Sunday, August 28, 2016

Beryl


Emerald with Pyrite, Calcite
In geology, beryl is a mineral composed of beryllium aluminium cyclosilicate with the chemical formula Be3Al2(SiO3). Beryls come in a number of varieties including the blue-green aquamarine, yellow-green heliodor, pink morganite, deep green emerald and the extremely rare red beryl.

The name comes from the ancient Greek word beryllos describing a blue-green stone the color of the sea.
Emeralds are a form of beryl, showing the deepest and richest green which is caused by trace amounts of chromium and sometimes vanadium. Emerald has been a favorite of royalty and the wealthy throughout history and was worshiped by Incas and Aztecs. Its attributes include the ability to foretell the future, bring good luck and protect against illness.

Emeralds in antiquity were mined by the Egyptians and in Austria, as well as Swat in northern Pakistan. A rare type of emerald known as a trapiche emerald is occasionally found in the mines of Colombia. A trapiche emerald exhibits a "star" pattern. It is named for the trapiche, a grinding wheel used to process sugarcane in the region. Colombian emeralds are generally the most prized.

Golden beryl can range in colors from pale yellow to a brilliant gold. Unlike emerald, golden beryl has very few flaws. The term "golden beryl" is sometimes synonymous with heliodor.

Both golden beryl and heliodor are used as gems.
Morganite, also known as "pink beryl", "rose beryl", "pink emerald", and "cesian (or caesian) beryl", is a rare light pink to rose-colored gem-quality variety of beryl. Orange/yellow varieties of morganite can also be found, and color banding is common.

Pink beryl was first discovered on an island on the coast of Madagascar in 1910. In December 1910, the New York Academy of Sciences named the pink variety of beryl "morganite" after financier J. P. Morgan.
Red beryl (also known as "red emerald") is a red variety of beryl. It was first described in 1904 for an occurrence at Juab County, Utah.

Red beryl is extremely rare and has only been reported from a handful of locations. The greatest concentration of gem-grade red beryl comes from the Violet Claim in the Wah Wah Mountains of mid-western Utah, discovered in 1958. While gem beryls are ordinarily found in pegmatites and certain metamorphic stones, red beryl occurs in topaz-bearing rhyolites. It is formed by crystallizing under low pressure and high temperature from miarolitic cavities of the rhyolite.