Chalcopyrite
Chalcopyrite (/ˌkælkəˈpaɪˌraɪt, -koʊ-/ 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.
| Chalcopyrite | |
|---|---|
| General | |
| Category | Sulfide mineral |
| Formula (repeating unit) | CuFeS2 |
| IMA symbol | Ccp |
| Strunz classification | 2.CB.10a |
| Crystal system | Tetragonal |
| Crystal class | Scalenohedral (42m) H-M symbol: (4 2m) |
| Space group | I42d |
| Unit cell | a = 5.289 Å, c = 10.423 Å; Z = 4 |
| Identification | |
| Formula mass | 183.54 g/mol |
| Color | Brass yellow, may have iridescent purplish tarnish. |
| Crystal habit | Predominantly the disphenoid and resembles a tetrahedron, commonly massive, and sometimes botryoidal. |
| Twinning | Penetration twins |
| Cleavage | Indistinct on {011} |
| Fracture | Irregular to uneven |
| Tenacity | Brittle |
| Mohs scale hardness | 3.5–4 |
| Luster | Metallic |
| Streak | Greenish black |
| Diaphaneity | Opaque |
| Specific gravity | 4.1–4.3 |
| Optical properties | Opaque |
| Solubility | Soluble in HNO3 |
| Other characteristics | magnetic on heating |
| References | |
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.