li 8 Elements of Mineralogy. 



is found in Finland, Bohemia, Silefia^ Saxony 

 and Hungary, 



II. VARIETY. 



ICdloiv. 

 Topaz, Hyacinth. 



Topas is of a gold colour; its texture fo^ 

 liaceous ; its form cubic, parallelipedal, or 

 prifmatic ; its fpecific gravity from 3,46 to 

 4,56 ; it lofes its colour only in a very iirong 

 heat, and of the ufual fluxes it yields only to 

 borax and microcofmic fait. 



According to Mr. Bergman^ 100 parts of 

 it contain 46 of argil}, 39 of filiceous Earth, 

 8 mild calcareous, and 6 of iron. Its great 

 fpecific gravity ihews thefe Earths to be very 

 perfectly united. 



Oriental hyacinth is of a reddifh yellow 

 colour, generally cryftalized in a prifmatic 

 form ; in a ftrong heat it becomes paler, and 

 according to Mr. Achard, may be melted in 

 a wind furnace in 2 hours, 



According to Mr. Bergman, 100 parts of 

 it contain 40 of argill, 25 of filex, 20 of 

 jnild calcareous Eartfy, $nd 13 of iron; and 



according 



