Cuprite

Cuprite is a supergene copper oxide mineral found in the oxidized zone of copper deposits. It is a minor ore of copper.

Cuprite with Chrysocolla

Physical Properties of Cuprite
Chemical Classification	oxide
Color	various shades of red, sometimes nearly black
Streak	brownish red
Luster	submetallic to adamantine
Diaphaneity	subtranslucent
Cleavage	none
Mohs Hardness	3.5 to 4
Specific Gravity	5.8 to 6.1
Diagnostic Properties	color, streak, luster
Chemical Composition	copper oxide, Cu2O
Crystal System	isometric
Uses	ore of copper

Sources: Geology.com