Diamonds and precious stones, a popular account of gems .. . mmediately the spinelor balas ruby from the oriental ruby, since thecrystals of the latter present the form of six-sidedprisms. The composition of the spinel ruby and balasruby differ essentially from that of the oriental ruby,the latter being a corundum formed nearly ex-clusively of alumina, while in the former only 70parts in 100 are alumina, and the remainder chieflymagnesia. The colour, moreover, is in part due tothe oxide of chromium, a substance of which theoriental ruby does not contain the slightest trace. In a scientific poi
Diamonds and precious stones, a popular account of gems .. . mmediately the spinelor balas ruby from the oriental ruby, since thecrystals of the latter present the form of six-sidedprisms. The composition of the spinel ruby and balasruby differ essentially from that of the oriental ruby,the latter being a corundum formed nearly ex-clusively of alumina, while in the former only 70parts in 100 are alumina, and the remainder chieflymagnesia. The colour, moreover, is in part due tothe oxide of chromium, a substance of which theoriental ruby does not contain the slightest trace. In a scientific point of view the balas ruby doesnot differ from the spinel ; and many special worksconfound the two completely. But in commercethe stone called Balas has a value very much belowthat of the spinel. CELEBRATED RUBIES. IIÇ In the inventory of the crown jewels of Francethe price of balas rubies is four or five times lessthan that of spinels. CELEBRATED RUBIES. The largest ruby known is one mentioned byChardin as having been engraved with the name ofSheik Fig. 54.—King of Persias Ruby, Tavernier gives a figure of another celebratedruby in the possession of the King of Persia: it isreproduced in Fig. 54. Its weight was 175 carats. A third, belonging to the King of Visapur, hadthe figure and dimensions of Fig. 55. It was cut,as will be seen, en cabochony and it had been boughtin 1653 for nearly $13,866. 120 PRECIOUS STONES. A fourth, seen by Tavernier in India, is repre-sented by Fig. 56. According to the judgment of Tavernier it wasof secondary beauty; yet this celebrated travelleroffered $11,160 to the diamond merchant who pos-sessed it, but could not obtain it at that price. A ruby possessed by Gustavus Adolphus, andpresented by him to the Czarina in 1777, at the
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectgems, booksubjectprec
