86 PHYSIOGRAPHY. 



Braunite Brewsterite. 



Compound Varieties. Massive : composition granular 

 individuals strongly coherent. 



1. Analysis. 



By TURNER. 



Protoxide of manganese . . . 86*940 



Oxygen 9851 



Water 0-949 



Baryta < . , . , 2-260 



Silica a trace. 



2. It is yet a rare mineral, having been brought only from a few pla- 

 ces in Thuringia, (Elgersburg, Ehrenstock and Friedrichsrode,) and from 

 Wunsiedel in the Bayreuth. 



BREISLAKITE. 



Acicular and capillary crystals ; bent and grouped like wool. 



Color reddish, or chesnut brown. 



1. Nitric acid, when heated, reduces it to a most impalpable powder 

 of a yellow color. In the flame of a lamp, the crystals suffer no change ; 

 but before the blow-pipe they melt into a black enamel. It gives with 

 salt of phosphors a green globule in the oxidating flame, which be- 

 comes red in the reducing flame of the blow-pipe, thus indicating a con- 

 siderable quantity of copper. 



2. Analysis. Dr. WOLLASTON is said to have made a chemical ex- 

 amination of this species ; the result of which was-, that it consisted of si- 

 lica, alumina, and a little iron. 



3. Breislakite lines the small cavities in the lava of Scalla, where it is 

 accompanied by Atacamite and Nepheline. It is also found under simi- 

 lar circumstances in the lava of Olebano, near Pozzuoli. 



BREUNERITE. (See Rhomb-Spar.} 



BREWSTERITE. Polyprismatic Kouphone- 



Sp a r . 



Primary form. Right oblique angled prism. M on 

 T = 93 40'. 



