External Links
Excellent lesson on rocks with interactive activities and good coverage of the following topics: types of rocks, how rocks change and rock cycle.
A great set of investigations and visualizations at Exploring Earth online book.
Rock picture gallery at About.com. With photos and basic data.
50 stunning masterpieces of geological photography.
Amazing and awe-inspiring geological photographs that will stir your imagination.
Learn how to differentiate the main types of rocks at About.com.
About.com - Sedimentary rocks.
Learn the essentials of the origin, features and types of sedimentary rocks at About.com.
Learn the essentials of the origin, features and occurrence of igneous rocks at About.com.
About.com - Metamorphic rocks.
Learn the essentials of the origin, features and types of metamorphic rocks at About.com.