Emerald

The emerald is a variety of the mineral beryl, colored green by trace amounts of chromium and sometimes iron. It is highly prized as a gemstone and ounce for ounce is the most valuable gemstone in the world, often made more so by inclusions. Beryl has a hardness of 8 on the 10-point Mohs scale of hardness.

See also: List of minerals

Further Reading

• Emerald & Other Beryls, John Sinkankas, Geoscience Press, 1994, hardcover textbook, ISBN 0801971144