RocksdayTopaz vs Zircon
How to tell them apart
A fluorine-bearing silicate and the Mohs reference for hardness 8. Crystals are often clear with sharp, diamond-shaped cross-sections.
Photo: Parent Géry, CC BY-SA 3.0
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
- Heft: Zircon feels noticeably heavier for its size (specific gravity 4.6–4.7 vs 3.49–3.57).
Key differences
- Topaz is lighter and less brilliant.
Side by side
| Property | Topaz | Zircon |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 8 | 7.5 |
| Luster | Vitreous | Adamantine |
| Streak | White | White |
| Colors | Clear, Yellow, Orange, Blue, Pink | Brown, Red, Yellow, Blue, Clear |
| Crystal system | Orthorhombic | Tetragonal |
| Specific gravity | 3.49–3.57 | 4.6–4.7 |
| Formula | Al₂SiO₄(F,OH)₂ | ZrSiO₄ |
| Found in | Ouro Preto, Brazil; Topaz Mountain, Utah | Sri Lanka; Ratanakiri, Cambodia |
Properties that are the same for both are grayed out.
How to identify topaz
- Harder than quartz (8).
- One perfect cleavage across the crystal — flat, mirror-like breaks.
- Feels heavier than quartz of the same size.
- Prisms with lengthwise striations.
Crystal system: Orthorhombic
Full Topaz 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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