Distinguishing the Feldspars

Steven Dutch, Professor Emeritus, Natural and Applied Sciences, Universityof Wisconsin - Green Bay


The Principal Feldspars

Potassium Feldspars: KAlSi3O8

Plagioclase Series

Mixtures of Feldspars

Other Feldspars

Summary of Feldspar Occurrence

Potassium Feldspars: KAlSi3O8

Plagioclase Series

Mixtures of Feldspars

Other Feldspars

  Crystal Class      
Microcline Triclinic      
Orthoclase Monoclinic      
Sanidine Monoclinic      
Anorthoclase Triclinic      
         
Albite Triclinic      
Oligoclase Triclinic      
Andesine Triclinic      
Labradorite Triclinic      
Bytownite Triclinic      
Anorthite Triclinic      
         

Plane-Polarized Light

Crossed Polarizers



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Created 20 December 1999, Last Update 20 December 1999