R. A. Daly. Amphiboles and Pyroxenes 



0° 10° 20° 30° 40° 50° 60° 70° 80° 90° 



2 V= 90° 



2 V: 



2V= 70° 



2 F=60o 



2 V= 50° 



0^ 10° 20° 30° 40° 50° 60° 70° 80° 90° 



Plate II. — Sliowing curves formed on the same plan as those of Plate I. The 

 extinction on (010) is here 15°. 



