Aquamarine is in the Beryl family which also includes Emerald and Morganite. While Emerald is generally known to have eye visible inclusions, Aquamarine is prized for its purity.
Aquamarine is found on almost every continent in the world. However, areas that are most famous for the gem are Brazil, Mozambique and Madagascar. Aquamarine is often confused with another birthstone Blue Topaz, however, Topaz is typically a darker more saturated blue. Since fine color Topaz is a much more abundant in the marketplace (and less expensive) than fine Aquamarine, it is often used as a suitable alternative for those shopping for a light blue gem.
A few years ago in 2012, the Smithsonian displayed the "Dom Pedro" Aquamarine, which is the world's largest cut Aqua, next to the infamous hope diamond. This obelisk shape gemstone weighs over 10,000 carats, making it one of the largest gemstones of any variety ever cut.