MODEL RELEASED. Copper bars. Technician inspecting manufactured bars of copper. Copper is a pinkish- red transition metal which is malleable, ductile and an excellent conductor of heat and electricity. It occurs as the minerals cuprite, azurite, chalcocite, chalcopyrite and malachite and occasionally as native copper crystals. The metal is usually extracted by smelting, leaching and electrolysis. Copper is used extensively in electrical cables and water pipes. Its alloys, brass (copper-zinc) and bronze (copper-tin), are also widely used.