Igneous rocks that cooled on the surface of the Earth.
Igneous rocks that cooled underground.
Rocks that are formed under conditions of intense heat and pressure, where pre-existing rock can be physically and chemically altered, transforming into an entirely new rock.
Formed in one of two ways: 1. erosion, subsequent deposition, and lithification of pre-existing rocks. Composed of grained cobbles and pebbles to extremely fine grained clay particles (clastic). 2. Precipitation of minerals from water, like evaporation, or through the actions of organisms in the water. Most likely to contain fossils.