| Colorless Gemstones |
|---|
| Gemstone | Crystal System | Density | Hardness | Refractive index | Treatments |
| Beryl | hexagonal | 2.72 | 7.5-8.9 | 1.577-1.583 | heat, radiation, fracture filling, oiling |
| Corundum | trigonal | 4.00 | 9.0 | 1.762-1.770 | none |
| Diamond | cubic | 3.52 | 10 | 2.417 | radiation, drilling, fracture filling |
| cubic | 2.29 | 6.00 | 1.483-1.487 | none | |
| Moonstone | monoclinic | 2.56 | 6.0-6.5 | 1.518-1.526 | none |
| Opal | amorphous | 2.15 | 5.0-6.5 | 1.450 | fracture filling |
| Quartz | hexagonal | 2.66 | 7.0 | 1.544-1.553 | fracture filling |
| Sapphire | hexagonal | 4.00 | 9 | 1.762-1.770 | heat, fracture filling |
| Spinel | cubic | 3.60 | 8 | 1.718 | none |
| Topaz | orthorhombic | 3.53 | 8 | 1.619-1.627 | blue is irradiated |
| Tourmaline | trigonal | 3.06 | 7.0-7.5 | 1.624-1.644 | heat |
| Zircon | tetragonal | 4.00 | 6.50 | 1.810-1.815 | none |