Sapphire
CorundumJewelryWiki Editorial·4 sources·Reviewed 2026-07-31
The same mineral species as ruby. Every corundum that is not red is called sapphire — the difference is colour, not durability.
Properties
| Property | Value | Authority |
|---|---|---|
| Mohs hardness | 9 [1] | — |
| Toughness | Excellent. [1] | — |
| Specific gravity | 3.95–4.03 [2] | — |
| Crystal system | Trigonal [4] Read from the species article, Corundum. | — |
| Suitability for daily wear | Excellent. The most durable common alternative to diamond for an engagement ring. [1] | — |
| Birthstone month | September [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)