{{short description|Copper aluminium arsenate mineral}} {{Infobox mineral | name = Liroconite | boxwidth = | boxbgcolor =#278aa0 | boxtextcolor = #fff | image = Liroconite-Strashimirite-171815.jpg | imagesize = 260px | alt = | caption = | category = Arsenate minerals | formula = Cu<sub>2</sub>Al[(OH)<sub>4</sub><nowiki>|</nowiki>AsO<sub>4</sub>]·4(H<sub>2</sub>O) | IMAsymbol = Lro<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.DF.20 | dana = | system = Monoclinic | class = Prismatic (2/m) <br/><small>(same H-M symbol)</small> | symmetry = ''I2/a'' | unit cell = a = 12.66, b = 7.57 <br/>c = 9.89&nbsp;[Å]; β = 91.25°; Z&nbsp;=&nbsp;4 | color = Bright blue to green | colour = | habit = Typically as striated flattened octahedral or lenticular crystals, also massive to granular | twinning = | cleavage = Indistinct on {110} and {011} | fracture = Irregular/uneven, conchoidal | tenacity = | mohs = 2–{{frac|2|1|2}} | luster = Vitreous to resinous | streak = Light blue | diaphaneity = Transparent, translucent | gravity = 2.9–3 | density = | polish = | opticalprop = Biaxial (−) | refractive = n<sub>α</sub> = 1.612 n<sub>β</sub> = 1.652 n<sub>γ</sub> = 1.675 | birefringence = δ = 0.063 | pleochroism = | 2V = Measured: 67° | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | references = <ref name=mindat>[http://www.mindat.org/min-2413.html Mindat.org: Liroconite mineral information and data]</ref><ref name=webmin>[http://www.webmineral.com/data/Liroconite.shtml Webmineral data]</ref><ref name=HBM>[http://rruff.geo.arizona.edu/doclib/hom/liroconite.pdf Handbook of Mineralogy]</ref> }} '''Liroconite''' is a complex mineral: Hydrated copper aluminium arsenate hydroxide, with the formula Cu<sub>2</sub>Al[(OH)<sub>4</sub>|AsO<sub>4</sub>]·4(H<sub>2</sub>O). It is a vitreous monoclinic mineral, colored bright blue to green, often associated with malachite, azurite, olivenite, and clinoclase. It is quite soft, with a Mohs hardness of 2–2.5, and has a specific gravity of 2.9–3.0. [[File:Liroconite-Clinoclase-120699.jpg|thumb|left|Vugs in gossan lined with lustrous, blue-green liroconite blades and sparkly, dark blue clinoclase microcrystals from Wheal Gorland (size: 3.4 × 3.0 × 2.0 cm)]] It was first identified in 1825 in the tin and copper mines of Devon and Cornwall, England. Although it remains quite rare it has subsequently been identified in a variety of locations including France, Germany, Australia, New Jersey and California.<ref name=mindat/>

The type locality for liroconite is Wheal Gorland in St Day, Cornwall in the United Kingdom.<ref name=mindat/> The largest crystal specimen on public display is in the Royal Cornwall Museum in Truro.<ref>{{cite web |title=Liroconite |last=Aubrey-Jones |first=David |date=2008 |url=http://britishrocks.com/}}</ref>

It occurs as a secondary mineral in copper deposits in association with olivenite, chalcophyllite, clinoclase, cornwallite, strashimirite, malachite, cuprite and limonite.<ref name=HBM/>

==Structure== Liroconite crystallizes in the monoclinic crystal system.<ref name=HBM/>{{rp|1}}<ref>{{Cite journal |last1=Kolesova |first1=R.V. |last2=Fesenko |first2=E.G. |date=Dec 1968 |title=Determination of the crystal structure of Liroconite Cu<sub>2</sub>Al[AsO<sub>4</sub>](OH)<sub>4</sub> <math>\cdot</math> 4 H<sub>2</sub>O |url=https://rruff-2.geo.arizona.edu/uploads/SPC13_324.pdf |journal=Soviet Physics – Crystallography |location=Rostov University |volume=13 |issue=3 |pages=396–402}}</ref> The crystal structure consists of a framework of AsO<sub>4</sub> tetrahedra, Jahn-Teller-distorted [CuO<sub>2</sub>(OH)<sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>] octahedra and [AlO<sub>2</sub>(OH)<sub>4</sub>] octahedra.<ref>{{ cite journal | first1 = Peter C. | last1 = Burns | first2 = Ray K. | last2 = Eby | first3 = Frank C. | last3 = Hawthorne | title = Refinement of the structure of liroconite, a heteropolyhedral framework oxysalt mineral | journal = Acta Crystallogr. C | year = 1991 | volume = 47 | issue = 5 | pages = 916–919 | doi = 10.1107/S0108270190010939 | bibcode = 1991AcCrC..47..916B }}</ref>

250px|Unit cell of liroconite

==See also== *Kernowite – an isostructural mineral with iron in place of aluminium

==References== {{reflist}}

{{Commons category}}

Category:Copper(II) minerals Category:Arsenate minerals Category:Monoclinic minerals Category:Minerals in space group 15

{{mineral-stub}}