It's Elemental

Archaeological evidence suggests that people have been using copper for at least 11,000 years. Relatively easy to mine and refine, people discovered methods for extracting copper from its ores at least 7,000 years ago. The Roman Empire obtained most of its copper from the island of Cyprus, which is where copper's name originated. Today, copper is primarily obtained from the ores cuprite (CuO₂), tenorite (CuO), malachite (CuO₃·Cu(OH)₂), chalcocite (Cu₂S), covellite (CuS) and bornite (Cu₆FeS₄). Large deposits of copper ore are located in the United States, Chile, Zambia, Zaire, Peru and Canada.

Used in large amounts by the electrical industry in the form of wire, copper is second only to silver in electrical conductance. Since it resists corrosion from the air, moisture and seawater, copper has been widely used in coins. Although once made nearly entirely from copper, American pennies are now made from zinc that has been coated with copper. Copper is also used to make water pipes and jewelry, as well as other items.

Pure copper is usually too soft for most uses. People first learned about 5,000 years ago that copper can be strengthened if it is mixed with other metals. The two most familiar alloys of copper are bronze and brass. Bronze, the first alloy created by people, is a mix of copper that contains as much as 25% tin. Early people used bronze to make tools, weaponry, containers and ornamental items. Brass, a mix of copper that contains between 5% and 45% zinc, was first used about 2,500 years ago. The Romans were the first to make extensive use of brass, using it to make such things as coins, kettles and ornamental objects. Today, brass is also used in some musical instruments, screws and other hardware that must resist corrosion.

Hydrated copper sulfate (CuSO₄·H₂O), also known as blue vitriol, is the best known copper compound. It is used as an agricultural poison, as an algicide in water purification and as a blue pigment for inks. Cuperic chloride (CuCl₂), another copper compound, is used to fix dyes to fabrics. Cuprous chloride (CuCl) is a poisonous white powder that is chiefly used to absorb carbon dioxide (CO₂). Copper cyanide (CuCN) is commonly used in electroplating.