16 



PHYSIOGRAPHY. 



Anatase Andalusite. 



1. Before the blow-pipe, it behaves like pure oxide of titanium. It 

 dissolves, with difficulty, in the salt of phosphorus, and the portion not 

 melted becomes white and semi-transparent. The experiments of VATJ- 

 QTJELIN prove it to be a pure oxide of titanium. 



2. It occurs in narrow, irregular veins, consisting of those species 

 which constitute the rocks themselves, viz. Albite, Quartz, Mica and 

 Augite, and is sometimes accompanied by Axinite and Crichtonite. 



Its chief localities are Bourg d'Osians, in Dauphiny and Switzerland ; 

 but it is also found in Cornwall, in Norway, in Spain and Brazil. 



ANDALUSITE. Prismatic Andalusite. MOHS. 



Primary form. Right rhombic prism. MonM'=912Q' 

 Secondary forms. 



Fig. 10. 



Fig. 11. 



M 



M on M' - - - 91 20' 



P on M' or M - 90 00 



P on c - 140 00 



d on c - 145 00 



g ong - 125 00 



Cleavage, parallel with M and M 7 distinct; parallel with 

 P scarcely perceptible. 

 Fracture uneven. 



Surface uneven and rough. Generally covered with 

 plates of Mica or Talc. 



Lustre vitreous. Color flesh-red passing into pearl- 

 grey. Streak white. Translucent on the edges. 



