Copper is the only metallic element that has a "reddish" color - itís actually a metallic orange color. All metallic elements, apart from gold & copper, are silvery-gray colored. Copper tends to form sharp-edged, irregular, twisted masses of moderately high density. It is moderately soft, but is extremely difficult to break. It has no cleavage, but has a distinctive hackly fracture. The largest occurrence of native copper on Earth is in northern Michigan's Keweenaw Peninsula. There, copper occurs in Mesoproterozoic-aged amygdaloidal flood basalts and conglomerates.
Copper (11.1 cm across): ~1050-1060 million year old copper mass from the upper Mesoproterozoic Portage Lake Volcanic Series of Michigan's Upper Peninsula, USA.
Native copper (~1.05-1.06 Ga) filling a fracture in the Nonesuch Shale (upper Mesoproterozoic, ~1.07-1.08 billion years) from the 2500 Level of the White Pine Mine, Upper Peninsula of Michigan, USA (Colorado School of Mines Geology Museum, Golden, Colorado, USA).
Copper on Mesozoic diabase from Adams County, southern Pennsylvania, USA. (public display, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA)
Copper - well-formed copper crystal embedded in irregular Cu mass.
Copper - large, 1.1 ton glacial boulder of oxidized native copper (~1050-1060 million year mineralization age) from near Houghton, Keweenaw Peninsula, Upper Peninsula of Michigan, USA (Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA).
Copper from Ajo, northwestern Pima County, southwestern Arizona, USA (CSM # 78.31, Colorado School of Mines Geology Museum, Golden, Colorado, USA).