Moldavite
TektiteJewelryWiki Editorial·1 source·Reviewed 2026-08-04
Bottle-green natural glass thrown out by a meteorite impact about 15 million years ago, found only around the Moldau river in the Czech Republic. It is heavily marketed and heavily faked — green bottle glass is cheap and the real thing is not — and IGS rates its wearability POOR.
Properties
| Property | Value | Authority |
|---|---|---|
| Mohs hardness | 5 [1] | — |
| Specific gravity | 2.27–3.40 [1] | — |
| Chemical formula | No fixed formula. IGS gives SiO2 plus various oxides — like obsidian, it is a glass and so a composition range rather than a compound. [1] | — |
| Crystal system | Amorphous [1] | — |
| Suitability for daily wear | POOR, in IGS’s own rating, and heat-sensitive. At Mohs 5 it belongs in a pendant, not a ring. [1] | — |
| Care cautions | IGS marks moldavite heat-sensitive: keep it away from a jeweller’s torch and from steam and ultrasonic cleaners. Given how widely it is imitated, buy from a seller who will state the origin in writing. [1] | — |
Sources
- International Gem Society — gemstone articles — International Gem Society (IGS, gemstone information articles (gemsociety.org))