The principal ores of copper are the oxides cuprite and melaconite, the carbonates malachite and chessylite, the basic chloride atacamite, the silicate chrysocolla, the sulphides chalcocite, chalcopyrite, erubescite and tetrahedrite.
Chrysocolla contains in the pure state 30% of the metal; it is an abundant ore in Chile, Wisconsin and Missouri.
Dioptase and chrysocolla (q.v.) are the most important forms.
These mountains are still the chief source of copper, but the ores, chiefly cuprite, malachite and chrysocolla, are also found in various parts of the Piedmont region.