The oldest continental rocks are found in cratons. A craton is a stable part of the continental lithosphere,
There are three main types of rocks:
- Igneous rocks, which are the products of magma cooling
- Sedimentary rocks, which are the products of erosion of all types of rocks or deposition of organic matter
- Metamorphic rocks, which are rocks of either of the two former types transformed by very different conditions of pressure and temperature than those under which they were formed