GEMS, ARTIFICIAL. Ever since the chemical composition of our most valued gems —the diamond, ruby, opal, &c.—has been known, attempts have been made, with more or less success, to reconstruct them in the laboratory by the influence of intense heat, electrical action, &c. Amongst the most successful workers in this field, we may men tion Ebelmen,* Despretz, Sainte-Claire Devine, and Becquerel.
There are at present no reasons for believing that diamonds of any appreciable size will be formed artificially; Despretz, however, succeeded, by intense voltaic action, in obtaining minute, dark-colored crystals of carbon.
Boron was discovered simultaneously in 1S07 by Davy in England, and by Gay Lussac and Tbenard in France. It is possible that, in the discovery of crystallized boron, we have advanced a step toward the artificial production of the diamond. Tlie boron crystals possess a brilliancy, hardness, and refractive power scarcely inferior to those of the diamond.
Sainte-Claire Deville and Caron have published a very important memoir in the Comptes Rendus (1858, vol. xlvi.), in which they describe various processes by which they have 'succeeded irr obtaining small crystals of white and green corundum, rubies. sapphires, etc. By the action of the vapors of fluoride of aluminium and boracic acid on one another, they obtained crystalized alumina (corundum) in large, but thin crystals, some of which were about .4 of an inch in length, and which in their hardness, and in all their optical and crystallo-graphic properties, resembled natural corundum. When a little fluoride of chromium was added, a similar process yielded violet-red rubies of a perfectly natural tint; with rather more fluoride of chromium, blue sapphires were yielded; and with still more of this ingredient, green corundum was obtained, presenting the natural tint of the variety known as ouvarotlite. A mixture of equal equivalents of
the fluorides of aluminium and glucinum, when similarly acted on by boracic acid, yielded crystals of chrysoberyl or cynophane, which, although very minute, were perfect in their form, and in all respects resembled the natural crystals. The action of fluoride of silicium on zirconia yields small crystals of zircon or hyacinth and by the action of silicic acid on a mixture of the fluorides of aluminum and glueinuni, hexagonal plates of extreme hardness were obtained, which in some respects resembled emerald (which they were attempting to form), but were not identical in composition with that gem.
Other researches on this subject are those of Becquerel, in the Comptes Rendus (1861, vol. liii. p. 1196). After having for many years tried to obtain gems from solutions of silicates, and by feeble electric currents, he then used intense currents, with high tension, and in this way succeeded in obtaining opals, etc. The latest and most suc cessful processes are those of M: Ch. Feil of Paris; who, following out the experiments of Ebelmen, which failed only in consequence of his inability to produce a sufficiently intense heat, has now attained perfect success by the aid of the oxy-hydrogen blow-pipe in fusing and bringing to a crystalline state the materials composing the ruby, emerald, sapphire, topaz, and amethyst, with the alumina base.