PRECIOUS STONES. 267 



portion of oxide of iron, it becomes a brown red, and constitutes the hya- 

 cinth of compostella. But among all these varieties, there are only two 

 that are really valuable, the amethyst and the water sapphire. The ame- 

 thyst of commerce to-day is mostly furnished by Brazil. In that part of 

 the world amethysts attain to an enormous size. A block of amethyst, 

 sent from Brazil to Calcutta, is said to have weighed ninety-eight pounds. 

 Some of the Brazilian specimens are of two colors. Count de Bournon 

 possessed a cut and polished stone of this kind, half violet and half yellow. 

 The ancients believed that wine, when drunk from an amethyst cup, lost 

 the power of causing intoxication. Accordingly the attributes of Bacchus 

 are frequently found engraved upon ancient cups of amethyst." 



Under the name of false jewels are comprised three kinds of articles, 

 the first being stones sufficiently hard to resist a file, the second being arti- 

 ficial productions of the nature of glass, and the third being what are called 

 doublets. 



"It is of some importance to examine this subject, because there is a 

 prevalent belief that all false stones necessarily have glass as their base, 

 and are consequently of little hardness. People often say when their 

 rubies or their topazes are declared false, ' Bat, see, here is a file ; try to 

 scratch these stones, you will not succeed.' Very true, but submit any 

 piece of quartz to the same test, and the result will be the same. Since, as 

 we have said, hyaline is very abundant in nature, it is easy to procure, at 

 insignificant prices, stones that perfectly resist the file, and show, often in 

 a remarkable manner, the whole series of colors that we admire in real 

 precious stones. The colorless varieties of sapphire and topaz which in 

 density, in hardness and in refractive power differ but little from the dia- 

 mond, are frequently cut into roses and brilliants and sold for diamonds. 

 A proof of this fact is furnished by the commercial price of the colorless 

 topaz, which is much is much greater than it could obtain as topaz. It is 

 valued in the secret hope that after cutting it may be sold for diamonds. 

 The doublet method of imitating precious stones, though varying in a 

 great many respects, is generally effected by giving the proj)er shape to a 

 morsel of strass (a peculiar kind of glass), removing from the upper 

 portion of it a certain thickness and replacing this by hard stone, in such 

 a way as to complete exactly the strass stone, then mounting the whole in 

 a setting that completely conceals the line of junction of the two stones. 

 Doublets are of two kinds — in both the under part is strass, but in one the 

 upper part is a plate of the real stone, in the other it is simj^ly hard stone, 

 generally quartz, and of no value. The description of the method of manu- 

 facture in the fifteenth century is given by Cardan, who has even preserved 

 for. us the name of the inventor. A fraud of a very bad character, and one 

 very difficult to find out, was employed by Zocolino. This venerable per- 

 sonage used to take a thin flake of real precious stone, such as carbuncle or 

 emerald, choosing such pieces as had but little color and were consequently 

 very cheap. Underneath he placed a piece of crystal, sufficiently thick, 



