54 ON THE PRIMITIVE FORMS OF CRYSTALS. 



2. Bight Quadrangular Prism, — Base a Rectangle. 



Cymophane. 

 Peridot. 

 Prehnite. 

 Stilbite. 



Anhydrite. Bournon, Journ. des Mines, vol. xiii. 

 p. 346. 



Tartrate of potash. Bournon, Cat. p. 191. 

 Tesselite or Prismatic apophyllite *; Journ. des 

 Mines, vol. xxiii. p. 385. 



3. Right Quadrangular Prism, — Base a Rhomb. 

 Topaz. 



Staurotide. 



Datholite. Journ. des Mines, vol. xix. p. 362. 



Mica. 



Talc. 



Spodumene. 

 Sulphate of barytes. 

 Sulphate of strontian. 

 Sulphate of soda. Bournon, Cat. p. 183. 

 Citric acid. Bournon, Cat. p. 194. 

 Tartrate of potash and soda. Bournon, Cat 

 p. 193. 



* See the Edinburgh Philosophical Jotirnal x 1819; N° Ir 

 p. 5. 



