RocksdayLazulite vs Sapphire
How to tell them apart
An azure-blue phosphate forming sharp, wedge-shaped crystals.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Gem corundum of any color except red. Blue sapphire gets its color from iron and titanium.
Photo: James St. John, CC BY 2.0
Quick tests
- Hardness: Sapphire is clearly harder: Mohs 9 versus 5.5–6.
- Heft: Sapphire feels noticeably heavier for its size (specific gravity 3.95–4.03 vs 3–3.1).
Key differences
- Sapphire is much harder.
Side by side
| Property | Lazulite | Sapphire |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 5.5–6 | 9 |
| Luster | Vitreous | Adamantine to vitreous |
| Streak | White | White |
| Colors | Blue | Blue, Yellow, Pink, Orange |
| Crystal system | Monoclinic | Trigonal |
| Specific gravity | 3–3.1 | 3.95–4.03 |
| Formula | MgAl₂(PO₄)₂(OH)₂ | Al₂O₃ |
| Found in | Rapid Creek, Yukon; Graves Mountain, Georgia | Sri Lanka; Madagascar |
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 sapphire
- Hardness 9 — only diamond scratches it.
- Barrel or tapered six-sided crystals.
- Heavy for its size.
Crystal system: Trigonal
Full Sapphire guide →More comparisons
Could you tell them apart from a blurry close-up?
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