Alexandrite
ChrysoberylJewelryWiki Editorial·4 sources·Reviewed 2026-08-04
The colour-change variety of chrysoberyl — green in daylight, red under incandescent light. At 8½ it is the hardest of the June birthstones by a wide margin; pearl, its co-birthstone, is among the softest gems in use.
Properties
| Property | Value | Authority |
|---|---|---|
| Mohs hardness | 8½ [1] | — |
| Chemical formula | BeAl2O4 Read from the species entry, Chrysoberyl. A variety shares its species’ formula — unlike hardness or density, which vary with composition and are not inherited here. [4] | — |
| Crystal system | Orthorhombic [3] Read from the species article, Chrysoberyl. | — |
| Birthstone month | June — one of three official June stones, with pearl and moonstone. [2] | — |
Sources
- 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)
- Handbook of Mineralogy — Mineral Data Publishing / Mineralogical Society of America (Handbook of Mineralogy, Mineral Data Publishing)