{{Short description|Lead arsenate chloride mineral}} {{Infobox mineral | boxbgcolor=#9c7a36| name = Mimetite | boxtextcolor = #fff | category = Arsenate minerals <br />Apatite group | boxwidth = | image = Mimetite - Congreso-León mines, San Pedro Corralitos, Chihuahua, Mexico.jpg | imagesize = 275px | caption = Golden-yellow botryoidal mimetite from Congreso-León mines, Mexico | formula = Pb<sub>5</sub>(AsO<sub>4</sub>)<sub>3</sub>Cl | IMAsymbol = Mim<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 = 8.BN.05 | system = Hexagonal | class = Dipyramidal (6/m) <br/><small>(same H-M symbol)</small> | symmetry = ''P6''<sub>3</sub>/m | unit cell = a = 10.250(2)&nbsp;Å, <br/>c = 7.454(1)&nbsp;Å; Z&nbsp;=&nbsp;2 | color = Pale to bright yellow, yellowish brown, yellow-orange, white, may be colorless | habit = Prismatic to acicular crystals; reniform, botryoidal, globular, | twinning = Rare on {11{{overline|2}}2} | cleavage = [10{{overline|1}}1] Imperfect | fracture = Brittle, conchoidal | tenacity = Brittle | mohs = 3.5–4 | luster = Resinous, subadamantine | refractive = n<sub>ω</sub> = 2.147 n<sub>ε</sub> = 2.128 | opticalprop = Uniaxial (−), anomalously biaxial | birefringence = 0.019 | pleochroism = Weak | streak = White | gravity = 7.1–7.24 | diaphaneity = Transparent to translucent | references = <ref name=HBM>{{cite book |editor-first1=John W. |editor-last1=Anthony |editor-first2=Richard A. |editor-last2=Bideaux |editor-first3=Kenneth W. |editor-last3=Bladh |editor-first4=Monte C. |editor-last4=Nichols |title=Handbook of Mineralogy |publisher=Mineralogical Society of America |location=Chantilly, VA |url=http://www.handbookofmineralogy.org/pdfs/mimetite.pdf |access-date=2025-05-01}}</ref><ref name=Mindat>{{mindat|name=Mimetite|id=2714|accessdate=12 February 2021}}</ref><ref name=Webmin>{{cite web |last1=Barthelmy |first1=David |title=Mimetite Mineral Data |url=http://www.webmineral.com/data/Mimetite.shtml |website=Mineralogy Database |publisher=Webmineral.com |access-date=12 February 2022 |date=2014}}</ref> }}

'''Mimetite''' is a lead arsenate chloride mineral ({{chem2|auto=1|Pb5(AsO4)3Cl}}) which forms as a secondary mineral in lead deposits, usually by the oxidation of galena and arsenopyrite.<ref name=HBM/> The name derives from the Greek {{lang|el|Μιμητής}} ''mimetes'', meaning "imitator" and refers to mimetite's resemblance to the mineral pyromorphite. This resemblance is not coincidental, as mimetite forms a mineral series with pyromorphite ({{chem2|Pb5(PO4)3Cl}}) and with vanadinite ({{chem2|Pb5(VO4)3Cl}}). Notable occurrences are Mapimi, Durango, Mexico, and Tsumeb, Namibia.

==Properties== [[Image:Mimétite 21207.jpg|thumb|left|100px|Mimetite from Namibia]] Mimetite typically forms short hexagonal crystals that are yellow to brown to orange in color, very brittle, moderately hard (Mohs hardness 3.5–4), and dense (specific gravity 7.24). It is distinctive for its lack of transparency, its resinous to adamantine luster, and its solubility in nitric acid.<ref name=sinkankas>{{cite book |last1=Sinkankas |first1=John |title=Mineralogy for amateurs |date=1964 |publisher=Van Nostrand Reinhold |location=Princeton, N.J. |isbn=0442276249 |pages=419–422 |url=https://archive.org/details/mineralogyforama0000sink/page/n9/mode/2up |url-access=registration |author-link=John Sinkankas}}</ref>

Mimetite forms a complete solid solution series with pyromorphite, with phosphate ({{chem|PO|4|3−}}) substituting for arsenate ({{chem|AsO|4|3−}}). The two minerals are almost identical in their properties and can be difficult to distinguish except by laboratory tests. Pyromorphite is the more common mineral at most locales.<ref name=sinkankas />

Campylite is a name applied to mimetite or pyromorphite that crystallizes as distinctive barrel-shaped crystals forming curved hemispherical aggregates.<ref name=sinkankas/> '''Bellite''' is a name formerly applied to a chromium-bearing mimetite, or possibly a mixture of crocoite, mimetite, and quartz, which forms attractive orange red crystals, but has been discredited as a distinct mineral species.<ref>{{cite journal |last1=Burke |first1=Ernst A.J. |title=A mass discreditation of GQN minerals |journal=The Canadian Mineralogist |date=2006-12-01 |volume=44 |issue=6 |pages=1557–1560|doi=10.2113/gscanmin.44.6.1557 |bibcode=2006CaMin..44.1557B |url=https://pubs.geoscienceworld.org/mac/canmin/article-abstract/44/6/1557/126815/A-MASS-DISCREDITATION-OF-GQN-MINERALS |url-access=subscription }}</ref>

==Occurrences== Mimetite is found in association with lead and arsenic minerals, including pyromorphite, cerussite, hemimorphite, smithsonite, vanadinite, anglesite, pyrite, mottramite, willemite, and wulfenite.<ref name=sinkankas/><ref name=HBM/> Good specimens have been reported from Gila County, Arizona, US; Ojocaliente, Zacatecas, Mexico; Cumberland, England; Johanngeorgenstadt, Saxony, Germany; Namibia; and Broken Hill, Australia.<ref name=sinkankas/>

==Mimetite specimen gallery== <gallery widths="145px" heights="130px"> File:Mimetite-139756.jpg|Mimetite from Tsumeb mine, Namibia File:Mimetite-cktsu-48a.jpg|Cluster of translucent, golden mimetite crystals File:Mimetite-289052.jpg|Spherical aggregates of botryoidal mimetite File:Mimetite-176701.jpg|Mimetite, Pingtouling Mine, Guangdong Province, China. Size: 2.2 x 2.1 x 1.8&nbsp;cm </gallery>

==References== {{Reflist}}

==External links== {{Commons category|Mimetite}} *{{cite EB1911|wstitle=Mimetite |volume=18 |short=x}} *[http://www.galleries.com/Mimetite Mineral Galleries]

Category:Lead minerals Category:Halide minerals Category:Arsenate minerals Category:Hexagonal minerals Category:Minerals in space group 176 Category:Luminescent minerals Category:Minerals described in 1835