Muriatic Genus. 63 



SPECIES III. 



Mild Magnefia combined with Silex, Calcareous 

 Earth, and a fmall proportion of Ar gill and 

 Iron* 



I. VARIETY. 

 Fibrous AfoeJloS) Alwnen Plumofum. 



The colour of this ftorie is generally green- 

 ifh, and it confifts of .filaments either parallel 

 to, or interwoven \vith each other. It is 

 rough to the touch, and brittle and uneven in 

 ks fraflure, hence it does not ftrike fire with 

 fteel. Its fpecific gravity is from 2,5 to 2,8. 



It does not effervefce with acids, and is fo- 

 luble in them but partially, and by particular 

 management. 



When fufficiently heated, it becomes fome- 

 what whiter and more brittle, but is infufible 

 per fe by the blow-pipe, unlefs it contains a 

 notable proportion of calx of iron. It is 

 difficultly fufible with mineral alkali, more 

 eafily with borax and microcofmic fait, and 

 with fcarce any effervefcence. It is never 

 tranfparent, and in that refpet, and in the 

 unevenefs of their fradure only, fome forts 



of 



