Calamine

Calamine, zinc carbonate, one of the most important ores of zinc, occurs both in veins and in beds, associated with blende, smithsonite, galena, and other ores, at Vieu Montagne near Aix-la-Chapelle, in Cornwall, the Mendip Hills, near Matlock, at Alston Moor in Cumberland, Holywell in Flintshire, Leadhills in Lanarkshire, and elsewhere. It is a white or grey mineral, generally translucent and vitreous, occurring in earthy, incrusting, stalactitic and other massive forms, or crystallising in the rhombohedral system. It has a hardness of 5, but is brittle. Its specific gravity is 4 or a little more. It effervesces with hydrochloric acid, and is infusible by itself; but with sodium-carbonate on charcoal gives the characteristic white areola of zinc-oxide, which becomes green on being re-heated with cobalt-nitrate. It takes its name from calamus, a reed, from the form it assumes in smelting. Dana applies this name to zinc-silicate, which in England is commonly termed Smithsonite, a name which he applies to this carbonate. Siliceous or electric calamine, which is frequently associated with the former ore, is a silicate of zinc also known as Hemimorphite (q.v.).