| Hardness. | Specific Gravity. | |
| (See Chapter VII.) | (See Chapter VIII.) | |
| Amber | 2-1/2 | 1.000 |
| Beryl | 7-3/4 | 2.709-2.810 |
| Chrysoberyl | 8-1/2 | 3.689-3.752 |
| Chrysolite | 6-7 | 3.316-3.528 |
| Corundum (the yellow variety known as "Oriental Topaz" [not "Topaz">[, see below) | 9 | 3.90-4.16 |
| Diamond | 10 | 3.502-3.564 |
| Garnets (various) | 6-1/2-7-1/2 | 3.4-4.5 |
| Hyacinth (a form of Zircon) | 7-1/2 | 4.7-4.88 |
| Quartz (Citrine) | 7 | 2.658 |
| Sapphire | 9 | 4.049-4.060 |
| Spinel | 8 | 3.614-3.654 |
| Topaz (for "Oriental Topaz," see above) | 8 | 3.500-3.520 |
| Tourmaline | 7-1/4 | 3.210 |
Brown and Flame-Coloured Stones.
| Hardness. | Specific Gravity. | |
| (See Chapter VII.) | (See Chapter VIII.) | |
| Andalusite | 7-1/2 | 3.204 |
| Diamond | 10 | 3.502-3.564 |
| Garnets (various) | 6-1/2-7-1/2 | 3.40-4.50 |
| Hyacinth (a form of Zircon), see below | 7-1/2 | 4.70-4.88 |
| Quartz (smoke coloured) | 7 | 2.670 |
| Tourmaline | 7-1/4 | 3.100 |
| Zircon (Hyacinth) | 7-1/2 | 4.70-4.88 |
Red and Rose-Coloured Stones.
| Hardness. | Specific Gravity. | |
| (See Chapter VII.) | (See Chapter VIII.) | |
| Carnelian (a variety of Chalcedony) | 6-1/2 | 2.598-2.610 |
| Diamond | 10 | 3.502-3.564 |
| Deep Red Garnet | 7-1/4 | 3.40-4.50 |
| Jasper | 7 | 2.668 |
| Opal (the "Fire Opal") | 5-1/2-6-1/2 | 2.21 |
| (average) | ||
| Ruby | 9 | 4.073-4.080 |
| Rhodonite | 5-1/2-6-1/2 | 3.413-3.617 |
| Sapphire | 9 | 4.049-4.060 |
| Spinel Ruby | 8 | 3.614-3.654 |
| Topaz | 8 | 3.500-3.520 |
| Tourmaline | 7-1/4 | 3.024 |
| Zircon | 7-1/2 | 4.70-4.88 |
Pink Stones.
| Hardness. | Specific Gravity. | |
| (See Chapter VII.) | (See Chapter VIII.) | |
| Beryl | 7-3/4 | 2.709-2.810 |
| Diamond | 10 | 3.502-3.564 |
| Ruby | 9 | 4.073-4.080 |
| Spinel | 8 | 3.614-3.654 |
| Topaz ("burnt" or "pinked"), see Chapter XIV., page 92 | 8 | 3.500-3.520 |
| Tourmaline | 7-1/4 | 3.024 |
Blue Stones.
| Hardness. | Specific Gravity. | |
| (See Chapter VII.) | (See Chapter VIII.) | |
| Beryl | 7-3/4 | 2.709-2.810 |
| Diamond | 10 | 3.502-3.564 |
| Dichorite (Water Sapphire) | 7-7-1/2 | 4.049-4.060 |
| Disthene (Kyanite) | 5-7 | 3.609-3.688 |
| Iolite (Cordierite) | 7-1/4 | 2.641 |
| Lapis lazuli | 5-1/2 | 2.461 |
| Sapphire | 9 | 4.049-4.060 |
| Topaz | 8 | 3.500-3.520 |
| Tourmaline | 7-1/4 | 3.160 |
| Turquoise | 6 | 2.800 |