Pearl
JewelryWiki Editorial·4 sources·Reviewed 2026-08-04
An organic gem, and the clearest case where stability rather than hardness governs care. Perfume, makeup and chlorine are the real hazards.
Properties
| Property | Value | Authority |
|---|---|---|
| Stability | Low. GIA: long-term exposure to heat and light can damage most organic gems including pearls; chlorine, perfume and makeup can damage or discolour delicate and porous gems like pearls. [1] | — |
| Specific gravity | 2.60–2.85 [2] | — |
| Common treatments | ALL types of pearl are routinely bleached with hydrogen peroxide to lighten them and even out their colour — GIA states this without qualification, and it is the single most under-appreciated fact about pearls. Dyeing is frequent and improves the appearance of lower-quality natural and cultured pearls. Some pearls are irradiated to produce dark grey. Some are given a colourless hard coating to improve durability. Bleaching as a one-step process is virtually impossible to detect. [4] | — |
| Suitability for daily wear | Wearable regularly with care, but should be put on after perfume and cosmetics and kept out of pools. [1] | — |
| Care cautions | Keep away from chlorine, perfume and cosmetics, and avoid prolonged heat and light. Chlorine also damages gold mountings. [1] | — |
| Birthstone month | June — one of three official June stones, with moonstone and alexandrite. [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)
- GIA — An Introduction to Gem Treatments — Gemological Institute of America (GIA, An Introduction to Gem Treatments (Robert Weldon))