Metamorphic rock Metamorphic rock Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means "change in form". The original rock (protolith) is subjected to heat (temperatures greater than 150 to 200 °C) and pressure ( or more), causing profound physical or chemical change. The protolith may be a sedimentary, igneous, or existing metamorphic rock. Metamorphic rocks make up a large part of the Earth's crust and form 12% of the Earth's land surface. They are classified by texture and by chemical and mineral assemblage (metamorphic facies). They may be formed simply by being deep beneath
This Is What Rock n' Roll Looks Like depth about the genre mix in "This Is What Rock n' Roll Looks Like": Although the song's title references the physical appearance of what rock and roll looks like, Porcelain Black revealed in an interview with AOL's "NoiceCreep" that rock and roll is not dependent on the physical appearance of someone. She stated: "This Is What Rock n' Roll Looks Like" received generally mixed reviews by critics, most of whom were surprised with Porcelain Black's outgoing persona and the pop production by RedOne. Gerrick D. Kennedy of "Los Angeles Times" complimented the song's production by stating that it could have