aquamarijn

Aquamarijn, or aquamarine, is a blue to blue-green variety of the mineral beryl (Be3Al2Si6O18). The name derives from Latin aqua marina, meaning sea water, a reference to its characteristic coloration. It is part of the emerald group of minerals and shares many physical properties with other beryls.

In appearance, aquamarijn ranges from pale sky-blue to vivid blue-green. The color is primarily due to trace amounts of iron impurities; deeper blue stones are typically more valuable. Aquamarijn is a hexagonal mineral, with a Mohs hardness of 7.5–8, a vitreous luster, and a relatively low density of about 2.68–2.74. It has no true cleavage and tends to fracture conchoidally. The refractive index is about 1.577–1.583, and it often displays a subtle blue-green pleochroism.

Geological occurrences include granitic pegmatites and hydrothermal veins. Major sources are Brazil (notably Minas Gerais and Bahia), as well as Madagascar, Nigeria, Zambia, Mozambique, Afghanistan, Russia, and the United States (Colorado, North Carolina).

Uses and treatment: aquamarijn is widely used in jewelry, cut as faceted gems or cabochons. Color-treated stones are common to deepen blue tones; heating to around 400–500°C can remove yellowish hues and stabilize color. Natural, untreated stones with vivid color are typically more valuable.

Care: clean with warm soapy water and avoid harsh ultrasonic cleaners, especially for stones with inclusions or fractures. Avoid rapid thermal changes that could stress the gem.