Mineral Identification Justin Moore
Biotite Mica
Luster - Vitreous to pearly
Cleavage – 1
Colour – Dark brown, greenish-brown, blackish-brown, yellow, white
Streak colour – colourless
Hardness – 2.5 to 3.9
Special properties – Have a perfect basal cleavage and thin sheets that flake off
Uses – Used to determine the age of rocks through potassium-argon or argon-argon dating.
Micaneous
Fluorite
Luster – Non-metallic
Cleavage – Octahedral cleavage
Colour – Variations of purple
Streak colour – Colourless
Hardness – 4
Special properties – Fluorescence under UV light
Use - Optics, high end telescopes and lenses
Sulfur
Hardness – 2.0
Colour - Yellow
Galena
Luster – Metallic
Cleavage – Cubic
Colour – Lead gray and silvery
Streak colour – Lead gray
Hardness – 2.5 – 2.75
Calcite
Luster – Vitreous to pearly on cleavage surfaces
Cleavage – Perfect Rombohedral
Colour – Colorless or white, also gray, yellow and green
Streak colour – Colourless
Hardness – 3
Uses - Used in gun sights for WW2
Talc
Formula – Mg3Si4O10(OH)2
Colour – Light to dark green, brown, white, grey
Cleavage – Basal
Hardness – 1
Luster – Wax-like or pearly
Streak – White to pearl green
Hematite
Formula - Fe203
Colour – Metallic gray, dull to bright red
Cleavage – None
Hardness – 5.5 to 6.5
Luster – Metallic
Streak – Bright red to dark red
Feldspar
Luster – Vitreous
Cleavage – Two or three planes
Colour – Pink, white, gray, brown
Streak colour – Colourless
Hardness – 6.0 to 6.5
Uses - Feldspar is used for K-Ar dating, argon-argon dating, thermoluminescence dating, and optical dating.
Gypsum
Colour – Colourless, white, yellow, tan, blue, pink, brown, reddish brown or gray
Hardness – 1.5 to 2
Luster – Vitreous to silky, pearly or waxy
Streak – White
Formula - CaS04 2H2O
Halite
Formula - NaCl
Colour – Colourless, white, blue, purple, red, pink, yellow, orange and gray
Cleavage – Cubic (3 directions)
Hardness – 2 – 2.5
Luster – Vitreous
Streak - Colourless
Magnetite
Formula - Fe II Fe III 204
Colour – Black, gray with brownish tint when reflected in the sun
Cleavage – Indistinct
Hardness – 5.5 to 6.5
Luster – Metallic
Streak – Black
Muscovite Mica
Formula - KAl2(AlSi3O10)(F1OH)2
Colour – White, grey, silvery
Cleavage – None
Hardness - 2 to 2.5
Luster – Vitreous, Silky, Pearly
Streak - White
Quartz
Formula – SiO2
Colour – Colourless, black
Cleavage – Indistinct
Hardness – 7
Luster – Vitreous (Waxy to dull when massive)
Streak - White
Pyrite
Formula – FeS2
Colour – Pale brass-yellow
Hardness – 6 to 6.5
Luster – Metallic, glistening
Streak – Greenish-black to Brownish-black
Graphite
Colour – Iron black to steel gray; deep blue
Cleavage – Basal
Hardness – 1 to 2
Luster – Metallic, earthy
Streak – Black