RocksdayAzurite vs Cavansite
How to tell them apart
An intensely deep blue copper carbonate. Over time it slowly converts to green malachite, and the two are often found together.
Photo: Ivar Leidus, CC BY-SA 4.0
A vivid blue calcium vanadium silicate forming tiny radiating rosettes on white zeolites.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Quick tests
- Acid (vinegar or dilute HCl): Azurite fizzes; Cavansite doesn't.
- Heft: Azurite feels noticeably heavier for its size (specific gravity 3.77–3.78 vs 2.21–2.31).
Key differences
- Azurite is deeper blue, heavier and fizzes in acid.
Side by side
| Property | Azurite | Cavansite |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 3.5–4 | 3–4 |
| Luster | Vitreous | Vitreous to pearly |
| Streak | Light blue | Light blue |
| Colors | Blue | Blue |
| Crystal system | Monoclinic | Orthorhombic |
| Specific gravity | 3.77–3.78 | 2.21–2.31 |
| Formula | Cu₃(CO₃)₂(OH)₂ | Ca(VO)Si₄O₁₀·4H₂O |
| Found in | Bisbee, Arizona; Tsumeb, Namibia | Wagholi, Pune, India; Owyhee Dam, Oregon |
Properties that are the same for both are grayed out.
How to identify azurite
- Deep 'azure' blue, often with green malachite.
- Fizzes in acid.
- Soft — a knife scratches it.
- Light blue streak.
Crystal system: Monoclinic
Full Azurite guide →How to identify cavansite
- Electric-blue radiating balls, usually under 1 cm.
- Sits on white stilbite or heulandite.
- Soft.
Crystal system: Orthorhombic
Full Cavansite guide →More comparisons
Could you tell them apart from a blurry close-up?
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