Free (or close to it) Gemology classes or tutorials. Please let us know if you find another one.
Barbara Smigel's Free Online Course - Barbara is a great teacher (professor really!) and has been generous enough to post the information she uses to teach her gemology course at the College of Southern Nevada online. It can also be taken for credit through their distance education program.
Gemology Made Easy - This is part of The Gemology Project. Not only offers great tutorials but also interviews with some of the worlds top professionals in gemology.
Ganoksin - offers free jewelry making, lapidary, and gemology articles
International Gem Society (IGS) - has some great online tutorials for free and even more for a small yearly membership fee.
Gemology Online - offers free tutoral sessions on Saturdays with some of the best gemologists in the business. Great references and links.
Minerology Tutorial - from the University of Texas
Minerology Tutorial - from the Univeristy of Wisconson
What is a Gem - from UC Berkeley