Clear Aquamarine gemstone above and Clouded Aquamarine gemstone (Cat’s eye) below.

The mineral beryl has the chemical formula Be3Al2(SiO3)6 and is beryllium aluminium cyclosilicate. The hexagon shaped crystals of beryl may be very small or range to several meters in size. Pure beryl is colorless, but it is frequently tinted by impurities. The possible colors are green, blue, yellow, red, and white.

Aquamarine ( from the Latin aqua marina, meaning “water of the sea”) is a blue or turquoise variety of beryl. It occurs at most localities which yield ordinary beryl. Clear yellow beryl occurs in Brazil. The deep blue aquamarine is called maxixe. Maxixe is commonly found in the country of Madagascar. Its color fades to white when exposed to sunlight and when subjected to heat treatment. But the color returns with irradiation.

The pale blue color of aquamarine is attributed to Fe2+. The Fe3+ ions produce golden-yellow color, and when both Fe2+ and Fe3+ are present, the color is a darker blue as in maxixe. Dark-blue maxixe color can be produced in green, pink or yellow beryl by irradiating it with high-energy particles such as gamma rays, neutrons and X ray.

The largest aquamarine of gemstone quality ever mined was found in Marambaia, Minas Gerais, Brazil, in 1910. It weighed 110 kg, and its dimensions were 48.5 cm (19 in) long and 42 cm (17 in) in diameter.

In the United States, aquamarines can be found at the summit of Mt. Antero, Sawatch range in Central Colorado, Big Horn Mountains in Wyoming , Brazil, Colombia, Zambia, Madagsacar, Malawi, Tanzania and Kenya.