36 Elements of Mineralogy. 



Eefchaft. 330 ; and in fadt, iron, precipitated 

 from the fparry acid by lime water, is white, 

 with blue fpecks. Green fluors owe alfo their 

 colour to iron. Rinman, 206. 



Moft fluors contain a mixture of argilla- 

 ceous and filiceous Earths, and fome marine 

 acid. The filiceous Earth, which fublimes 

 in diflilling thefe fpars, arife, from thefolution 

 of that pre-contained in the fpar, or from 

 .he corroiion of the glafs veflels, as Meflrs. 

 Mayer and Wiegleb have (hewn ; this acid pof- 

 feffing the fmgular property of diffblving 

 filiceous Earths, and confequently glafs. 



The varieties of this fpecies may be re- 

 duced to two, the tranfparent and opake ; of 

 which there are neceflarily many interme- 

 diate fhades. 



SERIES I. 



Tranfparent. 



Thefe are generally of a regular fhape, 

 cubic, rhomboidal, polygonal, and of diffe- 

 rent colours ; and hence called pfeudo-eme- 

 raids, fapphires, topazes, amethyfts, &c. 

 Some are amorphous. 



SERIES IL 



