» Geokem    Online publication with brief descriptions of most types of terrestrial and lunar igneous rocks, their regional distribution and classification, and examples of their geochemical trends and "fingerprints".    http://geokem.com/

» Greg Finn, Brock University    Page with links to course summaries for Petrology and Petrography, and related coursework.    http://www.brocku.ca/earthsciences/people/gfinn/

» Northwest Obsidian Research Lab    Offers a variety of analytical services related to obsidian trace element characterization ("sourcing") studies, obsidian hydration studies, and obsidian source studies, primarily in the context of    http://www.obsidianlab.com/

» Pegmatite International    Information on the mineralogy and petrology of pegmatites including an online publication and links to pegmatite-related sites.    http://www.pegmatology.com/

» Rob's Granite Page    This site is devoted to granite petrology with an emphasis on the Llano Uplift granites of central Texas. Also includes links to research, meetings and other scientists.    http://uts.cc.utexas.edu/~rmr/