ClipArt ETC
"Maximum extinction angles in the Pyroxene and Amphibole groups. Solid lines indicate extinction angles from c to c; broken lines from c to a. The extinction angle in an amphibole is generally less than 23 degrees; in a pyroxene it is generally greater. " -Johannsen, 1908

Extinction Angles

"Maximum extinction angles in the Pyroxene and Amphibole groups. Solid lines indicate extinction angles…

"Extinction angles on the (001) faces of the lime-soda feldspars." -Johannsen, 1908

Extinction Angles

"Extinction angles on the (001) faces of the lime-soda feldspars." -Johannsen, 1908

"Extinction angles on the (010) faces of the lime-soda feldspars." -Johannsen, 1908

Extinction Angles

"Extinction angles on the (010) faces of the lime-soda feldspars." -Johannsen, 1908