Types of Rocks • There are three main types of rocks: Igneous - formed when molten rock cools Sedimentary – formed by the “cementing together” of small grains of sediment Metamorphic – rocks changed by the effect of heat and pressure Igneous Rocks • These are rocks formed by the cooling of molten rock (magma.) Magma cools and solidifies forming igneous rocks volcano magma Sedimentary Rocks • Getting older Sedimentary Rocks are rocks formed when particles of sediment build up and are “cemented together” by the effect of pressure and minerals Fragments washed to the sea Rocks are broken up by the action of weather sea Sedimentary rocks Metamorphic Rocks • • Metamorphic rocks are formed by the effect of heat and pressure on existing rocks This can greatly affect the hardness, texture or layer patterns of the rocks Pressure from surface rocks metamorphic rock Magma heat forming here This powerpoint was kindly donated to www.worldofteaching.com http://www.worldofteaching.com is home to over a thousand powerpoints submitted by teachers This is a completely free site and requires no registration Please visit and I hope it will help in your teaching