Copper is a ductile metal, as its extensive employment in today’s electrical wires testifies. Copper was used as an interesting sort of stone before its smelting properties were realized. 5700 BCE, early metal workers at Çatalhöyük in southern Anatolia hammered cold copper in native form to make rough tools or other objects. A millennium later, workers in Mesopotamia had advanced copper working by adding a new element, whereby creating a new age of technology.
To get a purer grade of copper, it must be extracted from ore via smelting: heating the ore under the right conditions.
Pure copper is not easily cast into closed molds. Impurities in the copper produced by prehistoric metalworkers gave a more satisfactory result. Arsenic was a common, casual copper pollutant.
Purposefully mixing 10% tin with copper hardens the metal while still affording malleability. Copper-tin alloy – bronze – makes for a fine, tough metal, able to hold a hard, sharp, cutting edge, as well as being easily cast.
Bronze metallurgy developed as an outcome of trade and cultural exchange in the Near East. The consumption and know-how for producing bronze spread with trade.
The Bronze Age was when early civilizations arose – in the Near East, most notably Mesopotamia and ancient Egypt, and in East Asia, beginning with China, followed by Japan.
In the large, it is more meaningful to trace the onset of civil society in the Bronze Age than it is to adhere to a strict definition of a society arriving at the Age via bronze working. For instance, historians disagree about the dates of the Bronze Age in China, beginning with the replacement of stone tools by those of bronze, and ending with the arrival of iron-smelting technology.
Technology aside, human migrations continued, prompting major cultural changes in Europe and Asia. By 3000 bce, the Neolithic farming cultures in Europe had been largely replaced by a Bronze Age culture from western Russia, bringing new concepts about family, property, and personhood. From 2000 BCE, a new class of artisans had arisen in the Urals. They produced sophisticated weapons, bred and trained horses, and built chariots. These innovations quickly spread throughout Europe and into Asia.