# Parnauite

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> Source: https://en.wikipedia.org/wiki/Parnauite
> Source revision: 1345331729
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{{Infobox mineral
| name        = Parnauite
| boxwidth    =
| boxbgcolor  = #228B22
| image       = Parnauite-89334.jpg
| caption     = Parnauite
| category    = [Arsenate minerals](/source/Arsenate_minerals)
| formula     = Cu<sub>9</sub>(AsO<sub>4</sub>)<sub>2</sub>(SO<sub>4</sub>)(OH)<sub>10</sub> · 7H<sub>2</sub>O
| IMAsymbol   = Pna
| molweight   =
| strunz      = 8.DF.35
| dana        = 43.5.13.1
| system      = Orthorhombic
| unit cell   = 641.15 ų (calculated)
| color       = Pale blue, green, dark green, blue-green, yellow-green
| habit       = Fans and rosettes of lath-like crystals; fibrous; scaly crusts
| cleavage    = Good
| mohs        = 2
| streak      = Greenish white
| gravity     = 3.09
| opticalprop = Biaxial (−)
| refractive  = nα = 1.680(3), nβ = 1.704(3), nγ = 1.712(3)
| birefringence = δ = 0.032
| pleochroism = Weak
| 2V          = Measured: 60°(5); calculated: 58°
| dispersion  = r > v (strong)
| extinction  = Optic plane parallel to {100}.<br/>X = b, Y = a, Z = c.
| length fast/slow =
| fluorescence = None
| impurities  = P, C, Al
| references  =
<ref name="Webmineral">{{cite web |title=Parnauite Mineral Data |url=https://webmineral.com/data/Parnauite.shtml |website=Webmineral |access-date=13 December 2025}}</ref>
}}

'''Parnauite''' is a very rare secondary [copper](/source/copper) [arsenate–sulfate](/source/Arsenate_sulfate) mineral.<ref name="HoM">{{cite web |title=Parnauite (Handbook of Mineralogy) |publisher=Mineral Data Publishing |url=https://rruff.info/doclib/hom/parnauite.pdf |access-date=13 December 2025}}</ref> It forms near the Earth's surface in [oxidized](/source/oxidized) zones of various copper deposits. These copper minerals are altered by oxygen-rich water and new minerals grow as a thin coatings or small crystal clusters.<ref name="HoM" /> Parnauite is typically blue-green to green and commonly occurs as tiny bladed crystals in fan-shaped sprays or [rosettes](/source/rosettes). It may also appear as scaly crusts or crystal-like surface films.<ref name="Mindat">{{cite web |title=Parnauite: Mineral information, data and localities |website=Mindat.org |url=https://www.mindat.org/min-3124.html |access-date=13 December 2025}}</ref>

== Discovery ==
Parnauite was discovered in 1978 from the Majuba Hill Mine (Antelope Mining District), [Pershing County, Nevada](/source/Pershing_County%2C_Nevada).<ref name="Wise1978">{{cite journal |last=Wise |first=William S. |year=1978 |title=Parnauite and goudeyite, two new copper arsenate minerals from the Majuba Hill Mine, Pershing County, Nevada |journal=American Mineralogist |volume=63 |issue=7–8 |pages=704–708}}</ref> Another new copper arsenate, Goudeyite was also discovered from the same location. This shows that oxidation at Majuba Hill produces an unusually diverse set of secondary copper minerals.<ref name="Wise1978" />

Parnauite was named in honour of U.S. mineral collector John L. "Jack" Parnau. He is credited with collecting many different minerals from [Majuba Hill](/source/Majuba_Hill) that were later studied and found to be completely new minerals.<ref name="HoM">{{cite web |title=Parnauite (Handbook of Mineralogy) |publisher=Mineral Data Publishing |url=https://rruff.info/doclib/hom/parnauite.pdf |access-date=13 December 2025}}</ref>

Parnauite is also in institutional collections, including the [University of California](/source/University_of_California), [Santa Barbara, California](/source/Santa_Barbara%2C_California), and the [National Museum of Natural History, Smithsonian Institution](/source/National_Museum_of_Natural_History) in [Washington, DC](/source/Washington%2C_DC).<ref name="HoM" />

Majuba Hill's [lithology](/source/lithology) is composed of small [igneous intrusion](/source/igneous_intrusion)s, often described as a [volcanic plugs](/source/volcanic_plugs). It's made up of [porphyritic](/source/Porphyry_(geology)) [rhyolite](/source/rhyolite) and several types of [breccia](/source/breccia). These minerals helps explain why parnauite forms there. These igneous intrusions were emplaced into older [sedimentary](/source/sedimentary) [strata](/source/strata) that is largely made up of [shale](/source/shale).<ref name="USGS_pub">{{cite web |title=Tin, copper, and uranium at Majuba Hill, Nevada |website=U.S. Geological Survey |url=https://www.usgs.gov/publications/tin-copper-and-uranium-majuba-hill-nevada |access-date=13 December 2025}}</ref>

The deposit contains copper and [tin](/source/tin) [mineralization](/source/Mineralization_(geology)). In many parts of the mine, the ore is strongly [oxidized](/source/oxidized), meaning the original ore minerals have been chemically altered by oxygen-rich water near the surface. This oxidation produces a wide range of secondary copper minerals.<ref name="USGS_report">{{cite report |title=Tin, copper, and uranium at Majuba Hill, Nevada |publisher=U.S. Geological Survey |series=Trace Elements Investigations Report |number=81A |url=https://pubs.usgs.gov/tei/081a/report.pdf |access-date=13 December 2025}}</ref>

== Chemistry and properties ==
Parnauite is a [hydrated](/source/hydrated) copper arsenate–sulfate with the formula Cu<sub>9</sub>(AsO<sub>4</sub>)<sub>2</sub>(SO<sub>4</sub>)(OH)<sub>10</sub>·7H<sub>2</sub>O.<ref name="HoM" /> It is made mostly of copper, with arsenic and sulfur bound into oxygen-rich groups, [hydroxides](/source/hydroxides), and water molecules.

Under [polarized light](/source/polarized_light), parnauite is [biaxial](/source/biaxial) negative with weak [pleochroism](/source/pleochroism) (a slight color change with viewing direction).<ref name="HoM" /> Because [fibrous](/source/fibrous) parnauite can resemble other blue-green secondary copper minerals, identification often requires laboratory testing such as [X-ray diffraction](/source/X-ray_diffraction).<ref name="Mills2013">{{cite journal |last1=Mills |first1=Stuart J. |last2=Kampf |first2=Anthony R. |last3=McDonald |first3=Andrew M. |last4=Bindi |first4=Luca |last5=Christy |first5=Andrew G. |last6=Kolitsch |first6=Uwe |last7=Favreau |first7=Georges |year=2013 |title=The crystal structure of parnauite: a copper arsenate–sulphate with translational disorder of structural rods |journal=European Journal of Mineralogy |volume=25 |issue=4 |pages=693–704 |doi=10.1127/0935-1221/2013/0025-2329 |bibcode=2013EJMin..25..693M }}</ref>

== Extent ==
Parnauite is very rare and is known only in a relatively small number of locations worldwide.<ref name="HoM" /> Reported occurrences include:

* Majuba Hill Mine, the Burrus Mine, Nevada
* [Grandview Mine](/source/Grandview_Mine), Arizona.
* Small amounts in Colorado and Utah 
* Cap Garonne mine in [France](/source/France)
* varies locations in the [Black Forest](/source/Black_Forest) in Germany 
* Clara Mine in [Ľubietová](/source/%C4%BDubietov%C3%A1), [Slovakia](/source/Slovakia)
* The Tynagh mine in [County Galway, Ireland](/source/County_Galway%2C_Ireland)
* Several mines in [Cornwall](/source/Cornwall) and [Wales](/source/Wales)  
* [Tsumeb](/source/Tsumeb) area in [Namibia](/source/Namibia).

''Reference'':<ref name="HoM" />

== References ==
{{reflist}}

Category:Copper minerals
Category:Arsenate minerals
Category:Sulfate minerals
Category:Minerals in space group 31

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