

PHYSIOGRAPHY. 



Brewsterite. 



87 



Secondary form. 



Fig. 77. 



P on d - 93 50' P on c4 - 92 00' 



Pond - 119 30 d on c2 - 95 00 



Ponc2 - 114 30 d on d' - 175 00 



PoncS - 112 00 (172 HAIDINGER.) 



Cleavage, perfect parallel to P, traces parallel to T. 

 Fracture uneven. 



Faces slightly streaked parallel to their common inter- 

 sections. 



Lustre vitreous, pearly upon P. Color white, inclining 

 to yellow and grey. Transparent . . . translucent. 



Hardness =5-0 . . . 5-5.' Sp. gr. =2-12 . . . 2-20. 



1. Before the blow-pipe, it loses first its water and becomes opake, 

 then it froths and swells up, but is with difficulty fusible. It gives a skel- 

 eton of silica with salt of phosphorus. 



2. Analysis. 

 By THOMSON. 



Silica .... 58-800 



Alumina - ... 18912 



Lime - - - - 12-384 



Potash 1-500 



Water .... 11-700 



103-296. (The excess 

 of 33 p. c. was attributed lo soda employed in the analysis.) 



3. It is found lining cavities in a granitic rock at Strontian, in Argyll- 

 shire in Scotland. 



BRIGHT WHITE COBALT. (See Smaltine.) 



