Gemstones with RI 1.575
8 gemstones have a refractive index range that includes 1.575. Refractive index measures how much light bends when entering a gem — it's one of the most diagnostic properties for identification. Measured with a gemological refractometer.
| Gemstone | RI Range | SG Range | Crystal System | Optic Character |
|---|---|---|---|---|
| Variscite | 1.560 – 1.590 | 2.40 – 2.60 | Orthorhombic | DR_B- |
| Heliodor | 1.568 – 1.580 | 2.68 – 2.74 | Hexagonal | DR_U- |
| Coral | 1.486 – 1.658 | 2.60 – 2.70 | Aggregate | AGG |
| Emerald | 1.565 – 1.602 | 2.67 – 2.78 | Hexagonal | DR_U- |
| Lapis Lazuli | 1.500 – 1.670 | 2.70 – 2.90 | Aggregate | AGG |
| Morganite | 1.572 – 1.600 | 2.71 – 2.85 | Hexagonal | DR_U- |
| Chrysocolla | 1.460 – 1.630 | 2.00 – 2.40 | Amorphous | AGG |
| Pearl | 1.520 – 1.690 | 2.60 – 2.85 | Aggregate | AGG |