Aquamarine “Gem of the sea”

Aquamarine is the blue, or perhaps more correctly, blue-green or aqua variety of the mineral beryl. Other gemstone colour varieties that belong to beryl include emerald, morganite, and heliodor. Other colours of beryl are simply referred to by their colour, such as red beryl. Most gem aquamarines have been heat treated to produce the popular blue-green varieties from less desirable yellow or pale stones.

Aquamarine is the official state gem of Colorado. Colorado has an official state mineral (Rhodochrosite), but no official state rock.

Aquamarine (Lat. aqua marina, “Gem of the sea”) is a gemstone-quality transparent variety of beryl, having a delicate blue or turquoise color, suggestive of the tint of seawater. It’s closely related to the gem emerald. Colors vary and yellow beryl, called heliodor; rose pink beryl, morganite; and white beryl, goshenite are known.

Aquamarine is a beryl with a hexagonal crystal structure and a chemical formula of Be3Al2Si6O18, a beryllium aluminium silicate mineral. It has a specific gravity of 2.68 to 2.74 and a Mohs hardness of from 7.5 to 8. Aquamarine typically is on the low end of the specific gravity range, normally at less than 2.7. The pink variety exhibits a high specific gravity of around 2.8. Refractive indices range around 1.57 to 1.58.

Pale greenish blue or bluish green variety of beryl that is valued as a gemstone. The most common variety of gem beryl, it occurs in pegmatites, in which it forms much larger and clearer crystals than emerald, the dark green variety of beryl.

In the United States, aquamarines can be found at the summit of Mt. Antero in the Sawatch Range in central Colorado. In Brazil, there are mines in the states of Minas Gerais, Espírito Santo and Bahia. Zambia also produces nice aquamarine as well as Madagascar, Malawi, Tanzania and Kenya. Much of today’s aquamarine is heated to give it a better color blue. The deeper the blue color, the more valuable the gem is considered.

Other sources of Aquamarine are Nigeria, the island of Sri Lanka, Afghanistan and Russia.

The biggest aquamarine ever mined was found at the city of Marambaia, Minas Gerais, Brazil, in 1910. It weighed over 110 kg, and its dimensions were 48.5 cm long and 42 cm in diameter.