Granulite

Granulite is a high-grade metamorphic rock formed under hot, relatively dry conditions. It typically has a granoblastic texture and contains minerals stable at granulite-facies temperatures.

Granoblastic texture: A metamorphic rock texture made of interlocking, roughly equant mineral grains. Its equant grains are characteristic of many granulites.
Granulite facies: A high-temperature metamorphic facies characterized by mineral assemblages stable at granulite-grade conditions. It names the metamorphic conditions under which granulite commonly forms.
Lewisian complex: A Precambrian assemblage of ancient metamorphic rocks exposed in northwest Scotland. Its granulites preserve evidence of high-grade metamorphism in ancient continental crust.
Amphibolite: A metamorphic rock dominated by amphibole and plagioclase, commonly formed at medium to high grades. Amphibolite commonly contains hydrous amphibole where granulite assemblages are relatively dry.
Metamorphic facies: A group of metamorphic mineral assemblages associated with a particular range of pressure and temperature. Granulite names both a rock type and the high-grade conditions recorded by its minerals.
Metamorphic dehydration: The release of water from minerals during metamorphic reactions. Dehydration reactions help create the relatively dry conditions associated with granulites.
Limpopo Belt: A major Precambrian high-grade metamorphic belt between the Kaapvaal and Zimbabwe cratons in southern Africa. Its granulites record deep-crustal processes during the assembly of ancient continents.
Eclogite: A high-pressure metamorphic rock dominated by garnet and omphacitic pyroxene. Eclogite records much higher pressure than the conditions typical of granulite.
Orthopyroxene: A pyroxene mineral group whose crystals contain iron and magnesium but little calcium. Its presence in many granulites reflects high-temperature, relatively dry mineral stability.
Partial melting: The melting of some, but not all, minerals in a rock during heating. High temperatures that produce granulites can also cause partial melting.

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