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Foid Diorite

IUGS Definition ( QAPF Chart )

Foid Diorite: “A collective term for alkaline plutonic rocks consisting of feldspathoids (10%-60% of the felsic minerals), intermediate plagioclase and large amounts of mafic minerals.”
Photos
Chemistry
Typical Minerals
  • intermediate plagioclase: andesine or calcic oligoclase
  • feldspathoids
  • pyroxene: usually augite, but also diopside and orthopyroxene
  • accessory minerals: apatite, sphene, ilminite, zircon