GENERAL DESCRIPTIONS 



OF THE 



SPECIES. 



I 



ABRAZITE. (See Gismondin.) 

 ACHMITE. Achmitic Augite-Spar. 



Primary form. Oblique rhombic prism. MonM=934'. 



Secondary form. The primary, having the obtuse lat- 

 eral edges deeply truncated, together with the edges of the 

 base in such a manner as to give rise to a very acute 

 4-sided summit : the acute lateral edges also slightly trun- 

 cated in some instances. 



Cleavage, parallel with M distinct; traces, parallel with 

 the diagonals. Fracture imperfectly conchoidal. Surface, 

 broad secondary lateral planes streaked longitudinally ; the 

 rest, smooth and shining. 



Lustre vitreous. Color brownish-black, with a tinge of 

 yellow or green. Streak pale yellowish-grey. Translu- 

 cent on the edges, to opake. 



Brittle. Hardness =6-0. . .6-5. Sp. gr. =3-2. . .3-3. 



1. Before the blow-pipe it melts into a black globule, which move* 

 the magnetic needle. It affords no moisture by calcination, and is not 



attacked by the acids. 



2. Analysis. 



By BERZELIUS. 



Silica 55-25 



Peroxide of iron 31-25 



Soda 10-40 



Lime 0.72 



Protoxide of manganese, 1*08 

 1 



