Part 24

The principal color is yellow, in various shades, sometimes running into white or reddish-brown and black.

Amber is transparent to translucent, possesses single refraction, a resinous lustre to a high degree, becomes electric by rubbing, and burns readily before the blow-pipe.

Amber when heated becomes soft and pliable.

Amber is composed of:

Carbon 79. Hydrogen 10.5 Oxygen 10.5

Amber is imitated by gum copal, and even the insect enclosures which occur in real amber are copied.

These imitations can be detected by placing the specimen in water or alcohol. This is also a good test for pieces of real amber that have been melted or glued together.

Amber is thrown up by the sea, in rivers near the sea, or on the sea-shore, and has been found in nearly all parts of the world.

The Russian, Baltic, and Sicilian coasts have yielded the larger portion of the production, but supplies come also from Galizia, the Urals, Poland, China, and the United States.

For ornamental purposes the faceted amber beads are largely used, but of late years these have been closely imitated in glass.

CORAL.

Coral, although not a precious stone, has been largely used in jewelry, and as some of this beautiful substance is very valuable, a few words will not come amiss.

Red or precious coral is the work of a family of zoöphytes which live mostly in cavities of rock in the sea.

These polyps build their homes at a depth of two to seven hundred feet under the surface of the sea, and although the single groups of coral are sometimes several feet long, the usual size is about twelve inches high, and about one inch at the thickest part of any single branch.

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 ────────────────────┴───────────┴──────────────

GENERAL INDEX.

Achroite, 64 Actinolite, 29 Adularia, see moonstone Agate jasper, 120 Agate onyx, see onyx Agate, see quartz, 106, 119, 122, 123, 124, 126 Alexandrite, 8, 54, 56 Almandine, 9, 30, 80 Almandite, 29, 80 Amazon stone, 17, 88, 91 Amber, 17, 128 American ruby, 80, 83 Amethyst, 8, 9, 16, 17, 44, 49, 107, 110, 111 Amethystine quartz, see amethyst Antimony, 29 Apatite, 19, 87 Aquamarine, 8, 16, 53 Aquamarine chrysolite, 53 Arizona ruby, 80, 83 Asterias, see star sapphires Aurora red sapphire, see Oriental hyacinth Avanturine, 113, 114 Avanturine felspar, see sunstone Axinite, 17, 102

Balas ruby, 48 Banded agate, 119 Beckite, 120 Beryl, 14, 16, 17, 44, 50, 52, 53, 87 Blood-stone, see heliotrope " see hematite Bobrowska garnet, 80, 83 Bohemian garnet, 80 82 " diamond, see rock-crystal " topaz, see yellow quartz Bone turquois, 62 Bort, 38 Brazilian aquamarine, 85 " emerald, 64, 67 " ruby, 85 " sapphire, 85 " topaz, see topaz Bronzite, 30

Cachelong, 69, 70 Cairngorm, 107, 111 Calcite, 19 Cameo, 8 Cannel coal, see jet Cape garnet, 80, 83 Cape ruby, 80, 83 Carbon, 37 Carbonate, see carbon Carbuncle, 80 83 Carnelian, 17, 113, 123, 124 " onyx, 122 Cat’s-eye, corundum, 8, 54, 57, 115, 116 " quartz, 18, 58, 107, 113, 114, 115 Ceylon cat’s-eye, see corundum cat’s-eye " chrysolite, 64, 79 " opal, see moonstone " peridot, 64 Ceylonite, 47 Chalcedonyx, see chalcedony Chalcedony, 8, 9, 16, 17, 113, 118, 119, 120, 122, 124 Chrysoberyl, 16, 17, 45, 54, 56, 57, 79 Chrysolite, 17, 30, 53, 58, 78, 87, 99, 107 Chrysoprase, 17, 107, 113, 117 Cinnamon stone, see grossularite Cleavage, 10 Cloudy agate, 120 " chalcedony, see chalcedony Colors, 16 Coral, 130 Cordierite, see dichroite Corundum, 9, 17, 39, 45, 47, 48, 49 Crocidolite, 5, 18, 113, 115 Crystallization, 10 Cutting, 32 Cyanite, 17, 92 Cymophane, 54, 56, 57

Decimal system, 28 Demantoide, see Bobrowska garnet Diamond, 9, 11, 12, 14, 15, 17, 18, 20, 31, 32, 33, 35, 40, 41, 49, 51, 52, 60, 75, 101, 109 Dichroiscope, 14 Dichroite, 97 Diopside, 103

Egyptian jasper, 123 " pebbles, see Egyptian jasper Electricity, 31 Emerald, 8, 9, 16, 17, 18, 31, 44, 51, 87, 95, 107 Epidote, 17, 101 Essonite, see grossularite Euclase, 99 Eye agate, 119

False emerald, see fluor spar " lapis, 124 " ruby, see fluor spar " topaz, see fluor spar and yellow quartz Fancy sapphires, 44 Felspar, 20, 88, 91 Fish-eye, see moonstone Flint, 113 Fluor spar, 17, 19, 31, 104 Fortification agate, 119 Fossil turquois, 63 Fracture, 11 Fusibility, 28

Garnet, 12, 14, 15, 17, 21, 32, 42, 53, 64, 80, 107 Girasol, 46 Glass, 15 Golden beryl, 54 Goldstone, see avanturine Goutte d’eau, 85 Green felspar, see Amazon stone " garnet, 80, 99 " sapphire, see Oriental emerald Greenish-yellow sapphire, see Oriental chrysolite Grossularite, 30, 80, 82

Hair-stone, see cairngorm Heliotrope, 113, 116, 118, 120 Hematite, 18, 124 Hiddenite, 95 Hornstone, 113 Hungarian cat’s-eye, see quartz cat’s-eye Hyacinth, 42, 58, 59 Hydrophane, 69, 70 Hypersthene, 105