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Beryl




Beryl

Three varieties of beryl: Morganite, Aquamarine, and Heliodor
General
CategorySilicate Mineral species
Chemical formulaBe3Al2(SiO3)6
Identification
Molecular Weight537.50 gm
ColorGreen, Blue, Yellow, Colorless, Pink etc...
Crystal habitMassive to well Crystalline
Crystal systemHexagonal - Dihexagonal Dipyramidal
CleavageImperfect on the [0001]
FractureConcoidal
Mohs Scale hardness7.5-8
LusterVitreous
Optical PropertiesUniaxial (-)
Birefringenceδ = 0.004 - 0.007
Ultraviolet fluorescenceNone
StreakWhite
DensityAverage 2.76
DiaphaneityTransparent to opaque
References[1] [2]


The mineral beryl is a beryllium aluminium cyclosilicate with the chemical formula Be3Al2(SiO3)6. The hexagonal crystals of beryl may be very small or range to several meters in size. Terminated crystals are relatively rare. Beryl exhibits conchoidal fracture, has a hardness of 7.5–8, a specific gravity of 2.63–2.80. It has a vitreous luster and can be transparent or translucent. Its cleavage is poor basal and its habit is dihexagonal bipyramidal. Pure beryl is colorless, but it is frequently tinted by impurities; possible colors are green, blue, yellow, red, and white. The name comes from the Greek beryllos which referred to a precious blue-green color of sea water stone.[3] The term was later adopted for the mineral Beryl more exclusively.[4]

Additional recommended knowledge

Contents

Varieties

Varieties of beryl have been considered gemstones since prehistoric times. Recognized for its beauty, in the Bible, in Ezekiel 1:16, the wheels of God's throne are described as having the appearance of "gleaming beryl". Green beryl is called emerald, red beryl is bixbite or red emerald or scarlet emerald, blue beryl is aquamarine, pink beryl is morganite, colorless beryl is goshenite, and a clear bright yellow beryl is called golden beryl. Other shades such as yellow-green for heliodor and honey yellow are common. Red beryl is extremely rare and is not used in jewelry as the crystals it forms are very small. It is mined primarily in Utah. Blue beryl (aquamarine) when exposed to sunlight will not fade in color. Maxixe type beryl is a deep blue stone that fades to white when exposed to sunlight or is subjected to heat treatment, though the color returns with irradiation.

Deposits

Beryl is found most commonly in granitic pegmatites, but also occurs in mica schists in the Ural Mountains and is often associated with tin and tungsten ore bodies. Beryl is found in certain European countries such as Austria, Germany, and Ireland. It also occurs in Madagascar (especially morganite).

The most famous source of emeralds in the world is at Muzo and Chivor, Boyacá, Colombia, where they make a unique appearance in limestone. Emeralds are also found in the Transvaal, South Africa, Minas Gerais, Brazil, and near Mursinka in Urals. In the United States emeralds are found in North Carolina. New England's pegmatites have produced some of the largest beryls found, including one massive crystal with dimensions 5.5 m by 1.2 m (18 ft by 4 ft) with a mass of around 18 metric tons. It is New Hampshire's State Mineral. Other beryl locations include South Dakota, Colorado, Utah, Idaho, and California.

As of 1999, the largest known crystal of any mineral in the world is a crystal of beryl from Madagascar, 18 metres long and 3.5 metres in diameter.[5]

Applications

Massive beryl is a primary ore of the metal beryllium.

The druids used beryl for scrying,[citation needed] while the Scottish called them “stones of power”.[citation needed] The earliest crystal balls were made from beryl,[citation needed] later being replaced by rock crystal.[citation needed]

Synthetic beryl producer, including green emerald, red, purple, "Paraiba" color, etc.: Joint Venture Tairus

References and external links

  1. ^ http://www.mindat.org/min-819.html
  2. ^ http://www.webmineral.com/data/Beryl.shtml
  3. ^ http://www.mindat.org/min-819.html
  4. ^ http://www.webmineral.com/data/Beryl.shtml
  5. ^ G. Cressey and I. F. Mercer, Crystals, London, Natural History Museum, 1999
  • Sinkankas, John, 1994, Emerald & Other Beryls, Geoscience Press, ISBN 0-8019-7114-4
  • Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed., John Wiley and Sons, New York ISBN 0-471-80580-7
  • Minerals.net
  • Webmineral.com
  • Gems Explained
  • Mineral Galleries

See also

Look up beryl in Wiktionary, the free dictionary.
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Beryl". A list of authors is available in Wikipedia.
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