37.—Horn Silver.
Occurs in crystals, wax-like masses, or in crusts; when scratched shows a shining streak; becomes brown on exposure; quite soft, easily cut; a small piece placed on zinc and moistened, swells up, turns black and shows metallic silver on being pressed with a knife; dissolves in hartshorn; gravity 5.5.
Value.—An ore of silver, yielding seventy per cent.
Localities.-Found in slate with other silver ores. Lake Superior Mining Region; Austin and Comstock Lode, Nev.; Willow Springs and San Francisco districts, Eldorado Cañon, Ariz.; Poorman Mine, Idaho.