Editing Anglesite (section)

{{Short description|Lead sulfate mineral}}
{{Infobox mineral
| name        = Anglesite
| category    = [[Sulfate minerals]]
| boxwidth    = 
| boxbgcolor  = 
| image       = Anglésite, galène, soufre 300-4-5394.JPG
| imagesize   = 260px
| caption     = Anglesite from Morocco
| formula     = PbSO<sub>4</sub>
|IMAsymbol=Ang<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.AD.35
| dana        = 28.3.1.3
| system      = [[Orthorhombic]] 
| class       = Dipyramidal (mmm) <br/>[[H-M symbol]]: (2/m 2/m 2/m)
| symmetry    = ''Pnma''
| color       = Colorless to white, commonly tinted gray; orange, yellow, green, blue, rarely violet
| habit       = Granular, banded, nodular to stalactitic
| twinning    = 
| cleavage    = [001] good, [210] distinct
| fracture    = Conchoidal
| tenacity    = Brittle
| mohs        = 2.5–3.0
| luster      = Adamantine crystals, dull when massive earthy
| refractive  = n<sub>α</sub> = 1.878 <br>n<sub>β</sub> = 1.883<br> n<sub>γ</sub> = 1.895
| opticalprop = Biaxial (+)
| birefringence = 
| 2V          = 75° (measured), 68° (calculated)
| pleochroism = 
| streak      = White
| gravity     = 6.3
| density     = 
| melt        = 
| fusibility  = 1.5
| diagnostic  = 
| solubility  = 
| diaphaneity = Transparent to translucent
| other       = 
| references  = <ref>{{cite web |url=http://rruff.geo.arizona.edu/doclib/hom/anglesite.pdf |title=Anglesite |work=Handbook of Mineralogy |publisher=Rruff.geo.arizona.edu}}</ref><ref>{{cite web|url=http://webmineral.com/data/Anglesite.shtml |title=Anglesite Mineral Data |publisher=Webmineral.com |date= |accessdate=2014-05-15}}</ref><ref>{{cite web|url=http://www.mindat.org/min-233.html |title=Anglesite: Anglesite mineral information and data |publisher=Mindat.org |date= |accessdate=2014-05-15}}</ref>
}}

'''Anglesite''' is a [[lead]] [[sulfate mineral]] with the chemical formula PbSO<sub>4</Sub>. It occurs as an oxidation product of primary lead sulfide ore, [[galena]]. Anglesite occurs as prismatic [[orthorhombic]] crystals and earthy masses, and is isomorphous with [[barite]] and [[Celestine (mineral)|celestine]]. It contains 74% of [[lead]] by mass and therefore has a high [[specific gravity]] of 6.3. Anglesite's color is white or gray with pale yellow streaks. It may be dark gray if impure.

It was first recognized as a mineral species by [[William Withering]] in 1783, who discovered it in the [[Parys Mountain|Parys]] copper-mine in [[Anglesey]]; the name anglesite, from this locality, was given by [[François Sulpice Beudant|F. S. Beudant]] in 1832. The crystals from Anglesey, which were formerly found abundantly on a matrix of dull [[limonite]], are small in size and simple in form, being usually bounded by four faces of a prism and four faces of a dome; they are brownish-yellow in colour owing to a stain of limonite. Crystals from some other localities, notably from {{Interlanguage link multi|Monteponi|it}} in [[Sardinia]], are transparent and colourless, possessed of a brilliant adamantine lustre, and usually modified by numerous bright faces. The variety of combinations and habits presented by the crystals is very extensive, nearly two hundred distinct forms being figured by V. von Lang in his monograph of the species; without measurement of the angles the crystals are frequently difficult to decipher. There are distinct cleavages parallel to the faces of the prism (110) and the [[basal plane]] (001), but these are not so well developed as in the isomorphous minerals barite and celestite.<ref name="EB1911">{{EB1911|inline=y|wstitle=Anglesite|volume=2|page=10}}</ref>

Anglesite is a mineral of secondary origin, having been formed by the oxidation of galena in the upper parts of mineral lodes where these have been affected by weathering processes. At Monteponi the crystals encrust cavities in glistening granular galena; and from [[Leadhills]], in [[Scotland]], [[pseudomorph]]s of anglesite after galena are known. At most localities it is found as isolated crystals in the lead-bearing lodes, but at some places, in [[Australia]] and [[Mexico]], it occurs as large masses, and is then mined as an [[ore]] of lead.<ref name="EB1911"/>

Anglesite is sometimes used as a gemstone.<ref>{{cite book | last=Oldershaw | first=Cally |authorlink=Cally Oldershaw| title=Firefly guide to gems | url=https://archive.org/details/fireflyguidetoge0000olde | url-access=registration | publisher=Firefly Books | location=Toronto, Ont. Buffalo, N.Y | year=2003 | isbn=978-1-55297-814-6 | page=[https://archive.org/details/fireflyguidetoge0000olde/page/84 84]}}</ref>