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 |