Crystal system: Hexagonal
Chemical Formula/composition: Be₃Al₂Si₆O₁₈
Crystal habit:
Hardness:
Specific gravity:
Luster:
Toughness:
Cleavage:
Optics:
Color: colorless,pale yellow, less commonly red, orange, yellow, pink, green, blue
Other:
Varieties:
Localities:
Common simulants:
Synthetics:

Beryl is an important gem material with many varieties. These varieities are identified by color and emerald is the most valuable. The mineral beryl is a beryllium aluminosilicate that is colorless in pure form; impurities give beryl its varied coloration. Though beryl has good hardness, it has only average fire and brilliance. Emerald is the green variety and aquamarine, best known as the birthstone for March, is the blue-green variety of beryl.  Aquamarine is also a popular gem, though it is not nearly as high in price as emerald.

Other colors of beryl include:

The colorless variety Goshenite.
The greenish-yellow variety Heliodor.
The pink variety Morganite.
red-colored bery is called red beryl
bright golden-yellow beryl is called gold beryl

Emerald is the most valued beryl gemstones and is only rivaled by diamond and sapphire. Its green color is the most desirable green and all other green gemstones are compared to its intensity. The major colorant is chromium, and some chrome garnets and tourmaline may come close in color to emerald. Emerald specimens are often fractured and contain mineral inclusions. These flaws are so common as to be considered characteristic and help determine natural from synthetically-produced stones.
 

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