262 



PHYSIOGRAPHY. 



Vivianite. 



Secondary form. 



P on cl 

 P on d 

 T oncl 

 T on c2 

 T on 6 

 M on cl 

 M on d 



148 5' 



140 35 



134 



125 



108 



157 



120 



5 



40 

 30 

 45 

 45 



Cleavage, parallel with P highly perfect ; traces in oth- 

 er directions. Fracture, not observable. Surface, P 

 smooth ; the rest of the faces streaked parallel to the edg- 

 es of combination of P. 



Lustre pearly, almost metallic on P. The rest of the 

 faces possess vitreous lustre. 



Color pale blackish-green ... indigo blue. It is green at 

 right angles to the axis, but of a pure blue color parallel to 

 it. The united effect of both, produces the common dirty 

 indigo-blue color. Streak bluish white, very soon chang- 

 ing to indigo-blue. The powder produced by crushing 

 the mineral in a dry state, is liver-brown. Transparent... 

 translucent ; least transparent in the direction of the axis. 



Sectile. Thin laminae are perfectly flexible. 



Hardness = 1-5 ... 2-0, the lowest degrees upon P. 

 Sp. gr.=2'661, crystal from Cornwall. 



Compound Varieties. Small reniform and globular 

 shapes, and imbedded nodules ; also superficial coatings of 



