"To make flat tools, such as knives, the craftworkers carved their shape on a flat stone. Then they heated lumps of copper and tin together in a stone or pottery vessel, called a crucible, until they melted. The liquid was then poured in the stone mould.
Map: Diffusion of metallurgy in Europe and Asia Minor. The darkest areas are the oldest. is a time period characterized by the use of bronze, proto-writing, and other early features of urban civilization.
Ancient springs, screws and metal. Thousands of these things -- some measure as small as of an inch! -- were discovered by gold miners in the Ural Mountains of Russia in the Dug up from a depth of 3 to 40 feet in layers of earth.