Chemical Formula: CaSO4.2H2O and Cu2O

Chemical Name: Calcium Sulphate and Copper Oxide

Mineral Class: Sulphate and Oxide

Mineral Notes: Cuprite is an important ore of copper. It usually occurs in the upper parts of copper deposits and is usually associated with native copper. Cuprite's dark crystals often show internal reflections of deep red inside the almost black crystals.

Description: Gypsum crystals of almost optical quality sit upon a matrix of granular almost black Cuprite. Some of the Gypsum crystals show very unusual forms of twinning and one crystal has outstanding form. Underneath the specimen, amongst the earthy Cuprite are streaks of green Malachite.

 Location: Copper King Mine, Yavapai Co., Arizona, USA.