Gemstones with SG 4.00
15 gemstones have a specific gravity range that includes 4.00. 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 |
|---|---|---|---|---|
| Color-Change Sapphire | 3.99 – 4.01 | 1.762 – 1.770 | Trigonal | 9 |
| Low-Type Zircon | 3.90 – 4.10 | 1.780 – 1.815 | Tetragonal | 6–7.5 |
| Sphalerite | 3.90 – 4.10 | 2.369 – 2.500 | Cubic | 3.5–4 |
| White Sapphire | 3.99 – 4.01 | 1.762 – 1.770 | Trigonal | 9 |
| Yellow Sapphire | 3.99 – 4.01 | 1.762 – 1.770 | Trigonal | 9 |
| Pink Sapphire | 3.98 – 4.01 | 1.762 – 1.770 | Trigonal | 9 |
| Padparadscha Sapphire | 3.95 – 4.03 | 1.762 – 1.770 | Trigonal | 9 |
| Ruby | 3.97 – 4.05 | 1.762 – 1.770 | Trigonal | 9 |
| Sapphire | 3.95 – 4.03 | 1.762 – 1.770 | Trigonal | 9 |
| Star Ruby | 3.97 – 4.05 | 1.762 – 1.770 | Trigonal | 9 |
| Star Sapphire | 3.95 – 4.03 | 1.762 – 1.770 | Trigonal | 9 |
| Synthetic Color-Change Corundum | 3.97 – 4.05 | 1.762 – 1.770 | Trigonal | 9 |
| Almandine Garnet | 3.93 – 4.30 | 1.770 – 1.830 | Cubic | 7–7.5 |
| Star Garnet | 3.93 – 4.30 | 1.770 – 1.830 | Cubic | 7–7.5 |
| Malachite | 3.60 – 4.05 | 1.655 – 1.909 | Monoclinic | 3.5–4 |