RocksdayBournonite vs Galena
How to tell them apart
A lead copper antimony sulfide whose twinned crystals look like cogwheels.
Photo: CarlesMillan, CC BY-SA 4.0
Lead sulfide and the world's main lead ore. Bright silvery cubes that feel astonishingly heavy for their size.
Photo: Ivar Leidus, CC BY-SA 4.0
Quick tests
- Streak (rub on unglazed porcelain): Bournonite leaves a steel gray streak; Galena leaves lead gray.
Key differences
- Galena forms cubes and cleaves perfectly.
Side by side
| Property | Bournonite | Galena |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 2.5–3 | 2.5–2.75 |
| Luster | Metallic | Metallic |
| Streak | Steel gray | Lead gray |
| Colors | Gray, Black | Silver, Gray |
| Crystal system | Orthorhombic | Cubic |
| Specific gravity | 5.7–5.9 | 7.4–7.6 |
| Formula | PbCuSbS₃ | PbS |
| Found in | Cornwall, England; Hunan, China | Viburnum Trend, Missouri; Tri-State district, USA |
Properties that are the same for both are grayed out.
How to identify bournonite
- Steel-gray crystals twinned into gear-like shapes.
- Metallic and heavy.
- Soft — a knife scratches it.
Crystal system: Orthorhombic
Full Bournonite guide →How to identify galena
- Very heavy — noticeably heavier than any similar-sized rock.
- Bright silver-gray metallic, dulling over time.
- Breaks into perfect little cubes.
- Soft enough to scratch with a fingernail edge or coin.
Crystal system: Cubic
Full Galena guide →More comparisons
Could you tell them apart from a blurry close-up?
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