{{Short description|Phyllosilicate mineral}} {{Infobox mineral | name = Ussingite | boxwidth = | boxbgcolor = | image = Ussingite, Vuonnemite-294589.jpg | alt = | caption = Ussingite from Shkatulka pegmatite, Umbozero mine (Umbozerskii mine), Alluaiv Mt, Lovozero Massif, Kola Peninsula, Murmanskaja Oblast', Northern Region, Russia | category = Phyllosilicate minerals | formula = Na<sub>2</sub>AlSi<sub>3</sub>O<sub>8</sub>OH | IMAsymbol = Usg<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 = 9.EH.20 | system = Triclinic | class = Pinacoidal ({{overline|1}}) <br/><small>(same H-M symbol)</small> | symmetry = ''P''{{overline|1}} | unit cell = | color = pale to medium violet, reddish violet; sometimes barely tinted purple | colour = | habit = | twinning = | cleavage = | fracture = irregular/ uneven | tenacity = brittle | mohs = 6–7 | luster = sub-vitreous | streak = white | diaphaneity = transparent, translucent | gravity = | density = | polish = | opticalprop = | refractive = | birefringence = | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | prop1 = | prop1text = | references = <ref name=Mindat>[http://www.mindat.org/min-4122.html Mindat.org Mindat]</ref><ref name=Webmin>[http://www.webmineral.com/data/Ussingite.shtml Webmineral.com Webmineral data]</ref> }} '''Ussingite''' is a silicate mineral with formula Na<sub>2</sub>AlSi<sub>3</sub>O<sub>8</sub>(OH).<ref>{{Cite web |url=http://www.handbookofmineralogy.com/pdfs/ussingite.pdf |title=Handbook of Mineralogy (HOM – MSA) – Ussingite |access-date=2013-01-25 |archive-date=2021-03-05 |archive-url=https://web.archive.org/web/20210305040319/http://www.handbookofmineralogy.com/pdfs/ussingite.pdf |url-status=dead }}</ref>
It was named for Niels Viggo Ussing (1864–1911), Copenhagen, Denmark.
== References == {{Reflist}}
Category:Phyllosilicates Category:Triclinic minerals Category:Minerals in space group 2
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