Copper (Native)
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY-SA 4.0)
Mineral NameCopper (Native)
Chemical FormulaCu
Mohs Hardness2.5
Crystal Systemcubic
Lustermetallic
Streak Colorcopper red
Cleavagenone
Fracturehackly
Specific Gravity8.9
Colorscopper-red, brown, green
Transparencyopaque
Type LocalityLake Superior, Keweenaw County, Michigan, USA
Mineral GroupNative Elements
Useselectrical conductor, coinage, plumbing, alloys, collector
Associated Mineralscalcite, epidote, prehnite, silver, chalcocite, cuprite, zeolites
Rarityuncommon
Description
This specimen displays a complex, dendritic to crystalline aggregate of native copper, exhibiting a characteristic reddish-brown color with some areas showing a slight green tarnish. The intricate network of intergrown crystals creates a visually striking, open structure.
Geological Context
Native copper typically forms in the amygdaloidal cavities and fissures of basaltic lava flows, often associated with hydrothermal alteration. The Michigan deposits are famous for their large masses found in Precambrian flood basalts.
