Metamorphic rocks
Metamorphic rocks originate from igneous or sedimentary rocks. These rocks underwent changes due to great pressure and heat, without melting, to become metamorphic rocks. This happens when the rocks are in contact with cooling hot magma or when the rocks are in the areas where mountains are forming.
Some metamorphic rocks have layers. Some do not. Some may contain fossils. Examples of metamorphic rocks are marble, slate and gneiss.