# Rakovanite

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> Source: https://en.wikipedia.org/wiki/Rakovanite
> Source revision: 1292606889
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{{infobox mineral
| name      = Rakovanite
| category    = [Pascoite](/source/Pascoite) family
| boxwidth    = 330px
| boxbgcolor  =
| image       = Rakovanite.jpg
| imagesize   =
| alt         =
| caption     = Well formed rakovanite crystals from the type locality: Sunday Mine, Slick Rock Mining District, [San Miguel County](/source/San_Miguel_County%2C_Colorado), [Colorado](/source/Colorado). 
| formula     = (NH3)3Na3 [V10O28]12H2O
| IMAsymbol   = Rkv<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      = 8.CJ.45
| dana        = 40.4.7.4
| system      = [Monoclinic](/source/Monoclinic)
| class       = Prismatic (2/m) <br/><small>(same [H-M symbol](/source/H-M_symbol))</small>
| symmetry    = ''P''2<sub>1</sub>/n
| unit cell   = a = 12.0248(17), <br/>b = 17.121(3), <br/>c = 18.140(3) Å, <br/>β 106.242(8)°; Z&nbsp;=&nbsp;4
| color       = Orange
| streak      = Orange-yellow
| habit       = Blocky to prismatic on [100]
| cleavage    = 
| fracture    = Conchodial
| tenacity    = Brittle
| mohs        = 1
| luster      = Subadamantine
| diaphaneity = Transparent
| gravity     = 2.407 (calculated)
| density     = 
| polish      =
| opticalprop = Biaxial (+)
| refractive  = α<sub>589nm</sub> = 1.776(5)<br/> β<sub>589nm</sub> = 1.803(5)<br/> γ<sub>589nm</sub> = 1.910(6)
| birefringence = δ = 0.134
| other=Surface relief: very high<br>Orientation: X + b; Z Λ c= 8° in obtuse β<br>
It does not fluorescence in long- or short-wave ultraviolent radiation.

| pleochroism = X light yellow, Y orangish yellow, Z yellowish orange, Z > Y> X
| 2V          = 2Vz<sub>540nm</sub> =58(1); 2Vz<sub>589nm</sub> = 56(1); 2Vz<sub>650nm</sub> =53(1)°
| dispersion  = r < v, strong parallel
| absorption  =
| melt        =
| fusibility  =
| diagnostic  =
| solubility  =
| alteration  =
| references  = <ref>{{Cite web|title = Rakovanite: Rakovanite mineral information and data.|url = http://www.mindat.org/min-40447.html|website = www.mindat.org|accessdate = 2015-12-01}}</ref><ref name="Kampf" />}}

'''Rakovanite''', (NH<sub>4</sub>)<sub>3</sub>Na<sub>3</sub>(V<sub>10</sub>O<sub>28</sub>) · 12H<sub>2</sub>O; formerly given as Na<sub>3</sub>(H<sub>3</sub>V<sub>10</sub>O<sub>28</sub>)<sup>.</sup>15H<sub>2</sub>O; later, the ammonium ion was shown to be present and essential,<ref name=":0">{{Cite journal |last1=Kampf |first1=Anthony R. |last2=Hughes |first2=John M. |last3=Cooper |first3=Mark A. |last4=Hawthorne |first4=Frank C. |last5=Nash |first5=Barbara P. |last6=Olds |first6=Travis A. |last7=Adams |first7=Paul M. |last8=Marty |first8=Joe |date=2021-07-01 |title=The pascoite family of minerals, including the redefinition of rakovanite |url=https://pubs.geoscienceworld.org/canmin/article/59/4/771/607498/The-pascoite-family-of-minerals-including-the |journal=The Canadian Mineralogist |language=en |volume=59 |issue=4 |pages=771–779 |doi=10.3749/canmin.2000082 |bibcode=2021CaMin..59..771K |issn=1499-1276|url-access=subscription }}</ref> is a member of the [pascoite](/source/pascoite) family. It is a transparent, [brittle](/source/brittle) mineral occurring in the [monoclinic](/source/monoclinic) crystal system. It is orange in color and has an orange-yellow colored [streak](/source/streak_(mineralogy)). Rakovanite is soft with a [Mohs hardness](/source/Mohs_hardness) of 1 and a calculated [density](/source/density) of 2.407g cm<sup>−3</sup>. It does not fluoresce in long- or short-wave ultraviolet radiation. Rakovanite crystals are up to one mm in maximum dimension and vary in habit from blocky to prismatic on [001], commonly exhibiting steps and striations parallel to [001].  Its name honors John Rakovan, former professor, Department of Geology and Environmental Earth Science, [Miami University](/source/Miami_University),<ref name="Kampf">{{Cite journal|title = Rakovanite, Na<sub>3</sub>V<sub>10</sub>O<sub>28</sub>•15H<sub>2</sub>O, A New Member of the Pascoite Family with a Protonated Decavanadate Polyanion|journal = The Canadian Mineralogist|pages = 595–604|volume = 49|issue = 2|doi = 10.3749/canmin.49.2.595|first1 = A. R.|last1 = Kampf|first2 = J. M.|last2 = Hughes|first3 = J.|last3 = Marty|first4 = M. E.|last4 = Gunter|first5 = B.|last5 = Nash|year = 2011}}</ref> State Mineralogist and Senior Museum Curator, [https://geoinfo.nmt.edu/index.html New Mexico Bureau of Geology and Mineral Resources].

== Occurrence ==
Rakovanite was found on specimens from the Sunday mine and the West Sunday mine, Slick Rock district, San Miguel County, Colorado, US.<ref name="Kampf" />

It occurs as crystalline crusts on sandstone fractures in the mine walls of the Sunday and West Sunday mines. The best crystals were found perched on an [amorphous](/source/amorphous) dehydrated [vanadium](/source/vanadium) phase along with crystals tightly adhered to a corvusite-montroseite matrix.<ref name="Kampf" />

It forms from the oxidation of [montroseite](/source/montroseite)-[corvusite](/source/corvusite) assemblages. It is associated [calcite](/source/calcite), [corvusite](/source/corvusite), [hewettite](/source/hewettite), [hughesite](/source/hughesite), [montroseite](/source/montroseite), [munirite](/source/munirite), [paramontroseite](/source/paramontroseite), [pascoite](/source/pascoite), [rossite](/source/rossite), [sherwoodite](/source/sherwoodite), and other unidentified [vanadium](/source/vanadium) phases as well as at least two other potentially new decavanadate species. It forms aqueous solutions of relatively low pH when water reacts with pyrite in the deposit under ambient temperatures and generally oxidizing near-surface environments.<ref name="Kampf" />

==Atomic arrangement==
Rakovanite crystal unit consists of the [decavanadate](/source/decavanadate) polyanion similar to that found in other decavanadate-bearing mineral. The decavanadate polyanion is formed of ten distorted, edge-sharing octahedra.<ref name=":0" /> 

==Chemical composition==
{| class="wikitable"
|-
! Oxide !! wt% !! Normalized wt% 
|-
| Na<sub>2</sub>O || 8.08 (0.35) || 6.90 
|-
| K<sub>2</sub>O || 0.25 (0.02) || 0.21 
|-
| (NH<sub>4</sub>)<sub>2</sub>O|| 6.03 (0.42) || 7.09 
|-
| CaO || 0.03 (0.01) || 0.03 
|-
| V<sub>2</sub>O<sub>5</sub>|| 79.9 (0.56) || 70.08 
|-
| Al<sub>2</sub>O<sub>3</sub> || 0.05 (0.01)|| 0.04 
|-
| H<sub>2</sub>O ||   || 16.65 
|-

| Total ||   || 100.00 
|}

The empirical formula with calculated H<sub>2</sub>O and (NH<sub>4</sub>)<sub>2</sub>O contents is [(NH<sub>4</sub>)<sub>2.94</sub>K<sub>0.06</sub>]<sub>Σ3.00</sub>(Na<sub>2.97</sub>Al<sub>0.01</sub> Ca<sub>0.01</sub>)<sub>Σ2.99</sub>[V<sub>10</sub>O<sub>28</sub>]12H<sub>2</sub>O (–0.01 H for charge balance) and the ideal formula is (NH<sub>3</sub>)<sub>3</sub>Na<sub>3</sub> [V<sub>10</sub>O<sub>28</sub>]12H<sub>2</sub>O. <ref name=":0" />

==See also==
{{Portal|Earth sciences}}
* [Classification of minerals](/source/Classification_of_minerals_(disambiguation))
* [List of minerals](/source/List_of_minerals)
* [https://www.mindat.org/min-40447.html Rakovanite on Mindat]

==References==
{{Reflist|30em}}

Category:Oxide minerals
Category:Monoclinic minerals
Category:Minerals in space group 14

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Adapted from the Wikipedia article [Rakovanite](https://en.wikipedia.org/wiki/Rakovanite) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Rakovanite?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.