PHYSIOGRAPHY. 



Blue Vitriol. 



77 



Fig. 69. 



BLUE VITRIOL. Tetarto-Prismati c Vitriol- 

 Salt. MOHS. 



Primary form. Doubly oblique prism. P on M 127 

 30'. P on T 108. M on T 123 10'. 



Secondary form. 



M on T - 123 10' 



r on M 126 



r on T 110 



r on n - - 100 



r on P 103 



n on P - 120 



P on T - 127 



t on r - - 1 39 



K on n - - 109 



K on r 114 



s on n - 92 



s on r 139 



Cleavage very imperfect. Fracture conchoidal. Sur- 



face : the faces n commonly deeply striated parallel to 

 their edges of combination with M and T, which faces are 

 also sometimes striated, though not so generally as n. 



Lustre vitreous. Color sky-blue, in different shades, 

 commonly deep. Streak white. Semi-transparent . . . 

 translucent. 



Rather brittle. Hardness =2-5. Sp. gr.=2'213. 



Taste astringent and metallic. 



1. It is easily soluble in water, and gives a blue solution: a polished 

 surface of iron when immersed in this solution is covered with a film of 

 metallic copper. 



2. Analysis. 

 By BERZELIUS. 



Oxide of copper . . . 32-13 



Sulphuric acid . . . 31-57 



Water . . . 36-30 



