Dresserite
{{Short description|Carbonate mineral}}
{{Infobox mineral|boxbgcolor=#aaaaaa|image=Dresserite-lor05a.jpg|formula=BaAl2(CO3)2(OH)4 · H2O| IMAsymbol = Dsr{{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}} |strunz=5.DB.10|system=Orthorhombic|dana=16b.2.1.2|class=Dipyramidal
H-M symbol: mmm
(2/m 2/m 2/m)|unit cell=878.36|color=White|mohs=2.5 - 3|luster=Vitreous, silky|opticalprop=Biaxial (-)|refractive=nα = 1.518
nβ = 1.590
nγ = 1.601|birefringence=0.083|2V=30° - 40°|dispersion=Relatively strong|fluorescence=None|streak=White|gravity=2.96|density=2.96|diaphaneity=Transparent}}Dresserite is a mineral of the dresserite group, named in honor of John Alexander Dresser, geologist. It was approved by the IMA in 1968, but only a year after was it published.{{Cite web|title=Dresserite|url=https://www.mindat.org/min-1319.html|access-date=2021-08-10|website=www.mindat.org}} The rare mineral can only be found in Francon quarry, Canada. The quarry is located in the middle of the city of Montréal, but had been closed in 1981 and will not reopen in the future.{{Cite web|title=Dresserite (ridiculously rare) (ex Wouter van Tichelen Collection) {{!}} Francon Quarry, Montreal, Quebec, Canada (Type Locality)|url=https://www.mineralauctions.com/items/dresserite-ridiculously-rare-ex-wouter-van-tichelen-collection-86339|access-date=2021-08-10|website=www.mineralauctions.com|language=en}}
Properties
It is a member of the carbonates family,{{Cite web|title=Luminescence, fluorescence and phosphorescence of minerals|url=https://www.fluomin.org/uk/fiche.php?id=324|access-date=2021-08-10|website=www.fluomin.org}} mostly consisting of oxygen (44.29%), barium (34.56%) and aluminum (13.58%), but otherwise contains carbon (6.05%) and hydrogen (1.52%).{{Cite web|title=Dresserite Mineral Data|url=http://webmineral.com/data/Dresserite.shtml|access-date=2021-08-10|website=webmineral.com}} It is associated with weloganite, dawsonite, quartz, and plagioclase.{{Cite web|last=Minerals|first=Dakota Matrix|title=Dresserite mineral information and data|url=https://www.dakotamatrix.com/mineralpedia/5518/dresserite|access-date=2021-08-10|website=www.dakotamatrix.com|language=en}} It grows into tapering acicular crystals, elongated along [001] and bladed on {010}. It is typically in divergent spherical and hemispherical aggregates. It occurs in cavities in alkalic sill in limestone.{{Cite journal|title=Dresserite|url=http://www.handbookofmineralogy.org/pdfs/dresserite.pdf|journal=Handbook of Mineralogy|volume=5}} Size is up to 5 mm. It is soluble in dilute hydrogen chloride, and dissolves readily with a effervescence.{{Cite web|title=Mineralienatlas - Fossilienatlas|url=https://www.mineralatlas.eu/lexikon/index.php/MineralData?lang=de&mineral=Dresserite|access-date=2021-08-10|website=www.mineralatlas.eu|language=de}} It is the barium analogue of dundasite.{{Cite journal|last1=Jambor|first1=J. L.|last2=Fong|first2=D. G.|last3=Sabina|first3=Ann P.|date=1969-12-01|title=Dresserite, the new barium analogue of dundasite|url=https://pubs.geoscienceworld.org/canmin/article/10/1/84/10733/dresserite-the-new-barium-analogue-of-dundasite|journal=The Canadian Mineralogist|volume=10|issue=1|pages=84–89|issn=0008-4476}} Dresserite does not show any kind of luminescence whatsoever. The measured density of the mineral, due to its fibrous nature, is too low. The differential thermal analysis (DTA) curve of the mineral is similar to dundasite's in appearance. The principal endothermic peak is at 384°C. When heated up to this degree, dresserite loses all of its water and carbon dioxide.{{Cite journal|last=Mandarino|first=J. A.|year=1970|title=New Mineral Names|url=http://www.minsocam.org/ammin/AM55/AM55_1444.pdf|journal=American Mineralogist|volume=55|pages=1447}}