Ashburtonite

{{Short description|Rare lead copper silicate-bicarbonate mineral}} {{Infobox mineral | name = Ashburtonite | category = Cyclosilicates | image = File:Ashburtonite-596731.jpg | caption = | formula = HPb₄Cu₄Si₄O₁₂(HCO₃)₄(OH)₄Cl |IMAsymbol=Ahb<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> | strunz = 9.CF.05 | system = Tetragonal | class = Dipyramidal (4/m) <br/>H-M symbol: (4/m) | symmetry = ''I4/m'' | unit cell = a = 14.23, c = 6.1&nbsp;[Å]; Z&nbsp;=&nbsp;2 | color = Blue | habit = Prismatic, needle like in clusters | twinning = | fracture = Conchoidal | tenacity = Brittle | cleavage = None | mohs = | luster = Vitreous to adamantine | refractive = n_ω = 1.786 n_ε = 1.800 | opticalprop = Uniaxial (+) | birefringence= 0.0140 | streak = light blue | gravity = Greater than 4.07, calculated 4.69 | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = Transparent | references = <ref>[http://webmineral.com/data/Ashburtonite.shtml Webmineral]</ref><ref name=Mindat>[http://www.mindat.org/min-388.html Mindat]</ref><ref name=HBM>[http://rruff.geo.arizona.edu/doclib/hom/ashburtonite.pdf Handbook of Mineralogy]</ref><ref name="Grice"/> }}

'''Ashburtonite''' is a rare lead copper silicate-bicarbonate mineral with formula: HPb₄Cu²⁺₄Si₄O₁₂(HCO₃)₄(OH)₄Cl.<ref name="Grice">{{Cite journal |last1=Grice |first1=J. D. |last2=Nickel |first2=E. H. |last3=Gault |first3=R. A. |year=1991 |title=Ahsburtonite, a new bicarbonate-silicate mineral from Ashburton Downs, Western Australia: Description and structure determination |journal=American Mineralogist |volume=76 |pages=1701–1707 |authorlink2=Ernest Henry Nickel |url=http://rruff.info/rruff_1.0/uploads/AM76_1701.pdf }}</ref>

==Geological occurrence== Ashburtonite was first described as a secondary mineral in a shear zone in a series of shales and graywackes. It is an alteration product of galena and chalcopyrite.<ref name=HBM/> The secondary minerals within the shear consist of carbonates, arsenates, and sulfates of lead and copper, and to a much lesser extent of zinc and iron.<ref name="Grice"/> Ashburtonite is associated with beudantite, brochantite, caledonite, cerussite, diaboleite, duftite, malachite, plattnerite, adamite, antlerite, bayldonite, bindheimite, carminite, chenevixite, chlorargyrite, chrysocolla, cinnabar, hemimorphite, hydrozincite, jarosite, lavendulan, linarite, mimetite, olivenite, paratacamite, and rosasite.

Ashburtonite was first described in 1991 for an occurrence in the Anticline prospects {{convert|11|km|abbr=on}} southwest of Ashburton Downs in the Capricorn Range of Western Australia.<ref name=HBM/> It has also been reported from the Tonopah–Belmont Mine in the Big Horn Mountains of Maricopa County, Arizona.<ref name=Mindat/>

==References== {{reflist}}

Category:Tetragonal minerals Category:Minerals in space group 87 Category:Cyclosilicates

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