Cape Ann Granite
Cape Ann Granite

Alkali Feldspar Granite

IUGS Definition ( QAPF Chart )( QAP Chart )

Alkali feldspar granite: "A special term for a variety of granite in which plagioclase is less than 10% of the total feldspar."
Photos
Typical Minerals
  • alkali feldspar, orthoclase or microcline, may be perthitic
  • quartz
  • biotite
  • hornblende, arfvedsonite or riebekite if peralkaline
  • aegirine if peralkaline
  • opaque minerals: ilmenite, magnetite
  • accessory minerals: apatite, zircon, monazite