COPPER
Copper is the only metallic element that has a
"reddish" color - it’s 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).