Augite-Rich Gabbro Hand Sample
Augite-Rich Gabbro Gabbro Thin Section

Gabbro

IUGS Definition (QAPF Chart)(Olivine Gabbros)(Hornblende Gabbros)

Gabbro: "A coarse-grained plutonic rock composed essentially of calcic plagioclase (An>50), pyroxene, and iron oxides. If olivine is an essential constituent it is olivine gabbro—if quartz, quartz gabbro."
Photos
Typical Minerals
  • calcic plagioclase feldspar: anorthite, bytownite, labradorite
  • clinopyroxene: augite, diopside
  • olivine
  • accessory minerals: quartz, orthopyroxene, hornblende, biotite, apatite, ilmenite, magnetite