Basalt Hand Sample
Basalt Thin Section

Basalt

IUGS Definition ( QAPFv Chart )( QAPv Chart )

Basalt: A volcanic rock consisting primarily of plagioclase and clinopyroxene with mafic minerals greater than 35 percent (M>35%).
Photos
Typical Minerals
  • calcic plagioclase feldspar: anorthite, bytownite, labradorite
  • clinopyroxene: augite, pigeonite
  • olivine
  • accessory minerals: ilmenite, magnetite
  • glass or mesostasis