Dawsonite
(repeating unit)NaAlCO3(OH)2 IMA symbol Dws[1] Strunz classification 5.BB.10 Dana classification 16a.03.08.01 Crystal system Orthorhombic Crystal class Dipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m) Space group Imam Identification Formula mass 144.00 g/mol Color white Crystal habit encrustations or radial Cleavage perfect on {110} Fracture uneven Mohs scale hardness 3 Luster vitreous Streak white Diaphaneity transparent Specific gravity 2.436 Refractive index nα = 1.466
nβ = 1.542
nγ = 1.596 Birefringence δ = 0.130 2V angle 77° References [2][3]
H-M symbol: (2/m 2/m 2/m)
nβ = 1.542
nγ = 1.596
Dawsonite is a mineral composed of sodium aluminium carbonate hydroxide, chemical formula NaAlCO3(OH)2. 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.[2] It is named after geologist Sir John William Dawson (1820–1899).[3]
The type material is preserved in the collection of the Redpath Museum.[2]
See also
- Dihydroxialumini sodium carbonate, the commercial (artificial) form, used as an antacid
- List of minerals
- List of minerals named after people
References
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ a b c Dawsonite, Mindat.org, retrieved 2009-12-06.
- ^ a b Dawsonite, WebMineral.com, retrieved 2009-12-06.
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