PASTE

From Agepedia

PASTE; a glass made in imitation of gems. The base of all artificial stones is a compound of silex, potash, borax, red oxide of lead, and sometimes arsenic. Pure boracic acid and colorless quartz should be used. Hessian crucibles are better than those of porcelain. The fusion should be continued in a potter's furnace for twentyfour hours. The more tranquil and continued it is, the denser the paste, and the greater its beauty. Pastes. 1. 2. 3. 4. Bock crystal, 4056 grs. 3456 3600 Minium, 6300 " 5328 Potash 2154 " 1260 1944 1260 Borax, 276 " 360 216 360 Arsenic, 12 " 12 6 Ceruse of clichy, 8508 8508 Sand, 3600 Topaz. JSTo. 1. JVb. 2. Very white paste, 1008 3456 Glass of antimony, 43 Cassius's purple, 1 Peroxide of iron, 36 Ruby; paste, 2880, oxide of manganese, 72.Emerald; paste, 4608, green oxide of copper, 42, oxide of chrome, 2.Sapphire; paste, 4608, oxide of cobalt, 68, fused for 30 hours.Amethyst; paste, 4608, oxide of manganese, 36, oxide of cobalt, 24, purple of cassius, 1.Beryl; paste, 3456, glass of antimony, 24, oxide of cobalt, 1£.Styrian garnet; paste, 502, glass of antimony, 256, cassius's purple, 2, and oxide of manganese, 2. In all these mixtures, the substances are blended by sifting, fused very carefully, and cooled very slowly, being left on the fire from 24 to 30 hours.