ORDER VI. PRISMATIC AUGITE-SPAE. 287 



Cleavage, in the direction of two faces intersecting 

 each other at angles of 95 25', both being easi- 

 ly obtained, but one of them more perfect and 

 smooth. There are besides imperfect traces of 

 cleavage in various directions, which render it 

 probable that the forms of this species will be 

 found hemi-prismatic or tetarto-prismatic*. Frac- 

 ture uneven. 



Lustre vitreous, inclining to pearly, particularly 

 upon the perfect faces of cleavage. Colour white, 

 inclining to grey, yellow, red, and brown. Streak 

 white. Semi-transparent ... translucent on the 

 edges. 



Rather brittle. Hardness = 40... 5-0. Sp. Gr. 

 = 2-805, of a brownish-white variety from the 

 Bannat. 



Compound Varieties. Massive : composition 

 lamellar, generally longish, and aggregated into a 

 second large grained and angular composition ; 

 strongly coherent. 



OBSERVATIONS. 



1. A variety of the present species from Cziklowa has 



* A tetarto-prismatic crystal is quoted by Mr PHILLIPS. 

 Comparing it with Fig. 82., the obtuse edge produced by the 

 two faces of cleavage M and 7*, which he gives = 95 2(X, is 

 replaced by a face inclined at angles of 139 45' on T, and of 

 135 30' on M. P is inclined on M at an angle of 126, a face 

 replacing the obtuse edge between P and Jl/, on P at an angle 

 of 156 30', and another which replaces the acute edge between 

 P and the opposite face of M, is inclined towards P at an 

 angle of 94 15'. H. 



