Amphibolites are metamorphosed mafic rocks and consists principally of plagioclase and hornblende and/or clinopyroxene.
The photographs above (crossed polarized view on the left, plane polarized light on the right) show plagioclase (white, light gray), hornblende (strongly colored in right-hand photo), and moderately birefringent clinopyroxene. Note that in metamorphic rocks, plagioclase is typically xenoblastic (anhedral) and unzoned.
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