MOCK DIAMONDS—“PARIS BRILLIANTS”—THE MANUFACTURE OF PASTES—FALSE RUBY, TOPAZ, SAPPHIRE, EMERALD AND CARNELIAN—HOW TO DISTINGUISH TRUE AND FALSE GEMS—IMITATION PEARL AND CORAL—ARTIFICIAL GOLD—LIST OF PRECIOUS STONES.
“BRISTOL Stones,” “Irish Diamonds,” “Cape May Diamonds,” and “California Diamonds,” are skillfully-cut quartz crystals. They are easily detected by the file and by their lightness.
“Paris Brilliants” are more dangerous counterfeits, and are very often sold for genuine. The great establishment of Boarguiguon, in Paris, is the most famous manufactory of artificial gems in the world, employing about one hundred hands. The gems are such perfect imitations that they can be distinguished from real stones only by the closest scrutiny of those experienced in such matters. They fail chiefly in hardness; in brilliancy and gravity they nearly or quite equal the genuine.
Nature has made the most precious stones with the most common materials. The diamond is purified charcoal; while the matter of clay and white pebbles is the base of all other gems.
The chemist has imitated nature in the production of colored gems. The base of these imitations, called “pastes,” is “strass”—a white glass compound of 300 parts of pure sand, 96 of potash, 27 of borax, 514 of white lead, and one of arsenic. The mixture is put into a crucible and kept at a high heat for 24 hours. This is the philosopher’s stone which competes with Golconda. The uncolored glass is used in making mock diamonds and white topaz. Another paste which has very great brilliancy, and, unfortunately, the same gravity as the diamond, is made by melting 100 parts of pure sand, 150 of red lead, 30 of calcined potash, 10 of calcined borax and one of arsenic, keeping the mixture melted for two or three days and then cooling very slowly. Each ingredient is separately reduced to a fine powder.
False Ruby is made by fusing together of strass one ounce and six drams, glass of antimony 37 grains, and purple of cassius one grain; then add eight parts more of strass and fuse for thirty hours; cool and remelt pieces in a blow-pipe. Or, melt five ounces of strass and one dram of manganese.
False Topaz can be made from 1008 grains of strass, 43 grains of glass of antimony and one grain of purple of cassius.
False Sapphire.—Add to eight ounces of strass 52 grains of pure oxide of cobalt.
False Emerald.—To one pound of strass add one dram of verdigris and fifteen grains of crocus martis. Or, take 2304 grains of strass, 21 grains of green oxide of copper, and one grain of oxide of chrome. Or, take an ounce and a half of rock-crystal, six drams of dry soda, two drams of dry borax, two drams of red lead, one dram of nitre, twenty grains of red oxide of iron, and ten grains of green carbonate of copper.
False Carnelian.—Strass two pounds, glass of antimony one pound, rouge two ounces, manganese one dram.