Chemistry:Aquamarine (gem)

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Short description: Variety of beryl
Aquamarine
Aquamarine P1000141.JPG
Aquamarine on muscovite
General
CategorySilicate minerals, beryl variety
Formula
(repeating unit)		Be
3Al
2Si
6O
18
Identification
ColorPale blue to light green
FractureConchoidal
Mohs scale hardness7.5–8
StreakWhite[1]
DiaphaneityTransparent to translucent
Specific gravity2.65–2.85

Aquamarine is a pale-blue to light-green variety of beryl.[2] The color of aquamarine can be changed by heat (though this practice is frowned upon by collectors).[3]

Aquamarine has a chemical composition of Be
3Al
2Si
6O
18,[4] also containing Fe2+.[5] It has a hardness of 7.5–8 on the Mohs scale.[6] While aquamarine often contains no inclusions,[7] it can have them, noticeable or not, composed of content such as mica, hematite, or saltwater.[8]

Aquamarine is a common gemstone.[9] However, there is a rarer deep blue variant called maxixe,[7] but its color can fade due to sunlight.[1] The color of maxixe is caused by NO3.[10] Dark-blue maxixe color can be produced in green, pink or yellow beryl by irradiating it with high-energy radiation (gamma rays, neutrons or even X-rays).[11]

Name and etymology

The name aquamarine comes from aqua for 'water', and marine, deriving from marina for 'of the sea'.[12] The word aquamarine was first used in the year 1677.[13]

The word aquamarine has been used as a modifier for other minerals like aquamarine tourmaline, aquamarine emerald, aquamarine chrysolite, aquamarine sapphire, or aquamarine topaz.[8]

Value

Queen Elizabeth II wearing the Brazilian Aquamarine Parure in 2006. The star and collar are a Brazilian decoration, the Order of the Southern Cross.

The value of aquamarine is determined by its weight, colour,[4] cut, and clarity.[14] Due to its relative abundance, aquamarine is comparatively less expensive than other gemstones within the beryl group, such as emerald or bixbite (red beryl) but is typically more expensive than similarly coloured gemstones such as blue topaz.[7][9] Naturally occurring blue hued aquamarine specimens are more expensive than those that have undergone heat treatment to reduce yellow tones caused by ferric iron.[9] Cut aquamarines that are over 25 carats will have a lower price per carat than smaller ones of the same quality.[15]

In culture

Aquamarine is the birth stone for the month of March.[4] It has historically been used a symbol for youth and happiness due to its color, which has also, along with its name, made Western culture connect it with the ocean.[16][15] Ancient Romans believed that aquamarine could protect people who are travelling across the sea;[17] they also used aquamarine to prevent illnesses.

The Chinese used it to make seals, figurines, and engravings[citation needed]. The Japanese used it to make netsuke.[18]

Aquamarine became a state gem for Colorado in 1971.[19]

Occurrence

Aquamarine of 15,256 carats from Minas Gerais, Brazil

Aquamarine can be found in countries like Afghanistan, China , Kenya, Pakistan , Russia , Mozambique, the United States ,[20] Brazil , Nigeria, Madagascar , Zambia, Tanzania, Sri Lanka,[21] Malawi, India ,[4] Zimbabwe, Australia , Myanmar, and Namibia.[22] The state of Minas Gerais is a major source for aquamarine.[9]

Aquamarine can mostly be found in granite pegmatites.[9] It can also be found in veins of metamorphic rocks that became mineralized by hydrothermal activity.[4]

Notable examples

Aquamarine Origin Size Location
Dom Pedro aquamarine[23] Mined in 1980 in Brazil.[24] 10,363 carats National Museum of Natural History, Washington[25][26]
The Roosevelt Aquamarine[27] Given to Eleanor Roosevelt in 1936. 6,500 carats Franklin D. Roosevelt Presidential Library and Museum
The Hirsch Aquamarine Once owned by Louis XV. 109.92 carats

See also

References

  1. ↑ 1.0 1.1 Schumann, Walter (2006) (in en). Gemstones of the World. Sterling Publishing Company, Inc.. pp. 110. ISBN 978-1-4027-4016-9. https://books.google.com/books?id=uXCzger619QC&q=aquamarine+streak&pg=PA32. 
  2. ↑ Manutchehr-Danai, Mohsen (2013-03-09) (in en). Dictionary of Gems and Gemology. Springer Science+Business Media. pp. 24. ISBN 978-3-662-04288-5. https://books.google.com/books?id=2UX1CAAAQBAJ&q=Aquamarine+gem&pg=PA24. 
  3. ↑ Wenk, Hans-Rudolf; Bulakh, Andrei (April 2004) (in en). Minerals: Their Constitution and Origin. Cambridge University Press. p. 542. ISBN 978-0-521-52958-7. https://books.google.com/books?id=mjIji8x-N1MC&q=aquamarine+mineral&pg=PA542. 
  4. ↑ 4.0 4.1 4.2 4.3 4.4 "Aquamarine: the blue gemstone and March birthstone". geology.com. https://geology.com/gemstones/aquamarine. 
  5. ↑ Perkins, Dexter; Henke, Kevin R.; Simon, Adam C.; Yarbrough, Lance D. (2019-07-24) (in en). Earth Materials: Components of a Diverse Planet. CRC Press. pp. 82. ISBN 978-0-429-59119-8. https://books.google.com/books?id=eTSoDwAAQBAJ&q=aquamarine+mineral&pg=PA82. 
  6. ↑ Jones, Cindy (2005) (in en). Geology. Lotus Press. pp. 16–17. ISBN 978-81-89093-35-8. https://books.google.com/books?id=12u5FkbIUdMC&q=Aquamarine+geology&pg=PA16. 
  7. ↑ 7.0 7.1 7.2 Grande, Lance; Augustyn, Allison (2009-11-15) (in en). Gems and Gemstones: Timeless Natural Beauty of the Mineral World. University of Chicago Press. pp. 125. ISBN 978-0-226-30511-0. https://books.google.com/books?id=RnE9Fa4pbn0C&q=aquamarine. 
  8. ↑ 8.0 8.1 "Aquamarine | Birthstones | Gems | Geology & Soils | Online Resources | School of Natural Resources". University of Nebraska–Lincol. https://snr.unl.edu/data/geologysoils/birthstones/aquamarine.aspx. 
  9. ↑ 9.0 9.1 9.2 9.3 9.4 Oldershaw, Cally (2003) (in en). Firefly Guide to Gems. Firefly Books. pp. 124. ISBN 978-1-55297-814-6. https://books.google.com/books?id=wm_X_LzoN-cC&q=Aquamarine+Brazil&pg=PA124. 
  10. ↑ Manutchehr-Danai, Mohsen (2013-03-09) (in en). Dictionary of Gems and Gemology. Springer Science & Business Media. pp. 307. ISBN 978-3-662-04288-5. https://books.google.com/books?id=2UX1CAAAQBAJ&q=Maxixe+gem&pg=PA307. 
  11. ↑ Nassau, K. (1976). "The deep blue Maxixe-type color center in beryl". American Mineralogist 61: 100. http://www.minsocam.org/ammin/AM61/AM61_100.pdf. 
  12. ↑ Cresswell, Julia (2014) (in en). Little Oxford Dictionary of Word Origins. Oxford University Press. p. 174. ISBN 978-0-19-968363-5. https://books.google.com/books?id=LGGCBAAAQBAJ&q=aquamarine+oxford&pg=PA174. 
  13. ↑ "Aquamarine". Merriam-Webster Dictionary. https://www.merriam-webster.com/dictionary/aquamarine. Retrieved 2021-08-31. 
  14. ↑ "How to Value Aquamarine" (in en). https://sciencing.com/value-aquamarine-8122381.html. 
  15. ↑ 15.0 15.1 "Aquamarine Value, Price, and Jewelry Information – Gem Society" (in en). https://www.gemsociety.org/article/aquamarine-jewelry-and-gemstone-information/. 
  16. ↑ Pearl, Richard M. (2016-09-06) (in en). Popular Gemology. Read Books Ltd. pp. 95. ISBN 978-1-4733-5633-7. https://books.google.com/books?id=N9v7DAAAQBAJ&q=aquamarine+gemology&pg=PA95. 
  17. ↑ Webster, Richard (2012-09-08) (in en). The Encyclopedia of Superstitions. Llewellyn Worldwide. pp. 14. ISBN 978-0-7387-2561-1. https://books.google.com/books?id=m1-xCL47_7QC&q=Aquamarine+superstition&pg=PA14. 
  18. ↑ Rapp, George R. (2013-03-09) (in en). Archaeomineralogy. Springer Science & Business Media. pp. 97–98. ISBN 978-3-662-05005-7. https://books.google.com/books?id=cmKvBQAAQBAJ&q=Aquamarine+formation&pg=PA97. 
  19. ↑ Johnson, Lars W.; Voynick, Stephen M. (2021-06-08) (in en). Rockhounding for Beginners: Your Comprehensive Guide to Finding and Collecting Precious Minerals, Gems, Geodes, & More. Simon and Schuster. pp. 89. ISBN 978-1-5072-1527-2. https://books.google.com/books?id=xp0tEAAAQBAJ&q=Aquamarine+mineral&pg=PA89. 
  20. ↑ Oldershaw, Cally (2003) (in en). Firefly Guide to Gems. Firefly Books. pp. 125. ISBN 978-1-55297-814-6. https://books.google.com/books?id=wm_X_LzoN-cC&q=Aquamarine+gem&pg=PA125. 
  21. ↑ "Aquamarine Value & Worth" (in en). https://www.withclarity.com/education/gemstone-education/aquamarine/value-and-worth. 
  22. ↑ Grande, Lance; Augustyn, Allison (2009-11-15) (in en). Gems and Gemstones: Timeless Natural Beauty of the Mineral World. University of Chicago Press. pp. 126. ISBN 978-0-226-30511-0. https://books.google.com/books?id=RnE9Fa4pbn0C&q=aquamarine. 
  23. ↑ "Dom Pedro Aquamarine – Smithsonian Institution". https://geogallery.si.edu/10026429/dom-pedro-aquamarine. 
  24. ↑ "Introducing the Dom Pedro Aquamarine". https://www.smithsonianmag.com/science-nature/introducing-the-dom-pedro-aquamarine-22283399/. 
  25. ↑ Vastag, Brian (2 December 2012). "The Dom Pedro aquamarine's long and winding path to the Smithsonian". The Washington Post. https://articles.washingtonpost.com/2012-12-02/national/35584555_1_gem-aquamarine-hope-diamond. 
  26. ↑ "Magnificent Dom Pedro aquamarine to go on view in the Smithsonian's Natural History Museum". Smithsonian Science. Smithsonian Institution. http://smithsonianscience.org/2012/12/dom-pedro-aquamarine-to-go-on-view-at-the-smithsonians-natural-history-museum/. 
  27. ↑ "Six Famous Aquamarines". https://www.gemsociety.org/article/famous-aquamarines/. 



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