C6 PHYSIOGRAPHY. CLASS n. 



GENUS II. CRYONE-HALOIDE. 

 1. PRISMATIC CRYONE-HALOIDE. 



Prismatic Cryolite. JAM. Syst. Vol. II. p. 601. Man. 

 p. 28. Cryolite. PHILL. p. 197- Kryolith. WERN. 

 Hoffm. H. B. III. 1. S. 204. Kryolith. HAUSM. III. 

 S. 846. Kryolith. LEONH. S. 624. Alumine fluate'e 

 alcaline. HAUY. Traite', T. II. p. 398. Tabl. comp. 

 p. 23. Traite', 2de Ed. T. II. p. 157. 



Fundamental form. Scalene four- sided pyramid 

 of unknown dimensions. Vol. I. Fig. 9. Simple 

 forms and combinations unknown. 



Cleavage. P oo perfect. Pr + oo and Pr + oo 

 less perfect or coherent. Traces of P. Fracture 

 imperfect conchoidal, uneven. 



Lustre vitreous, a little inclining to pearly upon 

 the faces of P oo. Colour white, sometimes 

 verging upon red or yellowish-brown. Streak 

 white. Semi-transparent ... translucent. On 

 account of its low refractive power, it appears 

 more transparent when immersed in water. 



Brittle. Hardness = 2-5... 30. Sp. Gr. = 2-963 

 of a white variety. 



Compound Varieties. Massive: composition 

 granular, the individuals being of considerable size. 



OBSERVATIONS. 



1. The prismatic Cryone-haloide consists of 



Alumine 21-0 24-0. 



Soda 32-0 36-0. 



Fluoric Acid and Water 47-0 40-0. 



KLAPROTH. VAUQUELIN. 



It is considered by BERZELIUS to be the compounds Na F 

 + Al 2 F 3 . It is very easily fusible, even at the flame of 



