melakonite

Melakonite is a rare copper oxide mineral with the chemical formula CuO. It is the black oxide of copper. Melakonite is a member of the cuprite group, which includes cuprite (Cu2O) and tenorite (CuO). It is typically found in oxidized zones of copper deposits, often associated with other copper minerals like malachite, azurite, and cuprite. The mineral crystallizes in the monoclinic crystal system and commonly appears as small, black, earthy, or powdery masses. It can also form granular or prismatic crystals. Melakonite has a Mohs hardness of 3 to 3.5 and a specific gravity of 6.45. It is insoluble in water but soluble in acids. Its name is derived from the Greek word "melas," meaning black, referring to its characteristic color. While not a significant ore of copper due to its rarity, melakonite can be found in various locations worldwide, including the United States (Arizona, California), Chile, and France. It is often of mineralogical interest due to its occurrence and association with other copper minerals in secondary enrichment environments.