San Diego Natural History Museum--Your Nature ConnectionSDNHM Field Guide
[Beryl. Collection of the San Diego Natural History Museum.]

Beryl

From the Greek, berylloss, which indicated any green gemstone.

Description and Occurrence

Beryl is a common crystal and forms as a six-sided prism. Individual crystals can become very large, as long as 9 meters and weighing as much as 25 tons. The crystal face shows very fine striations (ridges) along its length. It usually occurs in granite rocks and pegmatites.

Beryl crystals come in a wide range of colors. The most highly prized form of beryl is the emerald (medium to dark toned green or bluish-green). Other beryl gems include aquamarine (light blue and light bluish-green), golden beryl (golden yellow), heliodor (yellow and brown), morganite (pink to light purplish-red), and goshenite (colorless).

Most beryl is not gemstone quality, and is used as the main industrial source for beryllium. Beryllium is used in the nuclear industry and in alloys for aircraft.

Beryl can be found in Columbia, Austria, Brazil, India, Australia, and the United States. In San Diego County, gemstone quality aquamarine and morganite have been found in pegmatites in Mesa Grande, Pala, and Ramona.

Field Notes: Best field marks are its six-sided shape and hardness.


Physical Properties

Color Streak Transparency Luster Hardness Cleavage Fracture Specific gravity Crystal form
bright green, blue, greenish-blue, yellow, red, pink, white, colorless white transparent to opaque vitreous 7.5 to 8 indistinct, one direction conchoidal, uneven 2.6 to 2.9 hexagonal

Photo: Beryl. Collection of the San Diego Natural History Museum
Photo credit: Linda West

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