Elements of Mineralogy. 

 iron than the yellow pyrites, and not unfre- 

 quently a mixture of calcareous Earth. It 

 fometimes magnetic before, and always 

 after calcination. It is incapable of vitrioli- 

 nation. The iron it affords is brittle. 



SPECIES XIX. 

 Mineralized by Sulphur and Arfenic. 



White, Grey, or Bluifh grey Pyrites , Marcaffiic 

 Raitjh gelb kiefs, Gijt kiefs, Arfenic Stein. 



32. It is found either in folid compact 

 fnafles of a moderate iize, or in grains, it 

 gives fire with fteel ; when burnt, it affords a 

 blue flame, and an arfenical fmell, and by 

 diftillation, orpirnent, or realgar, it is not 

 magnetic, either before or after calcination, 

 it contains much more of arfenic than of 

 fulphur. It is analyfed by digeftion in ma- 

 rine acid, to which the nitrous is gradually 

 added, otherwife the fulphur would be 

 deftroyed. See N? 34. 



SPECIES. XX. 



Mineralized by Arfenic fingly. 



Mifpickel. Speifs of the Bohemians. 



3 5. Its colour is generally of a bright white, 

 fefembiing a mixture of filver and tin, rarely 



variegated 



