230 PHYSIOGRAPHY. 



Glauberite Glauber Salt. 

 Secondary form. 



P on e or e' 137 9' ) g C M on e 147 40' 



e on e' 116 20 V | {P on/ 112 20 



M or M' on/ 131 35 ) I ( e or e' on/ 132 37 



The planes M and / are often wholly wanting. 



Cleavage, parallel with M and M' perfect; traces of P 

 but interrupted by conchoidal fracture. Fracture conchoi- 

 dal. Surface, planes e streaked parallel to their common 

 edges of combination, partly uneven, but smooth and shi- 

 ning. 



Lustre vitreous. Color yellowish or greyish-white. 

 Streak white. Semi-transparent , . . translucent. 



Brittle. Hardness = 2'5 . . . 3-0, Sp. gr, = 2-807. 



Taste feebly saline and astringent. 



1. Before the blow-pipe, it decrepitates, and melts into a white ena- 

 mel. Immersed in water, it loses its transparency, and is partly dissol- 

 ved. The same appears in a moist atmosphere. 



2. Analysis, 

 By BRONGNIART. 



Sulphate of lime .... 490 

 Sulphate of soda . . . . 51-0 



3. It occurs in imbedded crystals in Common Salt, at Villarubia, near 

 Ocanain New Castile. Another locality is Aussee in Uppe* Austria. 



GLAUBER SALT. Prismatic Glauber-Salt. 

 MOHS. 



Efflorescent, and in mealy crusts. 



