Chalcopyrite
Mineral CuFeS2
Also called Copper pyrites
About it
Brassier and softer than pyrite (a knife scratches it), with a greenish black streak; the commonest copper ore. Most 'peacock ore' sold is chalcopyrite tarnished with acid. Fine crystals come from Cornwall and China.
- Type
- Mineral
- Group
- Sulfide, chalcopyrite group
- Formula
- CuFeS2
- Hardness (Mohs)
- 3.5–4
- Specific gravity
- 4.1–4.3
- Streak
- greenish black
- Lustre
- metallic
- Crystal system
- Tetragonal
- Colours
- brass yellow, iridescent blue, purple, or red tarnish
- Transparency
- opaque
- Cleavage and fracture
- poor; uneven fracture, brittle
Typical values: real specimens vary. For more, see mindat.org.