Gemstones with SG 3.15
7 gemstones have a specific gravity range that includes 3.15. Specific gravity measures density relative to water — a key diagnostic property for gem identification. Measured by hydrostatic weighing or heavy liquids.
| Gemstone | SG Range | RI Range | Crystal System | Hardness |
|---|---|---|---|---|
| Tourmaline | 3.01 – 3.26 | 1.624 – 1.644 | Trigonal | 7–7.5 |
| Andalusite | 3.13 – 3.21 | 1.629 – 1.649 | Orthorhombic | 7–7.5 |
| Hiddenite | 3.15 – 3.21 | 1.660 – 1.676 | Monoclinic | 6.5–7 |
| Kunzite | 3.15 – 3.21 | 1.660 – 1.676 | Monoclinic | 6.5–7 |
| Chrome Tourmaline | 3.00 – 3.20 | 1.624 – 1.660 | Trigonal | 7–7.5 |
| Clinohumite | 3.13 – 3.35 | 1.625 – 1.675 | Monoclinic | 6 |
| Thulite | 3.10 – 3.38 | 1.691 – 1.704 | Orthorhombic | 6–7 |