The Birmingham age-herald., 1906-01-08

stones are made is known as "stnass.. This is made according to different re- cipes, but usually includes red lead, rock crystal, potassium carbonate, borax and white arsenic. The greater the amount of lead used in the production of the paste the greater will be the bri1laney and play of prismatic colors in the finish ed stone, and at the same time the high CT will be it's specific gravity. On the other hand, the stone loses in hardness what it gains in brilliance. An old-time, but still servieeable rough and ready test for stone is to see whether it will cratch or cut window glass, which is, as a rule, harder than most imitation stones.
 Expensive Process.
 It must not be imagined that these close limitations Of the real diamond or other stone can be produced cheapV. This is far from the case. A large capital is re- quired in the manufacture, and the high degree of purity necessary in all the ma terials employed necessitates an amount of care, and incidentally waste. which is exceedingly expensive. Moreover, tlte imitation gems have to be cut and finish ed in precisely the same manner as the real stones, and this is perhaps the most expensive part Of the procedure.
 Another method of deceiving the un- wary purchaser of precious stones is to
 
 have been 'faked" in some way to make them appear more valuable than they really are. device commonly praoticed Is that of cementing two stones so that they appear to be one large one. At first sight there does not seem to be any ob- ject in such a proceeding, but diamonds increase very much in value if they are large. For instance, while s10 would be a very fair price for a diamond weighing one carat, a15O might be paid for five carat stone of the same water.
 Eastern jewellers are particularly skill full in this direction. An Indian dealer will think nothing of selling for a. large sum beautiful stone, which on examina- tion by an expert proves to be, per haps, only skillfully prepared piece of bottel glass It Is not, of course, claimed that there Is necessarily anything fraud uent in the sldllful preparation of imita- tion stones to resemble more valuable gems. Many of the most reputable jew elers deal in these stones, charging a price for which no one would expect to procure the genuine article. So long as the customer Is taken into the jewellers confidence there is nothing to object to in the bargain.
 A .yellowish red stone called hyacinth. and also the blue sapphire, lose their color on being heated and may then be set as diamonds Similarly, various stones may be co1ored in such a manner as to make them resemble others of @ higher value
 The Doublet.
 A favorite method of preparing precious stones so as to make them appear more valuable than they really are Is by means of the "doublet." This may be done at the request of customer who wishes to make @ finer show than he or she would otherwise be able to do or it may be practiced by an interruptions dealer to deceive the unwary. 1t is said that a great deal of this work Is done on the continent. A doublet consists of an upper part, which is genuine, secured to a lower part of some less valuable stone or of glass. The two parts are cemented to- gether and ground, so as to leave no trace of the union. The fire of the gen. uine portion of the stone is seen through the imitation, which Is itself made of some paste with a high degree of bril- liancy If the doublet is secured by ce- ment the two portions will fall apart on immersion in hot water. When the base is composed of glass, however it is usual ly fused to the upper and genuine half, so that the fraud is very difficult to de- tect.
 Another way of preparing a doublet is to make the upper portion of rock crystal, or some similar transparent material with a high degree of hardness, and the lower portion of tinted glass, which seems to impart it's color to the whole. The fraud may be readily detected by holding the stone to the light; but as it Is usually employed in making up jewelry with closed settings the purchaser has no op- portunity of making this test.
 Finally, colored stones are initiated in 8 particularly ingenious way by means of rock crystal ground to resemble the usual appearance of the particular stone to be initiated, but with a hollow cavity in- side, which is filled with colored water. The cavity is then closed by means of d plate of rock crystal slNillfully fitted in, and there appears, perhaps an exquisite ruby, sapphire, emerald or amethyst, very difficult to distinguish from the genuine stone.