American Museum of Natural History
American Museum of Natural History: O Logy: If Rocks Could Talk
Learn about metamorphic, igneous, and sedimentary rocks and see many examples of each type.
SRI International
Performance Assessment Links in Science: Classifying Rocks
This is a performance task where students sort and classify rocks based on their properties, then demonstrate how they can transfer their understanding to decide on ways they might sort and classify other types of objects.