Aquamarine derives it name from the Latin term for seawater - and one look at this elegant gem's blue hues easily explains why.

According to legend, aquamarine was the treasure of mermaids and had the power to keep sailors safe at sea. It was also thought to possess a number of other mystical properties, including the ability to help couples smooth out their differences; protect against the wiles of the devil; cure headaches, insomnia and other ailments; quicken the intellect; and attract new friends. It is the symbol for youth, hope, health and fidelity.

It is also the birthstone for March and the recommended gem for couples celebrating their 19th wedding anniversary.

A variety of the mineral beryl, like the emerald, aquamarine is found in many exotic places around the world, including Afghanistan, Angola, Kenya, Madagascar, Mozambique, Nigeria, Pakistan, Sri Lanka, Russia, Zambia and Zimbabwe. But most of the gemstones available in the market today come from Brazil.

Aquamarine is found in a range of blue shades, from pale pastel to greenish-blue to deep blue. Deeper colors are unusual in smaller sizes; generally, it takes a larger stone to hold a darker shade. The most prized aquamarines are those displaying a deeper, pure blue, with no green tints. These are rarer and therefore more valuable. But if you prefer those with a greenish hue, you should be able to get them for a bargain price.

Like with any gem that is pale, aquamarines should be "eye clean" (no inclusions visible to the naked eye), since internal flaws are more noticeable in a pastel stone. This shouldn't be much of a problem - unlike its emerald sister, aquamarine is known for being relatively free of inclusions. This is why aquamarines are frequently cut with large step facets to show off their flawless surfaces. The most popular cuts for aquamarine are oval and emerald.

Settings for aquamarine can also safely expose more of the gemstone than is possible with emerald. Aquamarine's tendency toward having few inclusions makes it less susceptible to nicks or cracks than many other gems. With an "8" ranking on the Mohs hardness scale, the stone is very durable and can stand up to everyday wear. Its clear, pale brilliance makes it an appropriate stone for all types of jewelry - and it combines well with all jewelry metals and is flattering to most skin tones.

Aquamarine is commonly heat-treated to permanently remove green overtones. Unlike its sister stone the emerald, aquamarine generally isn't plagued by surface fractures - which means the stone isn't usually treated with fillers, resins or oils. Even so, avoid mechanical cleaners. To clean aquamarine, use warm soapy water.