Igneous rocks: Igneous rocks are formed from molten rock named smegma, this is found inside the earth. When smegma cools, it forms igneous rocks. If smegma cools underground, it cools slowly, this means that the rock produced contains crystals, eg. granite. If smegma erupts from a volcano, it cools quickly, this means that the resulting rock contains small crystals eg. basalt.
Characteristics: Formed from molten rock, randomly arranged crystals, very resitant, no fossils, intrustive or extrusive