American Mineralogist Crystal Structure database. Comprehensive crystal structure database covering every structure published in "The American Mineralogist", "The Canadian Mineralogist" and the "European Journal of Mineralogy".
The BGS Lexicon of Named Rock Units. Searchable database of information on British rock units.
The Commonground Database. Free database of rock and mineral data from the Colorado School of Mines .
Cornell's Digital Earth. Hosted by Cornell University's Institute for the Study of the Continents, this site includes an interactive, digital map of the world that allows users to retrieve & analyze information from a compilation of geological data about the Earth's surface and interior.
National Geophysical Data Center. NGDC manages environmental data in the fields of marine geology and geophysics, paleoclimatology, solar-terrestrial physics, solid earth geophysics, and glaciology (snow and ice); in each of these fields NGDC also operates a World Data Center .
This Dynamic Planet. This map shows the Earth's physiographic features, the current movements of its major tectonic plates, & the locations of its volcanoes, earthquakes, and impact craters.