Copper (chemical symbol Cu, from the Latin cuprum) is a reddish, malleable metal and an excellent conductor of heat and electricity. In circulation it develops a protective patina and can darken over time through oxidation. It was used since antiquity both in pure form and as the basis for alloys such as bronze and brass. Due to its low intrinsic value compared to gold and silver, copper was traditionally reserved for the smallest denominations in monetary systems. Pure copper was widely used for coinage from the early modern period through the 19th century, before being largely replaced by copper-based alloys offering better durability.
