Which gemstone is the blue variety of the mineral beryl?

Aquamarine is the blue to blue-green gemstone variety of the mineral beryl.

Its color is mainly caused by small amounts of iron in the beryl crystal structure. Beryl itself is a beryllium aluminum cyclosilicate, and its crystals commonly form as six-sided prisms. Aquamarine’s name comes from Latin words meaning “water of the sea,” reflecting its characteristic pale blue appearance.

Emerald is another famous beryl variety, but its green color is associated mainly with chromium or vanadium. The two gemstones can therefore belong to the same mineral species while differing in color-causing trace elements and typical inclusions. Aquamarine is usually transparent and has a Mohs hardness of about 7.5 to 8.

Gem-quality aquamarine has been found in Brazil, Pakistan, Afghanistan, Madagascar, Nigeria, and other locations. Heat treatment may be used to reduce green tones and produce a bluer appearance.