Minerals List

Mineral: Arsenopyrite
Ore: Sulfide
Chemical Formula: FeAsS
Comodity of Interest: None -Arsenic byproduct of smelting
Colour in TS: Very white with faint creamy to yellow to pink tint
Pleochroism in PPL: Weak
Anisotropism in XPL: Strong
Notes: Orthorhombic shape and zoning commonly observed.

Mineral: Azurite
Ore: Oxide
Chemical Formula: Cu₃(CO₃)₂(OH)₂
Comodity of Interest: Copper
Colour in TS: NA
Pleochroism in PPL: NA
Anisotropism in XPL: NA
Notes: NA

Mineral: Bauxite
Ore: Oxide
Chemical Formula:
Boehmite – AlO(OH)
Diaspore – HAlO₂
Gibbsite – Al(OH)₃
Comodity of Interest: Aluminum
Colour in TS: NA
Pleochroism in PPL: NA
Anisotropism in XPL: NA
Notes: NA

Mineral: Bornite
Ore: Sulfide
Chemical Formula: Cu₅FeS₄
Comodity of Interest: Copper
Colour in TS: Salmon pink
Pleochroism in PPL: NA
Anisotropism in XPL: NA
Notes: NA

Mineral: Chalcocite
Ore: Sulfide
Chemical Formula: Cu₂S
Comodity of Interest: Copper
Colour in TS: Greyish-white to bluish white
Pleochroism in PPL: Reflected – Weak to non- pleochroic (light blue, constant)
Anisotropism in XPL: None – deep blue
Notes: NA

Mineral: Chalcopyrite
Ore: Sulfide
Chemical Formula: CuFeS₂
Comodity of Interest: Copper
Colour in TS: Strong brassy yellow
Pleochroism in PPL: NA
Anisotropism in XPL: NA
Notes: Hand sample looks brassy yellow

Mineral: Chromite
Ore: Oxide
Chemical Formula: (Mg,Fe)Cr₂O₄
Comodity of Interest: Chromium
Colour in TS: Light grey, tan grungy colour
Pleochroism in PPL: Weak to none
Anisotropism in XPL: NA
Notes: Distinct shape, fairly euhedral

Mineral: Cinnabar
Ore: Sulfide
Chemical Formula: HgS
Comodity of Interest: Mercury
Colour in TS: White w/ bluish to greenish gray tint
Pleochroism in PPL:Weak along grain boundaries
Anisotropism in XPL: Strong Anisotropism green blue grey (light)
Notes: NA

Mineral: Copper
Ore: NA
Chemical Formula: Cu
Comodity of Interest: Copper
Colour in TS: Strong pink
Pleochroism in PPL: Non pleochroic
Anisotropism in XPL: Non anisotropic
Notes: NA

Mineral: Covellite
Ore: Sulfide
Chemical Formula: CuS
Comodity of Interest: Copper (uncommon)
Colour in TS: Indigo hue, with violet to bluish white tint
Pleochroism in PPL: Reflected – strong pleochroism (Dark to light blue to white)
Anisotropism in XPL: Yes – Pink, orange, blue (very distinct)
Notes: NA

Mineral: Freibergite
Ore: NA
Chemical Formula:
Comodity of Interest:
Colour in TS: Grey
Pleochroism in PPL: Non pleochroic
Anisotropism in XPL: Non anisotropic
Notes: Brownish red internal reflections

Mineral: Galena
Ore: Sulfide
Chemical Formula: PbS
Comodity of Interest: Lead
Colour in TS: Very bright, light white grey/silver
Pleochroism in PPL: Reflected – Non-pleochroic (white/grey)
Anisotropism in XPL: Non anisotropic
Notes: Has distinctive triangular pit (pluck) marks

Mineral: Gersdorffite
Ore: NA
Chemical Formula: NiAsS
Comodity of Interest: NA
Colour in TS: Light grey/bluish white
Pleochroism in PPL: Non pleochroic
Anisotropism in XPL: Non anisotropic
Notes: High reflectance

Mineral: Goethite – Limonite
Ore: Oxide
Chemical Formula: HFeO₂
Comodity of Interest: Iron
Colour in TS: NA
Pleochroism in PPL: NA
Anisotropism in XPL: NA
Notes: NA

Mineral: Gold
Ore: NA
Chemical Formula: Au
Comodity of Interest: Gold
Colour in TS: Very intense yellow-golden colour
Pleochroism in PPL: Non pleochroic
Anisotropism in XPL: Non anisotropic
Notes: Strong reflectance

Mineral: Graphite
Ore:
Chemical Formula: C
Comodity of Interest:
Colour in TS:
Pleochroism in PPL:
Anisotropism in XPL:
Notes:NA

Mineral: Hematite
Ore: Oxide
Chemical Formula: Fe₂O₃
Comodity of Interest: Iron
Colour in TS: Grey white with bluish tint
Pleochroism in PPL: Weak – none
Anisotropism in XPL: Moderate: greyish-light blue to dark blue/grey
Also, lime green/blue (subtle)
Notes: Harder than Ilmenite

Mineral: Ilmenite
Ore: Oxide
Chemical Formula: FeTiO₃
Comodity of Interest: Titanium
Colour in TS: Very light, pinkish brown creamy tint
Pleochroism in PPL: Weak – none
Anisotropism in XPL: Strong: light grey to dark brown/red or dark purple/blue to light salmon pink
Notes: NA

Mineral: Magnetite
Ore: Oxide
Chemical Formula: Fe₃O₄
Comodity of Interest: Iron
Colour in TS: Medium grey
Pleochroism in PPL: NA
Anisotropism in XPL: NA
Notes: Highly magnetic

Mineral: Malachite
Ore: Oxide
Chemical Formula: Cu₂(CO₃)(OH)₂
Comodity of Interest: Copper
Colour in TS:
Pleochroism in PPL:
Anisotropism in XPL:
Notes: NA

Mineral: Molybdenite
Ore: Sulfide
Chemical Formula: MoS₂
Comodity of Interest: Molybdenum
Colour in TS:
Pleochroism in PPL:
Anisotropism in XPL:
Notes: Hand sample is silvery-blue white, very soft

Mineral: Niccolite
Ore:
Chemical Formula: NiAs
Comodity of Interest:
Colour in TS: Distinct yellow, creamy pink to brown/tan orange (stronger than pyrite)
Pleochroism in PPL: Light tan/pink/yellow to stronger orange colour
Anisotropism in XPL: Salmon pink/rust red to green-blue/grey
Notes: High reflectance

Mineral: Orpiment
Ore: Sulfide
Chemical Formula: As₂S₃
Comodity of Interest: None – Arsenic
Colour in TS:
Pleochroism in PPL:
Anisotropism in XPL:
Notes: NA

Mineral: Pentlandite
Ore: Sulfide
Chemical Formula: (Fe,Ni)₉S₈
Comodity of Interest: Nickel
Colour in TS: Light creamy-yellow, yellower version of Pyrrhotite
Pleochroism in PPL:
Anisotropism in XPL:
Notes:

Mineral: Pyrite
Ore: Sulfide
Chemical Formula: FeS₂
Comodity of Interest: None
Colour in TS: Strong – yellowish white
Pleochroism in PPL: Reflected – non-pleochroic (yellowish tint constant throughout)
Anisotropism in XPL: Slight – subtle turquoise, deep red, green/blue
Notes: Hand sample has a light yellow, sometimes as euhedral crystals

Mineral: Pyrolusite
Ore: Oxide
Chemical Formula: MnO₂
Comodity of Interest: Manganese
Colour in TS:
Pleochroism in PPL:
Anisotropism in XPL:
Notes:

Mineral: Pyrrhotite
Ore: Sulfide
Chemical Formula: Fe1-x S
Comodity of Interest: None – rarely Fe and S
Colour in TS: Creamy, salmon pink-brown/tan
Pleochroism in PPL: Reflected- Variable: weak to strong creamy pink/tan
Anisotropism in XPL: Strong – yellowish grey, greenish blue tint, rust red
Notes: Slightly Magnetic

Mineral: Realgar
Ore: Sulfide
Chemical Formula: AsS
Comodity of Interest: None – Arsenic
Colour in TS:
Pleochroism in PPL:
Anisotropism in XPL:
Notes:

Mineral: Scheelite
Ore: Oxide
Chemical Formula: CaWO₄
Comodity of Interest: Tungsten
Colour in TS:
Pleochroism in PPL:
Anisotropism in XPL:
Notes:

Mineral: Silver
Ore:
Chemical Formula: Ag
Comodity of Interest: Silver
Colour in TS: Strong bright white, possible creamy tint
Pleochroism in PPL: Non pleochroic
Anisotropism in XPL: Non anisotropic
Notes:

Mineral: Sphalerite
Ore: Sulfide
Chemical Formula: (Zn,Fe)S
Comodity of Interest: Zinc
Colour in TS: Light/medium grey (Darker than Galena)
Pleochroism in PPL: Reflected – Non-pleochroic (moderate grey)
Transmitted – sometimes red
Anisotropism in XPL: Non-anisotropic
Notes: NA

Mineral: Stibnite
Ore: Sulfide
Chemical Formula: Sb₂S₃
Comodity of Interest: Antimony
Colour in TS: Strong white/greyishwhite
Pleochroism in PPL: Strong pleochroism (dull grey white, brownish grey)
Anisotropism in XPL: Strongly anisotropic
Notes: Undulose extinction

Mineral: Tetrahedrite
Ore: Sulfide
Chemical Formula: Cu₁₂Sb₄S₁₃
Comodity of Interest: Copper, Silver
Colour in TS: Greyish white to greenish/grey/white (tennanite)
Pleochroism in PPL:
Anisotropism in XPL:
Notes:

Mineral: Uraninite
Ore: Oxide
Chemical Formula: UO₂ or U₃O₈
Comodity of Interest: Uranium
Colour in TS:
Pleochroism in PPL:
Anisotropism in XPL:
Notes:

Mineral: Wolframite
Ore: Oxide
Chemical Formula: (Fe,Mn)WO₄
Comodity of Interest: Tungsten
Colour in TS:
Pleochroism in PPL:
Anisotropism in XPL:
Notes:

Key Concepts

Alteration Minerals: Epidote, Chlorite, Actinolite, Sericite, Tourmaline, Albite, Clay, Tremolite, Calcite

Kalb Hardness Test: The Kalb line light, in optical mineralogy is a test made on polishing relief, which is very similar to Becke Line test. Microscope focused clearly on the boundary between two minerals grains. Microscope is raised (stage lowered) and as the specimen begins to go out of focus, a “line of light” will move towards the softer mineral (due to differing mineral properties).

Paragenetic Sequence: if a mineral is on top on within another mineral, the one on top or within it likely formed first. More euhedral minerals usually form first as well.

Disseminated: Sulfide droplets remain suspended in magma flow.

Net-textured: likely through dynamic flow segregation.

Massive: sulfides settle at the bottom of the magma chamber; because of their heavy nature.

Tectonic deformation: fracture sulfides in fold hinges, thickening in hinges, concentric folds, small scale faults, fractures, brecciation.

Soft-Sediment deformation: slumping, smearing, folding, dish and pillar, ball and pillow, convolute bedding, fluid escape, disharmonic folds.

Diatreme: higher, breccia-filled volcanic pipes formed by gaseous explosions. More country rock.

Hypabyssal: lower, igneous rocks are usually fine or medium-grained rocks, however, large phenocrysts often occur within rocks termed porphyrys. No country rock.

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Credits: Based on student contributor Ariana Pumo during Fall 2015.
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