Ontonagon Co., Michigan, USA

Cu

Crystal System: cubic
Colour: copper-red; tarnishes to black or green in air
Lustre: metallic
Habitus: as cubic, dodecahedric, octahedral, or tetrahexahedral crystals. Filiform, herringbone, arborescent, wires, and massive.
Hardness: 2½ - 3
Fracture: hackly
Cleavage: none observed
Density: 8.93 g/cm³ 
Origin and geological occurrence: in the oxidation zone of Cu deposits; in basalts and sedimentary rocks.

www.mindat.org
Smorf link

Samples:

	1.6 Copper Massive aggregate, coated by green malachite. #native elements
	1.7 Copper Thin lamina of native copper, surficially tarnished. #native elements