Chalcopyrite, Copper pyrites, or yellow copperore, is the most widely occurring copper mineral and one of the most important ore sources of that metal, also containing iron, and sulphur. It occurs massive and in tetragonal crystals of a bright brass yellow colour as an original constituent of igneous rocks, in pegmatic dikes, and in contact with metamorphic deposits. May carry gold or silver and become an ore of those metals. It has the formulae CuFeS2 and a relative hardness of 4. Research Chalcopyrite