Greg Finn, Brock University - Page with links to course summaries for Petrology and Petrography, and related coursework. - http://www.brocku.ca/earthsciences/people/gfinn/
Pegmatite International - Information on the mineralogy and petrology of pegmatites including an online publication and links to pegmatite-related sites. - http://www.pegmatology.com/
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/
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/
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/