Cu

Copper is a chemical element with the symbol Cu (Latin: cuprum) and atomic number 29. It is a ductile metal with excellent electrical conductivity, and finds extensive use as an electrical conductor, heat conductor, as a building material, and as a component of various alloys.

Copper is an essential trace nutrient to all high plants and animals. In animals, including humans, it is found primarily in the bloodstream, as a co-factor in various enzymes, and in copper-based pigments. However, in sufficient amounts, copper can be poisonous and even fatal to organisms.

Copper has played a significant part in the history of humankind, which has used the easily accessible uncompounded metal for thousands of years. Civilizations in places such as Iraq, China, Egypt, Greece, India and the Sumerian cities all have early evidence of using copper. During the Roman Empire, copper was principally mined on Cyprus, hence the origin of the name of the metal as Cyprium, "metal of Cyprus", later shortened to Cuprum.

A number of countries, such as Chile and the United States, still have sizable reserves of the metal which are extracted through large open pit mines, however like tin there may be insufficient reserves to sustain current rates of consumption. High demand relative to supply has caused a price spike in the 2000s.