Amethyst Galleries
Amethyst Galleries: Mineral Gallery: Aquamarine, the Blue Variety of Beryl
This site has some background information on aquamarine, a blue form of beryl. Provides details about variety, uses, color, and more. Detailed and helpful information.
Other
Icga: Aquamarine, Gem of the Sea
A brief description of the physical properties of the aquamarine gemstone, along with a perspective on its history and metaphysical properties.