Copper (Native Element) 

Cu

Hardness: 2.5 - 3.5
Specific Gravity: 8.7 - 8.9

Characteristics: Color copper-red; dense, ductile, and malleable; tetrahexahedral or octohedral crystals; dissolves in nitric acid; cubic closest-pack structure similar to gold and platinum.

Found in basalts; hydrothermal deposits.

Copper is used in electrical engineering; roofing and building construction; in alloys such as bronze; in the fine arts.

(Primary text: Perkins, D. 2002. Mineralogy. Prentice Hall.)