SNAG - Society of North American Goldsmiths
http://www.snagmetalsmith.org/
Excellent links page and beautiful pictures!

Society of American Silversmiths
http://www.silversmithing.com/
Extensive site including online gallery, newsleters, technical information, and links.

The Crafts Report Online
http://www.craftsreport.com/
Lists artists, schools, shows, and suppliers.

Smithsonian Gem & Mineral Collection
http://www.min.uni-bremen.de/sgmcol/
Amazing collection, including the famous Hope Diamond.

A Gem of a Story
http://www.bsu.edu/teachers/academy/gems/
Virtual field trip to the Janet Annenberg Hooker Hall of Geology, Gems, and Minerals at the Smithsonian National Museum of Natural History in Washington, D.C. Includes high-resolution photographs in the "Archives" section and useful links.

Fine Jewelry Info - Jewelers of America
http://www.jewelers.org/ja_consumer/fineinfo.html
Care and history of precious metals and stones.

American Gem Society
http://www.ags.org/
Listed under "consumer" / "buying gems" you will find all you ever wanted to know about gemstones.

Birthstones
http://csd.unl.edu/csd/birthstones/birthstones.html
Informative pictorial essays on fourteen birthstones.

Paul Gross '73
http://www.designergoldjewelry.com/

Denison Howse Lee '93
http://www.denisonlee.com/

Doug Ostrander '73
http://www.dhgold.com/