Prehistoric Copper Age Copper occurs naturally as
native metallic copper and was known to some of the oldest civilizations on record. The history of native copper use dates to 9000 BC in the Middle East; a native copper pendant was found in northern Iraq that dates to 8700 BC. Evidence suggests that gold and
meteoric iron (but not smelted iron) were the only metals used by humans before copper. The history of copper metallurgy is thought to follow this sequence: first,
cold working of native copper, then
annealing,
smelting, and, finally, casting. The earliest archaeological support of
smelting (hot metallurgy) in Eurasia is found in the
Balkans and
Carpathian Mountains, as evidenced by findings of copper objects made by metal casting and smelting dated to around with the invention of copper
metallurgy. Production of cold worked non-smelted copper in the
Old Copper Complex in Michigan and Wisconsin is dated between 6500 and 3000 BC. A copper spearpoint found in Wisconsin has been dated to 6500 BC. Indigenous peoples of North America around the
Great Lakes may have also been mining copper during this time, making it one of the oldest known examples of
copper extraction in the world. There is evidence from prehistoric lead pollution from lakes in Michigan that people in the region began mining copper . The earliest evidence of
lost-wax casting copper comes from an amulet found in
Mehrgarh, Pakistan, and is dated to 4000 BC.
Investment casting was invented in 4500–4000 BC in Southeast Asia
Carbon dating has established mining at
Alderley Edge in
Cheshire, UK, at 2280 to 1890 BC. 's copper axe from the
Chalcolithic Era
Ötzi the Iceman, a male dated from 3300 to 3200 BC, was found with an axe with a copper head 99.7% pure; high levels of
arsenic in his hair suggest an involvement in copper smelting. Experience with copper has assisted the development of other metals; in particular, copper smelting likely led to the discovery of
iron smelting. Alloying copper with tin to make bronze was first practiced about 4000 years after the discovery of copper smelting, and about 2000 years after "natural bronze" had come into general use. Bronze artifacts from the
Vinča culture date to 4500 BC.
Sumerian and
Egyptian artifacts of copper and bronze alloys date to 3000 BC.
Egyptian blue, or cuprorivaite (calcium copper silicate), is a synthetic pigment that contains copper and started being used in
ancient Egypt around 3250 BC. The manufacturing process of Egyptian blue was known to the Romans, but by the fourth century AD the pigment fell out of use and the secret to its manufacturing process became lost. The Roman
Vitruvius said in the first century BC that the blue pigment was made from copper minerals or bronze, lime, and a
flux like
natron, and this basic recipe has been confirmed in modern times. The
Bronze Age began in Southeastern Europe around 3700–3300 BC, in Northwestern Europe about 2500 BC. It ended with the beginning of the Iron Age, 2000–1000 BC in the Near East, and 600 BC in Northern Europe. The transition between the
Neolithic period and the Bronze Age was formerly termed the
Chalcolithic period (copper-stone), when copper tools were used with stone tools. The term has gradually fallen out of favor because in some parts of the world, the Chalcolithic and Neolithic are coterminous at both ends. Brass, an alloy of copper and zinc, is of much more recent origin. It was known to the Greeks, but became a significant supplement to bronze during the Roman Empire. Copper was the most extensively used metal among natives of North America, with evidence for use going back 7000 years. Native copper is known to have been extracted from sites on
Isle Royale with primitive stone tools between 800 and 1600 AD. Copper, probably from pure nuggets found in the
Great Lakes area, was worked by repeated hammering and annealing in the North American city of
Cahokia (near modern-day Missouri) around 1000–1300 AD. There are several exquisite copper plates, known as the
Mississippian copper plates, that have been found in North America in the area around Cahokia, dating from this time period (1000–1300 AD). Peru has been considered the origin for early copper
metallurgy in pre-Columbian America, but the copper mask from Argentina suggests that the
Cajón del Maipo of the southern Andes was another important center for early copper workings in South America. In Sub-Saharan Africa, throughout the period from the first mines around 2000 BC in
Agades until the early 1800s, copper was viewed as more precious and prestigious than either gold or silver. Copper was widely traded in Africa and fulfilled a number of religious, political, and social functions. By contrast, local deposit of gold were ignored until contact with Portuguese and Arab traders. The cultural role of copper has been important, particularly in currency. Romans in the 6th through 3rd centuries BC used copper lumps as money. At first, the copper itself was valued, but gradually the shape and look of the copper became more important.
Julius Caesar had his own coins made from brass, while
Octavianus Augustus Caesar's coins were made from Cu-Pb-Sn alloys. With an estimated annual output of around 15,000 t,
Roman copper mining and smelting activities reached a scale unsurpassed until the time of the
Industrial Revolution; the
provinces most intensely mined were those of
Hispania, Cyprus and in Central Europe. The gates of the
Temple of Jerusalem used
Corinthian bronze, a copper, silver, and gold alloy treated with
depletion gilding, which successively removes oxidized copper to create a gold surface coat. The process was most prevalent in
Alexandria, where alchemy, inspired by the chemical treatment resulting in gold appearance, is thought to have begun.
Modern from Norway made from Swedish copper The
Great Copper Mountain was a mine in
Falun, Sweden, that operated from the 10th century to 1992. It satisfied two-thirds of Europe's copper consumption in the 17th century and helped fund many of Sweden's wars during that time. It was referred to as the nation's treasury; Sweden had a
copper backed currency. of the city of
Vyborg at the turn of the 17th and 18th centuries. The year 1709 carved on the printing plate. Copper is used in roofing, The
Norddeutsche Affinerie in Hamburg was the first modern
electroplating plant, starting its production in 1876. During the rise in demand for copper for the Age of Electricity, from the 1880s until the Great Depression of the 1930s, the United States produced one third to half the world's newly mined copper. Major districts included the Keweenaw district of northern Michigan, primarily native copper deposits, which was eclipsed by the vast sulphide deposits of
Butte, Montana, in the late 1880s, which itself was eclipsed by porphyry deposits of the Southwest United States, especially at
Bingham Canyon, Utah, and
Morenci, Arizona. Introduction of open pit steam shovel mining and innovations in smelting, refining, flotation concentration and other processing steps led to mass production. Early in the twentieth century,
Arizona ranked first, followed by
Montana, then
Utah and
Michigan.
Flash smelting was developed by
Outokumpu in Finland and first applied at
Harjavalta in 1949; the energy-efficient process accounts for 50% of the world's primary copper production. The
Intergovernmental Council of Copper Exporting Countries, formed in 1967 by Chile, Peru, Zaire, and Zambia, operated in the copper market as
OPEC does in oil, though it never achieved the same influence, particularly because the second-largest producer, the United States, was never a member; it was dissolved in 1988. In 2008, China became the world's largest importer of copper. ==Applications==