Hand Sample Missing
Thin Section Missing

Alkali Feldspar Syenite

IUGS Definition ( QAPF Chart )( QAP Chart )

Alkali Feldspar Syenite: “A special term for a variety of syenite in which plagioclase is less than 10% of the total feldspar.”
Photos
Typical Minerals
  • alkali feldspar: perthitic orthoclase or microcline
  • pyroxene: augite, aegerine, or hypersthene
  • minor olivine, fayalite
  • quartz (less than 5%)
  • accessory minerals: apatite, sphene