PHYSIOGRAPHY. 



Braunite. 



85 



BRAUNITE. Brachytypous Manganese-Ore. 

 HAIDINGER. 



Primary form. Octahedron with a square base. P on 

 P over the base, 108 39'. 



Secondary forms. 



1. Primary form, with the summits replaced by tangent 

 planes. Wunsiedel, Bayreuth. 



Fig. 76. 



Wunsiedel. 

 Elgersburg. 



Bt. Marcel, Piedmont. 



s on s over the summit 96 33' 



s on s at the base - 140 30' 



P on x and x, alternately - 144 4' and 128 IT 



xon x at the base - 154 25' 



Cleavage very distinct parallel with the primary faces. 

 Fracture uneven. Surface o possesses less lustre than P, 

 but is even, and sometimes faintly streaked parallel to the 

 edges of combination with P. Primary faces often a little 

 rounded ; faces s uneven, rough, and horizontally streaked 5 

 faces x smooth and even. 



Lustre imperfectly metallic. Color dark brownish black, 

 Streak of the same color. 



Brittle. Hardness = 6-0 ... 6-5. Sp. gr. = 4-818. 

 8 



