Geology - Windows to the Universe - University Corporation for Atmospheric Research
Includes Minerals and the Stuff They Are Made Of; Rocks and the Rock Cycle; Earth Layers and Moving Plates; Fossils and the History of the Earth; Scientists Who Study Rocks; Earth Science Literacy Framework

Geo-Mysteries with Rex the Dino Detective - The Children's Museum of Indianapolis
"Help Rex solve these mysteries about rocks, fossils, and minerals."

Interactives - The Rock Cycle - Annenberg Media; Introduction; Types of Rocks; How Rocks Change; The Rock Cycle Diagram; Test Your Skills

Rock Hounds - Learn How Rocks are Formed; Become a Rock Expert; Take the Rock Hound Quiz

The Mineral and Gemstone Kingdom - [site has ads] Complete information guide to Rocks, Minerals, and Gemstones