General Classification of Solid Earth Materials
Igneous rocks are rock formed from molten materials. These include intrusive rocks (rocks cooled from molten material [magma] below the surface) and extrusive rocks formed on the Earth's surface by volcanism.
Sediments are solid fragments of inorganic or organic material that come from the weathering of rock and soil erosion, and are carried and deposited by wind, water, or ice.
Sedimentary rocks are rocks that formed through the deposition and solidification of sediment, especially sediment transported by water (rivers, lakes, and oceans), ice ( glaciers), and wind. Sedimentary rocks are often deposited in layers, and frequently contain fossils.
Metamorphic rocks are rocks that were once one form of rock but has changed to another under the influence of heat, pressure, or fluids without passing through a liquid phase (melting).