MINERALOGY. Si 



SECT. L x 



E. Quartz. Quarizv,:n* . 



This ftone is very common in Europe, 

 and eafier to be known than defcribed. It 

 is diftino-uiihed from the other kinds of 

 the iiliceous order, by the following qua- 

 lities. 

 i. That it is moil generally cracked 



throughout, even in the rock itfelf, 



whereby 

 2. As well as by its own nature, it breaks 



irregularly, and into fharp fragments, 

 g. That it cannot eafily be made red hot, 



without cracking itill more. 



4. It never decays in the air. 



5. Melted with pot-afhes, it gives a more 

 folid and fixed glafs than any other of the 

 filiceous order. 



6. When there has been no interruption in 

 its natural accretion, its lubftance always 

 criftallifes into hexagonal prifms, pointed 



at one or both ends. 



7. It occurs in clefts, mTures, and fmall 

 veins in rocks. It very feldom forms 

 large veins, and flill feldomer whole 

 mountains, without being mixed with he- 

 terogeneous fubftances. 



SECT. U 



The Quartz is found, 



1, Pure, Qv.arizumpirum. 



A. Solid, of no vifible particles with a 

 gloffy furface. Parti cults impalpabilibus 

 fupe>ficie polita. Fat Quartz. 



* I fhall adopt this name of quartz inEnglifh as it has al- 

 ready gained a.cefs into the other European- languages. D. C. 



a, un- 



