"Aquamarine is one of several common gemstones belonging to the beryl mineral group. The name is derived from the Latin phrase "water of the sea", an accurate description of the gemstone's color, which ranges from a pale green to blue. This color is caused by trace amounts of iron that permeate the crystalline structure. The blue variety is the most valuable and greenish stones are sometimes changed to the highly prized blue shade by heating them in an electric furnace to 842° F (450° C). Brazil is the main source of aquamarine gemstones, although other locations where the mineral occurs include Zimbabwe, South Africa, Namibia, and the United States.
Enormous crystal masses, as large as 243 pounds (110 kilograms), have been discovered at some sites, and exquisite gems weighing two thousand carats or more have been cut from these formations. Unlike emerald, aquamarines are often completely flawless; an aquamarine gemstone with a visible flaw is rarely seen. However, the beautiful color of an aquamarine may fade upon prolonged exposure to light"