Red beryl

Red beryl
General
CategoryCyclosilicate beryl
Formula
(repeating unit)		Be
3Al
2Si
6O
18 with a mix of Mn3+
 ions
Crystal systemHexagonal
Space groupP6/mcc
Identification
ColorDark red
TwinningExtremely rare
CleavageIndistinct
FractureConchoidal
Mohs scale hardness7.5–8
LusterVitreous
Streakwhite
Specific gravity2.66–2.87
Optical propertiesUniaxial (−)
Refractive index1.560–1.577
Birefringenceδ = 0.0040–0.0080
Dispersion0.014
Ultraviolet fluorescenceNone

Red beryl, formerly known as bixbite and marketed as red emerald or scarlet emerald, is an extremely rare variety of beryl as well as one of the rarest minerals on Earth.[1][2]: 19  The gem gets its red color from manganese ions embedded inside of beryllium aluminium cyclosilicate crystals.[1] The color of red beryl is stable up to 1,000 °C (1,830 °F). Red beryl can come in various tints like strawberry, bright ruby, cherry, and orange.[3]

The largest crystals of red beryl are about 2 cm (0.79 in) wide and 5 cm (2.0 in) long. However, most crystals are under 1 cm (0.39 in) long.[1] Recently,[when?] the red variety of pezzottaite has been sold in markets as red beryl by some sellers.[4]

History

[edit]

Red beryl was discovered in 1904 by Maynard Bixby in the Wah Wah mountains in Utah.[5] In 1912 the gem was named bixbite by Alfred Eppler after Maynard Bixby.[6] The old synonym "bixbite" is deprecated, since it can cause confusion with the mineral bixbyite.[7]

The greatest concentration of gem-grade red beryl comes from the Ruby-Violet Claim in the Wah Wah Mountains of mid-western Utah, discovered in 1958 by Lamar Hodges, of Fillmore, Utah, while he was prospecting for uranium.[8] This claim was bought by Denise Knoeller as part of Red Emerald Inc. in 2020.[9]

Gem-quality red beryl have only been found in the Wah Wah mountains[10]

Rarity

[edit]

Red beryl is very rare and has been reported only from a handful of locations: Wah Wah Mountains, Paramount Canyon, Round Mountain and Juab County, all in the south-western United States.[11][12] The narrow geographic range suggests that the specific conditions needed for its formation do not occur frequently. This gem is a thousand times rarer than gold.[6]

The Utah Geological Survey estimated that one red beryl is found for every 150,000 diamonds.[1] According to Gemmological Association of Great Britain a 2 carat red beryl is as rare as a 40 carat diamond.[13]

Red beryl is valued roughly the same price or higher than emerald[12] despite being a hundred times rarer. Its rarity has made it less popular but red beryl crystals that are over 1 carat can sell for US$20,000.[2]: 123  In 2008, one carat could sell for US$5000 or more.[2]

Limited geographical occurrence means that the Red Emerald Inc controlled world production of natural red beryl as of 2021. [9]

Characteristics

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The dark red color of red beryl is attributed to Mn3+ ions.[14] Red beryl rough crystals can be easily distinguished by hexagonal crystal systems. This gem has been known to be confused with pezzottaite, a caesium analog of beryl, that has been found in Madagascar and more recently Afghanistan; cut gems of the two varieties can be distinguished from their difference in refractive index.[15] Red beryl is similar to emerald and dissimilar to other beryls in that it has inclusions like feathers and fractures. Some mineral inclusions include quartz, feldspar, hematite, and bixbyite.[13]

Chemistry

[edit]
Arrangement of coordination complexes forming the hexagonal structure of the beryl crystal.

The hexagonal crystal system found in beryls are formed of AlO6 octahedra, as well as BeO4 and SiO4 tetrahedra.[16] The hexagonal chanels of red beryl are primarily unoccupied and no detectable water has been found within Red beryl gets its color from natural chemical doping, whereby Mn3+O6 replaces AlO6 at certain positions.[17] The deep color Mn3+O6 may be in part explained by the Jahn-Teller effect on spin disallowed transitions.[17]

Formation

[edit]

While gem beryls are ordinarily found in pegmatites and certain metamorphic rock, red beryl forms in topaz-bearing rhyolites.[18] It is formed by crystallizing under low pressure and high temperature from a pneumatolytic phase along fractures or within near-surface miarolitic cavities of the rhyolite. Associated minerals include bixbyite, quartz, orthoclase, topaz, spessartine, pseudobrookite and hematite.[19] Synthetic red beryl is produced using hydrothermal process similar to that used for emeralds, however cobalt and manganese are used as dopants to produce a dark red gem.[20]

References

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  1. ^ a b c d "Red Beryl: One of the World's rarest gemstones – mined in Utah". geology.com. Retrieved 2021-08-30.
  2. ^ a b c Grande, Lance; Augustyn, Allison (2009-11-15). Gems and Gemstones: Timeless Natural Beauty of the Mineral World. University of Chicago Press. ISBN 978-0-226-30511-0.
  3. ^ "Red Beryl gemstone information". www.gemdat.org. Retrieved 2021-09-21.
  4. ^ "Bixbite (Red Beryl)". National Gem Lab. 2017-03-04. Retrieved 2021-09-21.
  5. ^ "Red Beryl Value, Price, and Jewelry Information – Gem Society". International Gem Society. Retrieved 2021-09-01.
  6. ^ a b "Glad You Asked: What gemstone is found in Utah that is rarer than diamond and more valuable than gold? – Utah Geological Survey". Retrieved 2021-09-04.
  7. ^ "The Mineral Beryl". Minerals.net. Archived from the original on 28 August 2017. Retrieved 28 August 2017.
  8. ^ "Red Emerald History". RedEmerald.com. Archived from the original on 3 December 2007. Retrieved 21 November 2007.
  9. ^ a b "Part of the Red Beryl Mine Is Producing Again, One Owner Says". nationaljeweler.com. Retrieved 2023-04-11.
  10. ^ Viticoli, S.; Gastaldi, L.; Flamini, A. (1984). "Unusual EPR Properties of Miku Emeralds". The Journal of Gemmology. 19 (2): 160–163. doi:10.15506/jog.1984.19.2.160. ISSN 0022-1252.
  11. ^ "Red Beryl". www.mindat.org. Archived from the original on 3 December 2013.
  12. ^ a b Oldershaw, Cally (2003). Firefly Guide to Gems. Firefly Books. p. 129. ISBN 978-1-55297-814-6.
  13. ^ a b DGA, Rona Bierrum FGA (27 August 2019). "Understanding Red Beryl". The Gemmological Association of Great Britain. Retrieved 2021-09-21.
  14. ^ "Color in the beryl group". Mineral Spectroscopy Server. minerals.caltech.edu. California Institute of Technology. Archived from the original on 22 August 2011. Retrieved 6 June 2009.
  15. ^ "Bixbite". The Gemstone List. Archived from the original on 12 March 2016.
  16. ^ Morosin, B. (1972-06-15). "Structure and thermal expansion of beryl". Acta Crystallographica Section B: Structural Crystallography and Crystal Chemistry. 28 (6): 1899–1903. Bibcode:1972AcCrB..28.1899M. doi:10.1107/S0567740872005199. ISSN 0567-7408.
  17. ^ a b Fridrichová, Jana; Bačík, Peter; Ertl, Andreas; Wildner, Manfred; Dekan, Július; Miglierini, Marcel (January 2018). "Jahn-Teller distortion of Mn3+-occupied octahedra in red beryl from Utah indicated by optical spectroscopy". Journal of Molecular Structure. 1152: 79–86. Bibcode:2018JMoSt1152...79F. doi:10.1016/j.molstruc.2017.09.081. ISSN 0022-2860.
  18. ^ "Red beryl value, price, and jewelry information". International Gem Society. Archived from the original on 28 August 2017. Retrieved 28 August 2017.
  19. ^ Ege, Carl (September 2002). "What gemstone is found in Utah that is rarer than diamond and more valuable than gold?". Survey Notes. Vol. 34, no. 3. Archived from the original on 8 November 2010. Retrieved 2 July 2011.
  20. ^ Shigley, James E.; McClure, Shane F.; Cole, Jo Ellen; Koivula, John I.; Lu, Taijin; Elen, Shane; Demianets, Ludmila N. (2001-04-01). "Hydrothermal Synthetic Red Beryl from the Institute of Crystallography, Moscow". Gems & Gemology. 37 (1): 42–55. doi:10.5741/gems.37.1.42. ISSN 0016-626X.
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