Feb 27, 2017. 1  Tonight, Casey Affleck took home the Academy Award for Best Actor for his role in Manchester by the Sea. While this might be a reason for celebration for the new Oscar-winner, not everyone was so eager to join in with the applause.
Bituminous coal is a sedimentary rock. Anthracite coal is considered a metamorphic rock.
A metamorphic rock used to be some other type of rock, but it was changed inside the Earth to become a new type of rock. The word metamorphism comes from ancient Greek words for change (meta) and form (morph). The type of rock that a metamorphic rock used to be, prior to metamorphism, is called the protolith. During metamorphism the mineral content and texture of the protolith are changed due to changes in the physical and chemical environment of the rock. Metamorphism can be caused by burial, tectonic stress, heating by magma, or alteration by fluids. At advanced stages of metamorphism, it is common for a metamorphic rock to develop such a different set of minerals and such a thoroughly changed texture that it is difficult to recognize what the protolith was.