Useful links

Wikipedia: Amethyst

Wikipedia: Gemstone

Gemstone.org: International Colored Gemstone Association

Minerals.net:The Mineral and Gemstone Kingdom

USGS Mineral Resources Program: An Overview of Production of Specific U.S. Gemstones

Healthynewage.com: Gem Essences for Spiritual Enhancement and Energetic Balancing

Associatedcontent.com: Every Month has its Stone: A Guide to Birthday Gemstones

Wordpress.org: Gemstone Blogs