Copper sulfide
Copper sulfides (British English spelling: copper sulphide) describe a family of chemical compounds and minerals with the formula CuxSy. Both minerals and synthetic materials comprise these compounds. Some copper sulfides are economically important ores.
Prominent copper sulfide minerals include Cu2S (chalcocite) and CuS (covellite). In the mining industry, the minerals bornite or chalcopyrite, which consist of mixed copper-iron sulfides, are often referred to as "copper sulfides". In chemistry, a "binary copper sulfide" is any binary chemical compound of the elements copper and sulfur. Whatever their source, copper sulfides vary widely in composition with 0.5 ≤ Cu/S ≤ 2, including numerous non-stoichiometric compounds.
Known copper sulfides
The naturally occurring mineral binary compounds of copper and sulfur are listed below. Investigations of "blaubleibender covellite" (blue remaining covellite) formed by natural leaching of covellite (CuS) indicate that there are other metastable Cu-S phases still to be fully characterised.