aquamarine

Aquamarine is a blue to blue-green variety of the mineral beryl (Be3Al2Si6O18). Its distinctive color is caused primarily by trace amounts of iron in the crystal lattice, typically in the Fe2+ state. The color range extends from pale, icy blue to deeper blue-green, with saturated stones valued more highly. Aquamarine crystals are usually transparent to translucent and can be cut into a variety of gem shapes for jewelry. It ranks 7.5 to 8 on the Mohs scale of hardness and has a vitreous luster; refractive index is about 1.57–1.58.

Geology and occurrence: Aquamarine forms in granitic pegmatites and some hydrothermal deposits. It is found in many countries, with notable sources including Brazil (especially Minas Gerais), Nigeria, Madagascar, Mozambique, Zambia, Russia, Pakistan, and the United States (California). It crystallizes in the hexagonal system and often contains inclusions that can influence appearance and value.

Treatment and care: Natural aquamarine is commonly heat-treated to deepen the blue color or reduce greenish tones; such treatment is widely accepted in the gemstone market and is typically stable. Some stones may be irradiated to alter color, though disclosure is expected where treatment has occurred. In jewelry, aquamarine is valued for its cool hue, clarity, and relatively good durability. It should be cleaned with mild soap and water and protected from harsh chemicals and ultrasonic cleaners if inclusions are present.

Name and symbolism: The name aquamarine derives from Latin aqua marina, meaning sea water. It is associated with calmness and protection for sailors in various cultures and is the traditional birthstone for March.