Beryl (Aquamarine)
Sumayar Village, Northern Pakistan

The aquamarine beryl specimen shown here is a group of light blue, terminated crystals from the pegmatite region of northern Pakistan. It measures 8cm x 8cm x 9cm, and the associated mineral is muscovite mica. The specimen was purchased for the museum in 1993 from Mountain Minerals International.

Beryl Be₃Al₂Si₆O₁₈

Cyclosilicates; Beryllium aluminum silicate, frequently with some sodium, lithium, and cesium

Color and Luster: Bright green(Var. emerald), blue, greenish-blue(Var. aquamarine), yellow(Var. golden beryl), red (Var. bixbite, pink(Var. morganite), white, colorless; vitreous; streak colorless(Var. goshenite)

Hardness: 7.5-8

Cleavage: Indistinct, one direction

Fracture: Uneven to concoidal

Crystals: Hexagonal; crystals common, usually six-sided prisms that are striated lengthwise

Beryl has a six-fold ring structure that forms simple hexagonal crystals which can reach enormous sizes weighing several tons. Beryl is the chief ore of the element beryllium, and is mined mainly from pegmatites where it is one of the major mineralogical constituents. Its clarity, diversity of brilliant colors, and hardness, make it one of the most popular of gemstones.

Photo by Lance Kearns

Descriptions taken from
The Audubon Society Field Guide to North American Rocks and Minerals