Rocks that are intrusive, as they are formed within the Earth's crust. e.g. granite. They form by magma crystallising within the crust.
Plutonic rocks
Rocks that are extrusive, as they are formed on the Earth's surface, e.g. basalt. These are igneous rocks that form by magma solidifying on the Earth's surface.
Volcanic rocks
Sedimentary rock formed from the remains of animal and plant life
Organic Sedimentary Rock
Sedimentary rock formed from the broken-down remains of pre-existing rock.