Pearl
Mineraloid
Pearl is a biogenic gem of nacre (aragonite) formed in mollusks. It is not an IMA-recognized mineral species.
Photos
About Aragonite
Full reference data — crystallography, X-ray diffraction, and cited physical properties — is on the Aragonite species page.
| Formula | Ca(CO3) |
|---|---|
| Hardness (Mohs) | 3.5-4 |
| Specific gravity | 2.93-2.95 |
| Density (calculated) | 2.913 |
| Crystal system | orthorhombic |
| Color range | red, violet, white |
| Luster | resinous, vitreous |
| Streak | red |