More From Geology Rocks. Slate is made of fine-grained interlocking crystals which lie flat in the same direction, known as the cleavage direction, along which the rock easily splits. Schist is made of medium-grained interlocking crystals. Its shiny appearance is due to the mineral mica. Crystals line up to give the rock wrinkly layers — this is called foliation. Gneiss is made of coarse-grained interlocking crystals. Enjoy our metamorphic rock facts for kids.
Find interesting information and a range of examples that help explain what metamorphic rocks are and what makes them different from other kinds of rocks. Metamorphic rocks can be formed by pressure deep under the Earth's surface, from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
Examples of metamorphic rocks include anthracite, quartzite, marble, slate, granulite, gneiss and schist. Anthracite is a type of coal with a high carbon count, few impurities and with a high luster meaning it looks shiny. Schist is often referred to as schistosity because of its large mica flakes. Large crystals cause schist rocks to reflect lots of light which gives it a very shiny appearance. The large crystals in schist indicate the amount of pressure and temperature that was used to make the rock.
Specific schist rocks are named for the dominant mineral that is a part of its make-up. Schist is derived from a German word meaning to split. Most schist rocks originate as some type of clay or mud.
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