Editing Vanadinite

{{Short description|Apatite supergroup, vanadate mineral}}
{{Good article}}
{{Use dmy dates |date=July 2020}}
{{Infobox mineral
|boxbgcolor=#c82f13| name        = Vanadinite
| boxtextcolor = #fff
| category    = [[Vanadate minerals]] <br />[[Apatite]] group
| boxwidth    =
| image       = Vanadinite - ACF mine, Mibladen, Morocco.jpg
| imagesize   = 260px
| alt         = 
| caption     = 
| formula     = Pb<sub>5</sub>(VO<sub>4</sub>)<sub>3</sub>Cl
| IMAsymbol   = Vna<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   = 1416.27&nbsp;g/mol
| strunz      = 8.BN.05
| system      = [[Hexagonal crystal system|Hexagonal]]
| class       = Dipyramidal (6/m) <br/>[[H-M symbol]]: (6/m)
| symmetry    = ''P''6<sub>3</sub>/m
| unit cell   = a = 10.3174, <br/>c = 7.3378&nbsp;[Å]; Z&nbsp;=&nbsp;2
| colour       = Bright red, orange-red, red-brown, brown, yellow, whitish, grey or colourless or weakly tinted in transmitted light; pale straw-yellow;. may be concentrically zoned 
| habit       = Prismatic or nodular; may be acicular, hairlike, fibrous; rarely rounded, globular
| twinning    =
| cleavage    = None
| fracture    = Uneven to conchoidal
| tenacity    = Brittle
| mohs        = 3–4
| lustre      = Resinous to sub-adamantine
| polish      =
| refractive  = n<sub>ω</sub> = 2.416, n<sub>ε</sub> = 2.350
| opticalprop = Uniaxial (−)
| birefringence = δ = 0.066
| dispersion  =
| pleochroism =
| fluorescence= Red-orange under near-UV (405nm)
| absorption  =
| streak      = Brownish yellow
| gravity     = 6.8–7.1 (measured) 6.95 (calculated)
| density     = 
| melt        = {{convert|3470|F|C}}
| fusibility  =
| diagnostic  =
| solubility  =
| diaphaneity = Transparent, translucent or opaque
| other       =
| references  = <ref name="WebMineral"/><ref name="MinDat"/><ref name=Handbook>{{cite book|editor1=Anthony, John W. |editor2=Bideaux, Richard A. |editor3=Bladh, Kenneth W. |editor4=Nichols, Monte C. |title= Handbook of Mineralogy|publisher= Mineralogical Society of America|place= Chantilly, VA, US|url=http://rruff.geo.arizona.edu/doclib/hom/vanadinite.pdf|chapter=Vanadinite|isbn=0962209732|volume=IV (Arsenates, Phosphates, Vanadates)|year=2000}}</ref>
}}

'''Vanadinite''' is a [[mineral]] belonging to the [[apatite]] group of [[Phosphate minerals|phosphate]]s, with the chemical formula [[lead|Pb]]<sub>5</sub>([[vanadium|V]][[oxygen|O]]<sub>4</sub>)<sub>3</sub>[[chlorine|Cl]]. It is one of the main industrial ores of the metal [[vanadium]] and a minor source of [[lead]]. A dense, brittle mineral, it is usually found in the form of red hexagonal [[crystal]]s. It is an uncommon mineral, formed by the oxidation of lead ore deposits such as [[galena]]. First discovered in 1801 in [[Mexico]], vanadinite deposits have since been unearthed in South America, Europe, Africa, and North America.

==Origins==
Vanadinite is an uncommon mineral, only occurring as the result of chemical alterations to a pre-existing material. It is therefore known as a secondary mineral. It is found in [[arid]] climates and forms by [[Redox|oxidation]] of primary lead minerals. Vanadinite is especially found in association with the lead sulfide, [[galena]]. Other associated minerals include [[wulfenite]], [[limonite]], and [[barite]].<ref name="MinDat"/><ref name="treasure"/>

It was originally discovered in [[Mexico]] by the Spanish mineralogist [[Andrés Manuel del Río]] in 1801. He called the mineral "brown lead" and asserted that it contained a new element, which he first named pancromium and later, erythronium. However, he was later led to believe that this was not a new element but merely an impure form of chromium. In 1830, [[Nils Gabriel Sefström]] discovered a new element, which he named vanadium. It was later revealed that this was identical to the metal discovered earlier by Andrés Manuel del Río. Del Río's "brown lead" was also rediscovered, in 1838 in Zimapan, [[Hidalgo (state)|Hidalgo]], Mexico, and was named vanadinite because of its high vanadium content. Other names that have since been given to vanadinite are johnstonite and lead vanadate.<ref>{{cite journal
| title =Highlights of Spanish chemistry at the time of the chemical revolution of the 18th century
| journal = Fresenius' Journal of Analytical Chemistry
| volume = 337
| issue = 2
| year = 1990
| doi = 10.1007/BF00322401
| pages = 225–228
| author = J. A. Pérez-Bustamante de Monasterio| s2cid = 197594307
}}</ref>

==Occurrence==
Vanadinite occurs as a secondary mineral in the [[oxidized zone]] of lead-bearing deposits; the vanadium is leached from wall-rock [[Silicate mineral|silicates]]. Associated minerals include [[mimetite]], [[pyromorphite]], [[descloizite]], [[mottramite]], [[wulfenite]], [[cerussite]], [[anglesite]], [[calcite]], [[barite]], and various [[iron oxide]] minerals.<ref name=Handbook/>

Deposits of vanadinite are found worldwide including [[Austria]], [[Spain]], [[Scotland]], the [[Ural Mountains]], [[South Africa]], [[Namibia]], [[Morocco]], [[Argentina]], [[Mexico]], and four states of the [[United States]]: [[Arizona]], [[Colorado]], [[New Mexico]], and [[South Dakota]].<ref name="MinDat"/><ref name="treasure"/><ref name="brit"/>

Vanadinite deposits are found in over 400 mines across the world. Notable vanadinite mines include those at [[Midelt|Mibladen]] and Touisset in Morocco; [[Tsumeb]], Namibia; [[Córdoba, Argentina|Cordoba]], Argentina; and [[Sierra County, New Mexico|Sierra County]], New Mexico, and [[Gila County, Arizona]], in the United States.<ref>{{cite web  | title = Vanadinite| publisher =Minerals.net|url =http://www.minerals.net/mineral/phosphat/vanadini/vanadini.htm| access-date = 2007-06-26 }}</ref>

==Structure==
Vanadinite is a lead chlorovanadate with the chemical formula Pb<sub>5</sub>(VO<sub>4</sub>)<sub>3</sub>Cl. It is composed (by weight) of 73.15% lead, 10.79% vanadium, 13.56% oxygen, and 2.50% chlorine. Each structural unit of vanadinite contains a chlorine ion surrounded by six [[divalent]] lead ions at the corners of a regular [[octahedron]], with one of the lead ions provided by an adjoining vanadinite molecule. The distance between each lead and chlorine ion is 317&nbsp;[[picometre]]s. The shortest distance between each lead ion is 4.48&nbsp;Å. The octahedron shares two of its opposite faces with that of neighbouring vanadinite units, forming a continuous chain of octahedrons. Each vanadium atom is surrounded by four oxygen atoms at the corners of an irregular [[tetrahedron]]. The distance between each oxygen and vanadium atom is either 1.72 or 1.76&nbsp;Å. Three oxygen tetrahedrons adjoin each of the lead octahedrons along the chain.<ref name="WebMineral"/><ref>{{cite web | title = The Structure of Vanadinite | author1 = J. Trotter | author2 = W. H. Barnes | name-list-style = amp | publisher = The Canadian Mineralogist | url =http://rruff.geo.arizona.edu/doclib/cm/vol6/CM6_161.pdf|year=1958 | access-date = 2007-06-26 }}</ref><ref>{{ cite journal | title = Crystal structure refinements of vanadinite and pyromorphite | first1 = Yongshan | last1 = Dai | first2 = John M. | last2 = Hughes | journal = [[The Canadian Mineralogist|Can. Mineral.]] | year = 1989 | volume = 27 | issue = 2 | pages = 189–192 | url = https://rruff.info/doclib/cm/vol27/CM27_189.pdf }}</ref>

{{multiple image
 | align = none
 | direction = horizontal
 | total_width = 700
 | image1 = Vanadinite-xtal-2x2x2-centroid-fit-3D-bs-17.png
 | caption1 = Crystal packing
 | image2 = Vanadinite-xtal-Cl-coordination-3D-bs-17.png
 | caption2 = Chloride coordination sphere
 | image3 = Vanadinite-xtal-Pb1-coordination-3D-bs-17.png
 | caption3 = Lead #1 coordination sphere
 | image4 = Vanadinite-xtal-Pb2-coordination-3D-bs-17.png
 | caption4 = Lead #2 coordination sphere
 | image5 = Vanadinite-xtal-V-coordination-3D-bs-17.png
 | caption5 = Vanadium coordination sphere
}}

Crystals of vanadinite conform to a [[Hexagonal crystal system|hexagonal]] system of [[Crystal structure#Classification|symmetry]]. This internal structure is often reflected in the hexagonal external shape of the crystals. The crystals are usually in the form of short hexagonal prisms, but can also be found as hexagonal pyramids, rounded masses or crusts. A [[Crystal structure|unit cell]] of vanadinite, the smallest divisible unit that possesses the same symmetry and properties, is in the form of a hexagonal prism. The unit cell of vanadinite is composed of two of its molecules and has the dimensions ''[[Hexagonal crystal system|a]]'' = 10.331&nbsp;[[Ångstrom|Å]] and ''c'' = 7.343&nbsp;Å, where ''a'' is the length of each side of the hexagon and ''c'' is the height of the prism. The volume of each unit cell of vanadinite, given by the formula V = ''a''<sup>2</sup>''c'' sin(60°), is 678.72&nbsp;Å<sup>3</sup>.<ref name="WebMineral"/><ref name="treasure"/>

==Characteristics==
Vanadinite is in the [[apatite]] group of [[Phosphate minerals|phosphate]]s, and forms a chemical series with the minerals [[pyromorphite]] (Pb<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>Cl) and [[mimetite]] (Pb<sub>5</sub>(AsO<sub>4</sub>)<sub>3</sub>Cl), with both of which it may form [[solid solution]]s. Whereas most chemical series involve the substitution of metallic ions, this series substitutes its anion groups; phosphate (PO<sub>4</sub>), [[arsenate]] ([[arsenic|As]]O<sub>4</sub>) and [[vanadate]] (VO<sub>4</sub>). Common [[impurities]] of vanadinite include [[phosphorus]], [[arsenic]] and [[calcium]], where these may act as an [[isomorphic]] substitute for vanadium (in the first two cases) or lead (in the second). Vanadinite when containing a high amount of the arsenic impurity is known as [[endlichite]].<ref name="MinDat">{{cite web  | title = Vanadinite | publisher = MinDat.org | url =http://www.mindat.org/min-4139.html  | access-date = 2007-06-09 }}</ref><ref name="treasure">{{cite book | title = Treasures of the Earth: The Minerals and Gemstone Collection&nbsp;– Vanadinite factsheet | publisher = Orbis Publishing Ltd |year= 1995  }}</ref>

Vanadinite is usually bright-red or orange-red in colour, although sometimes brown, red-brown, grey, yellow, or colourless. Its distinctive colour makes it popular among mineral collectors. Its [[Streak (mineralogy)|streak]] can be either pale yellow or brownish-yellow. Vanadinite may be [[transparency (optics)|transparent]], translucent or [[opacity (optics)|opaque]], and its [[Lustre (mineralogy)|lustre]] can range from [[resin]]ous to [[Lustre (mineralogy)|adamantine]]. Vanadinite is [[anisotropic]], meaning that some of its properties differ when measured along different axes. When measured perpendicular and parallel to its axis of anisotropy, its [[refractive index|refractive indices]] are 2.350 and 2.416 respectively. This gives it a [[birefringence]] of 0.066.<ref name="WebMineral">{{cite web  | title = Vanadinite Mineral Data| publisher = WebMineral.com | url =http://webmineral.com/data/Vanadinite.shtml  | access-date = 2007-06-09 }}</ref><ref name="MinDat"/><ref name="treasure"/>

Vanadinite is very brittle, producing small, [[conchoidal]] fragments when [[fracture]]d. Its hardness is 3–4 on the [[Mohs scale of mineral hardness|Mohs scale]], about the same as a copper coin. Vanadinite is particularly heavy for a translucent mineral. It has a [[molar mass]] of 1416.27&nbsp;[[gram|g]]/[[Mole (unit)|mol]] and its [[specific gravity]] can range between 6.6 and 7.2 because of impurities.<ref name="MinDat"/><ref name="treasure"/><ref name="brit">{{cite EB1911|wstitle=Vanadinite |last= Spencer|first= Leonard James |volume= 27 }}</ref>

==Uses==
Along with [[carnotite]] and [[roscoelite]], vanadinite is one of the main industrial ores of the element [[vanadium]], which can be extracted by [[Roasting (metallurgy)|roasting]] and [[smelting]]. Vanadinite is also occasionally used as a source of lead. A common process for extracting the vanadium begins with the heating of vanadinite with [[sodium chloride|salt]] (NaCl) or [[sodium carbonate]] (Na<sub>2</sub>CO<sub>3</sub>) at about 850&nbsp;°C to produce [[sodium metavanadate|sodium vanadate]] (NaVO<sub>3</sub>). This is dissolved in water and then treated with [[ammonium chloride]] to give an orange-coloured precipitate of [[ammonium metavanadate]]. This is then melted to form a crude form of [[vanadium pentoxide]] (V<sub>2</sub>O<sub>5</sub>). Reduction of vanadium pentoxide with [[calcium]] gives pure vanadium.<ref>{{cite web  |title= Vanadium |publisher= University College Cork |author= Donal O'Leary |url =http://www.ucc.ie/academic/chem/dolchem/html/elem/elem023.html |archive-url=https://web.archive.org/web/20170205220815/http://www.ucc.ie/academic/chem/dolchem/html/elem/elem023.html |archive-date=5 February 2017 |year=2000 |access-date= 2007-06-26}}</ref>

==Image gallery==
<gallery widths="133" heights="130">
File:Vanadinite-v0903b.jpg|Vanadinite in [[hexagonal]] shaped crystals
File:Vanadinite Specimen 36 1.JPG|Vanadinite that does not show the characteristic red colour
File:Mibladene Vanadinite.jpg|A cluster of vanadenite crystals, showing their hexagonal shape
File:Vanadinite, barytine 4.jpeg|Vanadinite on [[Baryte|barite]], from Mibladene, Upper Moulouya lead district, Midelt, Drâa-Tafilalet Region, Morocco
File:Endlichite 1.JPG|Crystals of vanadinite (var. endlichite), from Touissit, Touissit District, Oujda-Angad Province, Oriental Region, Morocco
File:Vanadinite, sidérite 90.3.9797.jpg|Crystals of vanadinite and [[siderite]], from Taouz Er Rachidia Province, Drâa-Tafilalet Region, Morocco
</gallery>

==See also==
*[[List of minerals]]

==References==
{{Reflist}}

== External links ==

* {{Commons category-inline}}
{{Authority control}}

[[Category:Vanadate minerals]]
[[Category:Lead minerals]]
[[Category:Hexagonal minerals]]
[[Category:Minerals in space group 176]]
[[Category:Minerals described in 1838]]