Chap. 10.] Turquoife and Malachite. 63 



calx of copper, it is denominated Armenian ftone. 

 Gypfeous earth combined with calx of copper, is 

 called turquoife and malachites. The pureft malachite, 

 according to Kirwan, contains feventy-five parts of 

 copper and twenty five of aerial or Carbonic acid; 

 calcareous earth is therefore not an eflential ingre- 

 dient. It is of a green colour, and is fometimes cut 

 and polifhed as a gem. 



