Chalcopyrite is a copper iron sulfide mineral that crystallizes in the tetragonal system. It has chemical composition CuFeS2. It has a brassy to golden yellow color and hardness of 3.5 to 4 on the Mohs scale. Due to its color it is often confused with pyrite though this mineral has a cubic and not a tetragonal crystal system and chalcopyrite is more often massive and less brittle. Chalcopyrite is also a darker yellow in color.

Chalcopyrite is one of the most important copper ores. Chalcopyrite ore occurs in a variety of ore types, from huge masses as at Timmins, Ontario, to irregular veins and disseminations associated with granitic to dioritic intrusives as in the porphyry copper deposits of the American cordillera and the Andes.