# Johannite

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> Markdown URL: https://mediated.wiki/source/Johannite.md
> Source: https://en.wikipedia.org/wiki/Johannite
> Source revision: 1345463864
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{{Short description|Rare uranium sulfate mineral}}
{{distinguish|Ioannites (disambiguation){{!}}Johannites}}
{{Infobox mineral
| name        = Johannite
| category    = [Sulfate mineral](/source/Sulfate_mineral)
| boxwidth    = 
| boxbgcolor  = 
| image       = Johannit - Ronneburg.jpg
| imagesize   = 260px
| alt         = 
| caption     = 
| formula     = Cu[UO<sub>2</sub>(OH)SO<sub>4</sub>]<sub>2</sub>·8H<sub>2</sub>O
| IMAsymbol   = Jh<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      = 7.EB.05 (10 ed) <br/><small>VI/D.21-10 (8 ed)</small>
| dana        = 31.8.2.1
| system      = Triclinic
| class       = Pinacoidal ({{overline|1}}) <br/><small>(same [H-M symbol](/source/H-M_symbol))</small>
| symmetry    = ''P''{{overline|1}}
| color       = Emerald-green, apple-green
| colour      = 
| habit       = Prismatic, tabular, coatings
| twinning    = Simple and repeated lamellar twinning
| cleavage    = good on {100}
| fracture    = 
| tenacity    = 
| mohs        = 2 - 2.5
| luster      = Vitreous
| streak      = Pale green
| diaphaneity = Transparent, Translucent
| gravity     = 3.32, 3.27 (calc.)
| density     = 3.32
| polish      = 
| opticalprop = Biaxial (+/-)
| refractive  = n<sub>α</sub> = 1.572 - 1.577 ; n<sub>β</sub> = 1.592 - 1.597 ; n<sub>γ</sub> = 1.612 - 1.616
| birefringence = δ = 0.040
| pleochroism = strong: x= colorless; y= pale yellow; z= greenish yellow or canary-yellow
| 2V          = 90°
| dispersion  = 
| extinction  = 
| length fast/slow =
| fluorescence= 
| absorption  =
| melt        = 
| fusibility  = 
| diagnostic  = 
| solubility  = 
| other       = 25px [Radioactive](/source/Radioactive), Bitter taste
| alteration  = 
| references  = <ref name="Handbook">[http://www.handbookofmineralogy.org/pdfs/johannite.pdf Handbook of Mineralogy - Johannite]</ref><ref name="Mindat">[http://www.mindat.org/min-2102.html Mindat - Johannite]</ref><ref name="Webmineral">[http://webmineral.com/data/Johannite.shtml Webmineral - Johannite]</ref>
}}

'''Johannite''' is a rare [uranium](/source/uranium) [sulfate mineral](/source/sulfate_mineral). It crystallizes in the [triclinic crystal system](/source/triclinic_crystal_system) with the chemical composition Cu[UO<sub>2</sub>(OH)SO<sub>4</sub>]<sub>2</sub>·8H<sub>2</sub>O. It crystallizes in the [triclinic](/source/triclinic) system and develops only small prism or thin to thick tabular [crystal](/source/crystal)s, usually occurs as flaky or spheroidal aggregates and efflorescent coatings. Its color is emerald-green to [apple](/source/Granny_Smith)-green and its streak is pale green.

Johannite is a strong radioactive mineral with a calculated activity of 87,501,143 [Bq](/source/Becquerel)/g (to the comparison: natural [potassium](/source/potassium): 31.2 Bq/g).

== Etymology and history ==
Johannite was first described in 1830 by [Wilhelm Karl Ritter von Haidinger](/source/Wilhelm_Karl_Ritter_von_Haidinger). It was named for [Archduke John of Austria](/source/Archduke_John_of_Austria) (1782–1859), the founder of the [Landesmuseum Joanneum](/source/Landesmuseum_Joanneum) (Styria, Austria).

== Occurrence ==
Johannite forms as secondary mineral by [oxidation](/source/oxidation) from [uraninite](/source/uraninite) as well as different other uranium minerals.

Localities include Argentina, Czech Republic, France, Gabon, Germany, Greece, Italy, Switzerland, United Kingdom and the United States. [Type locality](/source/Type_locality_(geology)) is the “Elias Mine” in [Jáchymov](/source/J%C3%A1chymov) (Czech Republic).

== Crystal structure ==
Johannite crystallizes in the triclinic crystal system in the [space group](/source/space_group) P{{overline|1}} with the [lattice parameters](/source/Lattice_constant) a&nbsp;=&nbsp;8.92&nbsp;[Å](/source/%C3%85ngstr%C3%B6m), b&nbsp;=&nbsp;9.59&nbsp;Å, c&nbsp;=&nbsp;6.84&nbsp;Å; α&nbsp;=&nbsp;110°, β&nbsp;=&nbsp;111.98°, γ&nbsp;=&nbsp;100.3° and one formula unit per [unit cell](/source/Crystal_structure).

== References ==
{{reflist}}

{{Commons category|Johannite|position=left}}

==Bibliography==
*<small>Palache, P.; Berman H.; Frondel, C. (1960). "''Dana's System of Mineralogy, Volume II: Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc. (Seventh Edition)"'' John Wiley and Sons, Inc., New York, pp. 606–607.</small>

Category:Copper(II) minerals
Category:Uranium(VI) minerals
Category:Sulfate minerals
Category:Triclinic minerals
Category:Minerals in space group 2

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