# Matlockite

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Matlockite
> Markdown URL: https://mediated.wiki/source/Matlockite.md
> Source: https://en.wikipedia.org/wiki/Matlockite
> Source revision: 1331688029
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

{{Short description|Rare lead halide mineral}}
{{Use dmy dates|date=August 2015}}
{{Use British English|date=August 2015}}
{{Infobox mineral
| name        = Matlockite
| boxwidth    = 
| boxbgcolor  = 
| image       = Matlockite-190524.jpg
| imagesize   = 260px
| alt         = 
| caption     = 
| category    = [Halide minerals](/source/Halide_minerals)
| formula     = [PbFCl](/source/Lead_fluorochloride)
| IMAsymbol   = Mtl<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      = 3.DC.25
| dana        = 9.2.11.1
| system      = [Tetragonal](/source/Tetragonal)
| class       = Ditetragonal dipyramidal (4/mmm) <br/>[H-M symbol](/source/H-M_symbol): (4/m 2/m 2/m)
| symmetry    = ''P4/nmm'' 
| unit cell   = a = 4.11 Å, c = 7.23 Å; Z = 2
| color       = 
| colour      = Colourless to yellow and greenish
| habit       = Flattened, tabular crystals occurring as aggregates, rosettelike, radiating, hemispherical; also massive
| twinning    = 
| cleavage    = {001}, perfect
| fracture    = Uneven to subconchoidal
| tenacity    = Brittle
| mohs        = 2.5 – 3
| luster      = Adamantine, pearly on {001}
| streak      = 
| diaphaneity = Transparent
| gravity     = 7.1 – 7.2
| density     = 
| polish      = 
| opticalprop = Uniaxial (−)
| refractive  = n<sub>ω</sub> = 2.150 n<sub>ε</sub> = 2.040
| birefringence = 
| pleochroism = 
| 2V          = 
| dispersion  = 
| extinction  = 
| length fast/slow =
| fluorescence = 
| absorption  = 
| melt        = 
| fusibility  = 
| diagnostic  = 
| solubility  = 
| impurities  = 
| alteration  = 
| other       = 
| prop1       = 
| prop1text   = 
| references  = <ref>[https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Matlockite Mineralienatlas]</ref><ref name=HBM>[http://handbookofmineralogy.org/pdfs/matlockite.pdf Handbook of Mineralogy]</ref><ref name=Mindat>[http://www.mindat.org/min-2593.html Mindat.org]</ref>
}}
'''Matlockite''' is a rare [lead](/source/lead) [halide mineral](/source/halide_mineral), named after the town of [Matlock](/source/Matlock%2C_Derbyshire) in [Derbyshire](/source/Derbyshire), England, where it was first discovered in a nearby mine.<ref name=HBM/> Matlockite (chemical formula: [PbFCl](/source/Lead_fluorochloride)) gives its name to the matlockite group which consists of rare minerals of a similar structure.

==Description==
The mineral, a lead fluorochloride (formula PbFCl), was discovered sometime around the early 1800s at Bage Mine at [Bolehill](/source/Bolehill%2C_Derbyshire) near Matlock, together with specimens of [phosgenite](/source/phosgenite) and [anglesite](/source/anglesite). In 1802, the mineralogist John Mawe described a mineral he called "glass lead" in his book Mineralogy of Derbyshire. <ref>{{cite web |last= |first= |title=Matlockite |url=https://rubyglint.com/rocks/matlockite |website=RubyGlint |access-date=January 7, 2026}}</ref> Although phosgenite was known at this time, it seems likely that matlockite itself remained unappreciated as a new mineral for some fifty years. It was given the name by Greg in 1851.<ref>[http://www.mindat.org/jrs/JRS%20Vol%2001-2.pdf Phosgenite and Matlockite in Derbyshire (Part 1)], T. Bridges, M.E. Smith, Journal of the Russell Society Volume 1, No. 2, p7-14, 1983 Retrieved on 2011-01-11</ref> The first mention of matlockite may have been in [Mawe's](/source/John_Mawe) ''Mineralogy of Derbyshire'' in 1802<ref>[Mawe, John](/source/John_Mawe). The Mineralogy of Derbyshire with a Description of the most Interesting Mines. 1802, London</ref> in which he gives a detailed description of phosgenite, which is then followed by a mention of a mineral he refers to as "glass lead" – a description which does rather equate to the appearance of matlockite. It is a light, translucent creamy-yellow colour, but heavy in weight having a density that is over 7.1.<ref name=Mindat/>

A very large specimen 10&nbsp;cm across, and originating from Derbyshire, exists in the collections of the [American Museum of Natural History](/source/American_Museum_of_Natural_History).<ref>Frondell, Clifford. [http://www.minsocam.org/msa/collectors_corner/arc/size_crystals.htm American Mineralogist, Vol 20, 469–473, 1935] Retrieved on 2011-01-11</ref> A 7&nbsp;cm specimen can be found in the collection of [Derby Museum and Art Gallery](/source/Derby_Museum_and_Art_Gallery).<ref name=Moyesvid>{{cite video |people=Nick Moyes  |date=9 April 2011 |title=Working with Wikipedia – a museum's perspective |url=http://vimeo.com/22379377 |access-date= 15 April 2011 |time=14:30}}</ref>

Matlockite has been reported from a variety of locations since its discovery at the [type locality](/source/Type_locality_(geology)) of Derbyshire. The mineral is also found in [Tiger, Arizona](/source/Tiger%2C_Arizona), [Laurium](/source/Laurium) in Greece, a mine near [Essen](/source/Essen) in Germany and near [Campiglia](/source/Campiglia_Marittima) in [Tuscany](/source/Tuscany). Samples have also been found at locations in South Africa, Peru, Chile, Australia, Austria, France and Italy.<ref name=HBM/><ref name=Mindat/>

==Matlockite group==
The matlockite group consists of a number of minerals which share a similar crystal structure.  The group includes bismuth, lead or calcium halides: [bismoclite](/source/bismoclite) {{chem2|(BiO)Cl}}, [daubréeite](/source/daubr%C3%A9eite) {{chem2|(BiO)(OH,Cl)}}, [laurionite](/source/laurionite) {{chem2|PbCl(OH)}}, [paralaurionite](/source/paralaurionite) {{chem2|PbCl(OH)}}, [rorisite](/source/rorisite) CaFCl, [zavaritskite](/source/zavaritskite) {{chem2|(BiO)F}} and the eponymous matlockite.<ref name="mindat">{{cite web|title=Matlockite Group|url=http://www.mindat.org/min-32146.html|publisher=Mindat.org|access-date=12 January 2011}}</ref>

==References==
{{reflist}}

==External links==
{{commons category}}

{{clear}}
{{Derby Museum}}

Category:Halide minerals
Category:Lead minerals
Category:Tetragonal minerals
Category:Minerals in space group 129
Category:Collection of Derby Museum and Art Gallery
Category:Chloride fluorides

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