This is the rock cycle. It shows which types of rock switch to what kind and how it happens. Look at the key to see which color represents how it changes.
http://library.thinkquest.org/05aug/00461/images/igneous.jpg http://www.worsleyschool.net/science/files/metamorphic/picmetamorphic.jpg
http://geology.com/rocks/pictures/hematite.jpg
http://geology.com/rocks/pictures/hematite.jpg