Selenite
GypsumJewelryWiki Editorial·2 sources·Reviewed 2026-08-04
The softest material sold in the gem trade — Mohs 1½–2, which means a fingernail will scratch it. It is carved into lamps, spheres and wands rather than jewellery for exactly that reason, and it dissolves slowly in water, so it should never be washed.
Properties
| Property | Value | Authority |
|---|---|---|
| Mohs hardness | 1½–2 [1] | — |
| Specific gravity | 2.317 [1] | — |
| Chemical formula | CaSO4 · 2H2O Read from the species entry, Gypsum. Selenite is its clear, crystalline variety. [1] | — |
| Crystal system | Monoclinic [1] | — |
| Suitability for daily wear | Unsuitable for jewellery worn on the hand or wrist. At Mohs 1½–2 a fingernail scratches it and it is the softest material commonly offered as a gem. [2] | — |
| Care cautions | Do NOT wash it. Gypsum is slightly water-soluble, so water dulls the surface permanently. Dust it dry with a soft brush. [2] | — |
Sources
- Handbook of Mineralogy — Mineral Data Publishing / Mineralogical Society of America (Handbook of Mineralogy, Mineral Data Publishing)
- International Gem Society — gemstone articles — International Gem Society (IGS, gemstone information articles (gemsociety.org))