Chalcopyrite

Chalcopyrite
General
CategorySulfide mineral
FormulaCuFeS2
IMA symbolCcp
Strunz classification2.CB.10a
Crystal systemTetragonal
Crystal classScalenohedral (42m)
H-M symbol: (4 2m)
Space groupI42d
Unit cella = 5.289 Å,
c = 10.423 Å; Z = 4
Identification
Formula mass183.54 g/mol
ColorBrass yellow, may have iridescent purplish tarnish.
Crystal habitPredominantly the disphenoid and resembles a tetrahedron, commonly massive, and sometimes botryoidal.
TwinningPenetration twins
CleavageIndistinct on {011}
FractureIrregular to uneven
TenacityBrittle
Mohs scale hardness3.5–4
LusterMetallic
StreakGreenish black
DiaphaneityOpaque
Specific gravity4.1–4.3
Optical propertiesOpaque
SolubilitySoluble in HNO3
Other characteristicsmagnetic on heating
References

Chalcopyrite (/ˌkælkəˈpˌrt, -k-/ KAL-kə-PY-ryte, -koh-) 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 scale. Its streak is diagnostic as green-tinged black.

On exposure to air, chalcopyrite tarnishes to a variety of oxides, hydroxides, and sulfates. Associated copper minerals include the sulfides bornite (Cu5FeS4), chalcocite (Cu2S), covellite (CuS), digenite (Cu9S5); carbonates such as malachite and azurite, and rarely oxides such as cuprite (Cu2O). It is rarely found in association with native copper. Chalcopyrite is a conductor of electricity.

Copper can be extracted from chalcopyrite ore using various methods. The two predominant methods are pyrometallurgy and hydrometallurgy, the former being the most commercially viable.