248 PHYSIOGRAPHY. CLASS II. 



4. The localities quoted a v e the Faroe islands, and seve- 

 ral iron mines in Sweden and Norway. 



GENUS VI. PETALINE-SPAR. 

 1. PEISMATIC PETALINE-SPAR. 



Prismatic Petalite. JAM. Man. p. 152. Petalite. PHILL. 

 p. 143. Petalit. LEONH. S. 485. Petalite. HAUY. 

 Traitd, 2de Ed. T. III. p. 137. 



Fundamental form. Scalene four-sided pyramid 

 of unknown dimensions. Simple forms, charac- 

 ter of combinations, &c. unknown. Combinations 

 not observed. 



Cleavage, a prism of 95 nearly, more distinct its 

 long diagonal. Fracture imperfect conchoidai. 



Lustre vitreous, inclining to resinous ; it inclines 

 to pearly upon perfect faces of cleavage. Colour 

 white, in various reddish and greyish shades, 

 sometimes inclining to green. Streak white. 

 Translucent. 



Brittle. Hardness = 6-0 ... 6-5. Sp. Gr. = 2-439, 

 a cleavable reddish-white variety. 



Compound Varieties. Massive: composition co- 

 lumnar, of various sizes of individuals, sometimes 

 impalpable and generally strongly coherent. If 

 the composition be impalpable, fracture becomes 

 splintery. 



OBSERVATIONS. 



1. The cleavage of the present species is said by HAUY 

 to take place parallel to the planes of a four-sided prism of 



