Table VII
Specific Gravities of Gem-Stones
| Opal | 2·15 |
| Moonstone | 2·57 |
| Iolite | 2·63 |
| Quartz | 2·66 |
| Beryl | 2·74 |
| Turquoise | 2·82 |
| Beryllonite | 2·84 |
| Phenakite | 2·99 |
| Euclase | 3·07 |
| Tourmaline | 3·10 |
| Enstatite | 3·10 |
| Andalusite | 3·18 |
| Spodumene | 3·18 |
| Apatite | 3·20 |
| Axinite | 3·28 |
| Diopside | 3·29 |
| Epidote | 3·37 |
| Peridot | 3·40 |
| Idocrase | 3·40 |
| Sphene | 3·40 |
| Diamond | 3·52 |
| Topaz | 3·53 |
| Spinel | 3·60 |
| Kyanite | 3·61 |
| Garnet (Hessonite) | 3·61 |
| Benitoite | 3·64 |
| Chrysoberyl | 3·73 |
| Garnet (Pyrope) | 3·78 |
| Garnet (Demantoid) | 3·84 |
| Corundum | 4·03 |
| Garnet (Almandine) | 4·05 |
| Zircon (a) | 4·20 |
| Zircon (b) | 4·69 |
Table VIII
Degrees of Hardness of Gem-Stones
| 5. | Kyanite (5–7), apatite, lapis lazuli |
| 5½. | Enstatite, beryllonite, sphene |
| 6. | Opal, moonstone, turquoise, diopside |
| 6½. | Spodumene, peridot, garnet (demantoid), benitoite, idocrase, epidote, axinite, jade (nephrite) |
| 7. | Iolite, quartz, tourmaline, jade (jadeite) |
| 7¼. | Garnet (hessonite, pyrope) |
| 7½. | Beryl, garnet (almandine), zircon, phenakite, euclase, andalusite |
| 8. | Topaz, spinel |
| 8½. | Chrysoberyl |
| 9. | Corundum |
| 10. | Diamond |