Other than the big four so called ‘precious stones’ (Diamond, Emerald, Ruby, Sapphire), Aquamarine is probably one of the best known and most popular gemstones available (together with Amethyst). Aquamarine is the blue or blue-green variety of gemstone quality beryl, and is the ‘cousin’ of the Emerald, which is the green form of beryl. Aquamarine makes for an excellent gemstone because of a few characteristics – it is not uncommon, it has excellent hardness, and it rarely has inclusions or flaws and typically has great transparency. The combination of these factors is why Aquamarine is such a popular jewelry gemstone.
Etymology & Sources
The term Aquamarine literally means ‘seawater’ in Latin, and the gemstone is most probably named because its color resembles that of the ocean or the sea. Aquamarine is found in a variety of countries round the world, but the largest source of the blue gemstone is Brazil, where there are many mines that produce the material. Other producers include countries like India, Pakistan, Myanmar, Madagascar, and a few others.
Aquamarine can range from light blue to dark blue and can also be blue-green. As with most other gemstones, the more saturated the color of the gemstone, the more desirable it is, and in Aquamarine’s case, deeper and more intense blues are generally favored over lighter blues. The gemstone rarely has inclusions and typically has good clarity, and the gemstone has a vitreous luster. Some forms of Aquamarine are especially rare and are considerably more expensive than regular Aquamarine. Cat’s eye aquamarine can be quite valuable, and Aquamarine that displays Asterism, known as Star Aquamarine, is exceedingly rare and can fetch very high prices.
As with other varieties of beryl, Aquamarine has excellent hardness, reaching 7.5 or 8 on the Mohs scale. It has specific gravity of roughly 2.7, and has refractive index values of between 1.565 and 1.595.
Aquamarine, along with other beryl varieties, is known for its hardness, and as such can be used for pretty much any jewelry application. Typically it is faceted into the normal gemstone cuts, and because it is relatively abundant, gemstones of larger cuts aren’t too difficult to find. The rare varieties of Aquamarine that display Chatoyancy (either Cat’s Eye or Asterism) are cut into cabochons to highlight and enhance the effect. Lower quality Aquamarine that has poorer clarity can also be fashioned into beads or free form stone shapes and used by hobbyist jewelry makers.
Cat’s Eye Aquamarine – Aquamarine that displays Cat’s Eye Chatoynacy. Quite rare and valuable, commonly cut into cabochons to display the chatoyant effect.
Star Aquamarine – Aquamarine displaying Asterism. Exceedingly rare, very highly sought after. Typically cut into cabochons to fully display the asterism.
Aquamarines are commonly heat treated to improve color – the natural stones are typically greener and lighter. Heat treatment helps develop these colors into the more desirable deeper and more intense shades. This treatment is widely practiced in the industry, and consumers should just make sure that they are well informed by the seller and that all treatments are disclosed.