspars Na feldspars (albite) - } plagioclase feldspars Ca feldspars (anorthite) - I 1 4 1 5 1 54 1 6 17 1 8 19 humite group norbergite -- chondrodite humite --- clinohumite mica group I-- biotite muscovite - I- lepidolite - - paragonite - glauconite - group forsterite } Fo Fa fayalite 01" pumpellyite group

enstatite-orthoferrosilit e opx -hedenbergite di" augite pigeonite - t-- aegirine aegirine - augite jadeite -- spodumene -- wollastonite -- serpentine I- silica group tridymite - sphene staurolite - talc ~ 1.4 1.5 1.54 1.6 1.7 1 8 1.9 topaz - zeolites - f--

Non-silicates

carbonates aragonite

sulphates barite - celestite - gypsum - anhydrite - ~ 2.15-2.44 ---

Appendix A.2 Refractive indices of positive uniaxial minerals

Silicates 14 1 5 16 17 18 19 20 - feldspathoid family leucite melilite group gehlenite - silica group - zircon

Non-silicates - 2.6-2.9 ___ brucite - Appendix A.3 Refractive indices of negative uniaxial minerals

Silicates 1.4 1.5 1.6 1.7 1.8 1.9 feldspathoid family nepheline - melilite group akermanite - silica group cristobalite vesuvianite

Non-silicates carbonates corundum apatite

Appendix A.4 Refractive indices of isotropic minerals

Silicates 1.4 1.5 1.6 1.7 1.8 1.9 feldspathoid family (leucite) soda lite group Non-silicates group -+2.4 (transparent members) fluorite halite Appendix B 2V size and sign of biaxial minerals

Positive (2V~) Negative (2Vo)

Silicates o 20 40 60 80 90 80 60 40 20 o amphiboles anthophyllite-gedrite tremolite-ferroactinolite -t-- the hornblende series glaucophane glaucophane-riebeckite riebeckite richterite katophorite f- - oxyhornblende kaersutite - - eckermannite arfvedsonite

Al 2SiOs polymorphs andalusite - kyanite . sillimanite - chlorite chloritoid - - clay minerals kaolin - f-- illite -- montmorillonite --- -- cordie rite epidote group zoisite clinozoisite epidote - - feldspar group K feldspar plagioclase feldspar 2Vy 2Va o 20 40 60 80 90 80 60 40 20 0 humite group norbergite - chondrodite I-f- humite -I- clinohumite mica group phlogopite - biotite -I-- muscovite lepidolite - I-- paragonite glauconite - olivine group Fe Fa pumpellyite pyroxene group En Fs ens tat i te--{) rth ofe rrosi Ii t e diopside-hedenbergite - augite pigeonite aegirine - aegirine-augite jadeite - spodumene - wollastonite - serpentine - antigorite silica group tridymite sphene -- 2V, 2V a o 20 40 60 80 90 80 60 40 20 0 staurolite 1- talc topaz - r- zeolites -- ~- 1-1------f- Non-silicates carbonates aragonite • sulphates barite • celestite • gypsum • anhydrite • wolframite I- Appendix C Properties of are minerals

Mineral Formula ~R% Colour ~VHN Anisotropy Distinguished properties/resemblance See range (associations) page Ag2S 30-31 light grey 20-60 distinct twin lamellae low temp. polymorph (greenish) (Pb-Sb-As-Bi-Ag-Au) MnS 25 light grey 140-270 isotropic lamellar twinning; brown or green internal reflections (sulphides, Mn-carbonates)

Ti0 2 20 light grey 580-620 weak abundant colourful internal reflections; 164 low temp. polymorph resembles rutile (Fe-Ti-O, )

Ag2S 30 light grey 20-60 isotropic high temp. polymorph (greenish) (Ag-sulphides, Cu-Pb-S, Au)

armalcolite (Fe,Mg)Ti2O, 13-14 grey ? moderate barrel shape (brownish) (Fe-Ti-O, ) FeAsS 52 white 1050-1130 distinct rhomb shape, twinning, zoning 140 (Sulphides, , Au-Bi-Te-Sn, W) Bi 60-65 bright white 10-20 distinct tarnishes brown, multiple twinning (Co-Ni-As-S, Au-Bi, Te) Bi,S3 40-50 white (bluish) 70-220 very strong fibrous, straight extinction (Co-Ni-As-S, Au-Bi-Te, Mo, Sn, W) Formula -R% Colour -VHN Anisotropy Distinguished properties/resemblance See range (associations) page blaubleibender Cu.+xS resembles but Ro blue in oil 144 covellite -- - - (Cu-Fe-S) Cu,FeS4 22 light pinkish 100 very weak tarnishes to blue or purple. 141 brown Intergrowths with (Cu-Fe-S)

boulangerite PbsSb4 S 11 38-41 light grey 90-180 distinct stronger anisotropy than bournonite (greenish) (Pb-Sb-S,Cu-Fe-S) bournonite CuPbSbS, 35-37 light grey 130-210 weak common twinning (bluish) (Pb-Sb-S,Cu-Fe-S) Mn,SiO.2 20-22 light grey 880-1190 weak resembles some oxides; (brownish) may be magnetic (Mn-Fe-Si-O, mainly in metamorphic rocks) bravoite (Fe,Ni,Co)S2 31-54 light grey to 670-1540 isotropic colour zoning 149 Ni,eo-Fe white (pyrite and other sulphides) (brownish)

C02CUS4 43 white 350-570 isotropic resembles linnaeite (pinkish) (Co-Cu-Fe-S) cassiterite Sn0 2 11-13 grey 1030-1080 distinct common twinning; strong colourless to 158 brown internal reflections; (W, Bi, As, B, sulphides) Cu2S 32 light grey 70-100 weak lancet shaped twinning 142 (bluish) ( colourful) (Cu-Fe-S) chalcopyrite CuFeSz 42-46 yellow 190-220 weak twinning,; more yellow and softer than 143 pyrite; as inclusions in sphalerite (Cu-Fe-Ni-S, sulphides) FeCrzO. 12 grey 1200-1210 isotropic rounded octahedra; resembles 160 (brownish) (weak but non-magnetic anisotropy) (Fe-Ti-O) HgS 28-29 light grey 50-100 moderate multiple twinning; abundant red 144 (bluish) internal reflections; rare (Hg-Sb--S, Fe-S) CoAsS 53 white 1180-1230 weak often idiom orphic cubic; colour 144 orthorhombic (pinkish) zonation; cleavage traces (Cu-Fe-S, Co-Ni-As-S)

cohenite Fe3C white weak resembles (Fe, Fe-O, Fe-Ni-S) meteorites Cu 81 metallic pink 120-140 isotropic scratches easily 177 (tarnishes) (Cu-O, Cu-Fe-S) covellite CuS 7-22 blue to 70-80 very strong plates and flakes; pleochroic 144 bluish light (fiery (Cu-Fe-S) grey orange) -KzMn,O,. 27 light grey 530-1050 distinct fibrous, botryoidal; resembles ; straight extinction (Fe-Mn-O)

cubanite CuFeZS3 40 light grey 150-260 strong lamellae within , orthorhombic (yellowish chalcopyrite brown) (Cu-Fe-S) Mineral Formula -R% Colour -VHN Anisotropy Distinguished properties/resemblance See range (associations) page

cubanite CuFe2S, 35 light grey isotropic intergrown with orthorhombic cubanite cubic (pinkish) (Cu-Fe-S) cuprite Cu2 0 25-30 light grey 180-220 strong deep red internal reflections (bluish) (Cu, Fe-OH, Cu-Fe-S, Ag) Cu.S, 22 light grey 60-70 isotropic 142 (bluish) (Cu-Fe-S) Cu, .••S ~ ~ ~ ~ resembles chalcocite electrum (Au,Ag) 83 light yellow 30-40 isotropic resembles gold 178 (Au-Te-Bi-Cu-Fe-As-Sb-Pb-S) Cu,AsS4 25-29 light grey 130-580 strong cleavage II (110) (pinkish) colourful (Cu-Fe-Sb-As-S) PbS 43 white 70-80 isotropic triangular cleavage pits 145 (Pb-Ag-Sb-As-S, sulphides) (Ni,Co,Fe )AsS 47-54 white 520-910 isotropic zoning, cleavage II (100) gives (pinkish) triangular pits (Fe-Co-Ni-As-S) glaucodot (Co,Fe)AsS 45-50 white 840-1280 distinct idiomorphic, cleavage; as inclusions orthorhombic in cobaltite (Co-Ni-As-S) goethite HFe0 2 17 grey 770-820 distinct Colloform, botryoidal or elongate 170 orthorhombic crystals; red to brown internal reflections (in limonite, Fe-minerals, gossans) gold Au 74 bright yellow 50 isotropic very bright; as inclusions in 178 sulphides; in fractures; soft (A u-Te-Bi-Cu-Fe-As-Sb-Pb-S) goldfieldite Cu,(Te,Sb )S4 32 light grey isotropic zoned (brownish) (Fe-Zn-S, Au-Ag-Te, Bi) graphite C 6-16 dark grey 10 strong deformed flakes; bireflectance strong; 178 (brownish) to cleavage grey (graphitic schists, graphite 'veins')

Fe,O, 25-30 light grey 920-1060 strong tabular crystals, microcrystalline 161 masses; lamellar twinning; weak bireflectance (Fe-Ti-O) hydrocarbon <5 dark grey isotropic rounded grains, interstitial masses, frosted surface, low reflectance but no internal reflections (sedimentary rocks, barite, carbonate, sulphide veins, U)

FeTi0 3 18-21 light grey 520-700 moderate occasional twinning; lamellar 162 (slightly inclusions of hematite pinkish) (Fe-Ti-O) iron Fe 65 bright white 120-290 isotropic rounded grains (Fe-Ni-S, moon, meteorites)

(Mn,Fe,Mg)(Fe,Mn),04 19 grey (brownish 720-750 isotropic rounded grains; fine aggregates; -greenish) strongly magnetic; resembles braunite (Mn-minerals; Fe-OH; in metamorphic rocks) Mineral Formula -R% Colour -YHN Anisotropy Distinguishing properties/resemblance See range (associations) page

Pb4FeSb,S8 36-41 light grey 70-130 strong acicular with cleavage and twin (greenish) lamellae parallel to length (Fe-Pb-Sb-Ag-S) kamacite (Fe,Ni) 60 white isotropic (Fe-Ni-S, Fe-Ti-Cr-O, (bluish) meteorites) lepidocrocite FeO(OH) 10--19 grey 690-780 very strong red to brown internal refiectioI)s 170 (In limonite, Fe-minerals, gossans) limonite FeO.OH.nH,O 16-19 bluish grey 690-820 strong abundant brown to red internal 170 (see goethite and ( colourful) reflections lepidocrocite) (replaces iron minerals)

linnaeite CoJS4 45-50 white 350-570 isotropic cleavage II (100) (pinkish) (Cu-Fe-Ni-S)

livingstonite HgSb4 S8 35-40 light grey 70-130 strong scarce red internal reflections; more ( colourful) opaque than cinnabar (Hg-Sb-S)

FeAs2 55 white 370-1050 very strong common twinning (yellowish) ( colourful) (Fe-Ni-As-S, Cu-Fe-S, U, Sn) mackinawite (Fe,Ni,Co,Cu)S 22-45 light grey 50-60 very strong lamellae in Cu-Fe-S or Fe-Ni-S (pink red) phases (Cu-Fe-Ni-S) maghemite y-Fe,OJ 26 light grey 360-990 isotropic magnetic (bluish) (Fe-Ti-O) magnetite Fe3 O. 21 light grey 530-600 isotropic magnetic; octahedra, rounded; lamellar 163 (often inclusions of hematite or ilmenite pinkish) (Fe-Ti-O) MnOOH 15-21 grey 370-800 strong elongate crystal aggregates; (brownish) cleavages; twin lamellae; red internal reflections; alters to (Fe-Mn-O-Si, veins)

marcasite FeS, 49-55 white 940-1290 strong radiating aggregates of twins; 147 orthorhombic (slightly ( colourful) intergrown with pyrite yellowish) (sulphides in sedimentary rocks, veins)

melnicovite- -FeS, 50 white isotropip very fine grained aggregate; minute 150 pyrite (brownish) or weak pits; banding anisotropy (sulphide in sedimentary rocks)

miargyrite AgSbS, 30-50 light grey 90-120 strong twinning; scarce red internal (bluish) reflections; as inclusions in galena (Ag-Pb-Sb-S)

NiS 52-56 yellow 190-380 strong aggregates of acicular grains; common twinning (Cu-Fe-Ni-S)

MoS, 15-37 grey to 20-30 very strong flakes, platelets, hexagonal; poor 147 white polish (Bi-Te-Au, Sn, W, sulphides)

niccolite NiAs 52-58 white 330-460 very strong cataclased grains in radiating 176 (orange botryoidal masses; twinning or pinkish) (Ni-Co-Ag-As-U, sulphides) Mineral Formula ~R% Colour ~VHN Anisotropy Distinguishing properties/resemblance See range (associations) page orpiment As,S, 25 light grey 20-50 strong radiating aggregates; abundant strong white to yellow internal reflections (realgar) (Fe,NihS, 44 white 200-230 isotropic triangular cleavage pits; alteration 148 (slightly along octahedral parting; as lamellae yellowish) in pyrrhotite (Cu-Ni-Fe-S) (Ca,Na,A)(Ti,Nb)O, 15 grey 920-1130 very weak cubic octahedral habit; lamellar A = rare earths twinning; strong white to brown internal reflections (Cu-Fe-Ti-O, alkaline igneous rocks) pitchblende UO'_3 16 grey 670-800 isotropic radioactive; botryoidal masses, 166 variation inR; shrinkage cracks (Ni-Co-Ag-Bi, Au, sulphides) Pt 70 bright white 120-130 isotropic zoning; exsolved, intergrown phases (yellowish) (incomplete of Pt group elements extinction) (Pt-Ir-Os-Rh-Ru-Pd, Fe-Cr-O, Cu-Fe-S)

proustite Ag3 AsS3 25-28 light grey 110-140 strong distinct bireflectance; red internal 148 (bluish) reflections (Ag-Pb-Sb-As-S) Fe,TiO, 15 grey distinct red yellow internal reflections; resembles rutile (Fe-Ti-O) psilomelane (Ba,Mn,Al,Fe,Si), 15~30 grey~light 200-810 strong fine crystalline aggregates, botryoidal; Mn,OJ6.(O,OH)6 grey (bluish) resembles cryptomelane (Mn-O, Fe-OH; a product)

pyrargyrite Ag3SbS 3 28-31 light grey 50-130 strong distinct bireflectance; red internal 148 (bluish) reflections (Ag-Pb-Sb-As-S)

pyrite FeS2 54 white 1030-1240 isotropic idiomorphic, fractured; framboids 149 cubic (yellowish) (weak (common sulphide in all rock types) anisotropy)

pyrolusite Mn0 2 30-36 light grey 80-1500 very strong coarse to cryptocrystalline; cleavage, (yellowish) if well twinning crystallised (Fe-Mn-O-OH; a weathering product; veins) pyrrhotite FeJ_xS 40 white 230-320 strong polycrystalline aggregates, twinning; 150 (brownish or (colourful) alters readily; magnetic pinkish) (Cu-Fe-Ni-S, Fe-Ti-O) (Ni,Co,Fe )As, 60 bright white 460-830 strong radiating zoned aggregates, skeletal; ( colourful) common lamellar twinning (Co-Ni-Fe-As, Ag, Ag-Sb-S) realgar AsS 20-21 light grey 50-60 strong abundant strong yellow to red internal reflections; interstitial (orpiment, Fe-As-Sb-S, Fe-OH) rutile TiO, 20-23 light grey 1070-1210 strong abundant bright internal reflections; 164 high temp. polymorph (bluish) twinning; acicular (Fe-Ti-O, Fe-S) Mineral Formula -R% Colour -VHN Anisotropy Distinguishing properties/resemblance See range (associations) page

safftorite (Co,Fe,Ni)Asz 55-66 white (bluish) 430-990 strong concentric radiating aggregates with (zoned) other minerals; star shaped twins (Co-Ni-Fe-As, Bi, U, Ag, sulphides)

CaWO. 10 dark grey 290-460 distinct rhombohedral cleavages; abundant white internal reflections (wolframite, Cu-Fe-As-S, Bi-S, Sn, Au) schriebersite (Fe,Ni)3P white weak elongate inclusions in iron minerals (Fe-Ni-S, meteorites, moon) Ag 95 bright white 50-120 isotropic scratches easily; skeletal or dendritic 179 (metallic) (Co-Ni-Fe-As, oxidised sulphides)

(Co,Ni,Fe )As3 _ X 53 white 270-970 isotropic cleavage traces, compositional zoning variable (yellowish (weak (Co-Ni-F-As-S, Au, Ag, U, Mo, Bi) bluish or anisotropy) pinkish) sphalerite (Zn,Fe)S 17 grey 190-210 isotropic colourless to red internal reflections; 151 irregular fractures and cleavage pits (sulphides) spinel MgAl,04 8 dark grey 860-1650 isotropic octahedral, rounded; internal 165 reflections; as inclusions in magnetite (Fe-Ti-O)

Cu2SnFeS4 28-29 light grey 140-330 strong cleavage, triangular pits, , (greenish to lamellar and cross-hatch twinning brownish) (sulphides, Sn-W-As-Bi-Au) Sb,S, 30-40 light grey 40-110 very strong acicular or bladed; distinct 153 to white bireflectance; cleavage traces; (slightly deformation twinning brownish) (Ag-Pb-Sb-S, Fe-S, Au, Hg-S) taenite (Fe,Ni) white isotropic lamellae in kamacite (yellowish) (Fe-Ni-S, Fe-Ti-Cr-O, meteorites) tennantite CulO(Zn,Fe), 31 light grey 320-370 isotropic polycrystaIIine aggregates 154 (As,Sb),SI3 (Cu-Fe-S, galena, sphalerite) tetradymite Bi,Te,S 50-52 white 30-50 distinct hexagonal cross sections, basal (yellowish) cleavage (Au-Bi-Te-S, Cu-Fe-S) (Cu,Ag) IO(Zn,Fe,Hg), 31 light grey 320-370 isotropic polycrystaIIine aggregates 154 (Sb,As),SI3 (Cu-Fe-S, galena, sphalerite) titanomagnetite (Fe,Ti),04 17 grey 720-730 isotropic homogeneous only if formed by rapid 163 (brownish or (weak cooling, otherwise intergrown with pinkish) anisotropy) Fe-Ti-O phases (Fe-Ti-O in igneous and metamorphic rocks) (H,O)<,Mn<.(O,OH)16 20 light grey strong columnar to fibrous aggregates, botryoidal; cleavage traces (Mn-Fe-O; deep sea Mn nodules) troilite FeS yellow strong resembles pyrrhotite; rare (brownish) ( colourful) (Fe-Ni-S, moon, meteorites) ulvospinel Fe,TiO. 17 brownish isotropic as fine intergrowths in titaniferous 163 grey magnetite; octahedra (Fe-Ti-Cr-O, igneous, moon) Mineral Formula -R% Colour -VHN Anisotropy Distinguishing properties/resemblance See range (associations) page VO, 17 grey 780-840 isotropic associated with pitchblende 166 (Ni-Co-Ag-Bi, Au)

wolframite (Fe,Mn)W0 4 17 grey 360-390 moderate bladed crystals, simple twins, reddish 175 (slightly brown internal reflections brownish) (Sn, Au, Bi) wiirtzite ZnS ~ ~ ~ resembles sphalerite but rare hexagonal Appendix D Mineral identification chart

This simple chart shows the optical properties of the common minerals listed in order of relative polishing hardness, and it can be used as an aid to mineral identification. Reflectance values (R %) are given with minerals plotted in their correct position, but some minerals are plotted in brackets in a second position because of their variable appearance.

Procedure

(1) Determine whether the unknown mineral is isotropic, weakly anisotropic or distinctly anisotropic. Weak anisotropy is seen using slightly uncrossed polars, whereas distinct anisotropy is easily vis• ible with exactly crosssed polars. (2) Note whether the mineral is colourless, slightly coloured or col• oured in PPL; white to grey minerals are considered to be colour• less for this purpose. Take care to consider the colour in relation to several adjoining minerals. (3) Estimate the brightness (reflectance) of the mineral as a percen• tage. This is usually rather difficult unless some minerals in the section have already been identified. An uncertainty of ±5 is typical for estimates of R % unless a good reference mineral is also in the section. If the mineral is distinctly bireflecting then estimate the minimum and maximum reflectance values. (4) Whether the mineral is hard or soft can usually be determined by its polishing behaviour, e.g. pits persist in hard minerals, soft minerals scratch easily. Also, hard minerals tend to stand proud of the surface whereas soft minerals are scoured out. The Kalb light line can be used to compare polishing hardness with other minerals in the section.

If the properties of the unknown mineral appear to correspond to one of the minerals on the chart then it is best to check all the mineral's characteristics with the information given for the selected mineral in the description of the ore minerals before concluding the identification. Isotropic Weak anisotropy Distinct anisotropy

PPL PPL PPL colourless ~ ~ ~ .coloured colourless • coloured colourless • coloured stibnite (30-40) pyrargyrite (28-31) covellite (7-22) (chalcocite) chalcocite (32) digenite (22) galena (43) gold (74) electrum (83) silver (95) (cinnabar) cinnabar (28-29) (bornite) bornite (22) (chalcopyrite) chalcopyrite (42-46) molybdenite (15-37) graphite (6-16) tetrahedrite (31) copper (81) sphalerite (17) pentIandite (52) pyrrhotite (40) niccolite (52-58) magnetite (21) chromite (12) (ilmenite) ilmenite (18-21) rutile (20-23) wolframite (17) (arsenopyrite) arsenopyrite (52) (cobaltite) cobaltite (53) uraninite (17) hematite (25-30) marcasite (49-55) pyrite (54) (pyrite) (cassiterite) I cassiterite (11-13) spinel (8) Appendix E Gangue minerals

The gangue minerals referred to here are the minerals that commonly accompany ore minerals in hydrothermal deposits. Although they are transparent and are best studied using transmitted-light microscopy, it is useful to be able to recognise the common gangue minerals in reflected light (see Fig. 1.7). The minerals listed all have low reflectance values but the eye can determine small differences in brightness even at these low values. The carbonates are exceptional in having large bire• fringences and this results in distinct bireflectance; the resulting strong anisotropy is often masked by internal reflections. It is relatively easy to recognize a mineral as being a carbonate but it is difficult, as it is in thin section, to determine the type of carbonate. As well as using optical properties, physical and textural properties can be used in recognising the gangue minerals: Quartz Lack of cleavage but irregular fractures; crystal shape, especially pyramidal terminations; lack of alteration. Barite Several sets of cleavage traces; bladed or tabular crystals; radiating aggregates. Fluorite Octahedral cleavage giving up to three cleavage traces and triangular cleavage pits; cubic crystals. K-feldspar Several cleavage traces; alteration. Carbonates Rhombohedral cleavage resulting in up to three cleavage traces; multiple twinning; rhomb shaped crystals. 10,------,

R% • quartz• orthoclase

fluorite•

OL------______~

Note that carbonates have a pronounced bireflectance and Ro which is shown by all grains of a is indicated by the wide end (maximum value) of the reflectance range.

Mineral Refractive indices Reflectances

quartz, SiO, no = 1.544 ne = 1.553 Ro =4.6 R, = 4.7 barite, BaS04 n" = 1.636 n, = 1.648 R. = 5.8 R, = 6.0 fluorite, CaF2 n = 1.434 R =3.2 orthoclase, KAlSi 3 O, n" = 1.518 n, = 1.522 R" =4.2 R, = 4.3 calcite, CaCO, n = 1.658 ne = 1.486 Ro = 6.1 R, = 3.8 dolomite, CaMg(C03 ), no = 1.679 n, = 1.500 Ro = 6.4 Re = 4.0 , no = 1.710 n, = 1.515 Ro = 6.9 Re = 4.2 Ca(Fe,Mg)(C03 ), siderite, FeCO, no = 1.875 ne = 1.635 Ro = 9.3 Re = 5.8 witherite, BaC03 n" = 1.529 n, = 1.677 R" = 4.4 R,=6.4 Bibliography

Atkin, B. P. and P. K. Harvey 1982. NISOMI-81: an automated system for opaque mineral identification in polished section. Process II: appli• cations in metallurgy, ceramics and geology. Conference Proceedings, The Metallurgical Society of AIME, Dallas, 77-91. Bastin, E. S. 1950. Interpretation of ore textures. Mem. Geol. Soc. Am. 45 Bloss, F. D. 1971. Crystallography and crystal chemistry. New York: Holt Rinehart and Winston. Bowen, N. L. and J. F. Schairer 1935. The system MgG-FeG-SiO,. Am. J. Sci. 229, 151-217. Bowie, S. H. U. and P. R. Simpson 1977. Microscopy: reflected-light. In Physical methods in determinative mineralogy, 2nd edn, J. Zussman (ed.). Londoil: Academic Press. Bowie, S. H. U. and K. Taylor 1958. A system of ore mineral identification. Mining Mag. (Lond.) 99,265-77,337-45. Buddington, A. F. and D. H. Lindsley 1964. Iron- minerals and synthetic equivalents. J. Petrol. 5, 310-57. Cameron, E. N. 1961. are microscopy. New York: John Wiley. Cervelle, B. 1979. The reflectance of absorbing anisotropic minerals. In Proceed• ings ofthe 1974 ore microscopy summer school at Athlone, M. J. Oppenheim (ed.). Special Paper no. 3, 49-57. Geol. Surv. of Ireland. Commission of Ore Microscopy 1977.IMAICOM quantitative data file, N. F. M. Henry (ed.). London: Applied Mineralogy Group, Mineralogical Society. Craig, J. R. and D. J. Vaughan 1981. are microscopy and ore petrography. New York: Wiley. Deer, W. A., R. A. Howie and J. Zussman 1962. Rock forming minerals, Vols 1-5. London: Longmans. Deer, W. A., R. A. Howie and J. Zussman 1966. An introduction to the rock• forming minerals. London: Longmans. Deer, W. A., R. A. Howie and J. Zussman 1978. Rock-forming minerals: single chain silicates, Vol. 2A. London: Longmans. Edwards, A. B. 1947. Textures of the ore minerals. Melbourne: Austral. Inst. Min. Metall. Freund, H. (ed.) 1966. Applied ore microscopy. New York: Macmillan. Galopin, R. and N. F. M. Henry 1972. Microscopic study of opaque minerals. London: McCrone Research Associates. Originally published by Heffer, Cambridge. Hallimond, A. F. 1970. The polarising microscope. York: Vickers Instruments. Henry, N. F. M. (ed.) 1970-8. Mineralogy and materials news bulletin for micro• scopic methods. London: Applied Mineralogy Group, Minera!ogical Society. Holdaway, M. H. 1971. Stability of andalusite and the silicate phase diagram. Am. J. Sci. 271,97-131. IMNCOM 1977. Quantitative data file, First Issue. International Mineralogical Association, Commission on are Microscopy. London: McCrone Research Associates. Judd, D. B. 1952. Colour in business, sciences and industry. New York: John Wiley.

241 BIBLIOGRAPHY

Kerr, P. F. 1977. Optical mineralogy. New York: McGraw-Hill. Leake, B. E. 1978. Nomenclature of amphiboles. Can. Mineral. 16, 501-=-20. Lister, B. 1978. Ore polishing. Institute of Geological Sciences Report 78/27. London: HMSO. Nickless, G. (ed.) 1968. Inorganic chemistry. Amsterdam: Elsevier. Oppenheim, M. J. (ed.) 1979. Proceedings of the 1974 ore microscopy summer school at Athlone. Geol. Surv. of Ireland, Special Paper no. 3. Palache, c., H. Berman and C. Frondel (eds) 1962. Dana's system ofmineralogy, 7th edn. Vols I, II, III. New York: John Wiley. Pauling, L. and E. H. Neuman 1934. The of binnite, (Cu,Fe ) 12As4 S13 and the chemical composition and structure of minerals ofthe tetrahedrite group. Z. Krist. 88, 54-62. Phillips, W. R. and D. T. Griffin 1981. Optical mineralogy. The non-opaque minerals. San Francisco: W. H. Freeman. Picot, P. and Z. Johan 1977. Atlas des mineraoux metalliques. Mem. B.R.G.M., Orleans, no. 90. PiII~r, H. 1966. Colour measurements in ore microscopy. Mineral. Deposita. 1, 175-92. Piller, H. 1977. Microscope photometry. Berlin: Springer-Verlag. Ramdohr, P. 1969. The ore minerals and their intergrowths. Oxford: Pergamon. Ribbe, P. H. 1974. Short course notes, Vol. 1: mineralogy. Mineralogical Society of America. Rumble, D. III (ed.) 1976. Short course notes, Vol. 3: Oxide minerals. Mineral• ogical Society of America. Shuey, R. T. 1975. Semiconducting ore minerals. Developments in , no. 4. Amsterdam: Elsevier. Smith, J. V. 1974. Feldspar minerals, Vols 1-3. Berlin: Springer-Verlag. Tuttle, O. F. and N. L. Bowen 1958. Origin of in the light of experimental studies in the system NaAISi,O,-KAISi,O,-SiO,-H,O. Mem. Geol. Soc. Am. 74. Uytenbogaardt, W. and E. A. J. Burke 1971. Tables for microscopic identification of ore minerals. Amsterdam: Elsevier. Vaughan, D. J. and J. R. Craig 1978. Mineral chemistry of . Cambridge: Cambridge University Press. Wahlstrom, E. E. 1959. Optical mineralogy, 2nd edn. New York: John Wiley.

242 Index

The pages on which minerals and other terms are most directly introduced or defined are shown in bold type. Numbers in italics refer to text illustrations. Reference is also made to tables, appendices and main text sections.

abnormal interference colour 192 aquamarine 56 absorption coefficient 204 aragonite 134, Table 3.1 acanthite App. C arfvedsonite 55, Table 4.10 accessory slot 4 argentite App. C actinolite (ferroactinolite) 46-7 armalcolite App. C aegirine, aegirine-augite 11, 114 arsenide 176 aegnigmatite 56 niccolite 177, App. C akermanite 90 arsenopyrite 139, App. C AI,SiO, polymorphs 30, 35-40 asbestos minerals andalusite 35 amosite 45 kyanite 37 anthophyllite 43 sillimanite 39-41 chrysotile 119 alabandite App. C crocidolite 52 albite twins 75, 80 augite 11, 110-11 alkali feldspars 34, 72-7 microcline-Iow albite 73-4 barite 172, 240 orthoclase-low albite 73-4 barkevikite 55 sanidine-high albite 72 Barrovian-type 40 63 ( s) see barite almandine 87-8 Bertin's surface 194 alteration 7 Bertrand lens 4, 16, 32 amosite 45 beryl 30,56 amphibole group 11, 31,41-56 biaxial figures 9, 192-7 alkali amphiboles 51-6 biaxial indicatrix 183 Ca-poor amphiboles 43-5 biotite 5, 92-3 Ca-rich amphiboles 46-50 annite 93 amphibolisation 47 lepidomelane 93 analcime 86-7 siderophyllite 93 analyser 4, 16 bireflectance 20 anatase 164, 165, App. C 8-9 andalusite 6, 10, 30,35 bismuth App. C 87-8 bismuthinite App. C anhydrite 171, 175 blaubleibender covellite 145, App. C anisotropic Blue John 169 crystals (transmitted light) 8, 183 blueschists 52 sections ( reflected light) 212 bornite 141, App. C anisotropy boulangerite App. C reflected light 20, 212-17 bournonite App. C ankerite 137,240 braunite App. C 177 bravoite 150, App. C annite 93 164, 165 anomalous interference colour 192 brucite 137, 169 anthophyllite-gedrite 43 'Buchan' -type metamorphism 40, 62 antigorite 119 buffing 29 antiperthite 70, 82 apatite 175, Table 1.2 calcite 136, 240,3.1, Table 1.2, Table 3.1 aperture diaphragm 3, 16,1.6 cancrinite 84 .

243 INDEX carbonates 132-8,3.2 crocidolite 52 ankerite 137 cross-hatched twinning 75 aragonite 136, Table 3.1 crossed polars calcite 134, Table 3.1 adjustment 27, 28 dolomite 137, Table 3.1 reflected light 20, 213 rhodochrosite Table 3.1 transmitted light 4 siderite 137, Table 3.1 crossite 51, Table 4.10 Table 3.1 cryptomelane App. e witherite Table 3.1 cryptoperthite 70, 73 carlsbad twins 80 crystal symmetry 206, 5.4 carlsbad-albite twinning 80 cubanite App. e carrollite App. e cummingtonite-grunerite 45 cassiterite 158-9, App. e cuprite 178, App. e celestine see celestite cyclosilicates 30 celestite 172 ring silicates 30 celsian feldspar 84 chain silicates 30-1 desert rose 175 single 31,2.1 determination of order of colour 191 double 31,2.2 Table 1.2 chalcocite 142, App. e diaphragm 3 chalcopyrite 143, App. e digenite 142, App. e chalcopyrrhotite 151 diopside-hedenbergite 11, 108 chlorite 34, 57-8 dispersion 12 chloritoid 30, 58 dispersion curves 204 chondrodite 88 djurleite 143, App. e chromite 160, App. e, Table 3.2 dolomite 137, Table 3.1, 240 chrysotile 119 dominant wavelength 210 cinnabar 144, App. e eckermannite-arfvedsonite 55-6 clay minerals 8, 32, 59-60 eclogite 88 illite 60 edenite 47 kaolin 59 electrum 178, App. e montmorillonite 60 emerald 56 smectite 60 enargite App. vermiculite 60 e enstatite-orthoferrosilite 105-7 cleavage epidote group 30, 63-7 reflected light 21 clinozoisite 64-5 transmitted light 6 epidote (pistacite) 66-7 clinohumite 88-9 zoisite 63-4 clinopyroxenes 11, 99-102, 103,108-17 exsolution lamellae 102-3 clinozoisite 64-5 extinction angle 10-11,200-1 cobaltite 144, App. e eyepiece 4 cohenite App. e collophane 175 fayalite 95-7 colour (of a mineral) feldspar group 7, 34,67-84 reflected light 19,209-11 alkali feldspars 72-7 transmitted light 5 celsian 84 colour diagram (eIE 1931) 210-11 plagioclase feldspars 78-84 components (of light) 190 feldspathoid family 34, 84-7 condenser 4 analcime 86 convergent lens 3 cancrinite 84 copper 177, App. e hauyne 84 cordierite 30, 61-2 kalsitite 84 corundum 160, Table 1.2 leucite 84 covelline see covellite nepheline 85-6 covellite 144-5, 210, App. e nosean 84 cristobalite 123 sodalite 86

244 INDEX

175 hydroxides 169-71 ferrianilmenite 156 brucite 169 ferritchromite 160 goethite 170 ferropseudobrookite 156 lepidocrocite 170 diaphragm 3, 17 limonite 170 first-order red plate 191 flash figures 196-7 idocrase 30, 129 fluorite 168, 240, Table 1.1, Table 1.2 illite 32, 60 focusing (of microscope) 5 ilmenite 156, 162, App. C forsterite 95-7 ilmeno-hematite 156 framboidal pyrite 149 incident illuminators 13-14, 1.4 framework silicates 34 inclusions 21 freibergite 154 inosilicates 30 Fresnel equation 203-6 chain silicates 30 single chain silicates 31,2.1 galena 145, App. C, Table 1.1 double chain silicates 31,2.2 gangue minerals App. E interference colours 8--9, 186-9 garnet group 6, 30, 87-8 interference figure 9-10, 192-6,4.20,4.21 gedrite 43 internal reflections 21 gehlenite 90 iron App. C 162 iron-titanium oxides 155-6 gersdorffite App. C isochromatic curves 194 glaucodot App. C isogyres 194-5 glaucophane--riebeckite 51-2 isotropism 8 goethite 170, App. C isotropic gold 178, App. C crystals ( transmitted light) 181 goldfieldite App. C sections (reflected light) 213 graphite 178, App. C grossular 87-8 jacobsite App. C grunerite 45 jadeite 112 gypsum 171, 174, Table 1.2 jamesonite App. C

habit 6 K-feldspar 72-7 halides 167-9 kaersutite 54 fluorite 168 Kalb light line 24, 1.7 halite 169 kalsilite 84 halite 169 kamacite App. C structure 3.15 kaolin(ite) 32,59 hastingsite 47 katophorite 54, Table 4.10 hauyne 84 kyanite 30,37, Table 4.10 hematite 161, App. C, Table 1.1 hemo-ilmenite 156 lepidocrocite 170, App. C hercynite 165-6, Table 3.2 lepidomelane 93 high albite 72-7, 78-81 leucite 84-5 hornblende series 11, 47-50 leucoxene 124, 162 edenite 47 light source 1 hastingsite 47 limonite 170, App. C pargasite 47 linnaeite App. C tschermakite 47 livingstonite App. C hue (of colour) 210 lizardite 119 huebnerite 175 loellingite App. C humite 88-9 low albite 73-7, 78-81 humite group 30, 88-9 hydrocarbon App. C mackinawite App. C hydrogrossular 87 maghemite 157, App. C, Table 3.2 hydromagnesite 169 magnetite 156, 163, App. C, Table 3.2

245 INDEX manganite App. C interference colour 8-9 marcasite 147, App. C interference figures 9-10 martite 162 biaxial 9-10 melilite group 30, 90 isotropism 8 melnikovite 150, App. C pleochroism 5 mesoperthite 70 relief 6 metacinnabarite 144 twinning 11 miargyrite App. C uniaxial 9 mica group 34, 90-4 zoning 11-12 biotite 92-3 mispickel see arsenopyrite glauconite 91 Moh's hardness Table 1.2 lepidolite 91 molybdenite 147, App. C muscovite 94 monochromatic (light) 186, 4.1 paragonite 91 montmorillonite group (smectites) 32,60 phlogopite 91-2 muscovite 94 microcline 74-7 sericite 94 micro hardness 25 micro-identation hardness 1.9 native elements 177-9 microscope, reflected light 12-16 copper 177 analyser 16 gold 178 Bertrand lens 16 graphite 178 incident illuminators 13-14 silver 179 light control 16-17 natrolite 130 light source 12 nepheline 85-6 objectives 15-16 nephrite 47 polariser 12 nesosilicates 30 use of 26-8 island silicates 30 microscope, transmitted light 1-5 orthosilicates 30 accessory slot 4 Newton's scale 186, 189 analyser 4 niccolite 176-7, App. C Bertrand lens 4 see niccolite condenser 3 norbergite 88-9 convergent lens 3 nosean 84 crossed polars 4 numerical aperture 15,1.5 eyepiece 4 focusing 5 objectives (lenses) 4, 15-16 light source 1 cleaning 23 objectives 4 oblique extinction 201 plane polarised light 3 oil immersion polariser 1 reflected light 22-3 stage 4 olivine group 8, 10, 30,95-7 sub-stage diaphragms 3 corona structures 97 use of 27-8 kelyphitic margin 97 migmatite 40 omphacite 113 millerite App. C ophiolite suites 52 mineral properties, transmitted light 5-12 optic axes 184 alteration 7 optic axial angle 10, 184 birefringence 8-9 optic axial plane 184 cleavage 6 optical constants 203 colour 5 dispersion curves of 204 dispersion 12 orpiment App. C extinction angle 10-11 orthoclase 67-70, 73-7,240, Table 1.2 maximum extinction angle 11 orthopyroxenes 10, 99, 102-4, 105-7 oblique 10 oxides 155-67 straight 10 cassiterite 158-9 habit 6 chromite 160

246 INDEX oxides cont. polishing corundum 160 hardness 23 hematite 161 procedure 28 ilmenite 162 relief 18, 23 iron-titanium oxides 155-6 feldspar 72-7 magnetite 163 polytypes 32 rutile 164-5 prehnite 34 spinel group 157-8 proustite 148, App. C spinel 165 pseudobrookite 156, App. C uraninite 166-7 pseudoleucite 85 oxyhornblende 54 psilomelane App. C pumpellyite 30, 98 pargasite 47 pyrargyrite 148, App. C path difference 186 pyrite 149-50, App. C pentlandite 148, App. C pyrolusite App. C periclase 137, 169 pyrope 87-8 perthite 70, 77 pyrophanite 162 perovskite App. C pyroxene group 6,31,99-117 phlogopite 91-2, 93 aegirine (acmite) 114 phosphate 175 aegirine-augite 114 apatite 175 augite 110-11 collophane 175 crystallisation trends 103-4 phyllosilicates 32 diopside-hedenbergite 108-9 polytypes 32 enstatite-orthoferrosilite 105-7 sheet silicates 32, 2.3 exsolution lamellae 102 picotite Table 3.2 jadeite 112 63 monoclinic (cpx) 99, 108-20 pigeonite 109, Table 4.10 omphacite 113 pitchblende 166, App. C orthopyroxenes (opx) 99, 105-7 plagioclase feldspars 11, 78-84, 90-3 pigeonite 109 albite 78 spodumene 116 albite twinning 80 wollastonite 116-17 anorthite 78 pyrrhotine see pyrrhotite carlsbad twinning 80 pyrrhotite 150-1, App. C celsian 84 lamellar twinning 80 quantitative colour 209-11 plane polarised light 3 quartz 6, 34, 121-2, 240, Table 1.2 platinum App. C a-quartz 120-1 pleochroic schemes 5, 197-201 {3-quartz 120-1 pleochroism quartz wedge 191 reflected light 19 transmitted light 5-6 rammelsbergite App. C pleonaste Table 3.2 realgar App. C polarisation reflectance 19, 203-9 colours 212-17 grey scale 19 figures 16 indicating surfaces 206-9 polarised light 180 reflected light circularly 202, 5.1 microscope 12-16 elliptically 202, 5.1 theory 202-17 linearly 180, 202,5.1 6, 181, 203 plane 180, 5.1 relative polishing hardness 23-5, 1.8 polariser 1 relief polished sections reflected light 24 appearance 17 transmitted light 6 preparation 28, 1.11 resolution 1.5 systematic description 19 retardation 187

247 INDEX rhodochrosite Table 3.1 stibnite 153, App. C richterite 53 straight extinction 10, 201 riebeckite 51-2 strontianite Table 3.1 rotation (of polarised light) 213-17 substitution, coupled 34 colours 213-17 sulphates 172-5 exercise 5.8 anhydrite 171-2 ruby 160 barite 172-3 ruby silvers 148-9 celestite 172-3 rutile 156, 164-5, App. C gypsum 174-5 sulphides 138-54 sa.fflorite App. C arsenopyrite 139-41 sanidine 72-7 bornite 141-2 sapphire 160 chalcocite 142-3 saturation (colour) 210 chalcopyrite 143 saussuritisation 80 cinnabar 144 scapolite 34,117-18 cobaltite 144 scheelite 176, App. C covellite 144-5 schriebersite App. C digenite 142 scratch hardness (Moh's) 26 galena 145-6 sensitive tint 191 marcasite 147 sericite 94 molybdenite 147 serpentine 7, 34, 119 pentlandite 148 an tigorite 119 proustite 148-9 chrysotile 119 pyrargyrite 148-9 lizardite 119 pyrite 149-50 sheet silicates 32,2.3 pyrrhotite 150-1 siderite 137-8, 240, Table 3.1 sphalerite 151-2 siderophyllite 93 stibnite 153 sign determination structures 3.3 biaxial 196, 4.20 tennantite 154 uniaxial 197,4.21 tetrahedrite 154 silica group 121)-3 sulphosalts 138-9, 146 coesite 121 cristobalite 123 taenite App. C quartz 121-2 talc 34, 126-7, Table 1.2 stishovite 121 tarnishing 18, 209 tridymite 122 tektosilicates 34 sillimanite 10, 20, 39-40 coupled substitution 34 silver 179, App. C, Table 1.1 framework silicates 34 skutterudite App. C tennantite 154, App. C sodalite 86 tetradymite 148, App. C sorocilicates 30 tetrahedrite 154, App. C spectral reflectance curves 204 thin sectio n 87-8 preparation 28, 1.11 sphalerite 151-3, App. C, Table 1.1 thucolite 167 sphene 30, 124 titanohematite 156 leucoxene 124 titanomaghemite 156 spinel 165-6, App. C, Table 3.2 titanomagnetite 156, App. C spinel group 157-8, Table 3.2 todorokite App. C solid solution 3.10 topaz 30, 127-8, Table 1.2 unit cell 3.9 tourmaline 30, 128-9 spodumene 116 dravite 128 stage (microscope) 4 elbaite 128 standard wavelengths 12, 209 schor! 128 stannite App. C tremolite-(ferro) actinolite 11,46-7 staurolite 30, 125-6 tridymite 122-3

248 INDEX troilite 150, App. C visual brightness 210 tschermakite 47 tungstate 175-6 witherite 240, Table 3.1 wolframite 175-6 wolfram see wolframite tungstenite 148 wolframite 175-6, App. C twinning wollastonite 32, 117 reflected light 21 wood 159 transmitted light 11 wurtzite 153, App. C wiistite 156 ulvospinel 163, App. C, Table 3.2 uniaxial figures 9, 197-200 uniaxial indicatrix 184 zeolite group 34, 84, 129-30 uralitisation 47 analcime-natrolite 130 uraninite 166-7 App. C chabazite-thomsonite 130 mesolite-scolecite 130 vermiculite 60 zircon 30, 131 vesuvianite 30, 129 zoisite 63-4 idocrase 129 zoning Vickers hardness number (VHN) 22, 25-6, reflected light 21 Table 1.2 transmitted light 11

249