RocksdayDioptase vs Uvarovite
How to tell them apart
An intensely emerald-green copper silicate that forms glittering short crystals.
Photo: Géry PARENT, CC BY-SA 4.0
An emerald-green chromium garnet that usually forms glittering crusts of tiny crystals on chromite.
Photo: Géry PARENT, CC BY-SA 4.0
Quick tests
- Scratch glass: Uvarovite scratches glass (Mohs 6.5–7); Dioptase can't (Mohs 5).
- Streak (rub on unglazed porcelain): Dioptase leaves a green streak; Uvarovite leaves white.
Key differences
- Uvarovite crystals are tiny, round and harder.
- Dioptase crystals are larger, elongated and softer.
Side by side
| Property | Dioptase | Uvarovite |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 5 | 6.5–7 |
| Luster | Vitreous | Vitreous |
| Streak | Green | White |
| Colors | Green | Green |
| Crystal system | Trigonal | Cubic |
| Specific gravity | 3.28–3.35 | 3.4–3.8 |
| Formula | CuSiO₂(OH)₂ | Ca₃Cr₂(SiO₄)₃ |
| Found in | Tsumeb, Namibia; Altyn-Tyube, Kazakhstan | Saranovskoye, Ural Mountains, Russia; Outokumpu, Finland |
Properties that are the same for both are grayed out.
How to identify dioptase
- Vivid emerald green, often a sparkling crystal crust.
- Short six-sided crystals with rhombic tips.
- Hardness 5 — a knife scratches it.
Crystal system: Trigonal
Full Dioptase guide →How to identify uvarovite
- Druzy crust of tiny, sparkling emerald-green crystals.
- Crystals rarely larger than a few millimeters.
- Often on black chromite.
Crystal system: Cubic
Full Uvarovite guide →More comparisons
Could you tell them apart from a blurry close-up?
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