Topaz
JewelryWiki Editorial·4 sources·Reviewed 2026-07-31
Hard enough on paper, but perfect cleavage and light sensitivity work against it.
Properties
| Property | Value | Authority |
|---|---|---|
| Mohs hardness | 8 [2] | — |
| Stability | Can fade or change colour from prolonged exposure to light — GIA lists topaz alongside tanzanite and kunzite. [1] | — |
| Refractive index | 1.609–1.643 [2] | — |
| Specific gravity | 3.49–3.57 [2] | — |
| Crystal system | Orthorhombic [4] | — |
| Birthstone month | November — shares November with citrine. [3] | — |
Sources
- GIA — More than the Mohs Scale: Understanding Gem Durability — Gemological Institute of America (GIA 4Cs, "More than the Mohs Scale" (14 March 2016))
- International Gem Society — reference charts (Mohs hardness, specific gravity, refractive index) — International Gem Society (IGS reference charts)
- Jewelers of America — Birthstones — Jewelers of America (Jewelers of America, Birthstones)
- Wikipedia — mineral article infoboxes (crystal system) — Wikipedia contributors (Wikipedia mineral infoboxes)