Igneous Rock Igneous rock forms when molten material, or magma, cools and hardens. Examples: granite, obsidian, pumice
Metamorphic Rock Metamorphic rocks form when heat or pressure or both cause changes in the other two types of rock. Examples are: marble, slate and quartzite.
Sedimentary Rock Sedimentary rock forms when small pieces of clay, silt or sand settle into layers on the bottoms of lakes and oceans. The pressure of the water and the layers above compress the pieces into rock. Examples: sandstone, limestone, shale
Igneous Rock Metamorphic Rock Sedimentary Rock THE ROCK CYCLE
CREDITS The Mailbox Magazine for Teachers Three Rocks. United Learning. 2003. Discovery Education. 12 December 2008 <http://streaming.discoveryeducation.com/> http://www.kidsgeo.com/geology-for-kids/0028-metamorphic-rocks.php All photographs are my own.