Copper is a chemical element with the symbol Cu. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; a freshly exposed surface has a reddish-orange color. It is used as a conductor of heat and electricity, a building material, and a constituent of various metal alloys.
The metal and its alloys have been used for thousands of years. In the Roman era, copper was principally mined on Cyprus, hence the origin of the name of the metal as Cyprium (metal of Cyprus), later shortened to Cuprum. Its compounds are commonly encountered as copper salts, which often impart blue or green colors to minerals such as turquoise and have been widely used historically as pigments. Architectural structures built with copper corrode to give green verdigris (or patina). Decorative art prominently features copper, both by itself and as part of pigments.
Copper has been in use at least 10,000 years, but more than 95% of all copper ever mined and melted has been extracted since 1900. As with many natural resources, the total amount of copper on Earth is vast (around 1014 tons just in the top kilometer of Earth's crust, or about 5 million years' worth at the current rate of extraction). However, only a tiny fraction of these reserves is economically viable, given present-day prices and technologies. Various estimates of existing copper reserves available for mining vary from 25 years to 60 years, depending on core assumptions such as the growth rate. Recycling is a major source of copper in the modern world.
As the global copper deficit intensifies and the price outlook remains strong, miners can be seen to focus on the expansion and development of new projects to meet increased demand. Production from brownfield expansions at Escondida in Chile, the restart of Glencore’s African copper operations, First Quantum Minerals’ new Cobre Panama mine and OZ Minerals’ construction of the Carrapateena copper mine in South Australia are expected to come online and increase output in the future.
Some metals and mining analysts remain optimistic on copper and anticipate that the significant copper deficit may continue, a view supported in a recent McKinsey Global Institute report which signalled strong growth for copper over the next two decades and alongside a depletion of copper ores after 2025 further exacerbating constrained supply.