Other
Mineralogical Society of America: Collector's Corner
In-depth resource for identifying rocks. Includes an interactive rock identification key to help you figure out the name of your rock.
Children's Museum
Children's Museum of Indianapolis: Geo Mysteries
This interactive site will engage students' curiosity as they learn about the various types of rocks and how they are formed. Also includes a fantastic timeline, showing the formation of rocks throughout history.
University of California
Fossweb: Pebbles, Sand, and Silt [Pdf]
This PDF resource provides four sequential activities for children in first and second grade which introduce concepts in earth science.