Granulite facies is a high-grade metamorphic rock formation characterized by high temperatures and pressures. It typically forms at depths of 15 to 30 kilometers within the Earth's crust. The rocks in this facies often contain minerals such as quartz, feldspar, and pyroxene, which indicate the intense conditions under which they were formed. The formation of granulite facies is associated with tectonic processes, such as continental collision and subduction. These processes lead to the alteration of pre-existing rocks, resulting in a dense, often banded appearance. Granulite facies rocks are important for understanding the thermal and tectonic history of the Earth's crust.