Alkali feldspar

From Wikipedia, the free encyclopedia
Jump to: navigation, search

The alkali feldspar group are those feldspar minerals rich in the alkali elements, potassium and sodium. The alkali feldspars include albite, anorthoclase, microcline, orthoclase and sanidine.[1] Albite is considered as one of the alkali feldspars according to its chemical composition and it is also the alkali endmember of the plagioclase series.[2]

Potassium and sodium feldspars are not perfectly miscible in the melt at low temperatures, intermediate compositions of the alkali feldspars therefore occur only in higher temperatures environments.[2]

References[edit]

  1. ^ "Alkali Feldspar". mindat.org. Retrieved 04-12-2011.  Check date values in: |accessdate= (help)
  2. ^ a b Klein, Cornelis and Cornelius S. Hurlbut, Jr. Handbook of Mineralogy, Wiley, pp. 446-449 (Fig. 11-95 ISBN 0-471-80580-7