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.
Cuprite occurs in most cupriferous mines, but never by itself in large quantities.
Cuprous oxide, Cu 2 0, occurs in nature as the mineral cuprite (q.v.).
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.