Ch. 14: Mechanical Purposes, Artificial, & Weights

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	330	THE DIAMOND

	be enticed could easily pay much more for a piece of the same value, for some fancied superiority. So cleverly were these glittering displays managed, that sufficient profits were made out of a foolish clientele to pay the high rentals of stores in the most expensive locations, and leave a large surplus for the managers. In the past, white sapphire, jargoon, white topaz, and rock crystal have all at times been sold occasionally as diamond, but of late years imitation diamonds, of whatever name, have been simply glass, for fine specimens of sapphire and jargoon excepted, glass looks better long enough to sell, than the other stones which though real, are not as deceptive. As enormous quantities of them are used, much ingenuity has been displayed in the manufacture of glass diamonds and the art has been brought to a high state of perfection. The imitation of gems is as old certainly as Egypt, but the fine white glass composition which with some variations is used now, was invented in the seventeenth century by Josef Strasser of Strasburg, and was called after him " Strass." It was composed of silica, potash, borax, red-lead and sometimes arsenic. Of the different proportions used now, the following is given as a good example: 300 parts powdered quartz, 470 parts red-lead, 163 parts potash (purified by alcohol), 22 parts borax, 1 part white arsenic, by weight, This makes a dense white glass and is the mixture called strass or paste, from which the fine imitations are made. Great care is exercised in cutting the fine imitations, not only in the work of faceting, but also in shaping and cutting to proportions which will hide as much as possible the inherent differences of reflection,

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