Hand Sample Photo
Thin Section Photo

Foid-Bearing Alkali Feldspar Syenite

IUGS Definition ( QAPF Chart )( FAP Chart )

Foid-Bearing Alkali Feldspar Syenite: “A collective term for alkali feldspar syenites containing small amounts of feldspathoids (less than 10% of the felsic minerals).”
Photos
Typical Minerals
  • alkali feldspar
  • minimal plagioclase feldspar
  • feldspathoids
  • augite, aegerine
  • hornblende and/or biotite
  • accessory minerals: zircon, apatite, magnetite, and ilmenite