Appendix A.1 Refractive indices of biaxial minerals 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 chloritoid - clay minerals kaolin - illite f-- montmorillonite cordierite - r-- epidote group zoisite clinozoisite - epidote - feldspar group K feldspars - } 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 phlogopite I-- biotite muscovite - I- lepidolite - - paragonite - glauconite - olivine group forsterite } Fo Fa fayalite 01" pumpellyite pyroxene group enstatite-orthoferrosilit e opx diopside-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 - ~ wolframite 2.15-2.44 --- Appendix A.2 Refractive indices of positive uniaxial minerals Silicates 14 1 5 16 17 18 19 20 beryl - feldspathoid family leucite melilite group gehlenite - silica group quartz - zircon Non-silicates cassiterite - rutile 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 scapolite - silica group cristobalite tourmaline vesuvianite Non-silicates carbonates calcite dolomite siderite rhodochrosite 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 analcime garnet group Non-silicates sphalerite spinel 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 acanthite Ag2S 30-31 light grey 20-60 distinct twin lamellae low temp. polymorph (greenish) (Pb-Sb-As-Bi-Ag-Au) alabandite MnS 25 light grey 140-270 isotropic lamellar twinning; brown or green internal reflections (sulphides, Mn-carbonates) anatase Ti02 20 light grey 580-620 weak abundant colourful internal reflections; 164 low temp. polymorph resembles rutile (Fe-Ti-O, pyrite) argentite 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, moon) arsenopyrite FeAsS 52 white 1050-1130 distinct rhomb shape, twinning, zoning 140 (Sulphides, oxides, Au-Bi-Te-Sn, W) bismuth Bi 60-65 bright white 10-20 distinct tarnishes brown, multiple twinning (Co-Ni-As-S, Au-Bi, Te) bismuthinite Bi,S3 40-50 white (bluish) 70-220 very strong fibrous, straight extinction (Co-Ni-As-S, Au-Bi-Te, Mo, Sn, W) Mineral Formula -R% Colour -VHN Anisotropy Distinguished properties/resemblance See range (associations) page blaubleibender Cu.+xS resembles covellite but Ro blue in oil 144 covellite -- - - (Cu-Fe-S) bornite Cu,FeS4 22 light pinkish 100 very weak tarnishes to blue or purple. 141 brown Intergrowths with chalcopyrite (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) braunite Mn,SiO.2 20-22 light grey 880-1190 weak resembles some manganese 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) carrollite C02CUS 4 43 white 350-570 isotropic resembles linnaeite (pinkish) (Co-Cu-Fe-S) cassiterite Sn02 11-13 grey 1030-1080 distinct common twinning; strong colourless to 158 brown internal reflections; cleavage (W, Bi, As, B, sulphides) chalcocite 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) chromite FeCrzO. 12 grey 1200-1210 isotropic rounded octahedra; resembles 160 (brownish) (weak magnetite but non-magnetic anisotropy) (Fe-Ti-O) cinnabar HgS 28-29 light grey 50-100 moderate multiple twinning; abundant red 144 (bluish) internal reflections; rare (Hg-Sb--S, Fe-S) cobaltite 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 iron (Fe, Fe-O, Fe-Ni-S) meteorites copper 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) cryptomelane -KzMn,O,. 27 light grey 530-1050 distinct fibrous, botryoidal; resembles psilomelane; straight extinction (Fe-Mn-O) cubanite CuFeZS3 40 light grey 150-260 strong lamellae within pyrrhotite, 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) digenite Cu.S, 22 light grey 60-70 isotropic 142 (bluish) (Cu-Fe-S) djurleite 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) enargite Cu,AsS4 25-29 light grey 130-580 strong cleavage II (110) (pinkish) colourful (Cu-Fe-Sb-As-S) galena PbS 43 white 70-80 isotropic triangular cleavage pits 145 (Pb-Ag-Sb-As-S, sulphides) gersdorffite (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 HFe02 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') hematite 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) ilmenite FeTi03 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) jacobsite (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 jamesonite 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