Most distinguishing features:High specific gravity is best indicator, colour and fracture are also helpful.
Industrial/economical uses:Primary ore for barium, also used as an additive to drilling mud (because of high SG). Has over 2000 uses in industry.
Most distinguishing features:Colour and habit
Industrial/economical uses:Altered into vermiculite, biotite is used as an insulation material and as filler in certain building supplies.
Other names/forms:Peacock ore
Most distinguishing features:Green-blue-purple iridescence is indicative, as is a brownish-bronze colour on fresh surfaces.
Industrial/economical uses:Mined as an ore of copper, but not as important as chalcopyrite.