The daily morning journal and courier., 1906-01-04
MAKING OF BOGUS GEMS
AN INDUSTRY THAT REQUIRES
 LARGE CAPITAL.

POIished-Cementing Two Small
 Stones Into One-Manufacture of
 Imitation Pearls.
 The passion for precious stones which has reigned in the minds of men and women almost from time immemorial has, of course, given rise to much counterfeiting of the more valuable stones, says the London Tid-Bits.
 All are more or less familiar with the cheap glass limitations where the worthlessnesss of the article is so ap- parent that there is no suggestion of fraud. Few, however, realize to what an extent skilled fraud exists in this trade, more especially on the Continent, where much of the diamond cutting is done. The manufacture of imitation gems of specially prepared glass is quite an important industry.
 It is now possible to produce in paste an imitation of almost every precious stone which is capable of de- ceiving the eyes of all but the most expert. Not only is there a superficial resemblance but a skillfully prepared paste" stone exhibits the same lustre and high indev of refraction and dis persion os would a diamond of the first water. The purity of the materials employed is such that an equal degree of clearness and transparency is given to the imitation as is found in the gen. uine stone. Color is initiated also so that a ruby. emerald, sapphire or other gem amde of glass is practically indis- guishable from the real jewel which may have cost hundreds of pounds.
 The material of which these imita- tion stones are made is known as "strass" This is made according to different recipes, but usually includes red lead, rock crystal, potassium car bonate, borax and white arsenic The greater the amount of lead used in the production of the paste the greater will be the brilliancy and play ofpris- matic colors in the finished stone, and at the same time the higher will be its 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 a stone is to see whether it will scratch or cut window glass, which is, as rule, harder than most imitation stones.
 It must not be imagined that these close limitations of the real diamond or other stone can be produced cheaply. This is far from the case. A large capi- tai is required in the manufacture, and the high degree of purity necessary in all the materials employed necessitates an amount of care, and incidentally waste, which is exceedingly expensive. Moreover, the imitation gems have to be cut and finished in precisely the same manner as the real stones, and this is perhaps the momst expensive part of the procedure.
 Another method of deceiving the un- wary purchaser of precious stones is to palm off on him genuine stones which have been "faked" in some way to make them appear more valuable than they really are. A device com monly practiced 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 object in such a proceeding, but diamonds increase very much in value if they are large, For instance, while 910 would be a very fair price for a diamond weighing one carat. R150 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 large sum beautiful stone which on exami. nation by an expert proves to be per. haps, only sktlfully prepared piece O bottle glass. It is not, of course claimed that there is necessarily any thing fraudulent in the skilful prepa' ration of imitation stones to resemble more valuable gems. Many of the mos reputable jewellers deal in these stones charging a price for which no on' would expect to procure the genuin' l article. So long as the customer i taken into the jewellers confdenc, there is nothing to object to in th' 1 bargain.
 1 A yellowish red stone called hyacinth and also the blue sapphire, lose thei color on being heated, and may then b set as diamonds. Similarity, varlou stones may be colored in such a man ne ras to make them resemble other of a higher value.
 A favorite method of preparing prec ious stones so as to make them appea more valuable than they really are i by means of the ''doublet.' This ma, | be done at the request of a custome who wishes to make a finer show tha1 he or she would otherwise be able t do or it may be practiced by an un schupulous dealer to deceive the un
 wary. It is said that a great deal o
 this work is done on the Continent. | doublet consists of an upper part which is genuine, secured to lowe
 part of some less valuable stone or O
 glass. The two warts are cemented to 1 gether and ground so as to leave n
 trace of the union. The firse of tn genuine portion of the stone is see
 through the imitation, which is itsel
 made of some paste with a high de gree of brflliancy. If the doublet is SC
 cured by cement the two portions wi
 fall apart on immersion in hot water
 When the base is composed of glass
 however it is usually fused to the III per and genuine half, so that the frau l is very difficult to detect.
 Another way of preparing a doublet
 to make the upper portion of rock crys