Copper occasionally occurs native, and is found in many minerals such as cuprite, malachite, azurite, chalcopyrite, and bornite. Large copper ore deposits are found in the U.S., Chile, Zambia, Zaire, Peru, and Canada. The most important copper ores are the sulfides, oxides, and carbonates. From these, copper is obtained by smelting, leaching, and by electrolysis. Copper compounds such as Fehling's solution are widely used in analytical chemistry in tests for sugar.
Natural copper contains two isotopes.
Twenty five other radioactive isotopes and isomers are known. Copper has a contraceptive effect when present in the uterus. It is added to some intrauterine contraceptive devices permitting reduction in their size with concomitant reduction in the associated side effects such as pain and bleeding. Used in cement, food and drugs, metallurgy, nylon, paper products, pigment and dyes, pollution control catalyst, printing and photo copying, pyrotechnics, and wood preservatives. The fumes and dust cause irritation of the upper respiratory tract.