200 On Gems. 



fras, oflfered it to sale at Amsterdam, and the late prince 

 OrlofF bought itpf him tor the empress of Russia. 



3d. The diamond of the great mogul is cut in rose^ 

 weigh* 279-i®,r carats, and is worth 380,000 guineas. 



4th. Another of the king of Portugal, which is cut, 

 weighs 215 carats, is extremely fine, and worth at least 

 36!), 800 guineas. 



5th. The diamond of the grand duke of Tuscany, now 

 of the emperor of Germany, weighs IsgJr carats, and is 

 valued at 109,520 guineas. 



6th. The diamond of the late king of France, called the 

 Pitt or Regent, weighs I36| carats: this gem is worth 

 208,333 guineas. It was sold by governor Pitt to the 

 duke of Orleans for 135,000 pounds. 



7th. The other diamond of the same monarch called the 

 Grand Sancis, weighs 55 carats *, and cost 25,000 guineas. 



8th. The diamond called the Pigot weighs 47| carats, 

 valued at 20,000 guineas : parted with by the Pigot family 

 by lottery in 1 800. 



Tlie Riihj. 



The nibv is a precious stone of a fine full red colour, 

 electrical by friction, giving fire with steel ; the most pon- 

 derous and the hardest of the precious stones after the dia- 

 mond : it crystallizes in long hexacdral pyramids applied 

 base to base without an intermediate prism. 



Its specific gravity is from 3-18 to 4*283. It is not vi- 

 trified in the fire without addition, and even resists the ac- 

 tion of the burning mirror. Flame urged by oxygen gas 

 easily fuses it. It does not lose its colour at the degree of 

 heat which is sufticient to melt iron. The borate of soda 

 and microcosmic salt fuse it, and give a transparent glass 

 of a pale green colour : with the mineral or vegetable alkali 

 the glass is opake, and of various colours. 



A perfect ruby above 3^ carats weight is more valuable 

 than a diamond equally heavy. If it weighs one carat, it is 

 worth 10 guineas; two carats, 40 guineas; three carats, 

 150 guineas; if six carats, above 1000 guineas. 



There are 108 rubies in the throne of the g'-eat mogul, 

 which from their weight are called carbuncles ; they are 

 from 100 to 200 carats each. 



The varieties of the ruby are called the oriental ruby, the 

 spinelle ruby, the balass ruby, and the rubicelle. The first 

 is of a deep red colour ; the second of a bright corn poppy- 



♦ Chaptal says io6 carats. 



flower 



