Dresserite
General
CategoryMineral
Formula
(repeating unit)		BaAl2(CO3)2(OH)4 · H2O
IMA symbolDsr[1]
Strunz classification5.DB.10
Dana classification16b.2.1.2
Crystal systemOrthorhombic
Crystal classDipyramidal
H-M symbol: mmm
(2/m 2/m 2/m)
Unit cell878.36
Identification
ColorWhite
Mohs scale hardness2.5 - 3
LusterVitreous, silky
StreakWhite
DiaphaneityTransparent
Specific gravity2.96
Density2.96
Optical propertiesBiaxial (-)
Refractive indexnα = 1.518
nβ = 1.590
nγ = 1.601
Birefringence0.083
2V angle30° - 40°
DispersionRelatively strong
Ultraviolet fluorescenceNone

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.[2] 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.[3]

Properties

It is a member of the carbonates family,[4] mostly consisting of oxygen (44.29%), barium (34.56%) and aluminum (13.58%), but otherwise contains carbon (6.05%) and hydrogen (1.52%).[5] It is associated with weloganite, dawsonite, quartz, and plagioclase.[6] 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.[7] Size is up to 5 mm. It is soluble in dilute hydrogen chloride, and dissolves readily with a effervescence.[8] It is the barium analogue of dundasite.[9] Dresserite does not show any kind of luminescence whatsoever.[4] 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.[10]

References

  1. ↑ 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.
  2. ↑ "Dresserite". www.mindat.org. Retrieved 2021-08-10.
  3. ↑ "Dresserite (ridiculously rare) (ex Wouter van Tichelen Collection) | Francon Quarry, Montreal, Quebec, Canada (Type Locality)". www.mineralauctions.com. Retrieved 2021-08-10.
  4. 1 2 "Luminescence, fluorescence and phosphorescence of minerals". www.fluomin.org. Retrieved 2021-08-10.
  5. ↑ "Dresserite Mineral Data". webmineral.com. Retrieved 2021-08-10.
  6. ↑ Minerals, Dakota Matrix. "Dresserite mineral information and data". www.dakotamatrix.com. Retrieved 2021-08-10.
  7. ↑ "Dresserite" (PDF). Handbook of Mineralogy. 5.
  8. ↑ "Mineralienatlas - Fossilienatlas". www.mineralatlas.eu (in German). Retrieved 2021-08-10.
  9. ↑ Jambor, J. L.; Fong, D. G.; Sabina, Ann P. (1969-12-01). "Dresserite, the new barium analogue of dundasite". The Canadian Mineralogist. 10 (1): 84–89. ISSN 0008-4476.
  10. ↑ Mandarino, J. A. (1970). "New Mineral Names" (PDF). American Mineralogist. 55: 1447.
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