Mineral Identification Table
An asterisk (*) means the rock contains only minor amounts of the mineral. Mineral Name Physical Properties Geologic Setting Industrial Uses Biotite1 (K, Mg, Fe, Al Silicate) Luster nonmetallic. Color dark green, brown, or black. Hardness 2.5-4. Platy cleavage (sheets). Streak white to gray. Schist, gneiss, granodiorite, granite*, rhyolite*.