Metamorphic rocks are one of the three main types of rock. Originally comprising either igneous or sedimentary rocks, metamorphic rocks are the products of change by heat and pressure, often at great depths in the earth's crust, into a completely new form. One of the classic examples of the result of a metamorphic process is the transformation of sedimentary mudstone into slate.Introducing Metamorphism provides a succinct introduction to metamorphism...