Coral is usually red, and rarely white or black, while the pale rose-pink is the most esteemed color.
Coral is mostly found at Calle, off the coast of Africa, but also on the coasts of Tunis, Algiers, Corsica, Barbary, Majorca, and Minorca.
Coral fishing-vessels leave Italy the beginning of March and return from the African coast in October; at one time as many as four hundred vessels were engaged in this industry.
TABLE OF HARDNESS AND
SPECIFIC GRAVITY.
| |
|---|
| | HARDNESS. | SPECIFIC
GRAVITY. |
|---|
| Achroite | 7. | — | 7.5 | 3. | — | 3.1 |
| Alexandrite | 8.5 | | | 3.65 | — | 3.8 |
| Almandine | 7.5 | | | 4. | — | 4.2 |
| Almandite | 7.5 | | | 4. | — | 4.2 |
| Amber | 2. | — | 2.5 | 1.065 | — | 1.08 |
| Apatite | 4.5 | — | 5. | 2.95 | — | 3.25 |
| Axinite | 6.5 | — | 7. | 3. | — | 3.3 |
| Beryl | 7.5 | — | 8. | 2.67 | — | 2.73 |
| Bobrowska garnet | 6. | | | 3.85 | | |
| Bohemian" | 7.5 | | | 3.69 | — | 3.78 |
| Brazilian emerald | 7. | — | 7.5 | 3. | — | 3.1 |
| " sapphire | 7. | — | 7.5 | 3. | — | 3.1 |
| Cachelong | 5.5 | — | 6. | 2. | — | 2.1 |
| Cat’s-eye | 8.5 | | | 3. | — | 3.8 |
| Ceylon chrysolite | 7. | — | 7.5 | 3. | — | 3.1 |
| "peridot | 7. | — | 7.5 | 3. | — | 3.1 |
| Chrysoberyl | 8.5 | | | 3.65 | — | 3.8 |
| Chrysolite | 6.5 | — | 7. | 3.3 | — | 3.5 |
| Chrysoprase | 7. | | | 2.56 | | |
| Cinnamon stone | 6.5 | | | 3.5 | — | 3.56 |
| Cyanite | 5. | — | 7. | 3.45 | — | 3.7 |
| Cymophane | 8.5 | | | 3.65 | — | 3.8 |
| Demantoide | 6. | | | 3.85 | | |
| Diamond | 10. | | | 3.5 | — | 3.6 |
| Dichroite | 7. | — | 7.5 | 2.56 | — | 2.67 |
| Diopside | 5. | — | 6. | 2.9 | — | 3.5 |
| Emerald | 7.5 | — | 8. | 2.67 | — | 2.73 |
| Epidote | 6. | — | 7. | 3.32 | — | 3.50 |
| Essonite | 6.5 | | | 3.5 | — | 3.56 |
| Euclase | 7.5 | | | 3.1 | | |
| Fluor spar | 4. | | | 3.1 | — | 3.2 |
| Garnet | 5. | — | 8. | 3.15 | — | 4.3 |
| Grossularite | 6.5 | | | 3.5 | — | 3.56 |
| Hematite | 5.6 | — | 6.5 | 4.2 | — | 5.3 |
| Hiddenite | 6.5 | — | 7. | 3.13 | — | 3.19 |
| Hyacinth | 7.5 | | | 4.4 | — | 4.7 |
| Hydrophane | 5.5 | — | 6. | 2. | — | 2.1 |
| Hypersthene | 6. | | | 3.3 | — | 3.4 |
| Idocrase | 6.5 | | | 3.35 | — | 3.45 |
| Indicolite | 7. | — | 7.5 | 3. | — | 3.1 |
| Jacinth | 7.5 | | | 4.4 | — | 4.7 |
| Jargoon | 7.5 | | | 4.4 | — | 4.7 |
| Jasper | 7. | | | 2.31 | — | 2.67 |
| Jet | 2.5 | | | 1.35 | | |
| Labrador | 6. | | | 2.62 | — | 2.76 |
| "hornblende | 6. | | | 3.3 | — | 3.4 |
| Lapis lazuli | 5. | — | 5.5 | 2.38 | — | 2.42 |
| Malachite | 3.5 | — | 4. | 3.6 | — | 4. |
| Moonstone | 6. | — | 6.5 | 2.4 | — | 2.6 |
| Obsidian | 6. | — | 7. | 2.25 | — | 2.8 |
| Olivine | 6.5 | — | 7. | 3.3 | — | 3.5 |
| Opal | 5.5 | — | 6. | 2. | — | 2.1 |
| Oriental amethyst | 9. | | | 3.9 | — | 4.1 |
| " aquamarine | 9. | | | 3.9 | — | 4.1 |
| " chrysolite | 9. | | | 3.9 | — | 4.1 |
| " emerald | 9. | | | 3.9 | — | 4.1 |
| " hyacinth | 9. | | | 3.9 | — | 4.1 |
| " topaz | 9. | | | 3.9 | — | 4.1 |
| Pearl | | | | 2.5 | — | 2.7 |
| Peridot | 6.5 | — | 7. | 3.3 | — | 3.5 |
| Phenacite | 7.5 | — | 8. | 2.96 | — | 3. |
| Pyrope | 7.5 | | | 3.69 | — | 3.78 |
| Quartz | 7. | | | 2.5 | — | 2.8 |
| " cat’s-eye | 6. | — | 6.5 | 2.65 | | |
| Rose quartz | 7. | | | 2.65 | — | 2.75 |
| Rubellite | 7. | — | 7.5 | 3. | — | 3.1 |
| Ruby | 9. | | | 3.9 | — | 4.1 |
| " cat’s-eye | 9. | | | 3.9 | — | 4.1 |
| Sapphire | 9. | | | 3.9 | — | 4.1 |
| " cat’s-eye | 9. | | | 3.9 | — | 4.1 |
| Siberite | 7. | — | 7.5 | 3. | — | 3.1 |
| Sphene | 5. | — | 5.5 | 3.4 | — | 3.56 |
| Spinel | 8. | | | 3.5 | — | 3.6 |
| Spodumene | 6.5 | — | 7. | 3.13 | — | 3.19 |
| Star ruby | 9. | | | 3.9 | — | 4.1 |
| " sapphire | 9. | | | 3.9 | — | 4.1 |
| " topaz | 9. | | | 3.9 | — | 4.1 |
| Sunstone | 6. | — | 7. | 2.56 | — | 2.72 |
| Syrian garnet | 7.5 | | | 4. | — | 4.42 |
| Titanite | 5. | — | 5.5 | 3.4 | — | 3.56 |
| Topaz | 8. | | | 3.4 | — | 3.6 |
| Tourmaline | 7. | — | 7.5 | 3. | — | 3.1 |
| Turquois | 6. | | | 2.6 | — | 2.8 |
| Uwarowite | 7.5 | | | 3.41 | — | 3.52 |
| Vesuvianite | 6.5 | | | 3.35 | — | 3.45 |
| Water sapphire | 7. | — | 7.5 | 2.56 | — | 2.67 |
| |