{{Infobox mineral | name = Dawsonite | category = Carbonate minerals | image = Dawsonite-165134.jpg | imagesize = 260px | caption = Dawsonite from Mont Saint-Hilaire, Rouville RCM, Montérégie, Québec, Canada | formula = NaAlCO<sub>3</sub>(OH)<sub>2</sub> | IMAsymbol = Dws<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 = 144.00 g/mol | strunz = 5.BB.10 | dana = 16a.03.08.01 | system = Orthorhombic | class = Dipyramidal (mmm) <br/>H-M symbol: (2/m 2/m 2/m) | symmetry = ''Imam'' | color = white | habit = encrustations or radial | twinning = | cleavage = perfect on {110} | fracture = uneven | mohs = 3 | luster = vitreous | refractive = ''n''<sub>α</sub> = 1.466<br/>''n''<sub>β</sub> = 1.542<br/>''n''<sub>γ</sub> = 1.596 | opticalprop = | birefringence = ''δ'' = 0.130 | 2V = 77° | pleochroism = | streak = white | gravity = 2.436 | density = | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = transparent | other = | references = <ref name="MinDat">{{MinDat-ref | name = Dawsonite | id = 1240 | accessdate = 2009-12-06}}.</ref><ref name="Webmineral">{{WebMineral-ref | name = Dawsonite | url = https://webmineral.com/data/Dawsonite.shtml | accessdate = 2009-12-06}}.</ref> }} '''Dawsonite''' is a mineral composed of sodium aluminium carbonate hydroxide, chemical formula NaAlCO<sub>3</sub>(OH)<sub>2</sub>. It crystallizes in the orthorhombic crystal system. It is not mined for ore. It was discovered in 1874 during the construction of the Redpath Museum in a feldspathic dike on the campus of McGill University on the Island of Montreal, Canada.<ref name="MinDat"/> It is named after geologist Sir John William Dawson (1820–1899).<ref name="Webmineral"/>
The type material is preserved in the collection of the Redpath Museum.<ref name="MinDat"/>
==See also== *Dihydroxialumini sodium carbonate, the commercial (artificial) form, used as an antacid *List of minerals *List of minerals named after people
==References== {{reflist}}
Category:Sodium minerals Category:Aluminium minerals Category:Carbonate minerals Category:Orthorhombic minerals Category:Minerals in space group 74 Category:Luminescent minerals
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