Aquamarine is the blue-green to blue gem variety of the of the mineral beryl. It’s been known and used as a gemstone since antiquity. The color of aquamarine can range from a very pale blue-green to a deep strong blue (“Santa Maria” blue is some of the finest blue aquamarine known); the value increases with the depth of saturation of the color, and as it shifts from a more greenish blue to a purer blue hue. Aquamarine is typically quite clean, and flawless larger gems are not uncommon. That said, large gems in the finest colors are quite rare.
There are several types of aquamarine named after particular locales. For example, very fine deep blue gem aquamarine was found in Santa Maria de Itabira, Brazil in the 1950’s. It became so well known that many deep blue aquas are referred to as “Santa Maria” aquamarine, although the name is also used for lesser quality material in an attempt to justify a higher price. Another variety is “Maxixe” beryl; it turns a beautiful deep blue when irradiated, but will fade to a pale color with exposure to daylight. Beryl can also be found with parallel growth tubes that create a “cats-eye” chatoyancy effect when properly oriented and polished.
Where is it found
Aquamarine is found in a wide variety of locations around the world. The most significant economic deposits are in Brazil, Nigeria and Mozambique, however, it can be found in literally dozens of countries around the world. In the US, gem aquamarine has been found in Maine, New Hampshire and Connecticut, as well as Pennsylvania, North Carolina and Georgia on the east coast. In the western US it can be found in Colorado, Wyoming, Idaho and California.
Aquamarine is often heated at low temperatures to reduce the greenish cast and increase the blue hue. This can be difficult to impossible to detect, and hence has no impact on pricing. Some aquamarine may also be irradiated and heated in an attempt to improve the color.
Use in jewelry
Because it is relatively common and has good hardness (7.5-8 on the Mohs scale), aquamarine is very popular in jewelry. Gems can often be found in larger sizes and are used in carvings and fantasy cuts as well as traditional faceted gems.
You can look at my current inventory of loose gemstones online here: http://www.earthstreasury.com/product-category/gemstones/aqua/