Amethyst#Cultural history
{{Short description |Mineral, quartz variety}}
{{Other uses}}
{{Use dmy dates|date=September 2024}}
{{Use American English|date=October 2015}}
{{Infobox mineral
| name = Amethyst
| category = Tectosilicates, quartz variety
| boxwidth =
| boxbgcolor = #784a76
| boxtextcolor = #ffffff
| image = Amatista Laye 2.jpg
| imagesize = 250px
| caption = Amethyst cluster from Artigas, Uruguay
| formula = Silica (silicon dioxide, SiO{{sub|2}})
| molweight =
| system = Trigonal
| class = Trapezohedral (32)
| symmetry = P3{{sub|2}}21 (no. 154)
| color = Purple, violet, dark purple
| habit = 6 sided prism ending in 6 sided pyramid (typical)
| twinning = Dauphine law, Brazil law, and Japan law
| cleavage = None
| fracture = Conchoidal
| mohs = 7 (lower in impure varieties)
| luster = Vitreous/glassy
| refractive = nω = 1.543–1.553
{{mvar|n{{sub|ε}}}} = 1.552–1.554
| opticalprop = Uniaxial (+)
| birefringence = +0.009 (B-G interval)
| pleochroism = Weak to moderate purple/reddish purple
| streak = White
| gravity = 2.65 constant; variable in impure varieties
| density =
| melt = {{gaps|1|650}}±75 °C
| fusibility =
| diagnostic =
| solubility = Insoluble in common solvents
| diaphaneity = Transparent to translucent
| other = Piezoelectric
}}
Amethyst is a violet variety of quartz. The name comes from the Koine Greek {{lang|grc-Grek|αμέθυστος|italic=no}} {{lang|grc-latn|amethystos}} from {{lang|grc-Grek|α|italic=no}}- {{lang|grc-latn|a-}}, "not" and {{lang|grc-Grek|μεθύσκω|italic=no}} (Ancient Greek) {{transliteration|grc|methysko}} / {{lang|el|μεθώ|italic=no}} {{transliteration|grc|metho}} (Modern Greek), "intoxicate", a reference to the belief that the stone protected its owner from drunkenness.{{EB1911 |inline=y |wstitle= Amethyst |volume= 1 |page= 852 |first= Frederick William |last= Rudler}} Ancient Greeks wore amethyst and carved drinking vessels from it in the belief that it would prevent intoxication.
Amethyst, a semiprecious stone, is often used in jewelry.
Structure
Amethyst is a violet variety of quartz ({{chem|Si|O|2}}) and owes its violet color to irradiation, impurities of iron ({{chem|Fe|3+}}) and in some cases other transition metals, and the presence of other trace elements, which result in complex crystal lattice substitutions.
{{cite book
|first1=Norman N. |last1=Greenwood
|first2=Alan |last2=Earnshaw
|year=1997
|title=Chemistry of the Elements |edition=2nd
|publisher=Butterworth–Heinemann
|isbn=0080379419
}}
{{cite journal
|first1=Fernando S. |last1=Lameiras
|first2=Eduardo H.M. |last2=Nunes
|first3=Wander L. |last3=Vasconcelos
|year=2009
|title=Infrared and chemical characterization of natural amethysts and prasiolites colored by irradiation
|journal=Materials Research
|volume=12 |issue=3 |pages=315–320
|doi=10.1590/S1516-14392009000300011 |doi-access=free
}}
{{cite book
|first = Michael |last = O'Donoghue
|year = 2006
|title = Gems |edition = 6th
|publisher = Butterworth-Heinemann
|isbn = 978-0-7506-5856-0
}}
The irradiation causes the iron {{chem|Fe|3+}} ions that replace Si in the lattice to lose an electron and form a {{chem|[|FeO|4|]|}}{{sup|0}} color center.
{{cite web
|author1=Lehmann
|author2=Moore
|year=1966
|title=Amethyst
|website=mindat.org
|url=https://www.mindat.org/min-198.html
}}
Amethyst is a three-dimensional network of tetrahedra where the silicon atoms are in the center and are surrounded by four oxygen atoms located at the vertices of a tetrahedron. This structure is quite rigid and results in quartz's hardness and resistance to weathering. The hardness of the mineral is the same as quartz, thus making it suitable for use in jewelry.
Hue and tone
Amethyst occurs in primary hues from a light lavender or pale violet to a deep purple. Amethyst may exhibit one or both secondary hues, red and blue.
{{cite web
|title=Amethyst: The world's most popular purple gemstone
|website=geology.com
|url=http://geology.com/gemstones/amethyst/
|access-date=29 August 2017
}}
High-quality amethyst can be found in Siberia, Sri Lanka, Brazil, Uruguay, and the Far East. The ideal grade, called "Deep Siberian", has a primary purple hue of around 75–80%, with 15–20% blue and (depending on the light source) red secondary hues.
{{cite book
|first = Richard W. |last = Wise
|year = 2005
|title = Secrets of the Gem Trade: The connoisseurs' guide to precious gemstones
|publisher = Brunswick House Press
|place = Lenox, MA
|isbn = 0-9728223-8-0
}}
"Rose de France" is defined by its markedly light shade of the purple, reminiscent of a lavender / lilac shade. These pale colors were once considered undesirable, but have recently become popular due to intensive marketing.
{{cite web
|last1=Arem |first1=Joel E.
|last2=Clark |first2=Donald
|last3=Smigel |first3=Barbara
|title=Amethyst: Value, price, and jewelry information
|website=gemsociety.org
|publisher = International Gem Society (IGS)
|url=https://www.gemsociety.org/article/amethyst-jewelry-and-gemstone-information/
|access-date=20 April 2021
}}
Green quartz is sometimes called green amethyst; the scientific name is prasiolite.
{{cite web
|title = Prasiolite gemstone information
|website = gemdat.org
|url = http://www.gemdat.org/gem-40112.html
|access-date = 19 April 2018
}}
Other names for green quartz are vermarine and lime citrine.
Amethyst frequently shows color zoning, with the most intense color typically found at the crystal terminations. One of gem cutters' tasks is to make a finished product with even color. Sometimes, only a thin layer of a natural, uncut amethyst is violet colored, or the color is very uneven. The uncut gem may have only a small portion that is suitable for faceting.
{{cite journal
|last1 = Lowell |first1 = J.
|last2 = Koivula |first2 = J.I.
|year = 2004
|title = Amethyst from four peaks, Arizona
|journal = Gems & Gemology
|volume = 40 |number = 3 |pages = 230–238
|doi = 10.5741/GEMS.40.3.230
|url = https://www.gia.edu/doc/Amethyst-from-Four-Peaks-Arizona.pdf
|url-status = live |access-date = 20 April 2021
|archive-url = https://ghostarchive.org/archive/20221009/https://www.gia.edu/doc/Amethyst-from-Four-Peaks-Arizona.pdf
|archive-date = 9 October 2022
}}
{{cite journal
|last1 = Troilo |first1 = Fabrizio |last2 = el Harfi |first2 = Abdelghani
|last3 = Mouaddib |first3 = Salahaddine |last4 = Bitarello |first4 = Erica
|last5 = Costa |first5 = Emanuele
|date = 1 May 2015
|title = Amethyst from Boudi, Morocco
|journal = Gems & Gemology
|volume = 51 |issue = 1 |pages = 32–40
|doi = 10.5741/GEMS.51.1.32
}}
{{multiple image
| align = left
| perrow = 1
| total_width = 250
| image1 = Geode Reference -25.jpg
| caption1 = Natural purple/violet amethyst
| image2 = Citrine améthysée.jpg
| caption2 = Heat-treated amethyst
}}
The color of amethyst has been demonstrated to result from substitution by irradiation of trivalent iron (Fe3+) for silicon in the structure,
{{cite book
|author = Rossman, George R.
|year = 1994
|chapter = Chapter 13. Colored varieties of the silica minerals
|pages = 433–468
|publisher = Mineralogical Society of America / Mineralogical Magazine
|title = Silica: Physical behavior, geochemistry, and materials applications
|editor1 = Heaney, Peter J.
|editor2 = Prewitt, Charles T.
|editor3 = Gibbs, Gerald V.
|series = Reviews in Mineralogy
|volume = 29 |issue = 399
|isbn = 978-0-939950-35-5
|bibcode = 1996MinM...60..390H
|doi = 10.1180/minmag.1996.060.399.16
|s2cid = 201093227
}}
in the presence of trace elements of large ionic radius, and to a certain extent, the amethyst color can naturally result from displacement of transition elements even if the iron concentration is low. Natural amethyst is dichroic in reddish violet and bluish violet, but when heated, turns yellow-orange, yellow-brown, or dark brownish and may resemble citrine,
{{cite web
|title = Amethyst
|website = Mindat.org
|url = http://www.mindat.org/min-198.html
}}
but loses its dichroism, unlike genuine citrine. When partially heated, amethyst can result in ametrine.
Amethyst can fade in tone if overexposed to light sources, and can be artificially darkened with adequate irradiation. It does not fluoresce under either short-wave or long-wave UV light.
Geographic distribution
Amethyst is found in many locations around the world. Between 2000 and 2010, the greatest production was from Marabá and Pau d'Arco, Pará, and the Paraná Basin, Rio Grande do Sul, Brazil; Sandoval, Santa Cruz, Bolivia; Artigas, Uruguay; Kalomo, Zambia; and Thunder Bay, Ontario. Lesser amounts are found in many other locations in Africa, Brazil, Spain, Argentina, Russia, Afghanistan, South Korea, Mexico, and the United States.
{{cite journal
|last1=Shigley |first1=J.E. |last2=Laurs |first2=B.M.
|last3=Janse |first3=A.J.A. |last4=Elen |first4=S.
|last5=Dirlam |first5=D.M.
|year=2010
|title=Gem Localities of the 2000s
|journal=Gems & Gemology
|volume=46 |number=3 |pages=188–216
|doi=10.5741/GEMS.46.3.188
|url=https://www.gia.edu/doc/Fall-2010-Gems-Gemology-Localities-of-the-2000s.pdf
|archive-url=https://ghostarchive.org/archive/20221009/https://www.gia.edu/doc/Fall-2010-Gems-Gemology-Localities-of-the-2000s.pdf
|archive-date=9 October 2022
|url-status=live |access-date=20 April 2021
}}
File:Amethyst Geode.png collected from Artigas, Uruguay.]]
Amethyst is produced in abundance in the state of Rio Grande do Sul in Brazil where it occurs in large geodes within volcanic rocks.
{{cite web
|title=Serviço Geológico do Brasil
|url=http://www.cprm.gov.br/publique/CPRM-Divulga/Canal-Escola/Algumas-Gemas-Classicas-1104.html
|access-date=31 January 2022
|website = cprm.gov.br
}}
{{cite web
|date=27 February 2018
|title=Os alemães e as pedras preciosas gaúchas
|url=https://gauchazh.clicrbs.com.br/cultura-e-lazer/almanaque/noticia/2018/02/os-alemaes-e-as-pedras-preciosas-gauchas-cje4tmdeu00d701qoek6rfc3c.html
|access-date=31 January 2022
|website=GZH
|lang=pt-BR
}}
{{cite web
|website=Ciência e Saúde (g1.globo.com/ciencia-e-saude)
|date=7 December 2012
|title=Maior pedra de água-marinha é brasileira e ficará exposta nos EUA
|id = da EFE
|url=http://g1.globo.com/ciencia-e-saude/noticia/2012/12/maior-pedra-de-agua-marinha-e-brasileira-e-ficara-exposta-nos-eua.html
|access-date=31 January 2022
|lang=pt-br
}}
{{Cite web
|id = Do G1 RS
|date = 4 July 2013
|title = Pedras de ametista são atrativos para turistas em cidade no Norte do RS
|website = g1.globo.com
|series = Nossa Terra 2013
|url = http://g1.globo.com/rs/rio-grande-do-sul/nossa-terra/2013/noticia/2013/07/pedras-de-ametista-sao-atrativos-para-turistas-em-cidade-no-norte-do-rs.html
|access-date = 31 January 2022
|lang = pt-br
}}
Many of the hollow agates of southwestern Brazil and Uruguay contain a crop of amethyst crystals in the interior. Artigas, Uruguay and neighboring Brazilian state Rio Grande do Sul are large world producers, with lesser quantities mined in Minas Gerais and Bahia states.
File:Geode di quarzo ametista dal rio grande do sul, brasile.JPG that formed when large crystals grew in open spaces inside the rock]]
Amethyst is also found and mined in South Korea.
{{cite journal
|first1=K.H. |last1=Yang
|first2=S.H. |last2=Yun
|first3=J.D. |last3=Lee
|year=2001
|title=A fluid inclusion study of an amethyst deposit in the Cretaceous Kyongsang Basin, South Korea
|journal=Mineralogical Magazine
|volume=65 |number=4 |pages=477–487
|doi=10.1180/002646101750377515
|bibcode=2001MinM...65..477Y |s2cid=129368598
|url=https://pubs.geoscienceworld.org/minmag/article-abstract/65/4/477/140036
|access-date=20 April 2021
}}
The large opencast amethyst vein at Maissau, Lower Austria, was historically important, but is no longer included among significant producers. Much fine amethyst comes from Russia, especially near Mursinka in the Ekaterinburg district, where it occurs in drusy cavities in granitic rocks. Amethyst was historically mined in many localities in south India, though these are no longer significant producers. One of the largest global amethyst producers is Zambia in southern Africa, with an annual production around 1000 tons.
{{cite journal
|last1=Anckar |first1=B.
|year=2006
|title=Amethyst Mining in Zambia
|journal=Gems & Gemology
|volume=42 |number=3 |pages=112–113
}}
Amethyst occurs at many localities in the United States. The most important production is at Four Peaks, Gila and Maricopa Counties, Arizona, and Jackson's Crossroads, Wilkes County, Georgia.
Smaller occurrences have been reported in the Red Feather Lakes, near Fort Collins, Colorado; Amethyst Mountain, Texas; Yellowstone National Park; Delaware County, Pennsylvania; Haywood County, North Carolina; Deer Hill and Stow, Maine, and in the Lake Superior region of Minnesota, Wisconsin, and Michigan.
Amethyst is relatively common in the Canadian provinces of Ontario and Nova Scotia. The largest amethyst mine in North America is located in Thunder Bay, Ontario.
Amethyst is the official state gemstone of South Carolina. Several South Carolina amethysts are on display at the Smithsonian Museum of Natural History.
{{cite web
|title = South Carolina state gemstone - amethyst
|date = 24 June 1969
|website = Sciway.net
|url = http://www.sciway.net/facts/sc-state-gemstone-amethyst.html
|access-date=4 February 2016
}}
History
{{multiple image
| align = right
| perrow = 2
| total_width = 300
| image1 = Intaglio Caracalla Cdm Paris Chab2101.jpg
| caption1 = Roman intaglio engraved gem of Caracalla in amethyst, once in the Treasury of Sainte-Chapelle
| image2 = Uninscribed amethyst scarab at the center of a string of amethyst ball beads. Middle Kingdom. From Egypt. The Petrie Museum of Egyptian Archaeology, London.jpg
| caption2 = Uninscribed amethyst scarab at the center of a string of amethyst ball beads from Egypt
}}
Amethyst was used as a gemstone by the ancient Egyptians and was largely employed in antiquity for intaglio engraved gems.
{{cite book
|first = Augosto |last = Castellani
|year = 1871
|url = https://archive.org/details/gemsnotesandext00castgoog
|title = Gems, Notes, and Extracts
|page = 34
|place = London, UK
|publisher = Bell and Daldy
|isbn = 1-141-06174-0
}} — Castellani was a 19th century Italian jeweler, now famous
The ancient Greeks believed amethyst gems could prevent intoxication,
{{cite book
|first = Marcell N. |last = Smith
|year = 1913
|url = http://www.farlang.com/gemstones/smith-diamonds-pearls-stones/page_087
|title = Diamonds, Pearls, and Precious Stones
|publisher = Griffith Stillings Press
|place = Boston, MA
|page = 74
}}
while medieval European soldiers wore amethyst amulets as protection in battle in the belief that amethysts heal people and keep them cool-headed.
{{cite book
|first = G.F. |last = Kunz |author-link = George Frederick Kunz
|year = 1913
|url = http://www.farlang.com/gemstones/kunz-curious-lore-stones/page_077
|title = Curious Lore of Precious Stones
|publisher = Lippincott Company
|place = Philadelphia, PA / London, UK
|page = 58–59, 77
}}
{{rp|style=ama|p= 77}}
Beads of amethyst were found in Anglo-Saxon graves in England.
{{cite book
|editor-first = Michael |editor-last = Lapidge
|year = 2000
|url =https://books.google.com/books?id=f65VUNvxQjkC&pg=PA261
|title = The Blackwell Encyclopaedia of Anglo-Saxon England
|page = 261
|publisher = Wiley
|isbn = 0631224920
}}
Anglican bishops wear an episcopal ring often set with an amethyst, an allusion to the description of the Apostles as "not drunk" at Pentecost in Acts 2:15.
{{cite book
|last = Bays |first = P.
|year = 2012
|title = This Anglican Church of Ours
|publisher = Woodlake Books
|isbn = 9781770644397
|url = https://books.google.com/books?id=oxu2zjbxjnwC
|page = 136
}} name=google
A large geode, or "amethyst-grotto", from near Santa Cruz in southern Brazil was presented at a 1902 exhibition in Düsseldorf, Germany.
Synthetic amethyst
Synthetic (laboratory-grown) amethyst is produced by a synthesis method called hydrothermal growth, which grows the crystals inside a high-pressure autoclave.
Synthetic amethyst is made to imitate the best quality amethyst. Its chemical and physical properties are the same as those of natural amethyst, and it cannot be differentiated with absolute certainty without advanced gemmological testing (which is often cost-prohibitive). One test based on "Brazil law twinning" (a form of quartz twinning where right- and left-hand quartz structures are combined in a single crystal{{cite web
|url = http://quartzpage.de/crs_twins.html
|title = twinning crystals
|website = Quartz Page (quartzpage.de)
}}
) can be used to identify most synthetic amethyst rather easily. Synthesizing twinned amethyst is possible, but this type is not available in large quantities in the market.
Treated amethyst is produced by gamma ray, X-ray, or electron-beam irradiation of clear quartz (rock crystal), which has been first doped with ferric impurities. Exposure to heat partially cancels the irradiation effects and amethyst generally becomes yellow or even green. Much of the citrine, cairngorm, or yellow quartz of jewelry is said to be merely "burnt amethyst".
{{cite book
|author =Michael O'Donoghue
|title=Synthetic, Imitation, and Treated Gemstones
|url=https://books.google.com/books?id=Jm3FwBiHaI4C&pg=PA124
|year=1997
|publisher=Taylor & Francis
|isbn=978-0-7506-3173-0
|pages=124–125
}}
Cultural history
=Ancient Greece=
File:Amethyst close cropped.jpg amethyst]]
The Greek word {{lang|grc-latn|amethystos}} may be translated as "not drunken", from Greek {{lang|grc-latn|a-}}, "not" + {{transliteration|grc|methustos}}, "intoxicated". Amethyst was considered to be a strong antidote against drunkenness.{{efn|
The earliest reference to amethyst as a symbol of sobriety is in a poem by Asclepiades of Samos (born {{circa|320 {{sc|BCE}} }}).
{{cite book
|author = Asclepiades of Samos
|section = XXX. Kleopatra's Ring
|translator-first = Edward |translator-last = Storer
|title = The Windflowers of Asklepiades and the Poems of Poseidippos
|place = London, UK
|publisher = Egoist Press
|year = 1920
|url = https://archive.org/stream/cu31924026460844#page/n17/mode/1up
|page = 14
}}
:
An epigram by Plato the Younger also mentions amethyst in connection with drinking: "The stone is an amethyst; but I, the tipler Dionysus, say, "Let it either persuade me to be sober, or let it learn to get drunk."
{{cite book
|editor1-first = George |editor1-last = Burges |display-editors = etal
|title = The Greek Anthology
|place = London, UK
|publisher =George Bell and Sons
|year = 1881
|page = [https://books.google.com/books?id=FDgRAAAAIAAJ&pg=PA369 369]
}}
:
Pliny says about amethysts: "The falsehoods of the magicians would persuade us that these stones are preventive of inebriety, and that it is from this that they have derived their name."
{{cite book
|author = Pliny the Elder
|title = Natural History
|section = Book 37, Chapter 40
|section-url=https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.02.0137%3Abook%3D37%3Achapter%3D40
}}
which is why wine goblets were often carved from it.
{{cite book
|author =Federman, David
|title=Modern Jeweler's Consumer Guide to Colored Gemstones
|url=https://books.google.com/books?id=flqvBQAAQBAJ&pg=PA28
|date=2012
|publisher=Springer Science & Business Media
|isbn=978-1-4684-6488-7
|page=28
}}
}}
In his poem "L'Amethyste, ou les Amours de Bacchus et d'Amethyste" (Amethyst or the loves of Bacchus and Amethyste), the French poet Rémy Belleau (1528–1577) invented a myth in which Bacchus, the god of intoxication, of wine, and grapes was pursuing a maiden named Amethyste, who refused his affections. Amethyste prayed to the gods to remain chaste, a prayer which the chaste goddess Diana answered, transforming her into a white stone. Humbled by Amethyste's desire to remain chaste, Bacchus poured wine over the stone as an offering, dyeing the crystals purple.{{efn|
The "myth" of Amethyste and Bacchus was invented by the French poet Remy Belleau (1528–1577).
{{cite book
|section = L'Amethyste, ou les Amours de Bacchus et d'Amethyste
|title = Les Amours et Nouveaux Eschanges des Pierres Precieuses: Vertus & Proprietez d'icelles |lang = fr
|trans-title = The loves and new transformations of the precious stones: Their virtues and properties
|first = Remy |last = Belleau |author-link = Remy Belleau
|place = Paris, FR
|publisher = Mamert Patisson
|year = 1576
|pages = [http://gallica.bnf.fr/ark:/12148/bpt6k522648/f21.image 4–6]
}} — Belleau's collection of poems
Variations of the story include that Dionysus had been insulted by a mortal and swore to slay the next mortal who crossed his path, creating fierce tigers to carry out his wrath. The mortal turned out to be a beautiful young woman, Amethystos, who was on her way to pay tribute to Artemis. Her life was spared by Artemis, who transformed the maiden into a statue of pure crystalline quartz to protect her from the brutal claws. Dionysus wept tears of wine in remorse for his action at the sight of the beautiful statue. The god's tears then stained the quartz purple.
{{cite web
|url = http://gemstone.org/gem-by-gem/english/amethyst.html
|title = Amethyst
|website = Gemstone.org
}}
This myth and its variations are not found in classical sources. However, the goddess Rhea does present Dionysus with an amethyst stone to preserve the wine-drinker's sanity in historical text.Nonnus, Dionysiaca, 12. 380
=Other cultural associations=
Tibetans consider amethyst sacred to the Buddha and make prayer beads from it.
{{cite book
|title = Tropical Gemstones
|first = Carol |last = Clark
|page = 52
}}
{{full citation|date=March 2024|reason=Year, edn. publ.}} Amethyst is considered the birthstone of February.
{{cite web
|title = February birthstone: Amethyst
|website = American Gem Society (americangemsociety.org)
|date = 12 January 2016
|url = https://www.americangemsociety.org/february-birthstones
|access-date = 4 February 2016
}}
In the Middle Ages, it was considered a symbol of royalty and used to decorate English regalia. In the Old World, amethyst was considered one of the cardinal gems, in that it was one of the five gemstones considered precious above all others, until large deposits were found in Brazil.
{{cite book |author1=Geary, T.F. |url=https://books.google.com/books?id=5abGjJ54mSoC&pg=PA69 |title=The Illustrated Bead Bible: Terms, tips & techniques |author2=Whalen, D. |publisher=Sterling Pub. |year=2008 |isbn=9781402723537 |page=69 |access-date=19 July 2015 |archive-url=https://www.cabochonsforsale.com/gemstone/amethyst |archive-date=16 January 2021 |url-status=live}}
Value
{{multiple image
|align=left
|perrow=2
|total_width=300
|image1=2012 Tucson 22nd Street Show 18.JPG
|image2=2012 Tucson Gem & Mineral Show 85.JPG
|footer=Amethyst geodes displayed at the 2012 Tucson Gem & Mineral Show
}}
Until the 18th century, amethyst was included in the cardinal, or most valuable, gemstones (along with diamond, sapphire, ruby, and emerald), but since the discovery of extensive deposits in locations such as Brazil, it has lost most of its value. It is now considered a semiprecious stone.
{{cite journal
|last1=Souza |first1=Tamires P. |last2=Watte |first2=Guilherme
|last3=Gusso |first3=Alaíde M. |last4=Souza |first4=Rafaela
|last5=Moreira |first5=José da S. |last6=Knorst |first6=Marli M.
|date=June 2017
|title=Silicosis prevalence and risk factors in semi-precious stone mining in Brazil
|journal=American Journal of Industrial Medicine
|volume=60 |issue=6 |pages=529–536
|doi=10.1002/ajim.22719 |pmid=28514023
|s2cid=24375063
}}
Collectors look for depth of color, possibly with red flashes if cut conventionally.
{{cite book
|title=The Gemstone Book: Gemstones, organic substances, & artificial products — terminology & classification
|year= 2011
|publisher= The World Jewellery Confideration (CIBJO)
|url= http://download.cibjo.org/CIBJO_Gemstone_Book_2011-1.pdf
| access-date= 27 June 2012 | url-status= dead
|archive-url= https://web.archive.org/web/20120812224254/http://download.cibjo.org/CIBJO_Gemstone_Book_2011-1.pdf
| archive-date= 12 August 2012 |df= dmy-all
}}
As amethyst is readily available in large structures, the value of the gem is not primarily defined by carat weight. This is different from most gemstones, since the carat weight typically exponentially increases the value of the stone. The biggest factor in the value of amethyst is the color displayed.
{{cite web
|title=Amethyst jewelry and gemstones information
|publisher=International Gem Society (IGS)
|url=http://www.gemsociety.org/article/amethyst-jewelry-and-gemstone-information/
|via=gemsociety.org |access-date=3 October 2014
}}
The highest-grade amethyst (called deep Russian) is exceptionally rare. When one is found, its value is dependent on the demand of collectors; however, the highest-grade sapphires or rubies are still orders of magnitude more expensive than amethyst.
Handling and care
The most suitable setting for gem amethyst is a prong or a bezel setting. The channel method must be used with caution.
{{cite report
|title=Gemstone Durability Design to Display
|publisher=Gemological Institute of America (GIA)
|url=https://www.gia.edu/doc/Gemstone-Durability-Design-to-Display.pdf
|via=gia.edu |url-status=live
|archive-url=https://web.archive.org/web/20190430160423/https://www.gia.edu/doc/Gemstone-Durability-Design-to-Display.pdf
|archive-date=30 April 2019
}}
Amethyst has a good hardness, and handling it with proper care will prevent any damage to the stone. Amethyst is sensitive to strong heat and may lose or change its colour when exposed to prolonged heat or light. Polishing the stone or cleaning it by ultrasonic or steamer must be done with caution.
Footnotes
{{notelist}}
See also
References
{{reflist|25em}}
- {{cite report
|last = Kostov |first = R.I.
|year = 1992
|title = Amethyst: A geological-mineralogical and gemmological essay
|publisher = Union of Scientists in Bulgaria
|place = Sofia, Bulgaria
|language = Bulgarian
}}
- {{cite book
|last = Lieber |first = W.
|year = 1994
|title = Amethyst: Geschichte, Eigenschaften, Fundorte
|publisher = Christian Weise Verlag
|place = München, DE
}}
External links
{{Commons and category|Amethyst|Amethysts}}
{{wiktionary | amethyst}}
{{Silica minerals}}
{{Gemstones}}
{{Jewellery}}
{{Authority control}}
Category:Provincial symbols of Ontario