ga A SYSTEM OF' 



. if. Loofe and friable, Pulverulent a Jive friabi- 

 lis. Mountain blue, Cceruleum montanum., 

 Germanice, Bergblau. 



This diiTolves in aquafortis with effervef- 

 cence. 



SECT. XXXV. 



B. Indurated, indurata. 



i. Pure calcareous earth mixed with calx of 

 copper. Armenian ftone, Lapis Armenus. 



Such, according to the defcription of 



authors, ought the nature of the ftone 



. called Lapis Armenus to be, though the 



druggifts fubftitute in its ftead a pale blue 



Lapis Lazuli, free from Marcafite. 



* SECT. XXXVI. 



2. Gypfeous Earth united with calx of Cop- 

 per, Terra gypfea Venere mixta. Is of a 

 green colour, and might perhaps be called 

 Turquoife ore, or Malachites - y though I do 

 not know if all forts of Turquoife ore are 

 of this nature. 



a. Semi-tranfparent, is found at Ardal 

 . in Norway *. 



* By chemiftry we know, that alcaline falts produce a blue 

 colour with copper, which is changed into green, as foon as 

 any acid is added ; and from thence the reafon is obvious, 

 why a green colour may be found among calcareous copper 

 ores, viz. when the vitriolic acid is in the neighbourhood of 

 it. 



SECT. 



