What is metamorphic rock?
A metamorphic rock can be foliated or nonfoliated. Foliated rock will display parallel alternating bands of different colored minerals or layering that were formed in response to directed pressure. Nonfoliated metamorphic rock is usually the product of the metamorphosis of fairly pure sedimentary rocks like sandstone (quartzite) and limestone (marble) and does not display foliation, but simply the recrystallization and enlargement of existing mineral crystals.