Granulite

Granulite is a class of high-grade metamorphic rocks that have experienced high-temperature and moderate-pressure metamorphism. Granulites are medium to coarse–grained and mainly composed of feldspars. Sometimes associated with quartz and anhydrous ferromagnesian minerals, with granoblastic texture and gneissose to massive structure.

This mineral of particular interest to geologists because many granulites represent samples of the deep continental crust. Some granulites experienced decompression from deep in the Earth to shallower crustal levels at high temperature; others cooled while remaining at depth in the Earth.

The minerals present in a granulite will vary depending on the parent rock and the temperature and pressure conditions experienced during metamorphism. A common type of granulite found in high-grade metamorphic rocks of the continents contains pyroxene, plagioclase feldspar and accessory garnet, oxides and possibly amphiboles.