Igneous Rock: Igneous rocks form as liquid lava cools, forming crystal structured tocks. There are many types of igneous rocks.
Sedimentary: Over the course of millions of years, forces of wind and water weather the igneous rocks down. Fine particles of dirt begin to cover the landscape. Often, these small rock particles end up being suspended in water, and find their way to the bottom of lakes, streams, and the ocean.
Slowly, the layer of sediment on the bottom depths of thousands of feet. The weight of all the sediment with tremendous force. In addition, a number of minerals, witch act like cement, bond the cement together, causing it to form sedimentary rock.
Metamorphic Rock: Metamorphic Rocks form deep within the earth when heat and pressure are applied to either igneous rocks or sedimentary rocks. This heat and pressure in essence cooks the rocks, changing their structure substantially.