PHYSIOGRAPHY. 



Ankerite Anorthite. 



Fig. 28. 



Massive : composition granular, individuals in most cases ea- 

 sily discernible, often mixed with Calcareous Spar. Faces 

 of composition uneven and rough. 



1. It becomes black before the blow-pipe without melting, and acts 

 upon the magnetic needle. With borax it melts into a pearl. The color 

 is darkened on the surface by being exposed to the air. 

 2. Analysis. 



By SCHROTTER. 



Carbonic acid with oxide of iron 



Lime .... 



Magnesia .... 



Oxide of manganese . 

 3. The Ankerite occurs in the Rathhausberg in Salzburg upon beds in 

 mica-slate, and in many places upon the beds of Heavy Spar, extending 

 from Stiria along the whole chain of the Alps. The Ankerite forms veins 

 in the transition limestone about the city of Quebec, and in the U. States 

 it occurs in connexion with the coal formation at West Springfield, (Mass.) 



35-308 

 50-113 

 11-846 



3-084 



ANORTHITE. 



PARTSCH. 



Primary form. Doubly oblique 

 prism. 



Anorthotomous Feldspar. 



Fig. 29. 



MonP 

 MonT 

 P onT 



94 12' 

 117 28 

 110 57 



