Rock Types - Geological Formations

An explanation of the geological processes which lead to the formation of different types of rock. Earth Science - Geology - Learning Points. There are three types of rock: sedimentary, igneous and metamorphic. Sedimentary rock forms when deep layers of mineral and organic particles are compacted over millions of years, e.g sandstone. Igneous rocks form when magma cools to a solid, e.g basalt. Metamorphic rock is formed when rock is subject to heat and pressure, e.g. slate is produced from shale hardened as pressure and heat have rearranged the layers. A Twig Curriculum Film. Delivering key learning points. Get straight to the facts in just three minutes – directly linked to core learning, Twig's curriculum films will fit neatly into your lesson plans.