RocksdayChalcopyrite vs Tetrahedrite
How to tell them apart
Copper iron sulfide and the world's most important copper ore. Brassy yellow, often tarnished to rainbow purples and blues.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
A steel-gray copper antimony sulfide named for its tetrahedral crystals; it often carries silver.
Photo: Ivar Leidus, CC BY-SA 4.0
Quick tests
- Streak (rub on unglazed porcelain): Chalcopyrite leaves a greenish black streak; Tetrahedrite leaves black to brown.
Key differences
- Chalcopyrite is brass-yellow.
Side by side
| Property | Chalcopyrite | Tetrahedrite |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 3.5–4 | 3.5–4 |
| Luster | Metallic | Metallic |
| Streak | Greenish black | Black to brown |
| Colors | Gold | Gray, Black |
| Crystal system | Tetragonal | Cubic |
| Specific gravity | 4.1–4.3 | 4.6–5.1 |
| Formula | CuFeS₂ | Cu₁₂Sb₄S₁₃ |
| Found in | Chile; Peru | Peru; Bolivia |
Properties that are the same for both are grayed out.
How to identify chalcopyrite
- Deeper, greener yellow than pyrite.
- Iridescent tarnish on older surfaces.
- A knife scratches it (pyrite resists).
- Greenish-black streak.
Crystal system: Tetragonal
Full Chalcopyrite guide →How to identify tetrahedrite
- Steel-gray tetrahedrons (four-sided pyramids).
- Metallic luster, no cleavage.
- Brownish-black streak.
Crystal system: Cubic
Full Tetrahedrite guide →More comparisons
Could you tell them apart from a blurry close-up?
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