Copper - Itauz Mine, Kazakhstan - 63 mm x 10 mm. Major crystal size: 8.5 mm wide - Mass: About 13 g.
Mineral: Copper
Locality: Itauz Mine, Dzhezkazgan, Karaganda Region, Kazakhstan
Dimensions: 63 mm x 10 mm. Major crystal size: 8.5 mm wide - Mass: About 13 g.

Description: Here you can see the black patina made of (probably) tenorite (CuO), and the spinel twin.