Copper, Native

a mineral of the class of native elements. The mineral contains Fe, Ag, Au, As, and other elements as admixtures or as solid solutions with Cu. Its crystal structure reveals a face-centered cubic lattice. Native copper occurs in plates and as porous and solid masses; crystals, complex twins, and dendrites are also found. The surface of native copper is often covered with films of green and of blue copper carbonate, copper phosphates, and the like. The mineral’s color, luster, malleability, and other properties are identical to those of metallic copper.

Native copper is usually formed in the oxidation zone of certain copper sulfide deposits in association with cuprite (Cu₂O), malachite, azurite, and other minerals. Single masses of native copper can weigh as much as 400 tons. Large commercial deposits of native copper in combination with calcite, native silver, and other minerals are formed upon the action of hydrothermal solutions, volcanic vapors, and gases enriched with volatile compounds of copper on igneous rocks (diabase, melaphyre); the deposit near Lake Superior (USA) is one such example. Native copper also occurs in sedimentary rocks, primarily cupriferous sandstone and shale.

The major native copper deposits include the Tura mines (Urals) and the Dzhezkazgan deposit (Kazakh SSR) in the USSR and deposits on the Keeweenaw peninsula (Michigan) and in Arizona and Utah in the United States. Native copper is used as an ore for the extraction of copper.