RocksdayMoissanite vs Zircon
How to tell them apart
Natural silicon carbide — extremely rare in nature. Moissanite sold in jewelry is lab-made.
Photo: Andrew Silver, Public domain
A heavy, brilliant silicate found as small crystals in many rocks. Natural zircon is not the same as synthetic cubic zirconia.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Quick tests
- Hardness: Moissanite is clearly harder: Mohs 9–9.5 versus 7.5.
- Streak (rub on unglazed porcelain): Moissanite leaves a greenish gray streak; Zircon leaves white.
- Heft: Zircon feels noticeably heavier for its size (specific gravity 4.6–4.7 vs 3.21–3.22).
- Luster: Moissanite looks metallic; Zircon doesn't.
Key differences
- Zircon is softer and heavier.
Side by side
| Property | Moissanite | Zircon |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 9–9.5 | 7.5 |
| Luster | Adamantine to metallic | Adamantine |
| Streak | Greenish gray | White |
| Colors | Clear, Green, Yellow | Brown, Red, Yellow, Blue, Clear |
| Crystal system | Hexagonal | Tetragonal |
| Specific gravity | 3.21–3.22 | 4.6–4.7 |
| Formula | SiC | ZrSiO₄ |
| Found in | Canyon Diablo meteorite, Arizona; Traces in kimberlite and meteorites | Sri Lanka; Ratanakiri, Cambodia |
Properties that are the same for both are grayed out.
How to identify moissanite
- Harder than everything except diamond.
- Very strong rainbow fire in cut stones.
- Facet edges look doubled.
Crystal system: Hexagonal
Full Moissanite guide →How to identify zircon
- Square prisms capped with pyramids.
- Very bright luster and heavy for its size.
- Facet edges look doubled through a cut stone.
Crystal system: Tetragonal
Full Zircon guide →More comparisons
Could you tell them apart from a blurry close-up?
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