Other
The image.com: Gem Gallery
Learn all about gemstones at this site. Here you can view gem images and read the very detailed descriptions and general information facts pertaining to select gems.
US Geological Survey
Usgs: Production of Specific u.s. Gemstones
Photos of the principal gemstones produced in the United States, including an introduction to historical and other background information for each one.
Georgia State University
Georgia State University: Hyper Physics: Amethyst
This colorful site contains pictures of amethyst crystals that are displayed in the Smithsonian Museum of Natural History.
Other
Gems Brokers: Zircon
Properties, myths, and facts of zircon are depicted in this commercial site.