For further information on rocks, try visiting some of these websites, they were helpful to me and I'm sure they would be for you too.
http://www.runet.edu/~swoodwar/CLASSES/GEOG202/physprov/geolglos.html
http://www.graniteland.com/stone/info/sedimentary-rock.php
http://www.troy.k12.ny.us/faculty/dibarij/earth%20science/earth%20science%20images/rockcycle.gif
http://www.thefreedictionary.com/metamorphic
http://www.answers.com/topic/rock-cycle?cat=technology
