{{Short description|Single chain inosilicate mineral}} {{Infobox mineral | name = Agrellite | category = Inosilicates | image = Museo di mineralogia, pietre fluorescenti, agrellite 3.JPG | caption = Agrellite showing fluorescence in ultraviolet light | formula = NaCa<sub>2</sub>Si<sub>4</sub>O<sub>10</sub>F |IMAsymbol=Are<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.DH.75 | system = Triclinic | class = Pinacoidal ({{overline|1}}) <br/><small>(same H-M symbol)</small> | symmetry = ''P''{{overline|1}} | color = White, grayish-white, greenish-white | habit = Lath - shaped like a small, thin plaster lath, rectangular in shape | twinning = | cleavage = perfect [110] | fracture = | mohs = 5.5 | luster = pearly | refractive = nα = 1.567 nβ = 1.579 nγ = 1.581 | opticalprop = biaxial | birefringence = δ = 0.014 | pleochroism = | streak = white | gravity = 2.88 | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = translucent | other = | references = <ref>http://www.mindat.org/min-57.html Mindat</ref><ref>http://www.webmineral.com/data/Agrellite.shtml Webmineral</ref> }}
'''Agrellite''' ({{chem2|NaCa2Si4O10F}}) is a rare triclinic inosilicate mineral with four-periodic single chains of silica tetrahedra.
It is a white to grey translucent mineral, with a pearly luster and white streak. It has a Mohs hardness of 5.5 and a specific gravity of 2.8. Its type locality is the Kipawa Alkaline Complex, Quebec, Canada, where it occurs as tabular laths in pegmatite lenses.<ref name=":0">{{Cite web|title=Agrellite|url=https://www.mindat.org/min-57.html|access-date=2021-12-08|website=www.mindat.org}}</ref> Other localities include Murmansk Oblast, Russia, Dara-i-Pioz Glacier, Tajikistan, and Saima Complex, Liaoning, China.<ref name=":0" /> Common associates at the type locality include zircon, eudialyte, vlasovite, miserite, mosandrite-(Ce), and calcite.<ref name=":0" />
Agrellite displays pink fluorescence strongly under shortwave and weakly under longwave ultraviolet light.<ref>{{Cite web|title=Handbook of Mineralogy|url=http://www.handbookofmineralogy.org/|access-date=2021-12-08|website=www.handbookofmineralogy.org}}</ref><ref name=":1">{{Cite web|title=Luminescence, fluorescence and phosphorescence of minerals|url=https://www.fluomin.org/uk/fiche.php?id=62|access-date=2021-12-08|website=www.fluomin.org}}</ref> The fluorescent activator is dominantly Mn<sup>2+</sup>, with minor Eu<sup>2+</sup>, Sm<sup>3+</sup>, and Dy<sup>3+</sup>.<ref name=":1" />
It is named in honor of Stuart Olof Agrell (1913–1996), a British mineralogist at Cambridge University.
==See also== * List of minerals * List of minerals named after people
==References== {{Commons category}} {{Reflist}}
Category:Sodium minerals Category:Calcium minerals Category:Inosilicates Category:Fluorine minerals Category:Triclinic minerals Category:Minerals in space group 2 Category:Minerals described in 1976
{{silicate-mineral-stub}}