INDEX. 369 



ISi-erZ (crjftaillzatiom). 



Varieties of form and colour* 



1. Magnetical olactJSaa, appears under the microfcope to 

 be prifmatical hexagones ; in Vefuvian and many vol- 

 canic afhes, 130. 145. & paffimi 



2. Points and flakes, black, in grey lava, from monte 



Catajo. 15. 



In grey Vefuvian Lava, 137. 145". 15$. 



In Porphyry, 223. 



In Mifpikkel or arfenical pyrites, fuppofed to be Vefu- 

 vian, 142. 



3. Lamellous and lamellae, or Sberl-mica and Glimmer^ 63. 

 In Vefuvian Lava, black, 145. 



In Piperino, 181. 



In oriental Bafakes, 230, 231 33. 



In Granite, 228. 



4. Feathers, black, round arid hexagonal, thin. 

 In Vefuvian Lava, 144. 155. 



5. Cubic black Mka, or Glimmer, called Hornllendt; 

 In Trapp, 7. 



In white Quartz, hiclofed in Piperino of monte Al- 

 bano^ 196; 



6. Regular Parallelopipeda. 



a. IWnte, bignefs and length of a finger, in black 



Lava, 85. 



In red Porphyry, 223. 



In black Porphyry, 224. 

 1. Black, large, a fpecies of HornUcn.*, breaks cubic. 



In antique Granito neroe bianco, 228. 

 c, Green, in green Porphyry, 225. 



j>. Cylindrical, columnar,' rifled and lengitkdinalfy^JlriateJ 

 trur^attd ; tilangeu-fierl or Stangen-fpath. 

 a. Green, vitreous, femi-pe,lucid, endowed with th 



double electricity. 



E b from 



