Formula:  Cu₂O
System: Isometric
Colour: Dark red to cochineal
Lustre: Adamantine, Sub-Metallic, Earthy
Hardness: 3½ - 4 

Its dark crystals with red internal reflections are in the isometric system hexoctahedral class, appearing as cubic, octahedral, or dodecahedral forms, or in combinations. Penetration twins frequently occur. 
From Tsumeb Mine, Tsumeb, Namibia