15.—Calamine.
Occurs in crystals and masses; glossy lustre; harder than marble; brittle; heated it swells up, becomes opaque and emits a green light; dissolves, when powdered, in hot sulphuric acid without effervescence; gravity 3.4.
Value.—An ore of zinc yielding from forty to sixty per cent.
Localities.—Found in limestone rock with other ores. Friedensville, Perkiomen, Phœnixville, Lancaster and Selin’s Grove, Pa.; Austin’s Mines in Wythe County, Va.; Claiborne County, Tenn.; Jefferson County, Mo.