In conclusion the author hopes that this little text may lead a few to pursue further this most fascinating theme and that the pursuit may bring much of pleasure as well as of profit. INDEX Absorption, 15 Adamantine luster, 40, 41 Agate, 128, 138, 172, 197 Alexandrite, 140 Almandite (_see_ Garnet) Altered stones, 247-249, 250-257 Amazonite, 176 Amethyst, 94, 170, 195, 196 Aquamarine, 143, 189 Azurite, 132, 148, 177, 199 Balances, Care and use of, 283-293 Beryl, 84, 143, 190 Bibliography, 301 Bloodstone, 172 Blue diamonds, 91 Blue-white diamonds, 91 Brazilian diamonds, 182 Brilliancy, 203 Brilliant cut stones, 233 Brilliant, Theory of the, 205 Brittleness of gems, 119 Brown stones, 95 Bubbles in gems, 103 Bubbles in glass, 81 Bubbles in scientific stones, 103 Burmah rubies, 154 Cabochons, 45, 216, 227 Carbon, 136 Carborundum, 54, 55, 56 Carnelian, 128, 138, 172 Cat's-eye, 44-46, 138, 171 Chalcedony, 138 Chrysoberyl, 45, 85, 122, 140, 157, 188 Chrysoberyl cat's-eye, 45, 46, 85, 188 Chrysolite, 176 "Cinnamon stone," 144 Citrine quartz, 161, 171, 195, 196 Cleaving of diamonds, 208 Cleaving of precious stones, 213 Color, cause of, in minerals, 15 Color of gems, 66-92 Colorless stones, 97 Corundum gems, 68-70, 73, 101, 121, 134, 137 Corundum gems, defects of, 101 Cultured pearls, 277-279 Cutting of diamonds, 209 Cutting of precious stones, 201-226 Demantoid garnet, 62, 64, 82, 130, 144, 169, 193 Density of minerals, 23 Diamonds, 61, 73, 91, 120, 134, 151-153, 179-186 Dichroism, 15-22, 113 Dichroscope, the, 17-20 Dispersion, 60-65 Double refraction, 5 Doublets, 41, 241-246 Emerald, 75-82, 143, 164, 189 Emerald, wearing qualities of, 109 Epidote, 9 Extraordinary ray, 16 Fancy diamonds, 91, 151 "Fire," cause of, 207 Forms of precious stones, 227-236 Garnet, 69, 82, 96, 130, 143, 144, 167-170, 192-194 Garnet, Almandite, 143, 168, 193 Garnet, Andradite, 82, 130, 144, 169, 193 Garnet, Demantoid, 62, 64, 82, 130, 144, 169, 193 Garnet, Pyrope, 144, 168, 192, 193 Glass, 62, 142 Glass imitations, 81, 237-249 "Golcondas," 180 "Grain base," price of pearls per, 271 Hardness, 47-54, 55-59, 113 Hardness and wearing qualities, 119-132 Hardness, Mohs's scale of, 48-51 Hardness, table of, 54 Hardness, test of, 51-54, 58 "Heliodor," 165 "Hope Blue" diamond, 91 Hyacinth, 166 Imitations of precious stones, 237-249 Imitations of pearls, 277-282 Imperfections, 111 Imperfections in corundum gems, 101 Imperfections in glass, 81 Imperfections in scientific stones, 104 Jacinth, 166 Jade, 128, 147, 175, 197 Jadeite, 128, 197 Jargoons, 166 Jasper, 128, 172 Kunzite, 195 Lapis lazuli, 132, 177, 199 Labradorite, 176 Luster, 38-42 "Make" of diamonds, 205-207 "Make" of precious stones, 220 Malachite, 132, 148, 177, 199 Metallic oxides, 137 Mineral species, 133-148