C "7 3 



hedrons* and their varieties, indeterminate ; found 

 in a fandy earth in the hither penfnfula of India, 

 in the ifland of Borneo, and in the Brazils. Dia- 

 monds are of a lamellated texture, and may be 

 fplit by a blow in a proper direction ; cut all 

 other fubftances, and take a mod exquifite po- 

 lifh. 



b. Sapphire is next in hardnefs to the diamond ; 

 the ftone worn by the high prieft of the Jews ; of 

 a fky blue colour, fometimes inclining to pink, 

 fometimes almoft white, and then called lux sap- 

 phire ; it is found cryftallized in lengthened hexa- 

 hedral prifms joined bafe to bafe. Anal. Silex 

 35. Argill 58. Carbonate of lime 5. Iron 2. 

 Bergman. 



c. Topaz of Brazil, colour various, the true 

 oriental is almoft colourlefs, or pale yellow ; the 

 Brazil is of a fine, yellow, tranfparent amber, cryf- 

 tallized in tetrahedral rhomboidal prifms, termi- 

 nated by tetrahedral pyramids. 



d. Topaz of Saxony, cryftallized in four-fided 

 rhomboidal prifms, terminating from the fides in 

 flat four-fided pyramids, longitudinally floated, 

 and of a foliaceous texture. Anal. Silex 52. Ar- 

 gill 44. Lime 2. Iron 0,03. Wiegleb. 



e. Beryl of Siberia, colour greyifh green, verg- 

 ing on the apple green, more rarely bluifh green ; 

 cryftallized in equi-angular hexahedral prifms 

 longitudinally ftreaked ; becomes eleclric by 



* Icofahedrons, ex smo-i, viginti ; et 3§oc, bafis. 



fri£tion, 



