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.
Jewelry Central
Jewelry Central: Sapphire
This commercial site contains information about the sapphire's physical properties and where it can be found. Also discusses the history and romance related to the stone and includes a description of its quality.