Amphibolite

Amphibolite is a metamorphic rock that contains amphibole, especially the species hornblende and actinolite, as well as plagioclase.

Amphibolite is a grouping of rocks composed mainly of amphibole and plagioclase feldspar, with little or no quartz. It typically dark-colored and dense, with a weakly foliated or schistose (flaky) structure. The small flakes of black and white in the rock often give it a salt-and-pepper appearance.