RocksdayLazulite vs Lazurite
How to tell them apart
An azure-blue phosphate forming sharp, wedge-shaped crystals.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
The deep blue mineral that gives lapis lazuli its color. Distinct crystals are rare.
Photo: Didier Descouens, CC BY-SA 4.0
Quick tests
- Streak (rub on unglazed porcelain): Lazulite leaves a white streak; Lazurite leaves bright blue.
Key differences
- Lazurite is massive and found in marble.
Side by side
| Property | Lazulite | Lazurite |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 5.5–6 | 5–5.5 |
| Luster | Vitreous | Dull to vitreous |
| Streak | White | Bright blue |
| Colors | Blue | Blue |
| Crystal system | Monoclinic | Cubic |
| Specific gravity | 3–3.1 | 2.38–2.45 |
| Formula | MgAl₂(PO₄)₂(OH)₂ | (Na,Ca)₈(AlSiO₄)₆(SO₄,S,Cl)₂ |
| Found in | Rapid Creek, Yukon; Graves Mountain, Georgia | Sar-e-Sang, Afghanistan; Lake Baikal, Russia |
Properties that are the same for both are grayed out.
How to identify lazulite
- Deep azure blue pyramidal crystals.
- Hardness about 6.
- Often in quartz veins.
Crystal system: Monoclinic
Full Lazulite guide →How to identify lazurite
- Intense ultramarine blue.
- Usually massive grains in white marble.
- Bright blue streak.
Crystal system: Cubic
Full Lazurite guide →More comparisons
Could you tell them apart from a blurry close-up?
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