http://www.mnh.si.edu/earth/
This interactive earth science site from The National Museum of Natural History, Smithsonian Institution tells the story of the earth's history through rocks. The three main sections of the site include Rocks at Earth's Surface, Rocks Below Earth's Surface, and Mining. The first section explores the types of rocks - granite, gneiss, and sandstone - and their minerals as well as the snapshots from history that they contain. The next section gives information on the heat and pressure of the rocks inside the earth, how they melt and come to the surface. The Mining section features a tour of three mines in the United States. The Geo Gallery includes high quality photos of rocks and minerals, a slide show, and a searchable database by name or group. The site has a multimedia version and a text version. The newest version of Flash Player is required for the multimedia version.