View source for Emerald

{{Short description|Green gemstone, a beryl variety}}
{{Other uses}}
{{Use American English|date=August 2015}}
{{Use dmy dates|date=March 2024}}
{{Infobox mineral
| name        = Emerald
| category    = [[Beryl]] variety
| boxwidth    =
| boxbgcolor  = #50C878
| boxtextcolor = black
| image       = Béryl var. émeraude sur gangue (Muzo Mine Boyaca - Colombie) 2.jpg
| imagesize   = 260
| caption     = Emerald crystal from [[Muzo]], [[Colombia]]
| symmetry    = (6/m 2/m 2/m) – dihexagonal dipyramidal
| unit cell   = ''a'' = 9.21 [[Ångström|Å]], ''c'' = 9.19 Å; ''Z'' = 2
| formula     = Be<sub>3</sub>Al<sub>2</sub>(<nowiki>SiO</nowiki><sub>3</sub>)<sub>6</sub>
| molweight   = 537.50
| color       = Bluish green to green
| habit       = [[Crystal habit|Massive]] to well [[Crystalline]]
| system      = [[Hexagonal crystal system|Hexagonal]] (6/m 2/m 2/m) [[Space group]]: P6/mсc
| twinning    =
| cleavage    = Imperfect on the [0001]
| fracture    = [[Conchoidal]]
| tenacity    =
| mohs        = 7.5–8
| luster      = [[Lustre (mineralogy)|Vitreous]]
| polish      =
| opticalprop = Uniaxial (−)
| refractive  = ''n''<sub>ω</sub> = 1.564–1.595,<br /> ''n''<sub>ε</sub> = 1.568–1.602
| birefringence = δ = 0.0040–0.0070
| dispersion  =
| pleochroism =
| fluorescence= None (some fracture-filling materials used to improve emerald's clarity do fluoresce, but the stone itself does not)
| absorption  =
| streak      = White
| gravity     = Average 2.76
| density     =
| melt        =
| fusibility  =
| diagnostic  =
| solubility  =
| diaphaneity = Transparent to opaque
| other       =
| references  = <ref name=Mindat />
}}
[[File:Emeraude gisements.jpg|thumb|Main emerald producing countries]]

'''Emerald''' is a [[gemstone]] and a variety of the [[mineral]] [[beryl]] (Be<sub>3</sub>Al<sub>2</sub>(SiO<sub>3</sub>)<sub>6</sub>) colored [[green]] by trace amounts of [[chromium]] or sometimes [[vanadium]].<ref name=Hurlbut>Hurlbut, Cornelius S. Jr., and Kammerling, Robert C. (1991). ''Gemology'', John Wiley & Sons, New York, p. 203, {{ISBN|0-471-52667-3}}.</ref> [[Beryl]] has a [[hardness]] of 7.5–8 on the [[Mohs scale]].<ref name=Hurlbut /> Most emeralds have many [[inclusion (mineral)|inclusions]],<ref>{{cite web |title=Emerald Quality Factors |url=https://www.gia.edu/emerald-quality-factor |publisher=Gemological Institute of America |access-date=1 November 2016|url-status=live|archive-url=https://web.archive.org/web/20161102090527/http://www.gia.edu/emerald-quality-factor|archive-date=2 November 2016}}</ref> so their toughness (resistance to breakage) is classified as generally poor. Emerald is a [[cyclosilicate]]. It occurs mainly in association with [[quartz]], [[muscovite]], [[albite]], [[Tourmaline|schorl]], [[microcline]], [[fluorite]], [[smoky quartz]] and [[elbaite]].<ref name="Mindat" />

== Etymology ==
The word "emerald" is derived (via {{langx|fro|esmeraude}} and {{langx|enm|emeraude}}), from [[Vulgar Latin]]: ''esmaralda/esmaraldus'', a variant of [[Latin]] ''smaragdus'', which was via {{langx|grc|σμάραγδος}} (smáragdos; "green gem"). The Greek word may have a Semitic, Sanskrit or Persian origin.<ref>{{Cite web|title=Definition of 'emerald'|url=https://www.collinsdictionary.com/dictionary/english/emerald|access-date=29 April 2024|website=Collins Dictionary |language=en}}</ref><ref>{{Cite web|title=smaragdus NOUN|url=https://www.oed.com/dictionary/smaragdus_n|access-date=29 April 2024|website=Oxford English Dictionary|language=en}}</ref><ref>{{OEtymD|emerald}}</ref> According to ''[[Webster's Dictionary]]'' the term emerald was first used in the 14th century.<ref>{{Cite web|title=Definition of EMERALD|url=https://www.merriam-webster.com/dictionary/emerald|access-date=25 September 2021|website=www.merriam-webster.com|language=en|archive-date=25 September 2021|archive-url=https://web.archive.org/web/20210925200117/https://www.merriam-webster.com/dictionary/emerald|url-status=live}}</ref>

== Properties determining value ==
[[File:5 Emeralds from Colombia.JPG|thumb|left|Cut emeralds]]

Emeralds, like all colored [[gemstone]]s, are graded using four basic parameters known as "the four ''C''s": ''color'', ''clarity,'' ''cut'' and ''carat weight''.  Normally, in grading colored gemstones, color is by far the most important criterion. However, in the grading of emeralds, clarity is considered a close second. A fine emerald must possess not only a pure verdant green [[hue]] as described below, but also a high degree of [[transparency and translucency|transparency]] to be considered a top gemstone.<ref name=Wise>Wise, R. W. (2001) ''Secrets of the Gem Trade: the connoisseur's guide to precious gemstones''. Brunswick House Press, p. 108, {{ISBN|0-9728223-8-0}}.</ref>

This member of the beryl family ranks among the traditional "big four" precious gems along with [[diamond]]s, [[Ruby|rubies]] and [[sapphire]]s.<ref>{{Cite web|title=Emerald Value, Price, and Jewelry Information|url=https://www.gemsociety.org/article/emerald-jewelry-and-gemstone-information/|access-date=16 November 2021|website=International Gem Society|language=en|archive-date=16 November 2021|archive-url=https://web.archive.org/web/20211116082504/https://www.gemsociety.org/article/emerald-jewelry-and-gemstone-information/|url-status=live}}</ref>

In the 1960s, the American jewelry industry changed the definition of ''emerald'' to include the green vanadium-bearing beryl. As a result, ''vanadium emeralds'' purchased as emeralds in the United States are not recognized as such in the United Kingdom and Europe. In America, the distinction between traditional emeralds and the new vanadium kind is often reflected in the use of terms such as "Colombian emerald".<ref name=Read>Read, Peter (2008) ''Gemmology'', 3rd rev. ed., NAG Press, p. 218, {{ISBN|0719803616}}.</ref>

=== Color ===

In [[gemology]],<ref>[http://gia4cs.gia.edu/EN-US/gr-colored-diamonds-gemstones.htm Grading Fancy-Color Diamonds] {{webarchive|url=https://web.archive.org/web/20141102115539/http://gia4cs.gia.edu/en-us/gr-colored-diamonds-gemstones.htm |date=2 November 2014 }}. Gemological Institute of America</ref> color is divided into three components: ''[[hue]]'', ''[[Saturation (color theory)|saturation]]'', and ''[[lightness|tone]]''. Emeralds occur in hues ranging from yellow-green to blue-green, with the primary hue necessarily being  Dark green. Yellow and blue are the normal secondary hues found in emeralds. Only gems that are medium to dark in tone are considered emeralds; light-toned gems are known instead by the species name ''[[Beryl|green beryl]]''. The finest emeralds are approximately 75% tone on a scale where 0% tone is colorless and 100% is opaque black. In addition, a fine emerald will be saturated and have a hue that is bright (vivid). Gray is the normal saturation modifier or mask found in emeralds;  a grayish-green hue is a dull-green hue.<ref name=Wise />

=== Clarity ===
[[File:Emerald in a quartz and pegmatite matrix.JPG|thumb|Brazilian emerald (grass-green variety of the mineral beryl) in a quartz-pegmatite matrix with typical hexagonal, prismatic crystals<ref>Bonewitz, R. (2005). ''Rock and gem''. New York: DK Pub. pp. 292–293. {{ISBN|0756633427}}.</ref>]]
Emeralds tend to have numerous inclusions and surface-breaking [[Cleavage (crystal)|fissures]]. Unlike diamonds, where the [[loupe]] standard (i.e., 10× magnification) is used to grade clarity, emeralds are graded by eye. Thus, if an emerald has no visible [[inclusion (mineral)|inclusions]] to the eye (assuming normal visual acuity) it is considered flawless. Stones that lack surface breaking fissures are extremely rare and therefore almost all emeralds are treated ("oiled", see below) to enhance the apparent clarity. The inclusions and fissures within an emerald are sometimes described as ''jardin'' (French for ''garden''), because of their mossy appearance.<ref>[http://www.gia.edu/emerald-quality-factor Emerald Quality Factors] {{webarchive|url=https://web.archive.org/web/20140223032811/http://www.gia.edu/emerald-quality-factor |date=23 February 2014 }}. Gemological Institute of America.</ref> Imperfections are unique for each emerald and can be used to identify a particular stone. Eye-clean stones of a vivid primary green hue (as described above), with no more than 15% of any secondary hue or combination (either blue or yellow) of a medium-dark tone, command the highest prices.<ref name=Wise /> The relative non-uniformity motivates the cutting of emeralds in [[cabochon]] form, rather than faceted shapes. Faceted emeralds are most commonly given an oval cut, or the signature emerald cut, a rectangular cut with facets around the top edge.

=== Treatments ===
Most emeralds are oiled as part of the post-[[lapidary]] process, in order to fill in surface-reaching cracks so that clarity and stability are improved. [[Cedar oil]], having a similar [[refractive index]], is often used in this widely adopted practice. Other liquids, including synthetic oils and polymers with refractive indexes close to that of emeralds, such as ''Opticon'', are also used. The least expensive emeralds are often treated with epoxy resins, which are effective for filling stones with many fractures.<ref>{{Cite journal|date=1991|title=Gems & Gemology|url=https://www.gia.edu/doc/SU91.pdf|journal=Gems & Gemology|volume=XXVII|access-date=19 May 2021|archive-date=19 May 2021|archive-url=https://web.archive.org/web/20210519013713/https://www.gia.edu/doc/SU91.pdf|url-status=live}}</ref><ref>{{Cite journal|date=2001|title=Emerald Treatments|url=https://www.ssef.ch/wp-content/uploads/2018/03/2001_Kiefert_Emerald_treatments.pdf|journal=Kiefert|access-date=19 May 2021|archive-date=19 May 2021|archive-url=https://web.archive.org/web/20210519013714/https://www.ssef.ch/wp-content/uploads/2018/03/2001_Kiefert_Emerald_treatments.pdf|url-status=live}}</ref> These treatments are typically applied in a vacuum chamber under mild heat, to open the pores of the stone and allow the fracture-filling agent to be absorbed more effectively.<ref>Liccini, Mark. [http://www.gemsociety.org/article/emerald-enhancement/ Understanding Emerald Enhancements and Treatments] {{webarchive|url=https://web.archive.org/web/20141221144224/http://www.gemsociety.org/article/emerald-enhancement/ |date=21 December 2014 }}. International Gem Society</ref> The U.S. [[Federal Trade Commission]] requires the disclosure of this treatment when an oil-treated emerald is sold.<ref name=ftc /> The use of oil is traditional and largely accepted by the gem trade, although oil-treated emeralds are worth much less than untreated emeralds of similar quality. Untreated emeralds must also be accompanied by a certificate from a licensed, independent gemology laboratory. Other treatments, for example the use of green-tinted oil, are not acceptable in the trade.<ref>{{cite book|last1=Read|first1=P. G.|title=Gemmology|publisher=Elsevier|isbn=978-1-4831-4467-2|page=180|url=https://books.google.com/books?id=b-7fBAAAQBAJ&q=oil+enhancement+emerald|access-date=30 March 2017|language=en|url-status=live|archive-url=https://web.archive.org/web/20170331024513/https://books.google.com.au/books?id=b-7fBAAAQBAJ&dq=oil+enhancement+emerald&source=gbs_navlinks_s|archive-date=31 March 2017|date=22 October 2013}}</ref> Gems are graded on a four-step scale; ''none'', ''minor'', ''moderate'' and ''highly'' enhanced. These categories reflect levels of enhancement, not ''clarity''. A gem graded ''none'' on the enhancement scale may still exhibit visible inclusions. Laboratories apply these criteria differently. Some gemologists consider the mere presence of oil or polymers to constitute enhancement. Others may ignore traces of oil if the presence of the material does not improve the look of the gemstone.<ref>{{cite book|last1=Matlins|first1=Antoinette Leonard|last2=Bonanno|first2=Antonio C.|title=Jewelry & Gems, the Buying Guide: How to Buy Diamonds, Pearls, Colored Gemstones, Gold & Jewelry with Confidence and Knowledge|publisher=Gemstone Press|isbn=978-0-943763-71-2|page=126|url=https://books.google.com/books?id=WUBWz22wRtEC&q=gemstone+enhancement+traces+of+oil&pg=PA126|access-date=30 March 2017|language=en|url-status=live|archive-url=https://web.archive.org/web/20170330180745/https://books.google.com.au/books?id=WUBWz22wRtEC&pg=PA126&dq=gemstone+enhancement+traces+of+oil&hl=en&sa=X&ved=0ahUKEwj8ruzuuv3SAhUT3mMKHXM_CdwQ6AEILTAD#v=onepage&q=gemstone%20enhancement%20traces%20of%20oil&f=false|archive-date=30 March 2017|year=2009}}</ref>

== Emerald mines ==
[[File:Trapiche emerald (cropped).jpg|thumb|A Colombian [[trapiche emerald]]]]
Emeralds in antiquity were mined in [[Ancient Egypt]] at locations on Mount Smaragdus since 1500 BC, and India and Austria since at least the 14th century AD.<ref>{{cite journal|doi=10.1126/science.287.5453.631|url=http://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_7/b_fdi_53-54/010020866.pdf|title=Oxygen Isotopes and Emerald Trade Routes Since Antiquity|journal=Science|year=2000|vauthors=Giuliani G, Chaussidon M, Schubnel HJ, Piat DH, Rollion-Bard C, France-Lanord C, Giard D, de Narvaez D, Rondeau B|pages=631–3|bibcode=2000Sci...287..631G|pmid=10649992|volume=287|issue=5453|url-status=live|archive-url=https://web.archive.org/web/20110807120139/http://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_7/b_fdi_53-54/010020866.pdf|archive-date=7 August 2011}}</ref> The Egyptian mines were exploited on an industrial scale by the Roman and Byzantine Empires, and later by Islamic conquerors. Mining in Egypt ceased with the discovery of the Colombian deposits. Today, only ruins remain in Egypt.<ref>"Romans organized the mines as a multinational business..." Finlay, Victoria. Jewels: A Secret History (Kindle Location 3098). Random House Publishing Group. Kindle Edition.</ref>

Colombia is by far the world's largest producer of emeralds, constituting 50–95% of the world production, with the number depending on the year, source and grade.<ref>{{cite news |last=Badawy |first=Manuela |title=Emeralds seek the 'De Beers' treatment |url=https://www.reuters.com/article/us-investment-emeralds-idUSBRE85C1P320120613 |date=13 June 2012 |work=Reuters |access-date=14 June 2012 |url-status=live |archive-url=https://web.archive.org/web/20120805121546/http://www.reuters.com/article/2012/06/13/us-investment-emeralds-idUSBRE85C1P320120613 |archive-date=5 August 2012  }}</ref><ref>{{cite book |url=https://books.google.com/books?id=lPXoMqGQkZUC&pg=PA21 |page=21 |title=Colombia |author=Dydyński, Krzysztof |publisher=Lonely Planet |year=2003 |isbn=0-86442-674-7}}</ref><ref>{{cite journal |author=Branquet, Y. Laumenier, B. Cheilletz, A. & Giuliani, G. | s2cid=55974313 | title=Emeralds in the Eastern Cordillera of Colombia. Two tectonic settings for one mineralization |journal=Geology |volume=27 |issue=7 |pages=597–600 |doi=10.1130/0091-7613(1999)027<0597:EITECO>2.3.CO;2 |year=1999 |bibcode = 1999Geo....27..597B |url=http://pdfs.semanticscholar.org/2d42/2152a59ac2b2d98dbed9dda5d1cdfddb9369.pdf |archive-url=https://web.archive.org/web/20190221022840/http://pdfs.semanticscholar.org/2d42/2152a59ac2b2d98dbed9dda5d1cdfddb9369.pdf |url-status=dead |archive-date=21 February 2019 }}</ref><ref>Carrillo, V. (2001). Compilación y análisis de la información geológica referente a la explotación esmeraldífera en Colombia. Informe de contrato 124. INGEOMINAS</ref> Emerald production in Colombia has increased drastically in the last decade, increasing by 78% from 2000 to 2010.<ref>{{cite web |last=Wacaster |first=Susan |title=2010 Minerals Yearbook: Colombia [ADVANCE RELEASE] |publisher=[[United States Geological Survey]] |date=March 2012 |url=https://minerals.usgs.gov/minerals/pubs/country/2010/myb3-2010-co.pdf |access-date=7 August 2012 |url-status=live |archive-url=https://web.archive.org/web/20120813012215/http://minerals.usgs.gov/minerals/pubs/country/2010/myb3-2010-co.pdf |archive-date=13 August 2012  }}</ref> The three main emerald mining areas in Colombia are [[Muzo]], Coscuez, and [[Chivor]].<ref>[http://www.emeralds.com/specimens/specimens/mining.html Emerald Mining Areas in Colombia] {{webarchive|url=https://web.archive.org/web/20100929185950/http://www.emeralds.com/specimens/specimens/mining.html |date=29 September 2010 }}, with location map of these three districts.</ref> Rare [[Trapiche emerald|"trapiche" emeralds]] are found in Colombia, distinguished by ray-like spokes of dark impurities.

[[Zambia]] is the world's second biggest producer, with its [[Kafubu River (Zambia)|Kafubu River]] area deposits (Kagem Mines) about {{convert|45|km|abbr=on}} southwest of Kitwe responsible for 20% of the world's production of gem-quality stones in 2004.<ref>Behling, Steve and Wilson, Wendell E. (1 January 2010) "[http://www.highbeam.com/doc/1G1-219077097.html The Kagem emerald mine: Kafubu Area, Zambia]", ''The Mineralogical Record'' {{webarchive|url=https://web.archive.org/web/20130510231830/http://www.highbeam.com/doc/1G1-219077097.html |date=10 May 2013 }}</ref> In the first half of 2011, the Kagem Mines produced 3.74 tons of emeralds.<ref>{{Cite web|title=What is Kagem Zambian Emerald?|url=http://www.sharongulezianjewelry.com/1/post/2016/01/-what-is-kagem-zambian-emerald.html|access-date=19 May 2021|website=Sharon Gulezian Jewelry|language=en}}{{Dead link|date=November 2025 |bot=InternetArchiveBot }}</ref>

Emeralds are found all over the world in countries such as Afghanistan, Australia, Austria, Brazil,<ref>"[http://economia.uol.com.br/ultimas-noticias/redacao/2012/01/18/maior-esmeralda-do-mundo-encontrada-no-brasil-sera-leiloada-no-canada.jhtm Maior esmeralda do mundo, encontrada no Brasil, será leiloada no Canadá] {{webarchive|url=https://web.archive.org/web/20140407061534/http://economia.uol.com.br/ultimas-noticias/redacao/2012/01/18/maior-esmeralda-do-mundo-encontrada-no-brasil-sera-leiloada-no-canada.jhtm |date=April 7, 2014 }}". UOL (18 January 2012)</ref> Bulgaria, Cambodia, Canada, China, Egypt, Ethiopia, France, Germany, India, Kazakhstan, Madagascar, Mozambique, Namibia, Nigeria, Norway, Pakistan, Russia, Somalia, South Africa, Spain, Switzerland, Tanzania, the United States, Zambia, and Zimbabwe.<ref name=Mindat>{{cite web |url=http://www.mindat.org/min-1375.html |title=Emerald at Mindat |publisher=Mindat.org |date=19 July 2010 |access-date=30 July 2010 |url-status=live |archive-url=https://web.archive.org/web/20100712200317/http://www.mindat.org/min-1375.html |archive-date=12 July 2010  }}</ref> In the US, emeralds have been found in [[Connecticut]], [[Montana]], [[Nevada]], [[North Carolina]], and [[South Carolina]].<ref name=Mindat /> In 1998, emeralds were discovered in the Yukon Territory of Canada.<ref>[http://www.geology.gov.yk.ca/pdf/emeralds.pdf Emeralds in the Yukon Territory] {{webarchive|url=https://web.archive.org/web/20140331003634/http://www.geology.gov.yk.ca/pdf/emeralds.pdf |date=31 March 2014 }}. Yukon Geological Survey.</ref>

=== Origin determinations ===
Since the onset of concerns regarding diamond origins, research has been conducted to determine if the mining location could be determined for an emerald already in circulation. Traditional research used qualitative guidelines such as an emerald's color, style and quality of cutting, type of fracture filling, and the anthropological origins of the artifacts bearing the mineral to determine the emerald's mine location. More recent studies using [[energy-dispersive X-ray spectroscopy]] methods have uncovered trace chemical element differences between emeralds, including ones mined in close proximity to one another.  American gemologist David Cronin and his colleagues have extensively examined the chemical signatures of emeralds resulting from fluid dynamics and subtle precipitation mechanisms, and their research demonstrated the chemical homogeneity of emeralds from the same mining location and the statistical differences that exist between emeralds from different mining locations, including those between the three locations: Muzo, Coscuez, and Chivor, in Colombia, South America.<ref>{{Cite journal |url=http://www.gem-a.com/publications/journal-of-gemmology/issues-2008-to-date/cronin-2012.aspx |title=Determining the geographical origins of natural emeralds through nondestructive chemical fingerprinting |last1=Cronin |first1=David |date=2012 |journal=Journal of Gemmology |last2=Rendle |first2=Andy |pages=1–13 |volume=33 |url-status=dead |archive-url=https://web.archive.org/web/20151117015242/http://www.gem-a.com/publications/journal-of-gemmology/issues-2008-to-date/cronin-2012.aspx |archive-date=17 November 2015  |doi=10.15506/JoG.2012.33.1.1 |url-access=subscription }}</ref>

== Synthetic emerald ==
[[File:Emerald.png|thumb|upright=0.45|left|Emerald showing its hexagonal structure]]

Both hydrothermal and [[flux method|''flux-growth'']] synthetics have been produced, and a method has been developed for producing an emerald overgrowth on colorless [[beryl]]. The first commercially successful emerald synthesis process was that of [[Carroll Chatham]], likely involving a lithium vanadate flux process, as Chatham's emeralds do not have any water and contain traces of vanadate, molybdenum and vanadium.<ref>{{cite book|last1=O'Donoghue|first1=Michael|title=Gemstones|date=1988|publisher=Springer Netherlands|location=Dordrecht|isbn=9789400911918|page=310|url=https://books.google.com/books?id=5BsyBwAAQBAJ&q=chatham%20emerald%20process%20vanadium&pg=PA310|url-status=live|archive-url=https://web.archive.org/web/20170330180757/https://books.google.com.au/books?id=5BsyBwAAQBAJ&lpg=PA310&dq=chatham%20emerald%20process%20vanadium&pg=PA310#v=onepage&q=chatham%20emerald%20process%20vanadium&f=false|archive-date=30 March 2017}}</ref> The other large producer of flux emeralds was [[Pierre Gilson]] Sr., whose products have been on the market since 1964. Gilson's emeralds are usually grown on natural colorless beryl seeds, which are coated on both sides. Growth occurs at the rate of 1&nbsp;mm per month, a typical seven-month growth run produces emerald crystals 7&nbsp;mm thick.<ref>Nassau, K. (1980) ''Gems Made By Man,'' Gemological Institute of America, {{ISBN|0-87311-016-1}}.</ref>

[[Hydrothermal synthesis|Hydrothermal]] synthetic emeralds have been attributed to [[IG Farben]], Nacken, [[Tairus]], and others, but the first satisfactory commercial product was that of [[Johann Lechleitner]] of [[Innsbruck]], Austria, which appeared on the market in the 1960s. These stones were initially sold under the names "Emerita" and "Esmeralda", and they were grown as a thin layer of emerald on top of natural colorless beryl stones.  Later, from 1965 to 1970, the [[The Linde Group|Linde]] Division of [[Union Carbide]] produced completely synthetic emeralds by hydrothermal synthesis. According to their patents (attributable to [[Edith Flanigen|E.M. Flanigen]]),<ref>Geological Magazine "Hydrothermal process for growing crystals having the structure of beryl in an alkaline halide medium" {{US patent|3567642}} Issue date: 2 March 1971</ref> acidic conditions are essential to prevent the chromium (which is used as the colorant) from precipitating. Also, it is important that the silicon-containing nutrient be kept away from the other ingredients to prevent nucleation and confine growth to the seed crystals. Growth occurs by a diffusion-reaction process, assisted by convection. The largest producer of hydrothermal emeralds today is Tairus, which has succeeded in synthesizing emeralds with chemical composition similar to emeralds in alkaline deposits in Colombia, and whose products are thus known as "Colombian created emeralds" or "Tairus created emeralds".<ref>{{cite journal|author1=Schmetzer, Karl |author2=Schwartz, Dietmar |author3=Bernhardt, Heinz-Jurgen |author4=Tobias Hager |url=http://www.gem-a.com/media/27904/2006%2030%201%20to%202.pdf |title=A new type of Tairus hydrothermally-grown synthetic emerald, colored by vanadium and copper |journal=Journal of Gemmology of Gemmological Association of Great Britain |volume=30 |issue=1–2 |year=2006–2007 |pages=59–74 |url-status=dead |archive-url=https://web.archive.org/web/20110711082633/http://www.gem-a.com/media/27904/2006%2030%201%20to%202.pdf |archive-date=11 July 2011  }}</ref> Luminescence in [[ultraviolet light]] is considered a supplementary test when making a natural versus synthetic determination, as many, but not all, natural emeralds are inert to ultraviolet light. Many synthetics are also UV inert.<ref>Hurlbut, Cornelius S. Jr. and Kammerling, Robert C. (1991) ''Gemology'', John Wiley & Sons, New York, p. 81, {{ISBN|0-471-52667-3}}.</ref>
[[File:SyntEmerald 0302.jpg|thumb|Emerald made by hydrothermal synthesis]]
Synthetic emeralds are often referred to as "created", as their chemical and gemological composition is the same as their natural counterparts. The U.S. [[Federal Trade Commission]] (FTC) has very strict regulations as to what can and what cannot be called a "synthetic" stone. The FTC says: "§&nbsp;23.23(c) It is unfair or deceptive to use the word "laboratory-grown", "laboratory-created", "[manufacturer name]-created", or "synthetic" with the name of any natural stone to describe any industry product unless such industry product has essentially the same optical, physical, and chemical properties as the stone named."<ref name=ftc>{{cite web |url=http://www.ftc.gov/bcp/guides/jewel-gd.htm |title=Guides for the Jewelry, Precious Metals, and Pewter Industries |publisher=U.S. [[Federal Trade Commission]] |date=30 May 1996 |access-date=30 July 2010 |url-status=live |archive-url=https://web.archive.org/web/20080907034021/http://www.ftc.gov/bcp/guides/jewel-gd.htm |archive-date=7 September 2008  }}</ref>

== Historical and cultural references ==
*Emerald is regarded as the traditional [[birthstone]] for May as well as the traditional gemstone for the [[astrological sign]] of [[Taurus (astrology)|Taurus]].<ref>{{cite book|last1= Morgan|first1= Diane|title= From Satan's crown to the holy grail : emeralds in myth, magic, and history|date=2007|publisher=Praeger|location=Westport, Conn. [u.a.]|isbn= 978-0-275-99123-4|page= 171|url= https://books.google.com/books?id=wb3ySfyMArUC&q=birthstone%20emerald&pg=PA171|access-date=30 March 2017|url-status= live|archive-url= https://web.archive.org/web/20170330180723/https://books.google.com.au/books?id=wb3ySfyMArUC&lpg=PA171&dq=birthstone%20emerald&pg=PA171#v=onepage&q=birthstone%20emerald&f=false|archive-date= 30 March 2017|df= mdy-all}}</ref>{{request quotation|date=June 2022}}
*Traditional [[alchemy|alchemical lore]] ascribes several uses and characteristics to emeralds:
<blockquote>
The virtue of the Emerald is to counteract poison. They say that if a venomous animal should look at it, it will become blinded. The gem also acts as a preservative against epilepsy; it cures leprosy, strengthens sight and memory, checks copulation, during which act it will break, if worn at the time on the finger.<ref>{{cite book
 |last1             = Ruland
 |first1            = Martin
 |author-link1      = Martin Ruland the Younger
 |translator-last1  = Waite
 |translator-first1 = Arthur Edward
 |translator-link1  = Arthur Edward Waite
 |orig-date         = 1612
 |chapter           = Smaragdus
 |trans-title       = Lexicon alchemia
 |title             = A Lexicon of Alchemy
 |date              = May 26, 2014
 |url               = https://books.google.com/books?id=vWmjAwAAQBAJ
 |location          = Altenmünster, Bavaria
 |publisher         = Jazzybee Verlag
 |publication-date  = 2014
 |page              = 
 |isbn              = 978-3-8496-4439-0
 |access-date       = 25 June 2022
 |quote             = The virtue of the Emerald is to counteract poison. They say that if a venomous animal should look at it, it will become blinded. The gem also acts as a preservative against epilepsy; it cures leprosy, strengthens sight and memory, checks copulation, during which act it will break, it worn at the time on the finger.
 |archive-date      = June 25, 2022
 |archive-url       = https://web.archive.org/web/20220625041552/https://books.google.com/books?id=vWmjAwAAQBAJ
 |url-status        = live
}}</ref>
</blockquote>
*According to French writer [[Pierre de Bourdeille, seigneur de Brantôme|Brantôme]] ({{circa}} 1540–1614) [[Hernán Cortés]] had one of the emeralds which he had looted from Mexico [[engraved gem|text engraved]], ''Inter Natos Mulierum non surrexit major'' ("Among those born of woman there hath not arisen a greater," [[Gospel of Matthew|Matthew]] 11:11), in reference to [[John the Baptist]]. Brantôme considered engraving such a beautiful and simple product of nature sacrilegious and considered this act the cause for Cortez's loss in 1541 of an extremely precious pearl,<ref group = note>To which he dedicated the work, ''A beautiful and incomparable pearl''{{citation needed|date=June 2022}}</ref> and even for the death of King [[Charles IX of France]], who died (1574) soon afterward.<ref>Compare:
{{cite book
 |last1            = de Bourdeill
 |first1           = Pierre
 |author-link1     = Pierre de Bourdeille, seigneur de Brantôme
 |editor-last1     = Lalanne
 |editor-first1    = Ludovic
 |editor-link1     = Ludovic Lalanne
 |volume           = 1: Grand Capitaines Estrangers
 |title            = Oeuvres complètes de Pierre de Bourdeille, seigneur de Brantome publièes d'après les manuscrits avec variantes et fragments inédits pour la Société de l'histoire de France
 |year             = 1864
 |url              = https://books.google.com/books?id=hh3RcvRZbLoC
 |language         = fr
 |location         = Paris
 |publisher        = Jules Renouard
 |publication-date = 1864
 |page             = 52
 |access-date      = 25 June 2022
|quote            = [...] la belle et incomparable perle de cet Hernand Cortez, qu'il rapporta des Indes, sur laquelle il fit graver ces mots: ''Inter natos mulierum non surrexit major'', [...] laquelle il perdit depuis [[Algiers expedition (1541)|devant Alger]] [...]. [...] Brantôme s'est trompé ici: le joyau dont il parle n'était point une perle, mais une émaraude.
 |archive-date     = 25 June 2022
|archive-url      = https://web.archive.org/web/20220625041412/https://books.google.com/books?id=hh3RcvRZbLoC
 |url-status       = live
}}</ref><ref name=Kunz1>{{cite book|last = Kunz|first = George Frederick|title = Magic of Jewels and Charms|url = http://www.farlang.com/gemstones/kunz-magic-jewels/page_350|isbn = 0-7661-4322-8|publisher = Lippincott Company|place = Philadelphia|year = 1915|pages = 305–306|url-status = live|archive-url = https://web.archive.org/web/20121017225741/http://www.farlang.com/gemstones/kunz-magic-jewels/page_350|archive-date = 17 October 2012|df = mdy-all}}</ref>
*In American author [[L. Frank Baum's Juvenile Speaker|L. Frank Baum]]'s 1900 children's novel ''[[The Wonderful Wizard of Oz]]'', and the [[The Wizard of Oz (1939 film)|1939 MGM film adaptation]], the protagonist must travel to an [[Emerald City]] to meet the eponymous character, the [[Wizard of Oz (character)|Wizard]].
*The chief deity of one of India's most famous temples, the [[Meenakshi Amman Temple]] in [[Madurai]], is the goddess [[Minakshi|Meenakshi]], whose idol is traditionally thought to be made of emerald.<ref>{{Cite web|title = Meenakshi Temple – Meenakshi Temple of Madurai, Meenakshi Amman Temple Madurai India|url = http://www.madurai.org.uk/religious-places/meenakshi-temple.html|website = www.madurai.org.uk|access-date = 18 January 2016|url-status = live|archive-url = https://web.archive.org/web/20160317015941/http://www.madurai.org.uk/religious-places/meenakshi-temple.html|archive-date = 17 March 2016|df = mdy-all}}</ref>

== Notable emeralds ==
{| class="wikitable sortable"
|-
!scope="col" | Emerald
!scope="col" | Origin
!scope="col" data-sort-type="number" | Size
!scope="col" | Location
|-
|Chipembele<ref>{{Cite web|date=8 November 2021|title=Gemfields finds largest emerald ever at Zambia mine|url=https://www.mining.com/gemfields-finds-largest-emerald-to-date-at-zambia-mine/|access-date=9 December 2021|website=MINING.COM|language=en-US|archive-date=9 December 2021|archive-url=https://web.archive.org/web/20211209164025/https://www.mining.com/gemfields-finds-largest-emerald-to-date-at-zambia-mine/|url-status=live}}</ref>
|Zambia, 2021
|7,525 carats (1.505&nbsp;kg)
|[[Israel Diamond Exchange]], Eshed – Gemstar<ref>{{cite web |last1=Addow |first1=Amina |title=World's largest uncut emerald weighs hefty 1.5 kg |url=https://www.guinnessworldrecords.com/news/commercial/2022/11/worlds-largest-uncut-emerald-weighs-hefty-1-5-kg-724380 |publisher=Guinness World Records Limited |access-date=15 October 2023 |date=2 November 2022 |archive-date=13 October 2023 |archive-url=https://web.archive.org/web/20231013051148/https://www.guinnessworldrecords.com/news/commercial/2022/11/worlds-largest-uncut-emerald-weighs-hefty-1-5-kg-724380 |url-status=live }}</ref>
|-
|[[Bahia Emerald]]<ref name="DT">{{Cite web|url=https://www.telegraph.co.uk/news/worldnews/northamerica/usa/8023359/Judge-to-decide-who-owns-250-million-Bahia-emerald.html|title=Judge to decide who owns 250 million Bahia emerald.html|work=[[The Daily Telegraph]], UK|date=24 September 2010|access-date=31 December 2010|first=Nick|last=Allen|url-status=live|archive-url=https://web.archive.org/web/20100928032613/http://www.telegraph.co.uk/news/worldnews/northamerica/usa/8023359/Judge-to-decide-who-owns-250-million-Bahia-emerald.html|archive-date=28 September 2010}}</ref>
|Brazil, 2001
|180,000 carats, crystals in host rock 752&nbsp;lb (341&nbsp;kg)
| Los Angeles County Sheriff's Department<ref>{{cite magazine | url = https://www.wired.com/2017/03/curse-bahia-emerald-giant-green-rock-wreaks-havoc-ruins-lives/ | title = The Curse of the Bahia Emerald, a Giant Green Rock That Ruins Lives | magazine = Wired | publisher = wired.com | access-date = 17 December 2018 | archive-date = 15 December 2018 | archive-url = https://web.archive.org/web/20181215143226/https://www.wired.com/2017/03/curse-bahia-emerald-giant-green-rock-wreaks-havoc-ruins-lives/ | url-status = live }}</ref>
|-
|Carolina Emperor<ref>{{cite web |url=http://www.cnn.com/2010/US/08/31/north.carolina.emerald/index.html |title=North Carolina emerald: Big, green and very rare |last=Gast |first=Phil |access-date=8 October 2013 |date=1 September 2010 |work=CNN |publisher=Cable News Network (Turner Broadcasting System, Inc.) |url-status=live |archive-url=https://web.archive.org/web/20130925153333/http://www.cnn.com/2010/US/08/31/north.carolina.emerald/index.html |archive-date=25 September 2013  }}</ref><ref>{{cite web |url=http://www.newsobserver.com/2012/03/16/1935490/nc-gems-to-shine-at-museum.html |title=N.C. gems to shine at museum |last=Stancill |first=Jane |access-date=8 October 2013 |date=16 March 2012 |work=[[The News & Observer]] |publisher=The News & Observer Publishing Co. |url-status=dead |archive-url=https://web.archive.org/web/20120327194244/http://www.newsobserver.com/2012/03/16/1935490/nc-gems-to-shine-at-museum.html |archive-date=27 March 2012  }}</ref>
|United States, 2009
|310 carats uncut, 64.8 carats cut
|[[North Carolina Museum of Natural Sciences]], Raleigh
|-
|[[Chalk Emerald]]
|Colombia
|38.40 carats cut, then recut to 37.82 carats
|[[National Museum of Natural History]], Washington
|-
|[[Duke of Devonshire Emerald]]
|Colombia, before 1831
|1,383.93 carats uncut
|[[Natural History Museum, London]]
|-
|Emerald of Saint Louis<ref>{{cite web | url = http://www.crpg.cnrs-nancy.fr/Science/Emeraudes/Gallery_st_louis_sertie.html | title = Emeraude de Saint Louis – St Louis Emerald | work = CRPG: Le Centre de Recherches Pétrographiques et Géochimiques | access-date = 8 February 2017 | url-status = live | archive-url = https://web.archive.org/web/20160304044320/http://www.crpg.cnrs-nancy.fr/Science/Emeraudes/Gallery_st_louis_sertie.html | archive-date = 4 March 2016 | df = mdy-all }}</ref>
|Austria, probably Habachtal
|51.60 carats cut
|[[National Museum of Natural History (France)|National Museum of Natural History]], Paris
|-
|[[Gachalá Emerald]]<ref>{{cite web | url = http://geogallery.si.edu/index.php/10002797/gachala-emerald | title = Gachala Emerald | work = National Museum of Natural History | publisher = Smithsonian Institution | year = 2017 | access-date = 8 February 2017 | url-status = live | archive-url = https://web.archive.org/web/20170211080411/http://geogallery.si.edu/index.php/10002797/gachala-emerald | archive-date = 11 February 2017 | df = mdy-all }}</ref>
|Colombia, 1967
|858 carats uncut
|[[National Museum of Natural History]], Washington
|-
|[[Mogul Mughal Emerald]]
|Colombia, 1107 A.H. (1695–1696 AD)
|217.80 carats cut
|[[Museum of Islamic Art, Doha]], Qatar
|-
| Rockefeller Emerald <ref>{{cite web |title=10 jewels that made history |url=https://www.christies.com/features/10-jewels-that-created-auction-history-and-changed-the-market-9549-3.aspx?sc_lang=en&lid=1 |website=Christies |access-date=22 December 2019 |archive-date=16 March 2020 |archive-url=https://web.archive.org/web/20200316045906/https://www.christies.com/features/10-jewels-that-created-auction-history-and-changed-the-market-9549-3.aspx?sc_lang=en&lid=1 |url-status=live }}</ref>
| Colombia
| 18.04  carats Octagonal step-cut
| Private collection
|-
|Patricia Emerald<ref>{{Cite web|title = Patricia Emerald|url = http://www.amnh.org/exhibitions/permanent-exhibitions/earth-and-planetary-sciences-halls/morgan-memorial-hall-of-gems/patricia-emerald|website = AMNH|access-date = 22 August 2015|url-status = live|archive-url = https://web.archive.org/web/20150905075133/http://www.amnh.org/exhibitions/permanent-exhibitions/earth-and-planetary-sciences-halls/morgan-memorial-hall-of-gems/patricia-emerald|archive-date = 5 September 2015|df = mdy-all}}</ref>
|Colombia, 1920
|632 carats uncut, dihexagonal (12 sided)
|[[American Museum of Natural History]], New York
|-
|Mim Emerald<ref>Bouillard, J.-C. and Jeanne-Michaud, A. (2016) "101 minéraux et pierres précieuses – qu'il faut avoir vus dans sa vie". Hors collection, Dunod. {{ISBN|2100742272}}.</ref>
|Colombia, 2014
|1,390 carats uncut, dihexagonal (12 sided)
|[[Mim Museum]], Beirut
|}

== Gallery ==
<gallery mode="packed" heights="140">
File:Émeraude, quartz 2.jpg|Emerald on quartz, from Carnaiba Mine, Pindobaçu, Campo Formoso ultramafic complex, Bahia, Brazil
File:Chalk emerald 03.jpg|The [[Chalk Emerald]] ring, containing a top-quality 37-carat emerald, in the U.S. National Museum of Natural History
File:Зүмірет.jpg|Emerald crystals
File:Beryl-130023.jpg|A 5-[[carat (mass)|carat]] emerald from Muzo with hexagonal cross-section
File:Gachala Emerald 3526711557 849c4c7367.jpg|[[Gachalá Emerald]], one of the largest gem emeralds in the world, at {{convert|858|carat|g}}. Found in 1967 at La Vega de San Juan mine in Gachalá, Colombia. Housed at the [[National Museum of Natural History]] in Washington,&nbsp;D.C.
File:Béryl var. émeraude sur gangue (Muzo Mine Boyaca - Colombie) -2.jpg|[[Colombian emeralds]]
File:Rough emerald crystals from Panjshir Valley Afghanistan.jpg|Rough emerald crystals from Panjshir Valley Afghanistan
File:Mim emerald.jpg|Large, di-hexagonal prismatic crystal of 1,390 carats uncut with a  deep green color. It is transparent and features few inclusions in the upper 2/3, and is translucent in the lower part. Housed at the [[Mim Museum]], Beirut, Lebanon.
</gallery>

== See also ==
{{Portal|Minerals}}
*[[List of emeralds by size]]
*[[List of minerals]]
*[[Mineral industry of Colombia]]
*[[Colombian emeralds]]
*[[Cardinal gem]]
*[[Sapphire]]
*[[Ruby]]
*[[Red beryl]]
*[[Turquoise]]

== Notes ==
{{reflist|group=note}}

== References ==
{{reflist|30em}}

== Further reading ==
* Ali, Saleem H. (2006). The Emerald City: Emerald mining in Brazil (+Gemstone mining in other countries) https://web.archive.org/web/20071014012610/http://www.uvm.edu/envnr/gemecology/brazil.html <!-- Link leads to: Puppim de Oliveira, Jose Antonio (2005–2006). "[http://www.uvm.edu/rsenr/gemecology/brazil.html Emerald Mining and Local Development: Three Case Studies in Brazil]". PDF. -->
* Cooper, J. C. (ed.) (1992). ''Brewer's Myth and Legend''. New York: Cassell Publishers Ltd. {{ISBN|0-304-34084-7}}.
* Giuliani, Gaston, Ed. (2022). Émeraudes, tout un monde. Led Editions du Piat, {{ISBN|978-2-917198-51-3}}
* Hurlbut, Cornelius S.; Klein, Cornelis (1985). ''Manual of Mineralogy'' (20th ed.). New York: John Wiley and Sons. {{ISBN|0-471-80580-7}}.
* Sinkankas, John (1994). ''Emerald & Other Beryls''. Prescott, Ariz.: Geoscience Press. {{ISBN|0-8019-7114-4}}.
* Tavernier, Jean-Baptiste (1925 [1676]). [http://www.farlang.com/diamonds/tavernier-travels-india-2/page_001 ''Travels in India''] (second edition), Volume II. Edited by William Crooke and translated by V. Ball. London: Oxford University Press.
* Weinstein, Michael (1958). ''The World of Jewel Stones''. New York: Sheriden House. {{oclc|519758}}.
* Wise, Richard W. (2003). ''Secrets of the Gem Trade: The Connoisseur's Guide to Precious Gemstones''. Lenox, Mass.: Brunswick House Press. {{ISBN|9780972822398}}. {{oclc|55662640}}. [http://www.rwwise.com/tec2.html Online Emerald chapters].

== External links ==
{{Commons category|Emeralds}}
* [http://gemstone.org/education/gem-by-gem/153-emerald ICA's Emerald Page] International Colored Gemstone Association Emerald Page

{{Jewellery}}
{{Gemstone}}
{{Colombian emeralds|state=collapsed}}
{{Authority control}}

[[Category:Beryl group]]