Comparison · Minerals
Bornite vs Chalcocite
Bornite and Chalcocite are easy to confuse because both are minerals. Both sit near Mohs 3–3.25, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Bornite and Chalcocite
- Both sit near Mohs 3–3.25, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Streak color differs: Bornite leaves a grayish black streak on unglazed porcelain, Chalcocite leaves dark gray to black.
- Both look metallic, so compare color, tarnish and weight rather than shine.
- Chalcocite feels noticeably heavier for its size (specific gravity 5.5–5.8 versus 4.9–5.3 for Bornite).
- Well-formed crystals give it away: Bornite is Orthorhombic (pseudocubic), Chalcocite is Monoclinic.
Bornite vs Chalcocite properties
| Property | Bornite | Chalcocite |
|---|---|---|
| Type | Minerals | Minerals |
| Mohs hardness | 3–3.25 | 2.5–3 |
| Luster | Metallic | Metallic |
| Streak | Grayish black | Dark gray to black |
| Transparency | Opaque | Opaque |
| Specific gravity | 4.9–5.3 | 5.5–5.8 |
| Crystal system | Orthorhombic (pseudocubic) | Monoclinic |
| Common colors | Copper red to brownish bronze (fresh), Iridescent purple-blue tarnish (peacock ore) | Blackish lead-gray, Black |
| Rarity | common | common |
| Typical specimen value | $2–$150+ | $2–$150+ |
Which is more valuable?
Typical specimens of Bornite and Chalcocite trade in a similar range, around $20.
About Bornite
Bornite is a copper iron sulfide mineral with the formula Cu5FeS4, prized by mineral collectors for the flashy iridescent tarnish that earns it the nickname peacock ore. Freshly broken surfaces show a coppery, brownish-bronze metallic color that oxidizes within hours to purple, blue, and pink iridescence. It is an important, though secondary, copper ore mineral found in many sulfide deposits worldwide.
About Chalcocite
Chalcocite is copper sulfide, Cu2S, and one of the richest copper ore minerals by weight, containing nearly 80 percent copper. It crystallizes in the orthorhombic system but commonly appears in fine-grained, massive, dark gray to black form rather than as distinct crystals. Unlike most sulfides, it is sectile, meaning a knife blade can shave off a curl rather than shatter it.
Bornite vs Chalcocite FAQ
Is Bornite the same as Chalcocite?
No. Both are minerals, but they are distinct species with different hardness, streak or luster. Both sit near Mohs 3–3.25, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Bornite from Chalcocite?
Both sit near Mohs 3–3.25, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Streak color differs: Bornite leaves a grayish black streak on unglazed porcelain, Chalcocite leaves dark gray to black. Both look metallic, so compare color, tarnish and weight rather than shine.
Which is harder, Bornite or Chalcocite?
They are about equally hard, both near Mohs 3–3.25.
Which is more valuable, Bornite or Chalcocite?
Typical specimens of Bornite and Chalcocite trade in a similar range, around $20.
