Moonstone
FeldsparJewelryWiki Editorial·4 sources·Reviewed 2026-08-04
A feldspar showing adularescence — the floating blue sheen — caused by light scattering between internal layers.
Properties
| Property | Value | Authority |
|---|---|---|
| Refractive index | 1.518–1.526 [1] | — |
| Specific gravity | 2.56–2.59 [1] | — |
| Crystal system | Monoclinic [3] Read from the species article, Orthoclase. | — |
| Care cautions | NEVER use an ultrasonic cleaner — GIA names this among the gems susceptible to heat and temperature change, which should be kept out of an ultrasonic REGARDLESS of whether they have been treated. Use warm soapy water or a solution formulated for delicate gems. [4] | — |
| Birthstone month | June — one of three official June stones, with pearl and alexandrite. [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)
- GIA — Ultrasonic Cleaners for Gems: What You Need to Know — Gemological Institute of America (GIA 4Cs, Ultrasonic Cleaners for Gems)