Chalcopyrite
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Chalcopyrite is a copper iron sulfide mineral and the most abundant copper ore mineral. It has the chemical formula CuFeS₂ and crystallizes in the tetragonal system. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mohs... Wikipedia
Chemical equation: CuFeS2
Cleavage: Indistinct on
Color: Brass yellow, may have iridescent purplish tarnish
Crystal habit: Predominantly the disphenoid and resembles a tetrahedron, commonly massive, and sometimes botryoidal
Crystal system: Tetragonal
Diaphaneity: Opaque
Fracture: Irregular to uneven