Editing Orpiment

{{Short description|Orange-yellow arsenic sulfide mineral}}
{{infobox mineral
| name        = Orpiment
| category    = [[Sulfide mineral]]
| boxwidth    = 
| boxbgcolor  = 
| image       = Orpiment-148270.jpg
| imagesize   =
| alt         =
| caption     = Orpiment crystal from Twin Creeks Mine, Potosi District, [[Humboldt County, Nevada]], United States (Size: 3.3 cm × 2.1 cm × 2.1 cm)
| formula     = As<sub>2</sub>S<sub>3</sub>
| IMAsymbol   = Orp<ref>{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3 |pages=291–320|doi=10.1180/mgm.2021.43 |bibcode=2021MinM...85..291W |s2cid=235729616 |doi-access=free}}</ref>
| molweight   = 
| strunz      = 2.FA.30
| dana        =
| system      = [[Monoclinic]]
| class       = Prismatic (2/m) <br /><small>(same [[H-M symbol]])</small>
| symmetry    = ''P''2<sub>1</sub>/n
| unit cell   = a = 11.475(5), b = 9.577(4) <br />c = 4.256(2)&nbsp;[Å], β = 90.45(5)°; Z&nbsp;=&nbsp;4
| color       = Lemon-yellow to golden or brownish yellow
| colour      = 
| habit       = Commonly in foliated columnar or fibrous aggregates; may be reniform or botryoidal; also granular or powdery; rarely as prismatic crystals
| twinning    = On {100}
| cleavage    = Perfect on {010}, imperfect on {100};
| fracture    = 
| tenacity    = [[Sectility|Sectile]]
| mohs        = 1.5–2
| luster      = Resinous, pearly on cleavage surface
| streak      = Pale lemon-yellow
| diaphaneity = Transparent
| gravity     = 3.49
| density     = 
| polish      = 
| opticalprop = Biaxial (−)
| refractive  = n<sub>α</sub> = 2.400 n<sub>β</sub> = 2.810 n<sub>γ</sub> = 3.020
| birefringence = δ = 0.620
| pleochroism = In reflected light, strong, white to pale gray with reddish tint; in transmitted light, Y = yellow, Z = greenish yellow 
| 2V          = Measured: 30° to 76°, Calculated: 62°
| dispersion  = r > v, strong
| extinction  = 
| length fast/slow =
| fluorescence= 
| absorption  =
| melt        = 
| fusibility  = 
| diagnostic  = 
| solubility  = 
| other       = 
| alteration  = 
| references  =<ref name=Handbook>{{cite web |last1=Anthony |first1=John W. |last2=Bideaux |first2=Richard A. |last3=Bladh |first3=Kenneth W. |last4=Nichols |first4=Monte C. |title=Orpiment |url=http://www.handbookofmineralogy.org/pdfs/orpiment.pdf |website=Handbook of Mineralogy |publisher=Mineral Data Publishing |access-date=14 March 2022 |date=2005}}</ref><ref name=Mindat>{{mindat|id=3021|title=Orpiment|accessdate=26 May 2022}}</ref><ref name=Webmin>{{WebMineral|url=http://webmineral.com/data/Orpiment.shtml|name=Orpiment|accessdate=26 May 2022}}</ref>
}}
'''Orpiment''', also known as ″'''yellow [[arsenic blende]]'''″ is a deep-colored, orange-yellow [[arsenic]] [[sulfide mineral]] with formula {{chem|As|2|S|3}}. It is found in volcanic [[fumarole]]s, low-temperature [[hydrothermal]] veins, and [[hot spring]]s and may be formed through [[sublimation (phase transition)|sublimation]].

Orpiment takes its name from the Latin ''auripigmentum'' (''aurum'', "gold" + ''pigmentum'', "[[pigment]]"), due to its deep-yellow color. Orpiment once was widely used in artworks, medicine, and other applications. Because of its toxicity and instability, its usage has declined.

== Etymology ==
The Latin ''auripigmentum'' (''aurum'', "gold" + ''pigmentum'', "[[pigment]]") referred both to its deep-yellow color and to the historical belief that it was thought to contain gold. The Latin term was used by [[Pliny the Elder|Pliny]] in the first century CE.{{Cn|date=April 2023}}

The Greek for orpiment was ''arsenikon'', deriving from the Greek word ''arsenikos'', meaning "male", from the belief that metals were of different sexes. This Greek term was used by [[Theophrastus]] in the fourth century BC.<ref name=":3">{{Cite book |last=Fitzhugh |first=Elizabeth West |title=Artists' Pigments: A Handbook of Their History and Characteristics, Volume 3 |publisher=Archetype Publications |year=1997 |isbn=978-1-904982-76-0 |location=Washington |pages=48–70 |chapter=Orpiment and Realgar}}</ref>

The Chinese term for orpiment is ''Ci-Huang'' (in Pinyin), meaning "female yellow".<ref name=":1">{{Cite journal |last=Schafer |first=Edward H. |date=1955 |title=Orpiment and Realgar in Chinese Technology and Tradition |url=https://www.jstor.org/stable/595009 |journal=Journal of the American Oriental Society |volume=75 |issue=2 |pages=73–89 |doi=10.2307/595009 |jstor=595009 |issn=0003-0279|url-access=subscription }}</ref>

The Persian for orpiment is ''zarnikh'', deriving from the word "''zar"'', the Persian for gold.{{Cn|date=April 2023}}

== Physical and optical properties ==
Orpiment is a common [[monoclinic]] arsenic sulfide mineral. It has a [[Mohs scale of mineral hardness|Mohs hardness]] of 1.5 to 2 and a [[specific gravity]] of 3.49. It melts at {{convert|300|°C|°F|-1}} to {{convert|325|°C|°F|-1}}. Optically, it is biaxial (−) with [[refractive index|refractive indices]] of ''a'' = 2.4, ''b'' = 2.81, ''g'' = 3.02.

== Visual characteristics ==
[[File:Orpiment - streak color.jpg|thumb|left|Bright golden-yellow [[Streak (mineralogy)|streak color]] of orpiment|186x186px]]
[[File:Realgar and orpiment-2.jpg|left|thumb|189x189px|Orpiment and Realgar on the same rock]]
Orpiment is a type of [[lemon-yellow]] to [[golden yellow|golden-]] or brownish-yellow [[crystal]] commonly found in [[Foliation (geology)|foliated]] [[Crystal_habit#Aggregate_habits|columnar]] or [[Crystal_habit#Aggregate_habits|fibrous]] aggregates, may alternatively be [[botryoidal]] or reniform, [[Crystal_habit#Aggregate_habits|granular]] or powdery, and, rarely, as [[Monoclinic crystal system|prismatic crystals]].<ref name=":2">{{Cite web |title=Realgar and Orpiment – Arsenic Sulfide Minerals |url=https://geology.com/minerals/realgar-orpiment.shtml |access-date=2023-04-15 |website=geology.com}}</ref> Used as a pigment, orpiment's color is often described as a lemon- or [[canary-yellow]], and occasionally as a golden- or brownish-yellow.

In the [[Munsell color system]], "orpiment" is designated "brilliant yellow", Munsell notation 4.4Y 8.7 /8.9.<ref>Kelly, K.L.; Judd, D.B. (1955). ''The ISCC-NBS Method of Designating Colors and a Dictionary of Color Names'' (Circular 553 ed.). Washington: U.S. Department of Commerce, National Bureau of Standards.</ref>

=== Orpiment and realgar ===
Orpiment and [[realgar]] are closely related minerals and are often categorized in the same group. They are both arsenic sulfides and belong to the [[monoclinic crystal system]]. They are found in the same [[mineral deposit|deposits]] and can form in the same geologic environments. As a result, orpiment and realgar share similar physical properties and histories of use by humans.<ref name=":2" />

In Chinese, the names for orpiment and realgar are ''Ci-Huang'' and ''Xiong-Huang'', respectively meaning "female yellow" and "male yellow". Their names symbolize their close natural conjunction, both physically in terms of their occurrence and properties and culturally in Chinese traditions.

Orpiment and realgar can be distinguished by their different visual characteristics. While orpiment typically has a vibrant golden-yellow color, realgar, in contrast, normally has an orange or reddish hue.<ref name=":1" />

== Permanence and conservation ==
Yellow orpiment (As<sub>2</sub>S<sub>3</sub>) degrades into [[arsenic oxide]]s. Because of their solubility in water, arsenic oxides readily migrate to the surrounding environment. In painted works using orpiment, migrating, degraded arsenic oxides are often detectable throughout the multi-layered paint system. This widespread arsenic migration has consequences for the conservation of orpiment as a pigment in works of art.<ref name=":4">{{Cite journal |last1=Keune |first1=Katrien |last2=Mass |first2=Jennifer |last3=Mehta |first3=Apurva |last4=Church |first4=Jonathan |last5=Meirer |first5=Florian |date=2016-04-21 |title=Analytical imaging studies of the migration of degraded orpiment, realgar, and emerald green pigments in historic paintings and related conservation issues |journal=Heritage Science |volume=4 |issue=1 |pages=10 |doi=10.1186/s40494-016-0078-1 |s2cid=40318538 |issn=2050-7445 |doi-access=free |hdl=11245.1/080e76f8-43f1-4464-afa3-8b9646e2484a |hdl-access=free }}{{Creative Commons text attribution notice|cc=by4|from this source=yes}}</ref> 

Orpiment is also sensitive to light exposure, decaying into a [[friable]] white [[arsenic trioxide]] over time. Similarly, on ancient, orpiment-coated manuscript paper in Nepal, orpiment used to deter insects has often turned white over time.{{cn|date=April 2023}}

Because of orpiment's solubility and instability as a pigment, preventing the degradation of orpiment may need to be prioritized in art conservation. Proper conservation methods should minimize exposure to strong light. Such methods should emphasize humidity control and avoid the use of water-based cleaning agents.<ref name=":4" />

== Use by artists ==
Orpiment has historically been used in artworks in many locales in the [[Eastern Hemisphere]]. It was one of the few clear, bright-yellow pigments available to artists until the 19th century.

=== Historical and regional use of orpiment ===
[[File:RAFAEL - Madonna Sixtina (Gemäldegalerie Alter Meister, Dresden, 1513-14. Óleo sobre lienzo, 265 x 196 cm).jpg|thumb|234x234px|Raphael (1483–1520), Sistine Madonna (1513–14)]]In Egypt, lumps of orpiment pigment have been found in a fourteenth-century BC tomb.<ref>Saleh, S.A. (1987). ''"Pigments, Plasters, and Salts Analyses," Wall Paintings of the Tomb of Nefertari: Scientific Studies for Their Conservation''. Cairo, Egypt and Century City, Calif. pp. 94–105.</ref> In China, orpiment is known to have been used to color Chinese [[lacquer]], despite no written sources mentioning this. Orpiment has also been identified on Central Asian [[wall painting]]s from the sixth to the thirteenth centuries{{specify|date=April 2023}}.<!--Would this be BCE or CE?--><ref>{{Cite journal |last=Garner |first=Henry |date=1963-08-01 |title=Technical Studies of Oriental Lacquer |url=https://doi.org/10.1179/sic.1963.013 |journal=Studies in Conservation |volume=8 |issue=3 |pages=84–98 |doi=10.1179/sic.1963.013 |issn=0039-3630|url-access=subscription }}</ref> In a traditional Thai painting technique, still in use today, yellow ink for writing and drawing on black paper manuscripts is made using orpiment.<ref>{{Cite journal |last=Pearman |first=Sara Jane |date=April 1977 |title=Thai Painting . Jean Boisselier , Janet Seligman |url=https://www.journals.uchicago.edu/doi/10.1086/arlisnanews.5.3.27945831 |journal=ARLIS/NA Newsletter |language=en |volume=5 |issue=3 |pages=102–103 |doi=10.1086/arlisnanews.5.3.27945831 |issn=0090-3515|url-access=subscription }}</ref>

Medieval European artists imported orpiment from Asia Minor.{{CN|date=April 2023}} Orpiment has been identified on Norwegian wooden [[Antependium|altar frontals]], polychrome sculptures, and folk art objects, including a [[crucifix]]. It was also used in twelfth- to sixteenth-century [[Eastern Orthodox]] [[icons]] from Bulgaria, Russia, and the former [[Yugoslavia]]. In [[Venice]], records show that orpiment was purchased for a Romanian prince in 1600. European use of orpiment was uncommon until the nineteenth century, during which it saw use as a pigment in [[Impressionism|Impressionist]] paintings.<ref name=":3" />
[[File:Wilton diptych.jpg|left|thumb|178x178px|Anonymous, The Wilton Diptych (c 1395-9), The National Gallery, London.]]
[[File:Jacopo Tintoretto - Portrait of Vincenzo Morosini - WGA22697.jpg|thumb|288x288px|Jacopo Tintoretto (c 1518–1594), Portrait of Vincenzo Morosini, The National Gallery (Presented by the Art Fund), London.]]

=== Orpiment as a pigment ===
In the Medieval Norwegian church of [[Tingelstad Church|Tingelstad]], orpiment was used in painting the [[Antependium|altar frontal]].{{cn|date=April 2023}}

Orpiment was commonly combined with [[indigo]] dye to make a dark, rich green.{{cn|date=April 2023}} In the ''[[Wilton Diptych]]'' (c 1395-9), this green pigment was used in [[egg tempera]] on the left panel for the green cloak of [[Edmund the Martyr]].{{cn|date=April 2023}}
[[File:Giovanni Bellini and Titian - The Feast of the Gods - Google Art Project.jpg|left|thumb|179x179px|Giovanni Bellini (c. 1430–1516) and Titian (−1576), The Feast of the Gods (1514–1529), National Gallery of Art, Washington, DC. Wikimedia Commons.]]
Renaissance artists such as [[Raphael]] also used orpiment as a yellow pigment. In Raphael's ''[[Sistine Madonna]]'' from 1513–14, orpiment is used to achieve yellow on the clothing of the figures and in the background.<ref>{{Cite web |title=Raphael, Sistine Madonna |url=https://colourlex.com/project/raphael-sistine-madonna/ |access-date=2024-05-04 |website=ColourLex |language=en-US}}</ref>

[[Tintoretto]]'s ''Portrait of Vincenzo Morosini'' from about 1575–80 uses the pigment in its details. Orpiment is used to replicate the gold embroidery on [[Morosini family|Morosini]]'s embroidered stole and to highlight the fur of the spotted ferret on his chest.<ref name=":3" />{{Rp|page=49}}

=== Limitations ===
Orpiment was one of the few clear, bright-yellow pigments available to artists until the 19th century. Its extreme toxicity and incompatibility with other, common, pigments, including [[lead]] and [[copper]]-based substances such as [[verdigris]] and [[azurite]], meant that its use as a pigment ended when [[Cadmium pigments|cadmium yellows]], [[Chrome yellow|chromium yellows]] and organic [[aniline dye]]-based colors were introduced during the 19th century.<ref>St. Clair, Kassia (2016). ''The Secret Lives of Colour''. London: John Murray. pp. 82–83. {{ISBN|978-1-4736-3081-9}}. {{OCLC|936144129}}.</ref>

== Other historical uses ==
Orpiment was traded in the [[Roman Empire]] and was used as a medicine in [[China]], even though it is very toxic. It has been used as fly poison<ref>{{Cite book|url=https://books.google.com/books?id=2PmrPnUY_3YC&q=orpiment+%22fly+poison%22&pg=PA246|title=Popular philosophy: or, The book of nature laid open upon Christian principles, by the ed. of The Cheap magazine|last=Miller|first=George|date=1826|language=en}}</ref> and to tip [[Arrow poison|arrows with poison]].<ref>{{Cite book|url=https://books.google.com/books?id=3jZBAQAAMAAJ&q=poison+arrows|title=Mesny's Chinese Miscellany|last=Mesny|first=William|date=1899|publisher=China Gazette Office.|language=en}}</ref> Because of its striking color, it was of interest to [[alchemy|alchemists]], both in China and Europe, searching for a way to make gold. It also has been found in the wall decorations of [[Tutankhamun]]'s tomb and ancient Egyptian scrolls, and on the walls of the [[Taj Mahal]].<ref name="StClair">{{Cite book |last=St. Clair |first=Kassia |title=The Secret Lives of Colour |publisher=John Murray |year=2016 |isbn=978-1-4736-3081-9 |location=London |pages=82–83 |oclc=936144129}}</ref> For centuries, orpiment was ground down and used as a pigment in painting and for [[sealing wax]], and was even used in ancient China as a [[correction fluid]].<ref>{{cite web |url=http://news.xinhuanet.com/newscenter/2006-07/29/content_4890298.htm |title=雌黄在古代充当"涂改液" |website=news.xinhuanet.com |access-date=9 August 2022 |archive-url=https://web.archive.org/web/20160806100548/http://news.xinhuanet.com/newscenter/2006-07/29/content_4890298.htm |archive-date=6 August 2016 |url-status=dead}}</ref> Orpiment is mentioned in the 17th century by [[Robert Hooke]] in ''[[Micrographia]]'' for the manufacture of small [[Shot (pellet)|shot]].<ref>{{cite web|last=Hooke|first=Robert|title=Micrographia|url=http://www.gutenberg.org/files/15491/15491-h/15491-h.htm|publisher=Project Gutenberg|access-date=24 October 2012}}</ref> Scientists like [[Richard Adolf Zsigmondy]] and [[Hermann Ambronn]] puzzled jointly over the amorphous form of {{chem|As|2|S|3}}, "orpiment glass", as early as 1904.<ref name="zmond">{{cite book | chapter=Richard Adolf Zsigmondy: Properties of Colloids | title=Nobel Lectures, Chemistry 1922–1941 | chapter-url=http://nobelprize.org/nobel_prizes/chemistry/laureates/1925/zsigmondy-lecture.html | location=Amsterdam | publisher=Elsevier Publishing Company | year=1966 }}</ref>

== Industry uses ==
Orpiment is used in the production of [[infrared]]-transmitting glass, [[Oilcloth|oil cloth]], [[linoleum]], [[semiconductor]]s, [[photoconductor]]s, pigments, and [[fireworks]].  Mixed with two parts of [[slaked lime]] (calcium hydroxide), orpiment is still commonly used in rural India as a [[Chemical depilatory|depilatory]].  It is used in the [[Tanning (leather)|tanning]] industry to remove hair from hides.

Orpiment has been used as [[bookends]]. In 2023, the UK [[Office for Product Safety and Standards]] recalled 40 pieces sold by [[TK Maxx]] between June and October 2022, due to the mineral's toxicity.<ref>{{cite web |last1=Mcneil |first1=Daniel |title=Government issue recall of household accessory from TK Maxx & Homesense – what to do |url=https://www.yorkshireeveningpost.co.uk/read-this/government-issue-recall-of-household-accessory-from-tk-maxx-homesense-what-to-do-4042935 |website=Yorkshire Evening Post |access-date=18 April 2023 |date=27 February 2023}}</ref><ref>{{cite web |title=Product Recall: Yellow Orpiment Mineral Bookends sold by TK Maxx (2302-0126) |url=https://www.gov.uk/product-safety-alerts-reports-recalls/product-recall-yellow-orpiment-mineral-bookends-sold-by-tk-maxx-2302-0126 |website=GOV.UK |access-date=18 April 2023 |language=en |date=24 February 2023}}</ref>

== Crystal structure ==
<gallery>
File:Orpiment-unit-cell-3D-balls.png|{{center|Orpiment's [[Crystal structure#Unit cell|unit cell]]}}
File:Orpiment-layer-3D-balls.png|{{center|Orpiment's [[crystal structure]] consists of sheets}}
File:Orpiment-layers-stacking-3D-balls.png|{{center|The sheets are stacked into layers}}
</gallery>

==Gallery==
<gallery widths="145" heights="140">
File:Orpiment.ვკ.jpg|Orpiment from [[Racha]], northern [[Georgia (country)|Georgia]] region
File:Orpiment-Realgar-Quartz-154641.jpg|Orpiment and [[realgar]] on a [[Porosity#Types_of_geologic_porosities|vuggy]], quartz matrix, Nishinomaki Mine, [[Gunma Prefecture]], Japan
File:MFN MIN 1977 0028 Auripigment.jpg|Orpiment from La Libertad, [[Quiruvilca District|Quiruvilca]], Peru
File:Orpiment-d06-185b.jpg|El'brusskiy arsenic mine, [[Kabardino-Balkarian Republic]], Northern Caucasus Region, Russia
</gallery>

==See also==
* [[List of inorganic pigments]]

== References ==
{{Reflist}}

==External links==
* [http://webexhibits.org/pigments/indiv/overview/orpiment.html Webexhibits "Pigments Through the Ages: Orpiment"]
* [http://dafyomi.org/index.php?masechta=chulin&daf=88b Babylonian Talmud Tractate Chullin] see [[Rashi]] 'haZarnich' {{in lang|he}}
* [http://colourlex.com/project/orpiment/ Orpiment], Colourlex
{{Commons category| Orpiment}}

[[Category:Arsenic minerals]]
[[Category:Sulfide minerals]]
[[Category:Inorganic pigments]]
[[Category:Alchemical substances]]
[[Category:Monoclinic minerals]]
[[Category:Minerals in space group 14]]
[[Category:Blendes]]