24 Elements of Mineralogy. 



Thefe fpars when pure are always colour- 

 lefs, but fometimes they are found green, 

 brown, reddifh, yellowifh, and even black^ 

 from a mixture of metallic particles. 



De la Hire and Huygens, denote fhom,- 

 boidal fpar under the name of talc. 



SERIES II. 



Under this feries I range a variety of ftones. 

 of the fame fpecies, but which are known 

 under various denominations arrifmg from, 

 external properties, or the apparent mode 

 of their origination -, fuch as opake-fpars, 

 ftalacltites, tophufes, incruftations, petrifacr 

 tions, agaric -mineral, chalk, limeftone, 



Opake Spars. 



Thefe are chryftalize4 under the lame re- 

 gular forms as the tranfparent fpars, and 

 fometimes appear in a globular form ; their 

 texture is alfo lamellar, they are of different 

 colours like the foregoing; the red frer 

 quently receive that tinge from manganefe. 

 16 Roz. 15, 



Stalactites* 



