Green Stones.
| Hardness. | Specific Gravity. | |
| (See Chapter VII.) | (See Chapter VIII.) | |
| Aquamarine | 7-3/4 | 2.701-2.800 |
| Chrysoberyl | 8-1/2 | 3.689-3.752 |
| Chrysolite | 6-7 | 3.316-3.528 |
| Chrysoprase (Quartz) | 7 | 2.670 |
| Diamond | 10 | 3.502-3.564 |
| Dioptase | 5 | 3.289 |
| Emerald and Oriental Emerald | 7-3/4 | 2.690 |
| Euclase | 7-1/2 | 3.090 |
| Garnet (see also Red Garnet) | 6-1/2-7-1/2 | 3.400-4.500 |
| Heliotrope (Chalcedony) | 6-1/2 | 2.598-2.610 |
| Hiddenite (a variety of Spodumene) | 6-1/2-7 | 3.130-3.200 |
| Jade | 7 | 3.300-3.381 |
| Jadeite | 7 | 3.299 |
| Malachite | 3-1/2 | 3.710-3.996 |
| Peridot (a variety of Chrysolite) | 6-7 | 3.316-3.528 |
| Plasma (a variety of Chalcedony) | 6-1/2 | 2.598-2.610 |
| Quartz | 7 | 2.670 |
| Sapphire | 9 | 4.049-4.060 |
| Topaz | 8 | 3.500-3.520 |
| Tourmaline | 7-1/4 | 3.148 |
Violet Stones.
| Hardness. | Specific Gravity. | |
| (See Chapter VII.) | (See Chapter VIII.) | |
| Amethyst | 7 | 2.661 |
| Diamond | 10 | 3.502-3.564 |
| Quartz (Amethyst) | 7 | 2.670 |
| Sapphire | 9 | 4.049-4.060 |
| Spinel | 8 | 3.614-3.654 |
| Tourmaline | 7-1/4 | 3.160 |
Chatoyant Stones.
These stones are easily recognisable by their play of colour. (See Chapter XIV.)
Black Stones.
| Hardness. | Specific Gravity. | |
| (See Chapter VII.) | (See Chapter VIII.) | |
| Diamond | 10 | 3.502-3.564 |
| Garnet | 6-1/2-7-1/2 | 3.400-4.500 |
| Jet | 3-1/2 | 1.348 |
| Onyx (a variety of Chalcedony) | 6-1/2 | 2.598-2.610 |
| Quartz | 7 | 2.670 |
| Tourmaline (not unlike Black Resin in appearance) | 7-1/4 | 3.024-3.300 |