Emerald 10045 225607714 2008-07-14T15:09:38Z Tj9991 192259 Reverted edits by [[Special:Contributions/81.111.144.3|81.111.144.3]] to last version by 87.68.157.69 (using [[WP:HG|Huggle]]) {{otheruses}} {{Infobox mineral | name = Emerald | category = [[Beryl]] variety | boxwidth = | boxbgcolor = | image = Émeraude (Brésil).jpg | imagesize = 225 | caption = Emerald with host rock | formula = [[Beryllium]] [[aluminium]] [[silicate]] with [[chromium]], <!-- -->Be<sub>3</sub>Al<sub>2</sub>(SiO<sub>3</sub>)<sub>6</sub>::Cr| molweight = | color = Green | habit = Hexagonal Crystals | system = Hexagonal | twinning = | cleavage = Poor Basal Cleavage (Seldom Visible) | fracture = Conchoidal | Melting Poi = 1278°C | mohs = 7.5 - 8.0 | luster = Vitreous | refractive = 1.576 - 1.582 | opticalprop = | birefringence = | pleochroism = Distinct, Blue-Green/Yellow-Green | streak = White | gravity = 2.70 - 2.78 | density = | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = | other = }} '''Emeralds''' are a variety of the [[mineral]] [[beryl]] (Be<sub>3</sub>Al<sub>2</sub>(<nowiki>SiO</nowiki><sub>3</sub>)<sub>6</sub>,) colored [[green]] by trace amounts of [[chromium]] and sometimes [[vanadium]].<ref> Hurlbut, Cornelius S. Jr, & Kammerling, Robert C., 1991, ''Gemology'', p. 203, John Wiley & Sons, New York</ref> Beryl has a [[Hardness (materials science)|hardness]] of 7.5 - 8 on the 10 point [[Mohs scale of mineral hardness]].<ref> Hurlbut, Cornelius S. Jr, & Kammerling, Robert C., 1991, ''Gemology'', p. 202, John Wiley & Sons, New York</ref> Most emeralds are highly [[inclusion (mineral)|included]], so their brittleness (resistance to breakage) is classified as generally poor. The word "emerald" comes from [[Latin]] ''smaragdus'', via [[Greek language|Greek]] ''smaragdos'', its original source being a [[Semitic]] word ''izmargad'' or the [[Sanskrit]] word, ''marakata'', meaning "emerald" or "green".<ref name=Fernie>{{cite book | last = Fernie M.D. | first = W.T. | title = Precious Stones for Curative Wear | publisher = John Wright. & Co. | year = 1906}}</ref> ==Properties determining value== [[Image:Beryl emeralds cut XH.jpg|thumb|left|Cut emeralds]] Emeralds come in many shades of green and bluish green. There is a wide spectrum of clarity, dependent on the inclusions and fractures in the crystal. Clear stones with dark yet vibrant color command the highest prices. Almost all emeralds contain numerous flaws, cracks, and inclusions, which can negatively affect the clarity. These are given the name "jardin", from the French word for garden. The value of an emerald depends on cut, color, clarity, and [[Carat (mass)|carat]]. Currently the best emeralds come from the Muzo mine in [[Colombia]].<ref>[http://micro.magnet.fsu.edu/birthstones/pages/emerald.html Emerald]</ref> ==Treatments== Most emeralds are oiled as part of the post [[lapidary]] process, in order to improve their clarity. [[Cedar]] oil, having a similar [[refractive index]], is often used in this generally accepted practice. The [[U.S.]] [[Federal Trade Commission]] requires the disclosure of this treatment when a treated emerald is sold.<ref>[http://www.ftc.gov/bcp/guides/jewel-gd.shtm#%A7%2023.22%20Deception%20as%20to%20gemstones Guides for the Jewelry, Precious Metals, and Pewter Industries]</ref> The amount of oil entering an emerald microfissure is roughly equivalent to the size of a period ([[full stop]]) in print{{Fact|date=March 2007}}. The use of green-tinted oil is generally not considered acceptable by the gem trade. ==Emerald localities== Emeralds in antiquity were mined by the [[Ancient_Egypt|Egyptians]] and in [[Austria]], as well as [[Swat (Pakistan)|Swat]] in northern [[Pakistan]].<ref>Giuliani et al (2000): “Oxygen Isotopes and Emerald Trade Routes Since Antiquity.” Gaston Giuliani, Marc Chaudisson, Henri-Jean Schubnel, Daniel-H. Piat, Claire Rollion-Bard, Christian France-Lanord, Didier Giard, Daniel de Narvaez, Benjamin Rondeau. ''Science'', January 28, 2000, pp. 631-633.</ref><ref>Giuliani et al (2000b): “La route des emeraudes anciennes.” Gaston Giuliani, Michèle Heuze, Marc Chaudisson. ''Pour la Science'', November 2000, pp. 58-65.</ref> 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 has raylike spokes of dark carbon impurities that give the emerald a [[Asterism (gemmology)|six-pointed radial pattern]]. It is named for the ''trapiche'', a grinding wheel used to process [[sugarcane]] in the region. Colombian emeralds are generally the most prized due to their transparency and fire. Some of the most rare emeralds come from three main emerald mining areas in Colombia: Muzo, Coscuez, and Chivor. Fine emeralds are also found in other countries, such as [[Zambia]], [[Brazil]], [[Zimbabwe]], [[Madagascar]], [[Pakistan]], [[India]], [[Afghanistan]] and [[Russia]]. In the US, emeralds can be found in Gastonia, [[North Carolina]]. In 1998, emeralds were discovered in the [[Yukon]] Territory, [[Canada]].<ref>http://www.geology.gov.yk.ca/special/index.html</ref> ==Synthetic emerald== [[Image:Emerald.png|thumb|100px|left|Emerald showing its hexagonal structure]] Emerald is a rare and valuable gemstone and, as such, it has provided the [[incentive]] for developing synthetic emeralds. Both hydrothermal and ''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]]. Because Chatham's emeralds do not have any water and contain traces of vanadate, molybdenum and vanadium, a lithium vanadate flux process is probably involved. The other large producer of flux emeralds is [[Pierre Gilson]] Sr., which has been on the market since 1964. Gilson's emeralds are usually grown on natural colorless beryl seeds which become coated on both sides. Growth occurs at the rate of 1 mm per month, a typical seven-month growth run producing emerald crystals of 7 mm of thickness (Nassau, K. ''Gems Made By Man'', 1980). [[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 "Symeralds", and they were grown as a thin layer of emerald on top of natural colorless beryl stones. Although not much is known about the original process, it is assumed that Leichleitner emeralds were grown in acid conditions. 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 (US3,567,642 and US3,567,643), 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 in order to prevent nucleation and confine growth to the seed crystals. Growth occurs by a diffusion-reaction process, assisted by convection. Typical growth conditions include pressures of 700-1400 bars at temperatures of 500 to 600 °C with a temperature gradient of 10 to 25 °C. Growth rates as fast as 1/3 mm per day can be attained{{Fact|date=March 2007}} Luminescence in [[ultraviolet light]] is considered a supplementary test when making a natural vs. 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, & Kammerling, Robert C., 1991, Gemology, p. 81, John Wiley & Sons, New York</ref> 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 "synthetic" stone. The FTC says: "§ 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>[http://www.ftc.gov/bcp/guides/jewel-gd.htm Guides for the Jewelry, Precious Metals, and Pewter Industries<!-- Bot generated title -->]</ref> Wispy veil-like inclusions are common in flux-grown synthetic emeralds. ==Emerald in different cultures, and Emerald lore== [[Image:gachalaemerald.jpg|thumb|250px|right|The [[Gachala Emerald]] is one of the largest gem emeralds in the world at 858 [[Carat (mass)|carat]]s (172 g). This stone was found in 1967 at La Vega de San Juan mine in Gachalá, Colombia. It is housed at the [[National Museum of Natural History]] of the [[Smithsonian Institution]] in Washington DC.]] Emerald is regarded as the traditional [[Birthstone#Birthstones|birthstone]] for May, as well as the traditional gemstone for the [[astrological sign]]s of [[Taurus (astrology)|Taurus]] , [[Cancer (astrology)|Cancer]] and sometimes [[Gemini (astrology)|Gemini]]. One of the more quaint anecdotes on emeralds was by the 16th century historian [[Brantome]], who referred to the many impressive emeralds the Spanish under [[Cortez]] had brought back to Europe from Latin America. On one of Cortez most famous emeralds he had the text engraved ''Inter Natos Mulierum non sur-rexit mayor'' (Among them borne of woman there hath not arisen a greater Man. XI, 11) which referred to [[John the Baptist]]. Brantome considered engraving such a beautiful and simple product of nature sacrilegious and considered this act the cause for Cortez loss of an extremely precious pearl (to which he dedicated a work ''A beautiful and incomparable pearl'') and even for the death of King [[Charles IX]] who died soon after.<ref name = Kunz1> {{cite book | last = Kunz | first = George Frederick | title = Magic of Jewels and Charms | publisher = Lippincott Company | year = 1915}} Page 305 </ref> ===High Priest Breastplate=== In [[Exodus]] chapters 28 and 39, a number of precious stones are mentioned to be placed in the High Priest's Breastplate, representing the different tribes of Israel. This is generally considered to be (one of) the origin(s) of our present day tradition of [[birthstones]]. According to [[Bahya ben Asher|Rebbenu Bachya]], and the [[King James Version]], the [[Hebrew language|Hebrew]] word ''Nofech'' in [[Exodus]] 28:18 means ''Emerald'', and was the stone on the [[Hoshen]] representing the [[tribe of Judah]]. However, the [[Septuagint]] translates the word as ''Anthrax'', meaning ''[[coal]]'', probably in reference to the colour of burning coal, and therefore many rabbinical sources, and most scholars, consider ''Nofech'' to mean a red [[garnet]] – traditionally called a ''[[carbuncle (gemstone)|carbuncle]]'', which happens to be the [[Vulgate]]'s translation of the word.<ref name=Farrington>{{cite book | last = Farrington, PhD. | first = Oliver Cummings | title = Gems and Gem Minerals | publisher = Chicago, Mumford | year = 1903}} page 61. [[Oliver C. Farrington]] also clearly states the exchange/confusion of the "Carbuncle" and the "Emerald" in the different translations over time</ref> There is a wide range of views among traditional sources about which tribe the stone refers to.<ref name=Kunz>{{cite book | last = Kunz | first = George Frederick | title = A Curious Lore of Precious Stones, Chapter 8: High Priest Breastplate | publisher = Lippincott. Co. | year = 1913}} URL: [http://www.farlang.com/gemstones/kunz-curious-lore-stones/page_324 Emeralds and High Priest Breast Plate], page 275. [[George Frederick Kunz]] discusses different interpretations of the "Emerald" in this chapter. 1) Emeralds were known and used by the Egyptians and at that time dug in Nubia. 2) The *size* of the stones on the breastplate make it very unlikely to be Emeralds, since they were not found at that size in those times. 3) Emerald is a fairly hard material to engrave and the tools existing in that era may probably have not been able to work with Emeralds; another reason why Emeralds are less likely to have been used</ref> There are many complexities to identifying the Emerald as being the third stone or perhaps another stone on the breast plate. Multiple translations of the bible<ref name=Kunz/> have created confusion about the nomenclature of the different stones. Another important fact is that in actuality there are two different breastplates made within a period of 800 years, and where it is assumed the first breastplate did not carry an Emerald but a green [[Felspar]], and a real Emerald in the second breastplate.<ref name = Kunz/> Finally the 12th stone in the Breastplate (which in the original text was actually listed as the 6th stone)<ref name = Kunz/> has more generally been identified as ''Beryl'' which was already included in the group of stones generally referred to as ''Smaragdus'' by [[Theophrastus]] in the Greek era.<ref name=Theophrastus>{{cite book | last = Caley | first = Earle | title = Theophrastus On Stones | publisher = Ohio State University | year = 1956}} </ref> Further unreferenced claims regarding the possibility of what gemstone the Emerald could really have been include Jasper, and even [[Rubies]]. In some cultures, the emerald is the traditional gift for the 55th [[wedding anniversary]]. It is also used as a 20th and 35th wedding anniversary stone. ==Famous emeralds== * [[Gachala Emerald]] (origin: Colombia) * [[Chalk Emerald]] (origin: Colombia) * [[Meidan-i-Noor]] (origin: Colombia) == Notes == {{reflist|2}} == References == *Cooper, J.C. (Ed.) (1992). ''Brewer's Myth and Legend''. New York: Cassell Publishers Ltd. ISBN 0-304-34084-7. *Sinkankas, John (1994). ''Emerald & Other Beryls''. Geoscience Press. ISBN 0-8019-7114-4 *Hurlbut, Cornelius S.; Klein, Cornelis (1985). ''Manual of Mineralogy'' (20th ed.). New York: John Wiley and Sons. ISBN 0-471-80580-7 *Weinstein, Michael (1958). ''The World of Jewel Stones''. Sheriden House. *Nassau, Kurt (1980). ''Gems made by man''. Gemological Institute of America. ISBN 0-87311-016-1 *Ali, Saleem H. (2006). The Emerald City: Emerald mining in Brazil (+Gemstone mining in other countries) http://www.uvm.edu/envnr/gemecology/brazil.html ==External links== {{commonscat|Emeralds}} *[http://www.farlang.com/gemstones/emeralds Historical References of Emeralds] (full texts on) Famous Emeralds, and many of full text references used here. *[http://www.gemstone.org/gem-by-gem/english/emerald.html ICA's Emerald Page] International Colored Stone Emerald Page *[http://www.mindat.org/min-1375.html Mindat Emerald Page] Mindat on Emerald with locality information *[http://webmineral.com/data/Beryl.shtml Webmineral Beryl Page] Webmineral with crystallographic and mineralogical information {{Jewellery Materials}} [[Category:Beryllium minerals]] [[Category:Aluminium minerals]] [[Category:Silicate minerals]] [[Category:Gemstones]] [[ar:زمرد]] [[az:Zümrüd]] [[bn:পান্না]] [[bs:Smaragd]] [[bg:Изумруд]] [[ca:Maragda]] [[cs:Smaragd]] [[da:Smaragd]] [[de:Smaragd]] [[et:Smaragd]] [[es:Esmeralda]] [[eo:Smeraldo]] [[eu:Esmeralda]] [[fa:زمرد]] [[fr:Émeraude]] [[gl:Esmeralda]] [[bpy:এসমেরআলডা]] [[id:Zamrud]] [[it:Smeraldo]] [[he:ברקת]] [[sw:Zumaridi]] [[la:Smaragdus (lapis)]] [[lv:Smaragds]] [[lt:Smaragdas]] [[nah:Quetzalitztli]] [[nl:Smaragd]] [[ja:エメラルド]] [[no:Smaragd]] [[pl:Szmaragd]] [[pt:Esmeralda]] [[ro:Smarald]] [[qu:Q'umir umiña]] [[ru:Изумруд]] [[sco:Emerant]] [[simple:Emerald]] [[sk:Smaragd]] [[sl:Smaragd]] [[sr:Смарагд]] [[fi:Smaragdi]] [[sv:Smaragd]] [[th:มรกต]] [[vi:Ngọc lục bảo]] [[tr:Zümrüt (maden)]] [[zh:祖母綠]]