Copper (II) oxide is used for blue-green pigmentation in ceramics. As a naturally occurring compound produced from mining, it is also used as a precursor to other cooper applications, including fungicide and wood preservatives.
Copper (II) oxide, is the inorganic compound with the formula CuO. A black solid, it is one of the two stable oxides of copper, the other being Cu2O or copper(I) oxide (cuprous oxide). As a mineral, it is known as tenorite.