Chalcopyrite vs Pyrite
| Property | Chalcopyrite | Pyrite |
|---|---|---|
| Formula | CuFeS2 | FeS2 |
| Crystal System | Tetragonal | Cubic (Isometric) |
| Mineral Class | 02 Sulfides and Sulfosalts | 02 Sulfides and Sulfosalts |
| Mohs Hardness | 3.5-4.0 | 6.0-6.5 |
| Color | Brass-yellow, often with iridescent tarnish | Pale brass-yellow |
| Luster | Metallic | Metallic |
| Streak | Greenish-black | Greenish-black to brownish-black |
| Transparency | Opaque | Opaque |
| Cleavage | Poor | Indistinct |
| Fracture | Conchoidal to uneven | Conchoidal to uneven |
Key Differences
- ◆ Chalcopyrite is deeper, more brassy-yellow than pyrite's paler brass-yellow color.
- ◆ Pyrite is harder (6–6.5) than chalcopyrite (3.5–4); chalcopyrite can be scratched with a knife.
- ◆ Chalcopyrite has a greenish-black streak; pyrite has a greenish-black to brownish-black streak.
- ◆ Chalcopyrite is the most important copper ore (CuFeS2); pyrite is an iron sulfide (FeS2).
- ◆ Chalcopyrite often shows iridescent tarnish (peacock ore); pyrite typically stays bright.