As cubes, dodecahedra, and as tetrahexahedra; rarely as octahedra and complex combinations. Commonly flattened on {111}, elongated along [001]. Also as irregular distortions, in twisted, wirelike shapes; filiform, arborescent, massive
Native copper is an uncombined form of copper that occurs as a natural mineral. Copper is one of the few metallicelements to occur in native form, although it most commonly occurs in oxidized states and mixed with other elements. Native copper was an important ore of copper in historic times and was used by pre-historic peoples.
The mines of the Keweenaw native copper deposits of Upper Michigan were major copper producers in the 19th and early 20th centuries, and are the largest deposits of native copper in the world.[6] Native Americans mined copper on a small scale at this and many other locations,[7] and evidence exists of copper trading routes throughout North America among native peoples, proven by isotopic analysis. The first commercial mines in the Keweenaw Peninsula (which is nicknamed the "Copper Country" and "Copper Island") opened in the 1840s. Isle Royale in western Lake Superior was also a site of many tons of native copper. Some of it was extracted by native peoples, but only one of several commercial attempts at mining turned a profit there.[6] An archived record of native copper originally found up river from Lake Superior, on the west branch of the Ontonagon River, via being dragged by a glacier is seen in the Ontonagon Boulder now in the possession of the Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution.
^Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (2005). "Copper"(PDF). Handbook of Mineralogy. Mineral Data Publishing. Retrieved 4 July 2022.
Thurner, Arthur W. Strangers and Sojourners - A History of Michigan's Keweenaw Peninsula (Detroit, Michigan, U.S.A.: Wayne State University Press, 1994) ISBN0-8143-2396-0.B
