Petrology and other geology related sites. Site list is updated occasionally.

http://www.geolab.unc.edu/Petunia/IgMetAtlas/mainmenu.html Atlas of igneous and metamorphic rocks, minerals, and textures. An atlas site with thin section photomicrographs and descriptions of 39 minerals, 20 plutonic textures, 14 volcanic textures, and 21 metamorphic textures. The user can switch between plane-polarized light and cross-polarized light views in selected images.

http://sorrel.humboldt.edu/~jdl1/petrography.page.html A tutorial site with almost 200 photomicrographs, mostly in cross-polararized light. Presented at the introductory (non-major) level

http://mccoy.lib.siu.edu/projects/crelling2/atlas/ Online atlas of over 200 photomicrographs of coals, cokes, chars, carbons, and graphite.

http://www.brocku.ca/earthsciences/people/gfinn/minerals/database.htm Images of 27 minerals in plane- and cross-polarized light along with crystallographic, optical, chemical, and occurrence information.

http://www.gly.bris.ac.uk/www/teach/opmin/mins.html#menu Minerals under the microscope online textbook.

http://micro.magnet.fsu.edu/primer/virtual/virtualpolarized.html Interactive Java tutorial of polarized light microscopy. Good information on general microscopy.

http://geologyindy.byu.edu/Petroglyph/default.htm Demo page of the PetroGlyph 1.0, a virtual microscope that simulates the features of optical and electron microscopes.

http://strata.geol.sc.edu/caco3-petrology.html Extensive carbonate petrology image collection.

http://www.ees.nmt.edu/Geol/classes/geol524/Diag/CarbDiag.html Carbonate diagenesis help page –  aspects of carbonate diagenesis.

http://eol.jsc.nasa.gov/ This NASA web page allows the user to browse through satellite images of various places on Earth.