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Properties in bold are particularly distinct for that mineral. Click on the icon next to the mineral name to see pictures.
| Mineral | Formula | Colour | Comparative Colour | Bireflectance | Anisotropy | Relative Hardness | Habit | Noteworthy Features | Associated Minerals | Internal Reflections | Reflectivity | Hardness | Crystal System | Notes |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Alabandite | MnS | Gray | C to Sphalerite: distinctly lighter | None | Isotropic / sometimes weakly anomalous | ~Sphalerite | Euhedral crystals / Anhedral aggregates / similar to Sphalerite | Cleavage / Lamellar Twinning / Zonal Textures | Chalcopyrite Mn-Carbonate Mn-Sphalerite Pyrite Pyrolusite Pyrrhotite | Common / dark Green to Brown | Low 22% | Soft (240-251) | Cubic | |
| Allargentum | Ag1-xSbx | White / slightly Grayish | C to Silver: Grayish | None | Weak | >Silver | Lamellar intergrowths in Silver | Silver | None | High 70% | Hexagonal | Originally identified as Dyscrasite (Ag3Sb) | ||
| Allemontite / Stibarsen | A mixture of As or Sb with AsSb | White | Weak | Distinct | ~Antimony | Very fine myrmekitic intergrowth best seen under high magnification | Intergrowth is often more visible after slight oxidation or etching | Stibnite in Co-Ni-Ag-Bi-As ores and pegmatites | None | Moderate to High 50-70% | Extra Soft (85-100) | Trigonal | ||
| Ancanthite | Ag2S | Gray with Greenish tint | C to Galena, Silver: darker, Greenish Gray | Very Weak | Distinct if well polished | Less than most minerals | Euhedral Cubic crystals / Anhedral polycrystalline aggregates | Twinning visible when well polished / Irregular inclusions in Galena | Covellite Galena Polybasite Proustite Pyrargyrite Pyrite Sphalerite Tetrahedrite | None | Low 30% | Extra Soft (23-26) | Monoclinic (Pseudo-Cubic) | Polishing scratches visible due of softness / The hi-T polymorph (Argentite) always returns to Acanthite on cooling. Evidence of Argentite is from the pseudomorphous Acanthite with its cubic morphology |
| Antimony | Sb | White | C to Arsenic: slightly more White / C to Galena: brighter White / C to Silver: less bright / C to Dyscrasite: similar | Weak | Distinct / Yellowish Gray, Brownish, Blueish Gray | >Stibnite <Arsenic | Fine to coarse grain aggregates / rarely Euhedral | Cleavage / Twinning (often polysynthetic) | Arsenopyrite Co-Ni-Arsenides Pyrite Stibarsen Stibnite | None | High 73-78% | Extra Soft (50-69) | Trigonal | |
| Argentite | Ag2S | Gray with Greenish tint | C to Galena, Silver: darker, Greenish Gray | Very Weak | Distinct if well polished | Less than most minerals | Euhedral Cubic crystals / Anhedral polycrystalline aggregates | Twinning visible when well polished / Irregular inclusions in Galena | Covellite Galena Polybasite Proustite Pyrargyrite Pyrite Sphalerite Tetrahedrite | None | Low 30% | Extra Soft (23-26) | Monoclinic (Pseudo-Cubic) | Polishing scratches visible due of softness / The hi-T polymorph (Argentite) always returns to Acanthite on cooling. Evidence of Argentite is from the pseudomorphous Acanthite with its cubic morphology |
| Arsenic | As | White / tarnishes rapidly | C to Antimony: slightly darker Gray / C to Skutterudite and Safflorite: slightly darker Gray / C to Galena: White with a Creamy tint | Grayish White to Yellow or Blueish Gray / Weak in air / distinct in oil | Distinct / Gray to Yellowish Gray | >Bismuth >Silver | Fine to coarse grained Anhedral aggregates / Colloform bands | Twinning / basal cleavage often visible | Arsenopyrite Proustite Pyrite Rammelsbergite Skutterudite Stibarsen | None | High 51-56% | Extra Soft to Soft (72-173) | Trigonal | Very fast (a few hours) tarnishing is typical |
| Arsenopyrite | FeAsS | White | C to Pyrite: White / C to Loellingite, Safflorite: Creamy White / C to Antimony: Grayish White / C to Galena, Sphalerite: White with pale Yellow tint | Weak | Strong / Blue, Green | >Skutterudite >Magnetite <Pyrite <Cobaltite | Euhedral to Subhedral rhomb shapes / Anhedral Granular masses when abundant | Lamellar Twinning common | Chalcopyrite Cobaltite Galena Glaucodcot Gold Loellingite Molybdenite Pyrite Pyrrhotite Sphalerite | None | High 52% | Hard to Very Hard (715-1354) | Monoclinic | |
| Berthierite | FeSb2S4 | White-Gray with Pink or Brown tint | Strong and characteristic (//a) Brownish Pink (//b) Grayish White (//c) White | Very Strong / Blue, Gray, White, Brown, Pink | ~Stibnite <Sphalerite | Euhedral Needlelike / Subhedral aggregates | Arsenopyrite Chalcopyrite Galena Gudmundite Pyrite Pyrrhotite Sphalerite Stibnite | None | Low to Moderate 30-42% | Soft (168-228) | Orthorhombic | |||
| Bismuth | Bi | White to Creamy White / Pinkish Cream | C to Silver: Creamy / C to Arsenic: Pinkish Creamy / C to Sulfosalts: Pinkish Creamy | Weak but distinct Creamy to Pinkish | Distinct to Strong | <All associated minerals | Irregular masses / with inclusions of Anhedral crystals | Twinning common, can be induced by grinding or scratching | Arsenopyrite Bismuthinite Cassiterite Chalcopyrite Co-Ni-Arsenides Galena Molybdenite Pyrite Pyrrhotite Silver Sphalerite Sulfosalts Wolframite | None | Moderate 42% | Extra Soft (16-18) | Trigonal | |
| Bismuthinite | Bi2S3 | White / in Oil with Blueish Gray tint | C to Bismuth: darker, Blueish Gray / C to Chalcopyrite: Blueish Gray / C to Galena: lighter, Creamy White | Weak to distinct (//a) Blueish Gray-White (//b) Gray-White (//c) Creamy White | Very Strong / especially in oil / Gray, Yellow, Violet / Straight Extinction / Large crystals often undulose | >Bismuth <Chalcopyrite | Subhedral Lath-like / less commonly as Granular masses | Cleavage / Stress-induced Twinning / Undulose Extinction often seen | Arsenopyrite Bismuth Cassiterite Chalcopyrite Molybdenite Pyrite Pyrrhotite Sphalerite Stannite Wolframite | None | High 60-70% | Soft (110-136) | Orthorhombic | |
| Bixbyite | (Mn,Fe)2O3 | Gray with Cream to Yellow tint | C to Braunite, Jacobsite, Hausmannite: lighter, Yellowish / C to Hematite: Brownish | Usually None / Sometimes very Weak in oil | Isotropic / sometimes weakly anomalous | >Hausmannite ~Braunite | Euhedral crystals / Granular aggregates | Cleavage / Lamellar Twinning / Zonal growth | Braunite Hausmannite Hematite Pyrolusite | None | Moderate 37-49% | Hard to Very Hard (946-1402) | Cubic | |
| Bornite | Cu5FeS4 | Pinkish Brown to Orange / tarnishes Purplish / Violet / Iridescent | Weak bireflectance may be visible on grain boundaries | Very weak | >Galena >Chalcocite <Chalcopyrite | Irregular polycrystalline aggregates / Coatings on Chalcopyrite / Lamellar intergrowth with Chalcopyrite | Cleavage may be visible / Twinning rare and difficult to see / Lamellar exsolution / Replacement textures with Chalcopyrite Enargite Digenite common / Alters on grain boundaries and fractures to Covellite | Chalcopyrite Covellite Digenite Enargite Galena Hematite Linnaeite Magnetite Pyrite Sphalerite Tetrahedrite | None | Low 2-22% | Extra Soft (87-100) | Orthorhombic (Pseudo-Tetragonal) | ||
| Boulangerite | Pb5Sb4S11 | White with Blueish Gray | C to Galena: darker Greenish Gray / C to Stibnite: slightly lighter / C to Jamesonite: darker | Distinct / Gray-White to Green-Gray | Distinct / Tan, Brown, Blueish Gray | <Galena | Granular / Fibrous aggregates | Chalcopyrite Galena Pb-Sb-Sulfosalts Sphalerite Tetrahedrite | Rare / Red | Low 22% | Extra Soft to Soft (92-125) | Monoclinic | ||
| Brannerite | (U,Ca,Ce)(Ti,Fe)2O6 | Gray | None | None | Euhedral prisms / Needle-like grains / Subhedral aggregates | Often forms as replacement (sometimes pseudomorph) after Uraninite and Rutile / May have "dusting" of small radiogenetic Galena crystals | Anatase Coffinite Galena Magnetite Pitchblende Pyrite Pyrrhotite Rutile Sphalerite Tetrahedrite Uraninite | Common / Coarse crystals: Brownish Gray / Fine grained material: Blue-Gray to Blueish White, dark Brown to Yellowish | Moderate 37-42% | Moderate (690) | Monoclinic (Metamict) | |||
| Braunite | (Mn,Fe,Si)2O3 | Gray with Brownish tint | C to Magnetite: less Brown / C to Pyrolusite, Psilomelane: darker / C to Manganite, Hausmanite: similar but weaker bireflectance / C to Bixbyite, Jacobsite: more Gray | Weak but distinct / Gray | Weak but distinct / Gray to Blue / often undulose | >Magnetite <Bixbyite | Anhedral Granular masses / Subhedral to Euhedral crystals | Zonal Textures | Bixbyite Hematite Jacobsite Magnetite Pyrolusite | Rare / dark Brown to deep Red | Low 15% | Hard (920) | Tetragonal | |
| Bravoite | (Fe,Ni,Co)S2 | Composition dependent / Fe-rich: Creamy to Pinkish / Co- and Ni-rich: Pinkish to Brownish to Violet | None | None | >Sphalerite <Pyrite | Isolated cubes / Octahedral crystals | Zonal texture very characteristic / Darker zones are Ni and Co rich | Bismuth Chalcopyrite Galena Linnaeite Maucherite Niccolite Safflorite Siegenite Sphalerite Tetrahedrite | None | Low 18% | Moderate to Very Hard (668-1535) | Cubic | ||
| Breithauptite | NiSb | Pink with Violet tint | C to Niccolite: darker, Violet tint | Strong / Pinkish to Pinkish Violet | Very Strong / Blueish Green, Blueish Gray, Violet Red | <Niccolite >Rammelsbergite >Safflorite | Subhedral to Euhedral grains | Zonal Textures | Ag-Sulfosalts Chromite Galena Niccolite Pentlandite Pyrrhotite Safflorite Silver | None | Moderate to High 31-54% (lowest for Co and Ni-rich) | Moderate (412-584) | Hexagonal | Similar to Niccolite / Although Violarite appears similar, it is not zoned |
| Carrollite | CuCo2S4 | Creamy White / rare slight Pinkish tint | None | None | >Chalcopyrite <Pyrite | Anhedral Granular masses / Subhedral and Euhedral Octahedra | Bornite Chalcocite Chalcopyrite Co-Pyrite Copper minerals Digenite Pyrrhotite Siegenite | None | Moderate to High 38-52% | Cubic | ||||
| Cassiterite | SnO2 | Brownish Gray | C to Stannite, Wolframite, Ilmenite, Rutile, Magnetite: Brownish Gray | Distinct / Gray to Brownish Gray | Distinct Gray / in oil, masked by internal reflections | <Pyrite | Compact Anhedral masses / Zoned Subhedral to Euhedral crystals | Twinning common / Cleavage may be visible | Arsenopyrite Bismuth Bismuthinite Galena Hematite Magnetite Pyrite Pyrrhotite Rutile Sphalerite Stannite Wolframite | Common / Yellow to Yellow-Brown (lighter than Sphalerite) | Moderate 43% | Very Hard (1168-1332) | Tetragonal | Similar to Sphalerite but is anisotropic and has lighter coloured internal reflections |
| Chalcocite | Cu2S | Blueish White | C to Galena, Pyrite, Bornite, Copper: Blueish Gray to Blueish White / C to Covellite: White | Very Weak | Weak to distinct emerald Green to light Pinkish | >Acanthite ~Digenite <Bornite | Anhedral polycrystalline aggregates / vein fillings with Fe and Cu-Fe Sulphides (e.g. Bornite, Chalcopyrite, Digenite, Pyrite) | Often in exsolution intergrowth with Bornite or low-temperature Cu- Sulphides | Bornite Enargite Galena Sphalerite Stannite Tetrahedrite - Tennantite | None | Low 11% | Extra Soft (84-87) | Orthorhombic | Often appears Isotropic, especially in supergene fine-grained aggregates |
| Chalcophanite | Mn2O5•nH2O | White to Gray | Very strong and characteristic, especially in oil / White to Gray | Very Strong / White to Gray | Aggregates of tabular and radiating crystals / Colloform bands in secondary Mn-ores | Perfect basal cleavage | Filling veins in Mn-oxides e.g. Hausmannite Psilomelane Pyrolusite | Zn-rich: deep Red / Otherwise None | Moderate 32% | Soft (188-253) | Trigonal | |||
| Chalcopyrite | CuFeS2 | Yellow to Brassy Yellow | C to Pyrite: more Yellow / C to Gold: distinct Greenish tint | Weak | Weak but distinct / Gray-Blue to Yellow-Green | ~Galena <Sphalerite | Medium to coarse grained Anhedral aggregates / less commonly as well-developed Tetrahedra | Twinning common / Basket weave exsolution with Bornite common / Can contain laths of Cubanite / Can contain “stars" of Sphalerite / Can contain “worms" of Mackinawite or Pyrrhotite | Bornite Cubanite Digenite Galena Magnetite Pentlandite Pyrite Pyrrhotite Sphalerite Tetrahedrite | None | Low 9-27% | Soft (187-203) | Tetragonal | Often alters along cracks and grain boundaries to Covellite |
| Chalcostibite | CuSbS2 | White with Pinkish Gray tint | C to Silver, Galena, Grayish / C to Sphalerite: Pinkish | Distinct in oil / Creamy to Brown | Distinct / Pinkish to Greenish or Blueish Gray | >Silver <Chalcopyrite <Sphalerite | Anhedral grains / less commonly as Euhedral prismatic crystals | Cleavage / Triangular pits may be visible / May be intergrown with Enargite | Arsenopyrite Chalcocite Chalcopyrite Cinnabar Covellite Galena Jamesonite Pyrite Silver Sphalerite Tetrahedrite | Rare / pale Red | Moderate 45% | Soft (283-309) | Orthorhombic | |
| Chromite | (Fe,Mg)(Cr,Al)2O4 | Dark Gray to Brownish Gray | C to Magnetite, Sphalerite: darker / C to Ilmenite: less Brown-Red | None | Weak / Usually absent | >Magnetite <Hematite | Subhedral to Euhedral crystals / Coarse crystalline aggregates / Cataclastic effects common | Zonal Textures with lighter (Fe-Rich) rims common | Ilmenite Magnetite Millerite Pentlandite Platinum Pyrrhotite | Common / Red Brown / None in Fe-rich samples | Moderate 36-44% | Very Hard (1278-1456) | Cubic | May have exsolution lamellae of Hematite, Ilmenite, Magnetite, Rutile, Ulvöspinel |
| Cinnabar | HgS | White with Blueish Gray tint | C to Galena: darker, Blueish | Distinct in oil | Distinct / in oil often masked by internal reflections | >Antimony <Galena <Pyrite | Subhedral to Euhedral crystals / polycrystalline aggregates of Euhedral grains | Bornite Cassiterite Chalcopyrite Enargite Galena Gold Marcasite Orpiment Pyrite Realgar Stibnite Tetrahedrite | Intense and common / Red | Low 13% | Extra Soft to Soft (82-156) | Trigonal | Looks similar to Proustite and Pyrargyrite | |
| Cobaltite | (Co,Fe)AsS | White with Pink or Violet tint | C to Arsenopyrite: Pinkish / C to Pyrite: Whiter | Weak / White to Pinkish | Weak to distinct in oil / Blue-Gray to Brown | >Skutterudite <Pyrite | Euhedral crystals / Polycrystalline aggregates | Twinning / Zoning / Cleavage | Arsenopyrite Bismuth Chalcopyrite Gold Ni-Co Arsenides Niccolite Silver Uraninite | None | Low 24-30% | Hard to Very Hard (935-1131) | Orthorhombic (Pseudo-Cubic) | Weak anisotropy makes Cobaltite distinct from Niccolite or Breithauptite |
| Coffinite | U(SiO4)1-xOH)4x | Gray | Very Weak | Very weak / Absent | ~Pitchblende | Euhedral Tetragonal crystals / Fine aggregates / Colloform bands | Botryoidal encrustations and intergranular films, especially near organic matter | Bismuth Loellingite Pitchblende Pyrite Rammelsbergite Sphalerite Uraninite | Rare and weak in air / Common Brownish in oil | High 51% | Soft (230-302) | Tetragonal | ||
| Cohenite | Fe3C | Creamy White | C to Pyrrhotite: lighter Creamy / C to Iron: similar | Weak but distinct | Weak but distinct | >Iron | Irregular grains | Twinning common in larger grains | Graphite Kamacite Schreibersite Troilite | None | Low 8% | Orthorhombic | Rare on earth / Found in meteorites with 6-8 wt% Ni | |
| Coltan / Columbite Tantalite | (Fe,Mn)(Ta,Nb)2O6 | Gray-White with Brown tint | C to Magnetite: slightly less Brown | Weak | Distinct / Straight extinction | Euhedral crystals / Anhedral aggregates | May be Zoned / Cleavage may be visible | May be within Cassiterite / May contain inclusions of Cassiterite Galena Hematite Ilmenite Rutile Uraninite Wolframite | Common in Fe-rich / deep Red | Low 15% | Soft to Very Hard (240-1021) | Orthorhombic | Occurs as oriented intergrowths with Uraninite | |
| Copper | Cu | Pink / tarnishes Brownish | C to Silver: Pink | Weak | Isotropic / Fine scratches will appear Anisotropic | >Chalcocite <Cuprite | Coarse to fine grained aggregates / Dendritic or spear-like crystals | Lamellar Twinning visible if etched / Zoning due to Ag or As common | Bornite Chalcocite Cuprite Enargite Iron Magnetite Pyrrhotite | None | High 65-92% | Extra Soft (79-99) | Cubic | |
| Cosalite | Pb2Bi2S5 | White with Pink or Gray tint | C to Galena: Yellowish to Green tint | Weak to distinct | Weak to Moderate / Pinkish Yellow, Blueish, Violet Gray | >Galena | Granular masses / Bundles of Subhedral Elongated Laths / Fibrous crystals | No Twinning | Arsenopyrite Bi and Sb Sulfosalts Bismuth Chalcopyrite Glaucodot Gold Pyrite Pyrrhotite Sphalerite Tetrahedrite Wolframite | None | Moderate 41-46% | Extra Soft to Soft (74-161) | Orthorhombic | |
| Covellite | CuS | Indigo Blue with Violet tint / Blueish White in Air | Purple to Violet-Red to Blue-Gray in oil | Strong to Extreme / Red-Orange to Brownish | <Chalcopyrite | Subhedral to Anhedral masses / Laths / Platelike crystals | Bornite Chalcopyrite Digenite Enargite Pyrite Sphalerite Tennantite / May occur with Covellite | None | Low 4-24% | Soft (128-138) | Hexagonal | Blaubleibender Covellite stays blue in oil, hence the name. | ||
| Cubanite | CuFe2S3 | Creamy Gray to Yellowish Brown | C to Pyrrhotite: more Yellow, less Pink / C to Chalcopyrite: more Gray-Brown | Grayish to Brownish | Strong / Brownish to Blue | >Chalcopyrite <Pyrrhotite | Laths within coarse-grained Chalcopyrite / Irregular Granular aggregates | Arsenopyrite Galena Mackinawite Magnetite Pentlandite Pyrrhotite Sphalerite | None | Moderate 35% | Soft (247-287) | Orthorhombic | ||
| Cuprite | Cu2O | Air: light Blueish Gray / Oil: darker / more Blue | C to Chalcopyrite, Hematite: darker and Greenish | Very Weak | Strong / Anomalous Gray-Blue to Olive-Green | >Chalcopyrite | Euhedral octahedra / fine-grained mass | Replaces Copper minerals | Delafossite Goethite Marcasite Pyrite Tenorite | Common / Deep Red characteristic | Low 27% | Soft (193-207) | Cubic | |
| Delafossite | CuFeO2 | Air: Yellow-Rose-Brown to Rose-Brown / Oil: Pinkish Gray to Brown-Gray | C to Enargite, Tenorite: more Yellow | Distinct | Distinct to Strong / Blueish Gray / Straight extinction | <Cuprite <Goethite | Masses of subparallel crystals / Sheaf-like bundles / fine inclusions in Goethite | Concentric and Botryoidal textures common | Bornite Chalcocite Copper Covellite Cuprite Galena Goethite Limonite Pyrite Tennantite Tenorite | None | Low to Moderate 18-39% | Moderate (412-488) | Trigonal | |
| Digenite | Cu9S5 | Grayish Blue | C to Galena, Bornite: Blue / C to Chalcocite: darker Blue | None | Isotropic / Weakly anomalous | ~Chalcocite ~Galena | Irregular aggregates of Anhedral grains with lamellar intergrowths (with Cu-Sulphides or Bornite) | Alters to Covellite | Chalcopyrite Enargite Pyrite Tetrahedrite | None | Low 19% | Extra Soft to Soft (86-106) | Cubic | |
| Dyscrasite | Ag3Sb | White | C to Galena: Creamy White / C to Silver: slightly Grayer / C to Antimony: slightly Creamy | Weak / White to Creamy White | Weak to distinct | >Galena >Silver <Chalcopyrite | Euhedral Plate-like / Square crystals / Aggregates of Anhedral crystals | Arsenic Cobaltite Galena Pyrite | None | High 60% | Soft (153-179) | Orthorhombic | The “Dyscrasite" of Cobalt, Ontario, Canada is not Dyscrasite. It's Allargentum | |
| Enargite | Cu3AsS4 | Pinkish Gray to Pinkish Brown / darker in Oil | C to Bornite: Pinkish White / C to Chalcocite, Galena: Pinkish to Grayish Brown | Distinct in oil: (//a) Grayish Pink (//b) Pinkish Gray (//c) Grayish Violet | Strong / Blue, Green, Red, Orange | >Galena >Chalcocite >Bornite ~Tennantite <Sphalerite | Anhedral to Subhedral grains | Cleavage / No Twinning | Arsenopyrite Bornite Chalcocite Chalcopyrite Covellite Galena Pyrite Sphalerite Tennantite | Rare / Deep Red | Low 24% | Soft (285-327) | Orthorhombic | |
| Famatinite | Cu3SbS4 | Pale Pinkish Orange | C to Enargite: lighter | Distinct to strong in oil / Orange-Brown to Grayish Violet | Very Strong / Brown to Gray-Green | >Bornite >Chalcopyrite ~Enargite <Sphalerite | Anhedral to Euhedral grains | Polysynthetic Twinning common / Star-shaped patterns may occur | Bornite Chalcocite Chalcopyrite Enargite Galena Proustite Pyrargyrite Pyrite Sphalerite Tetrahedrite | None | Low 24% | Soft (205-397) | Tetragonal | |
| Freibergite | Ag-Tetrahedrite | Gray / faint Yellow-Brown tint in Oil | C to Proustite: Brownish / C to Galena: Grayish Brown / C to Sphalerite: lighter | None | Isotropic | >Ag-sulfosalts <Galena <Sphalerite | Irregular masses / inclusions of Anhedral crystals | Argentite Bornite Chalcopyrite Co-Fe-Ni Arsenides Enargite Galena Proustite Silver | Rare / Brownish Red when visible | Moderate 32% | Soft (263-340) | Cubic | ||
| Galena | PbS | White / sometimes with Pink tint | C to Sphalerite: White / C to Tennantite: Pinkish | None | Isotropic / Weakly anomalous | >Proustite ~Chalcopyrite <Tetrahedrite | Anhedral masses / Euhedral cubes | Perfect cleavage usually visible / Triangular pits | Often contains inclusions of Chalcopyrite Pb-Bi and Pb-Sb Sulfosalts Silver Sphalerite Tetrahedrite / May occur as inclusions in Chalcopyrite Sphalerite | None | Moderate 42% | Extra Soft (59-65) | Cubic | |
| Gersdorffite | NiAsS | White with Yellow or Pink tint | C to Skutterudite: more Yellow / C to Linnaeite: less Pink / C to Niccolite: Blueish | None | Isotropic / Weakly anomalous | >Linnaeite ~Loellingite <Pyrite | Euhedral crystals | Cleavage common / may show zonal growth | Bismuth Bornite Chalcopyrite Cobaltite Niccolite Pyrite Silver Skutterudite Uraninite | None | High 54% | Hard (844-935) | Cubic | Sometimes occurs as pseudoeutectic intergrowths with Niccolite, Maucherite, Pyrrhotite, Chalcopyrite |
| Glaucodcot | (Co,Fe)AsS | White to light Cream | C to Arsenopyrite: more Blueish White | Weak / Weaker than Arsenopyrite | Distinct / less than for Arsenopyrite | <Arsenopyrite <Cobaltite | Subhedral to Euhedral crystals | Often with inclusions | Arsenopyrite Cobaltite Galena Niccolite Pyrite Rammelsbergite Safflorite Skutterudite | None | Moderate 50% | Very Hard (1097-1115) | Orthorhombic | |
| Goethite | FeO•OH | Gray with Blueish tint | C to Sphalerite: more Blueish / C to Hematite: darker / C to Lepidocrocite: darker | Weak in air; distinct in oil but often masked by internal reflections | Distinct / Gray-Blue, Gray-Yellow, Brownish | ~Lepidocrocite <Magnetite <Hematite | Porous Colloform bands with radiating Fibrous texture / Porous pseudomorphs after Pyrite | Nearly always secondary as veins, fracture fillings, or Botryoidal coatings | Chalcopyrite Galena Hematite Lepidocrocite Mn-Oxides Pyrite Pyrite Pyrrhotite Sphalerite | Common / Brownish Yellow to Reddish Brown | Low 15% | Moderate (667) | Orthorhombic | Internal reflection colours helps differentiate Goethite and Lepidocrocite |
| Gold | Au | Bright Golden Yellow | C to Chalcopyrite: no Greenish tint | None | Isotropic / Incomplete extinction | >Galena <Tetrahedrite <Chalcopyrite | Isolated grains / small veins | Arsenopyrite Chalcopyrite Pyrite | None | High 77-88% | Extra Soft (53-58) | Cubic | Addition of Silver to form Electrum changes color to whitish and increases reflectivity | |
| Graphite | C | Brownish Gray to Grayish Black | C to Molybdenite: darker | Very strong / Brownish Gray to Grayish black | Very Strong / straw Yellow to Brown or Violet Gray | <Almost all minerals | small Plates / isolated Laths / bundles of blades | Basal cleavage may be visible / Undulose Extinction common | Inclusions in Magnetite Pyrite Pyrrhotite Sphalerite | None | Low 6-27% | Extra Soft (42705) | Hexagonal | Much more common than Molybdenite |
| Hausmannite | Mn3O4 | Blueish to Brownish Gray | C to Jacobsite: Grayer / C to Bixbyite: darker / C to Braunite: less Brown | Very distinct in oil / Blueish Gray to Brownish Gray | Strong / Yellow Brown to Blueish Gray | >Manganite >Pyrolusite <Jacobsite <Bixbyite <Braunite | Coarse-grained equigranular Anhedral crystals / often in veinlets | Irregular Twinning / alters to Pyrolusite and Psilomelane | Mn-Oxides | Common / Blood Red, especially in oil | Low 16% | Moderate (437-572) | Tetragonal | |
| Hematite | α-Fe2O3 | Gray | C to Ilmenite, Magnetite: White / C to Pyrite: Blueish Gray / C to Goethite, Lepidocrocite: White | Weak | Distinct / Gray-Blue, Gray-Yellow | >Magnetite <Pyrite | Bladed or Needle-like subparallel radiating aggregates | Lamellar Twinning / Exsolution lenses or lamellae common in Ilmenite or Magnetite | Bornite Cassiterite Chalcopyrite Magnetite Pyrite Rutile Sphalerite Umenite | Common / Deep Red | Low 25-30% | (1000-1100) | Hexagonal | |
| Idaite | Cu5FeS6 to Cu3FeS4 | Reddish Orange / Red-Brown to Yellowish Gray | Strong Reddish Orange / Red-Brown to Yellowish Gray | Strong to Extreme /Green or Gray-Green | >Covellite | Tabular crystals with Covellite, Pyrite, or Bornite if Hypogene / Lamellae and veinlets in Bornite if Supergene | Bornite Covellite Pyrite | None | Low to Moderate 27-34% | Soft (176-260) | Tetragonal | |||
| Ilmenite | FeTiO3 | Brownish with Pink or Violet tint | C to Magnetite: darker, Brownish | Distinct / Pinkish Brown / dark Brown | Strong / Greenish Gray to Brownish Gray | >Magnetite <Hematite | Subhedral to Anhedral grains / Exsolution lamellae or lenses in Hematite or Magnetite | Lamellar Twinning | Chromite Hematite Magnetite Pentlandite Pyrite Pyrrhotite Rutile Tantalite | Rare / dark Brown | Low 16% | Moderate (566-698) | Trigonal | |
| Iron | Fe | White / slight Blueish or Yellowish | C to Pentlandite: much Whiter / C to Cohenite: slightly Blueish | None | Isotropic | <Troilite <Magnetite <Cohenite | Irregular patches / drop-like grains in stony meteorites | Intergrowths of γ-Fe and α-Fe form Widmanstät;ten structures which are brought out by etching / Oxidizes to Hematite, Goethite, Lepidocrocite | Chromite Copper Ilmenite Schreibersite Troilite | None | High 58% | Soft (110-117) | Cubic | |
| Jacobsite | (Fe,Mn)2O4 | Rose Brown to Brownish Gray | C to Magnetite, Braunite: Olive-Green / C to Hausmannite: less Gray / C to Bixbyite: Olive-Gray | None | Isotropic / Weakly anomalous | ~Magnetite <Braunite | Anhedral grains / rounded Subhedral crystals | Alters to other Fe-Mn minerals | Occurs with and/or alters to Goethite Hematite Psilomelane Pyrolusite | Common / Deep Red, especially when Mn-rich | Low 21% | Hard (720-813) | Cubic | |
| Jamesonite | Pb4FeSb6S14 | White | C to Galena: similar or slightly Greenish / C to Stibnite: lighter | Strong / White to Yellow Green | Strong / Gray, Tan, Brown, Blue | <Galena | Needle or Lath-like crystals / Bundles | Cleavage parallel to long dimension / Twinning | Arsenopyrite Boulangerite Chalcopyrite Galena Pyrargyrite Pyrite Sphalerite Tetrahedrite | Reddish in Bi-Jamesonite | Moderate 36-44% | Extra Soft (66-86) | Monoclinic | |
| Kamacite α-Fe | α-Fe | α-Fe contains < ~6% Ni and is slightly Blueish | C to Pentlandite: much Whiter / C to Cohenite: slightly Blueish | None | Isotropic | Fine exsolution of Cohenite occurs in α-Fe | Intergrowths of γ-Fe and α-Fe form Widmanstät;ten structures which are brought out by etching / Oxidizes to Hematite, Goethite, Lepidocrocite | Chromite Copper Ilmenite Schreibersite Troilite | None | High 58% | Soft (110-117) | Cubic | Found in Iron meteorites / Rare on earth / cf. Iron | |
| Kobellite | Pb2(Bi,Sb)2S5 | White | C to Galena: slightly darker | Distinct / Greenish White to Violet-Gray | Distinct / Gray to Gray-Brown | >Bismuth <Galena | Granular to tabular aggregates | Well developped cleavage / Twinning / Intergrowths with Tetrahedrite | Arsenopyrite Bismuth Bismuthinite Chalcopyrite Pyrite Pyrrhotite | None | Moderate 44% | Extra Soft to Soft (100-117) | Orthorhombic | |
| Lepidocrocite | γ-FeO•OH | Grayish White | C to Goethite: lighter and Whiter / C to Hematite: Greenish tint | Weak to distinct | Strong/ Gray | <Goethite | Occurs in Crusts and veinlets / Porous pseudomorphs | Common / Reddish | Low 11-18% | Moderate (402) | Orthorhombic | Internal reflection colours helps differentiate Goethite and Lepidocrocite / From the weathering Iron oxides and sulphides | ||
| Linnaeite | Co3S4 | Creamy White | C to Skutterudite: Grayish White / C to Ullmanite, Gersdorffite: Creamy or Yellowish | None | Isotropic | >Chalcopyrite >Sphalerite <Pyrite | Euhedral crystals / Subhedral aggregates | May have lamellar intergrowths with associated minerals | Bismuth Bornite Chalcopyrite Covellite Millerite Niccolite Pyrite Pyrrhotite Safflorite | None | Moderate 50% | Moderate (450-613) | Cubic | |
| Loellingite | FeAs2 | White with Yellowish tint | C to Arsenopyrite: less Yellow / C to Rammelsbergite, Safflorite: similar | Weak but distinct / Blueish White to Yellowish White | Very Strong / Orange-Yellow, Red-Brown, Blue, Green | >Chalcopyrite >Sphalerite <Arsenopyrite | Interlocking to radiating aggregates of Euhedral crystals / Sometimes as skeletal crystals | Twinning common | Antimony Arsenic Arsenides Arsenopyrite Chalcopyrite Dyscrasite Galena Uraninite | None | High 52% | Hard (859-920) | Orthorhombic | |
| Mackinawite | Fe1+xS | Pinkish to Reddish Gray | C to Pyrrhotite: similar | Distinct to Strong / Pinkish tray to Gray | Very Strong / Grayish White, Blueish, Brownish | ~Pyrrhotite | Small worm-like grains / Lamellae / less commonly as small Plates | Most easily found as bright grains under nearly crossed polars | Chalcopyrite Cubanite Pentlandite Pyrrhotite | None | Low to Moderate 16-43% | Extra Soft to Soft (74-181) | Tetragonal | Valleriite's anisotropy has a more pronounced orange tint |
| Maghemite | γ-Fe2O3 | Blueish Gray | C to Goethite: Gray, lighter / C to Hematite: Blueish Gray / C to Magnetite: Blueish | None | Isotropic | >Magnetite <Hematite | Lamellae / porous patches | Forms as a rare oxidation product of Magnetite | Rare / Brownish Red | Low 23% | Moderate (412) | Cubic | ||
| Magnetite | Fe3O4 | Gray with Brownish tint | C to Hematite: darker Brown / C to Ilmenite: less Pink / C to Sphalerite: lighter | None | Isotropic / Weakly anomalous | >Pyrrhotite <Ilmenite <Hematite <Pyrite | Euhedral / Subhedral / Octahedral Grains / skeletal crystals / Anhedral polycrystalline aggregates | Often contains exsolution or oxidation lamellae of Hematite Ilmenite and ulvöspinel / Alters to Hematite and Goethite | Bornite Chalcopyrite Galena Pentlandite Pyrite Pyrrhotite Sphalerite | None | Low 20% | Moderate to Hard (681-792) | Cubic | |
| Manganite | MnO(OH) | Gray to Brownish Gray | C to Pyrolusite: darker Gray | Weak / Brownish Gray | Strong / Yellow, Blueish Gray, Violet-Gray | <Hausmannite <Jacobsite | Prismatic to Lamellar crystal aggregates | Cleavage / Twinning / often intergrown with Pyrolusite and Psilomelane | Braunite Goethite Hausmannite | Common / Blood Red | Low 14-21% | Moderate to Hard (630-743) | Monoclinic | |
| Marcasite | FeS2 | Yellowish White with slight Pinkish or Greenish tint | C to Pyrite: Whiter / C to Arsenopyrite: Greenish Yellow | Strong / Brownish to Yellowish Green | Strong / Blue, Green-Yellow, Purple-Gray | ~Pyrite | Subhedral / Lamellar intergrowths with Pyrite in Euhedral crystals / Radiating Colloform bands | Twinning | Pyrite and other common Sulphides | None | Moderate to High 49-56% | Very Hard (1288-1681) | Orthorhombic | Forms as hypogene crystals and as supergene veinlets in Pyrrhotite and Iron oxides |
| Maucherite | Ni11As8 | White | C to Cobaltite: similar / C to Loellingite: Brownish Gray / C to Breithauptite: Blueish Gray | None | Weak to distinct in oil / Gray | >Chalcopyrite >Sphalerite <Safflorite <Loellingite | Euhedral crystals / Anhedral aggregates | Twinning / May be intergrown with Niccolite or Gersdorffite | Chalcopyrite Cubanite Siegenite | None | Moderate 48% | Moderate to Hard (623-724) | Tetragonal | |
| Mawsonite | Cu7Fe2SnS10 | Brownish Orange | Strong / Orange to Brown | Very Strong / Straw-Yellow to Royal Blue | >Bornite | Irregular inclusions | Inclusion in Bornite | Chalcocite Chalcopyrite Enargite Galena Pyrite Stannite Tetrahedrite | None | Low to Moderate 27-35% | Soft (166-210) | Tetragonal | ||
| Miargyrite | AgSbS2 | in Air: White / in Oil: Blueish tint | C to Galena: darker with Green-Gray tint / C to Freibergite: Blueish / C to Pyrargyrite: Whiter | Moderate / White to Blueish Gray | Strong / Blue-Gray to Brownish / masked by internal reflections | >Pyrargyrite <Stephanite <Galena | Granular Anhedral aggregates | Twinning | Galena Polybasite Pyrargyrite Silver Sphalerite Stephanite Tetrahedrite | Common / Deep Red | Low to Moderate 30-35% | Extra Soft to Soft (88-130) | Monoclinic | |
| Millerite | NiS | Yellow | C to Chalcopyrite: lighter, not Greenish / C to Linnaeite, Pentlandite: Yellower | Distinct in oil / Yellow to Blue or Violet | Strong / Lemon-Yellow to Blue or Violet | >Chalcopyrite <Pentlandite | Radiating aggregates / Anhedral Granular masses | Twinning / Cleavage/ common as oriented intergrowths with Linnaeite, Violarite, Pyrrhotite | Ni-bearing Sulphides often as replacement or alteration | None | Moderate to High 50-59% | Soft (192-376) | Trigonal | |
| Molybdenite | MoS2 | White to Gray with Blueish tint | C to Graphite: lighter | Strong to Extreme | Very Strong / White with Pinkish tint / dark Blue if polars not comptetely crossed | <Almost all minerals | Small deformed Plates / Irregular inclusions / Less commonly as Rosettes or Colloform bands | Cleavage / Twinning / Undulose extinction / Often in veins | Bismuth Bismuthinite Bornite Cassiterite Chalcopyrite Pyrite Sulphides Wolframite | None | Low to Moderate 19-39% | Extra Soft (8-100) | Trigonal | |
| Niccolite (nickeline) | NiAs | Yellowish Pink to Brownish Pink | C to Maucherite, Skutterudite, Bismuth, Arsenic: more Pink / C to Breithauptite: Pinkish Yellow | Strong | Very Strong / Yellow, Greenish Violet-Blue, Blue-Gray | >Chalcopyrite >Breithauptite <Skutterudite <Pyrite | Isolated Subhedral and Euhedral crystals / Anhedral aggregates / Concentric bands / Complex intergrowths (with Pyrrhotite, Chalcopyrite, Maucherite) | Commonly intergrown with Arsenides / Often twinned and in radial aggregates | Intergrowths with Chalcopyrite Maucherite Pyrrhotite | None | Moderate to High 46-56% | Soft (363-372) | Hexagonal | |
| Orpiment | As2S3 | Gray | C to Realgar: slightly lighter / C to Sphalerite: lighter | Strong in Air: (//a) White; (//b) dull Gray / Reddish: (//c) dull Gray-White / in Oil: (//a) Gray-White; (//b) dark Gray; (//c) Gray-White | Strong / in oil masked by internal reflections | >Realgar | Tabular interlocking Anhedral masses / Needle or Lath-like crystals | Often formed on Realgar | Arsenic Arsenopyrite Enargite Loellingite Pyrite Realgar Sphalerite Stibnite | Common and intense / White to Yellow | Low 22-28% | Extra Soft (22-58) | Monoclinic | |
| Para rammelsbergite | NiAs2 | Whiter than associated Co-Ni-Fe Arsenides | Very Weak to distinct / Yellowish to Blueish White | Strong / less than Rammelsbergite and without Blue | >Niccolite <Skutterudite | Tabular crystals with rectangular outlines / Mosaics of intergrown crystals | May be zoned / Twinning rare | Cobaltite Gersdorffite Niccolite Proustite Pyrite Rammelsbergite Silver Skutterudite | None | High 59% | Moderate to Hard (681-830) | Orthorhombic | Solid solution with Polybasite | |
| Pearcite | Ag16As2S11 | Gray | C to Pyrargyrite: darker Brownish / C to Tetrahedrite: similar | Air: Weak; oil: distinct / Green to Gray with Violet tint | Blue, Gray, Yellow-Green, Brown / Air: Moderate / Oil: Strong | >Argentite ~Pyrargyrite <Stephanite | Platelike to equant grains | With, or in, Galena Pyrite Sphalerite Tetrahedrite | Common / Deep Red | Low 29% | Soft (180-192) | Monoclinic | ||
| Pentlandite | (Fe,Ni)9S8 | Light Creamy to Yellowish | C to Pyrrhotite: lighter / C to Linnaeite: darker, not Pinkish | None | Isotropic | >Chalcopyrite <Pyrrhotite | Granular veinlets / “flames" / lamellae in Pyrrhotite or Chalcopyrite | Alters to Violarite and Millerite along cracks and grain boundaries | Cubanite Mackinawite Magnetite Pyrite | None | Moderate 47% | Soft (268-285) | Cubic | |
| Platinum | Pt | White | None | Isotropic / Incomplete extinction | >Sphalerite <Pyrrhotite | Isolated Euhedral to Subhedral crystals | May be zoned / exsolution Laths of Iridium and Osmium | Chalcopyrite Chromite Magnetite Pentlandite Pyrrhotite | None | High 70% | Soft (297-339) | Cubic | May occur with other small grains of Platinum minerals | |
| Polybasite | Ag16Sb2S11 | Gray | C to Galena: darker / C to Pyrargyrite: darker Brownish / C to Tetrahedrite: similar | Air: Weak; oil: distinct / Green to Gray with Violet tint | Blue Gray, Yellow-Green, Brown / Air: moderate / Oil: Strong | >Argentite ~Pyrargyrite <Stephanite | Forms complete solid solution with Pearcite | Complete solid solution with Pearcite | Common / Deep Red | Low 30% | Soft (108-141) | Monoclinic | Similar occurrences as Pearcite | |
| Proustite | Ag3AsS3 | Blueish Gray | C to Pyrargyrite: darker | Distinct / Yellowish to Blueish Gray | Strong / masked by internal reflection | ~Pyrargyrite | Forms complete solid solutions with Pyrargyrite | Complete solid solutions with Pyrargyrite | Always / Scarlet Red | Low 23-28% | Extra Soft to Soft (70-105) | Trigonal | Same characteristics as Pyrargyrite except that Proustite occurs in more As-rich environments | |
| Psilomelane (General name for massive, hard manganese oxides) | BaMn2+Mn4+8O16(OH)4 | Blueish Gray to Grayish White | C to Pyrolusite: darker / C to Braunite, Manganite, Jacobsite, Hausmannite, Bixbyite: lighter | Strong / White to Blueish Gray | Strong / White to Gray | Very fine acicular crystals in concentric layers / Botryoidal masses | Often intergrown with Pyrolusite and Cryptomelane | Mn-Oxides | Rare / Brown | Low 15-30% | Soft to Hard (203-813) | |||
| Pyrargyrite | Ag3SbS3 | Blueish Gray | C to Proustite: slightly lighter / C to Galena: Grayish Blue | Distinct to Strong | Strong / Gray to dark Gray / in oil, masked by internal reflections | >Polybasite <Galena | Irregular grains / Aggregates | Twinning / Zonal Textures | Arsenopyrite Chalcopyrite Galena Ni-Co-Fe Arsenides Pyrite Sb-sulfosalts Sphalerite Tetrahedrite | Common / Intense Red | Low 27% | Soft (107-144) | Trigonal | Solid solution with Proustite |
| Pyrite | FeS2 | Yellowish White | C to Marcasite: Yellower / C to Arsenopyrite: Creamy Yellow / C to Chalcopyrite: lighter | None | Often Weak / Blue-Green to Orange-Red | >Arsenopyrite >Marcasite <Cassiterite | Euhedral cubes and pyritohedra / Anhedral crystalline masses / Colloform bands of very fine grains | Growth zoning / Twinning | Super common, occurs with most ore minerals | None | High 52% | Very Hard (1505-1620) | Cubic | The most abundant Sulphide ™ |
| Pyrolusite | MnO2 | Creamy White | C to Magnetite, Hematite: Yellowish / C to Manganite: White | Distinct in oil / Yellowish White to Gray-White | Very Strong / Yellowish, Brownish, Blue | Very variable depending on grain size and orientation | Coarse-grained tabular crystals / banded aggregates | Cleavage / Twinning / Very fine grained material may be intergrown with Psilomelane, Hematite, Fe-hydroxides | Bixbyite Braunite Magnetite Manganite | None | Low to Moderate 28-40% | Soft (146-243) | Tetragonal | |
| Pyrrhotite (Hexagonal) | Fe1-xS / (~Fe9S10) | Creamy Pinkish Brown | C to Pentlandite: darker / C to Cubanite: more Pinkish | Very distinct / Creamy Brown to Reddish Brown | Very Strong / Yellow-Gray, Grayish Blue | >Chalcopyrite ~Pentlandite <Pyrite | Anhedral Granular masses | Twinning common, especially where stressed / Lamellar exsolution intergrowths of hexagonal and monoclinic forms common / Weathering of hexagonal Pyrrhotite yields a rim of monoclinic Pyrrhotite (usually slightly lighter in colour) | Most other common Sulphides | None | Moderate 36% | Soft (230-259) | Hexagonal | Pentlandite exsolution lamellae and flames common in Ni-ores / often contains Mackinawite lamellae |
| Pyrrhotite (Monoclinic) | (~Fe7S8) | Creamy Pinkish Brown | C to Pentlandite: darker / C to Cubanite: more Pinkish | Very distinct / Creamy Brown to Reddish Brown | Very Strong / Yellow-Gray, Grayish Blue | >Chalcopyrite ~Pentlandite <Pyrite | Anhedral Granular masses | Twinning common, especially where stressed / Lamellar exsolution intergrowths of hexagonal and monoclinic forms common / Weathering of hexagonal Pyrrhotite yields a rim of monoclinic Pyrrhotite (usually slightly lighter in colour) | Most other common Sulphides | None | Moderate 36-42% | Soft to Moderate (373-409) | Monoclinic | |
| Rammelsbergite | NiAs2 | White more so than other Ni-Co-Fe Arsenides | Very Weak in air; distinct in oil / Yellowish to Blueish | Strong / Pinkish, Brownish, Greenish, Blueish | ~Skutterudite <Safflorite <Loellingite | Fine-grained aggregates of interlocking crystals / Zoning / Spherulitic radiating textures / Fibres | Simple or complex Twinning / May be intergrown with Niccolite and Co-Ni-Fe Arsenides / Sometimes as overgrowths on dendrites of Silver or Bismuth | Bismuth Co-Ni-Fe Arsenides Niccolite Silver | None | High 57% | Moderate to Hard (630-758) | Orthorhombic | Similar to Safflorite | |
| Realgar | As4S4 or AsS | Dull Gray | C to Sphalerite: similar / C to Cinnabar: darker / Orpiment slightly darker | Weak but distinct / Gray with Reddish to Blueish tint | Strong / in oil masked by internal reflections | <Orpiment | Irregular / Plate-like masses with Orpiment | Arsenic Arsenopyrite As-sulfosalts Enargite Proustite Pyrite Stibnite Tennantite | Common and intense / Yellowish Red | Low 21% | Extra Soft (47-60) | Monoclinic | ||
| Rutile | TiO2 | Gray / faint Blueish tint | C to Magnetite, Chromite: similar / C to Ilmenite: no Brownish tint / C to Cassiterite: lighter | Distinct | Strong / masked by internal reflections | >Ilmenite <Hematite | Euhedral to Subhedral / Needlelike | Common in hydrothermally altered rocks | Ilmenite Tantalite Ti-Hematite Ti-Magnetite | Common and intense / White, Yellowish, Reddish Brown | Low 19% | Hard (894-974) | Tetragonal | |
| Safflorite | (Co,Fe,Ni)As2 | White with Blueish tint | C to Bismuth: Blueish / C to Silver: Grayish White | Very Weak / Blueish to Gray | Strong | >Skutterudite <Loellingite | Concentric layers of Radiating masses of Anhedral to Subhedral crystals / Euhedral crystals / Starlike triplets | Twinning common | Other Arsenides | None | High 54% | Hard (792-882) | Orthorhombic | |
| Scheelite | CaWOs4 | Gray-White / darker in Oil | C to Gangue: similar in air / lighter in oil | None | Distinct / masked by internal reflections | <Wolframite | Equant to Lath-like polycrystalline aggregates / Partial replacement of Wolframite | Fluoresces pale blue to yellow under UV light / Intergrown with Fe-oxides, Huebnerite, Ferberite, Cassiterite | Intergrown with Cassiterite Fe-oxides Ferberite Huebnerite | Common / White | High 54% | Soft to Moderate (383-464) | Tetragonal | |
| Schreibersite | (Fe,Ni)3P | in Air: White / in Oil: Brownish Pink tint | C to Cohenite: lighter / C to Iron: similar | In oil distinct / Pinkish Brown to Yellowish | Weak but distinct in oil | >Cohenite ~Iron | Oriented Needle and tablet-like inclusions in Iron meteorites | Inclusions in Iron in meteorites | None | Low 10% | Soft (125) | Tetragonal | ||
| Siegenite | (Co,Ni)3S4 | Creamy White with slight Pink tinge | C to Cattierite: less Pinkish | None | lsotropic | ~Linnaeite | Euhedral and Subhedral crystals / Anhedral polycrystalline aggregates | Cattierite Pyrite Uraninite Vaesite | None | Moderate 47% | Moderate (459-548) | Cubic | ||
| Silver | Ag | Bright White with Creamy tint / tarnishes rapidly | C to Antimony, Arsenic: brighter and Creamy | None | Isotropic / Fine scratches often look Anisotropic | >Proustite >Galena <Tetrahedrite | Irregular masses / veinlets / Inclusions / Dendrites within Arsenides | Lamellar intergrowths with Allargentum / Incomplete extinction / Tarnishes rapidly | Ag-sulfosalts Argentite Co-Fe-Ni Arsenides Cu-Sulphides Galena | None | High 93% | Extra Soft (60-65) | Cubic | |
| Skutterudite | (Co,Ni)As2-3 | Cream-White to Grayish White / often in zones | C to Cobaltite: White / C to Safflorite: Yellowish | None | Isotropic / sometimes weakly anomalous | >Linnaeite <Arsenopyrite <Pyrite ~Safflorite | Characteristically radial blade-like crystals with well-developed growth zoning / Euhedral single crystals | May be intergrown with Niccolite Bismuth other Co-Fe-Ni Arsenide | Intergrowth with Bismuth Niccolite | None | High 55% | Moderate to Hard (606-824) | Cubic | Occurs in Ag-Bi-U rich deposits |
| Sphalerite | (Zn,Fe)S | Gray / sometimes with Brown tint | C to Magnetite: darker | None | Isotropic / sometimes weakly anomalous | >Chalcopyrite >Tetrahedrite <Pyrrhotite <Magnetite | Irregular Anhedral masses | Growth zoning of light and dark bands / Often featureless except for internal reflections / Commonly contains inclusions of Chalcopyrite, Pyrrhotite, Galena, and less commonly, Stannite | Chalcopyrite Galena Pyrite Pyrrhotite | Common / Yellow-Brown to Reddish Brown | Low 16% | Soft (138-160) | Cubic | Internal reflections and the lack of cleavage allows you to distinguish from Magnetite |
| Stannite | Cu2FeSnS4 | Brownish Olive-Green | C to Tetrahedrite: darker Brownish Gray / C to Sphalerite: lighter, Yellow-Brown to Olive-Green | Distinct / light Brown to Brown-Olive-Gray | Moderate / Yellow-Brown, Olive-Green, Violet-Gray | >Chalcopyrite >Tetrahedrite <Sphalerite | Anhedral grains / Granular aggregates / oriented intergrowths with Chalcopyrite, Sphalerite and Tetrahedrite | Cleavage / compound Twinning, sometimes in microline pattern | Bismuth Chalcopyrite Sphalerite Tetrahedrite Tungsten | None | Low 26% | Soft (140-326) | Tetragonal | Common with Bismuth and Tungsten minerals / In many ore types as a minor phase |
| Stephanite | Ag5SbS4 | Gray with Pinkish Violet tint | C to Galena: darker, Pinkish / C to Polybasite, Pyrargyrite: lighter | Weak but distinct / Gray to Pinkish Gray | Strong in oil / Violet to Green | >Polybasite >Pyrargyrite <Tetrahedrite | Anhedral aggregates / Euhedral columnar crystals | Compound Twinning common | Arsenides Ni-Co-Fe Sulfosalts Silver | None | Low 28% | Extra Soft to Soft (26-124) | Orthorhombic | |
| Stibnite | Sb2S3 | White to Grayish White | C to Bismuthinite: darker / C to Antimony: Grayish | Strong / Grayish White to White | Very Strong / often undulose / Blue, Gray, Brown, Pinkish Brown | >Orpiment <Chalcopyrite | Granular aggregates / Lath-like crystals often with deformation textures | Pressure Twinning / Undulose Extinction / Deformation textures | Chalcopyrite Pyrite Pyrrhotite Sphalerite | None | Low to Moderate 30-48% | Extra Soft to Soft (48-153) | Orthorhombic | |
| Stromeyerite | AgCuS | Gray with Violet Pinkish tint | C to Chalcocite: Lavender-Gray | Weak but distinct in oil / Gray-Brown to light Gray with Blue or Pink tint | Strong / Light Violet, Purple, Brown, Orange-Yellow | <Galena <Chalcocite | Hypogene phase in Granular aggregates / Supergene phase in small veinlets | Often intergrown with other Silver numerals | Cu-Fe and Fe Sulphides Silver Sphalerite | None | Low to Moderate 26-31% | Extra Soft (30-32) | Orthorhombic | |
| Sylvanite | (Au,Ag)Te2 | Creamy White | C to Galena: lighter | Distinct / Creamy White to Brownish | Strong / light Blueish Gray to dark Brown | >Argentite <Pyrargyrite | Skeletal blades | Well-developed cleavage / characteristic polysynthetic twinning / Often intergrown with other Gold-Tellurides | Argentite Bornite Chalcopyrite Galena Gold Pyrite Sphalerite | None | High 53-63% | Soft (154-172) | Monoclinic | |
| Taenite | γ-Fe | γ-Fe contains ~ 27-60% Ni and is slightly Yellowish | C to Pentlandite: much Whiter / C to Cohenite: slightly Blueish | None | Isotropic | Intergrowths of γ-Fe and α-Fe form Widmanstät;ten structures which are brought out by etching / Oxidizes to Hematite, Goethite, Lepidocrocite | Chromite Copper Ilmenite Schreibersite Troilite | None | High 58% | Soft (110-117) | Cubic | Found in Iron meteorites / Rare on earth / cf. Iron | ||
| Tennantite | Cu12As4S13 (May contain Fe, Zn, Sb etc,) | Gray / sometimes with Greenish or Blueish tint | C to Galena, Chalcocite: Greenish / C to Pearcite: similar | None | Isotropic | >Galena >Chalcopyrite <Sphalerite | Occurrences the same as for Tetrahedrite except in more As-rich envIronments | Complete solid solution with Tetrahedrite | Common / Reddish | Low 29% | Soft (294-380) | Cubic | ||
| Tenorite | CuO | in Air: Gray to Gray-White / in Oil: strongly pleochroic | C to Cuprite: Brownish Blueish / C to Chalcocite: Brownish / C to Goethite: lighter Yellowish | Distinct | Strong / Blue to Gray | >Chalcocite <Goethite<Cuprite | Aggregates of acicular crystals / concentrically grown aggregates | May have Lamellar Twinning | Cu and Fe oxides in weathering zone | None | Low 20-28% | Soft (190-300) | Monoclinic | |
| Tetradymite | Bi2Te2S | White with Creamy tint | C to Chalcopyrite: lighter / C to Galena: Yellowish | Weak | Distinct / Blueish Gray to Yellow Gray | >Bismuth <Galena | Tabular Plates / Granular aggregates | Basal cleavage common / Twinning rare / Intergrowths with Telluro-Bismuthinite | Galena Gold Pb-Bi Sulfosalts | None | High 55-61% | Extra Soft (25-76) | Trigonal | |
| Tetrahedrite | Cu12SbS13 (May contain Fe, Zn, Ag, As, Hg etc.) | Gray with Olive or Brownish tint | C to Galena: Brownish or Greenish / C to Chalcocite: Blue-Gray / C to Sphalerite: lighter | None | Isotropic | >Galena ~Chalcopyrite <Sphalerite (Hardness varies with composition) | Irregular masses of Anhedral grains interstitial to Fe and Cu-Fe sulphides / Rounded inclusions in Galena and Sphalerite | Forms complete solid solution with Tennantite / Growth zoning especially in more As-rich members | Arsenopyrite Galena Sphalerite | Rare / Increasingly common as As-content increases / Reddish | Moderate 32% | Soft (312-351) | Cubic | |
| Troilite | FeS is Troilite | Creamy Pinkish Brown | C to Pentlandite: darker / C to Cubanite: more Pinkish | Very distinct / Creamy Brown to Reddish Brown | Very Strong / Yellow-Gray, Grayish Blue | >Chalcopyrite ~Pentlandite <Pyrite | Anhedral equigranular masses with Iron | Occurs in meteorites | Most other common Sulphides | None | Moderate 39% | cf. Pyrrhotite | ||
| Ullmannite | NiSbS | White with Blueish tint | C to Gersdorffite: less Yellow / C to Skutterudite: more Yellow / C to Linnaeite: White | None | Isotropic | >Linnaeite ~Gersdorffite <Pyrite | Dispersed Subhedral to Euhedral crystals | Cleavage may be visible / Triangular cleavage pits | Arsenides Cu-Fe Sulphides Co-Fe-Ni Antimonides | None | Moderate 47% | Moderate (592-627) | Cubic | |
| Ulvöspinel | Fe2TiO4 | Brown to Reddish Brown | C to Magnetite: darker Brown | None | Isotropic | >Magnetite | Very fine dark isotropic exsolution lamellae / Less commonly as octahedral crystals / Matrix containing oriented cubes of Magnetite | Very fine, dark isotropic exsolution lamellae in Ti-Magnetite, giving a “doth weave" texture | Ilmenite Magnetite | None | Low 15% | (-650) | Cubic | |
| Uraninite | UO2, usually partly oxidised | Brownish Gray | C to Magnetite: Less Pink / C to Sphalerite: Brownish | None | Isotropic | >Magnetite <Pyrite | Colloform / Oolitic / Dendritic masses | Growth-zoning / Twinning common / Cleavage may be visible / May contain inclusions of Gold | Cu-Fe Sulphides Pyrite Uranium minerals | Common / Dark Brown to Reddish Brown | Low 14% | Moderate (499-548) | Cubic | |
| Valleriite | (Fe,Cu)S2 (Mg,Al)(OH)2 | Bronze to Gray | Very Strong | Strong to Extreme / White to Gray-bronze with satin-like texture | >Chalcopyrite ~Cubanite <Pyrrhotite | Veinlets / Interstitial fillings / Small inclusions within and surrounding Chalcopyrite ,Magnetite, Pentlandite andPyrrhotite | Bronze anisotropy appears in a satin-like wavy pattern | Chalcopyrite Magnetite Pentlandite Pyrrhotite | None | Low 10-23% | Extra Soft (30) | Hexagonal | Mackinawite has a sharper extinction and less of an orange anisotropism | |
| Violarite | FeNi2S4 | Brownish Gray with Violet tint | C to Pentlandite: darker, Violet tint / C to Pyrrhotite: lighter / C to Millerite: Brownish Violet | None | Isotropic | >Chalcopyrite >Sphalerite ~Pentlandite <Pyrrhotite | Porous alteration product along grain boundaries and fractures / Equant Anhedral grains | Sometimes as fine lamellar intergrowths with Millerite and Chalcopyrite / Porous alteration product along grain boundaries and fractures of Pentlandite, Pyrrhotite, and Millerite / Equant Anhedral grains with Pyrite, Millerite Pyrrhotite | Millerite Pentlandite Pyrite Pyrrhotite | None | Moderate 45% | Soft (241-373) | Cubic | |
| Wolframite / Ferberite - Hübnerite Series | (Fe,Mn)WO4 | Air: Gray to White / Oil: Gray with Brown or Yellow tint | C to Sphalerite: similar / C to Magnetite: darker / C to Cassiterite: lighter | Weak | Weak to distinct / Yellow to Gray | >Magnetite >Scheelite <Pyrite <Arsenopyrite | Euhedral Platelets / masses of interpenetrating Laths | Cleavage / Twinning common | Arsenopyrite Bismuth Bismuthinite Cassiterite Chalcopyrite Gold Molybdenite Scheelite | Common / Deep Red, especially in oil | Low 15% | Soft (319-390) | Monoclinic | Wolframite is technically not a mineral name. It ought to be referred to as the Ferberite-Hübnerite Series |
| Zincite | ZnO | Pinkish Brown | None / Masked by internal reflections | Masked by internal reflections | <Franklinite <Hausmannite | Anhedral grains | Cleavage may be visible / Forms oriented intergrowths with Hausmannite | Franklinite Hausmannite | Common / Red to Yellowish | Low 11% | Soft (205-221) | Hexagonal |