{{Short description|Sulfate-fluoride mineral}} {{infobox mineral | name = Kogarkoite | image = Kogarkoite - Poudrette quarry, Mont Saint-Hilaire, Quebec, Canada.jpg | imagesize = | alt = | caption = | category = Sulfate mineral | formula = Na<sub>3</sub>(SO<sub>4</sub>)F | IMAsymbol = Kog<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.BD.15 | dana = | system = Monoclinic | class = Pyramidal (2/m) <br/><small>(same H-M symbol)</small> | symmetry = ''P2''<sub>1</sub>/m | unit cell = a = 18.07, b = 6.94 <br/>c = 11.44 [Å]; β = 107.72°; Z = 12 | color = Colorless, pale sky-blue, pale pink, lilac | habit = Tabular crystals, granular, earthy aggregates, pseudorhombohedral | twinning = Common | cleavage = | fracture = | tenacity = | mohs = 3.5 | luster = Vitreous to dull | streak = White | diaphaneity = Transparent to translucent | gravity = 2.66 | density = | polish = | opticalprop = Biaxial (+) | refractive = n<sub>α</sub> = 1.439 n<sub>β</sub> = 1.439 n<sub>γ</sub> = 1.442 | birefringence = δ = 0.003 | pleochroism = | 2V = Small, approaching zero | dispersion = | extinction = | length fast/slow = | fluorescence = Cream to pale blue under SW UV and green under LW UV | absorption = | melt = | fusibility = | diagnostic = | solubility = Slowly soluble in water | impurities = | alteration = | other = | references = <ref name=HBM>[http://rruff.geo.arizona.edu/doclib/hom/kogarkoite.pdf Handbook of Mineralogy]</ref><ref name=Mindat>[http://www.mindat.org/show.php?id=2236&ld=1#themap Mindat.org]</ref><ref name=Webmin>[http://webmineral.com/data/Kogarkoite.shtml Webmineral data]</ref> }} '''Kogarkoite''' is a sodium sulfate fluoride mineral with formula Na<sub>3</sub>(SO<sub>4</sub>)F. It has a pale blue color, a specific gravity of about 2.67 and a hardness of 3.5. The crystal is monoclinic and is a type of naturally occurring antiperovskite. Kogarkoite is named after the Russian petrologist Lia Nikolaevna Kogarko (born 1936) who discovered the mineral.
==Discovery and occurrence== Kogarkoite was first described in 1973 for an occurrence on Alluaiv Mountain, Lovozero Massif, Kola Peninsula, Russia.<ref name=Mindat/> On Alluaiv it occurs in pegmatitic veins in nepheline syenite. It occurs with sodalite in syenite xenoliths in an alkali intrusive complex at Mont Saint-Hilaire, Canada. In Hortense Hot Spring, Chaffee County, Colorado, it occurs as a sublimate.<ref name=HBM/> It occurs at Lake Natron near Ol Doinyo Lengai, Tanzania and Suswa Volcano, Lake Magadi, Kenya.<ref name=HBM/><ref name=Mindat/>
==See also== *List of minerals *List of minerals named after people
==References== {{Reflist}}
Category:Sodium minerals Category:Sulfate minerals Category:Fluorine minerals Category:Monoclinic minerals Category:Minerals in space group 11
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