Edingtonite
Edingtonite from Ice River Alkaline Complex, Golden Mining Division, British Columbia, Canada
General
CategoryTectosilicate
Formula
(repeating unit)		BaAl2Si3O10·4H2O
IMA symbolEdi[1]
Strunz classification9.GA.15
Crystal systemOrthorhombic
Identification
ColorWhite, gray, pink
Crystal habitPrismatic pseudotetragonal crystals; massive.
TwinningOn [110] and [001]
CleavagePerfect on [110]
Mohs scale hardness4 - 4.5
Specific gravity2.73 - 2.78
Optical propertiesBiaxial (-)
Refractive indexnα = 1.538 nβ = 1.549 nγ = 1.554
Birefringenceδ = 0.016
2V angle54 - 62°
Dispersionr < v; strong
Other characteristicsPyroelectric and piezoelectric
References[2][3][4]

Edingtonite is a white, gray, brown, colorless, pink or yellow zeolite mineral. Its chemical formula is BaAl2Si3O10·4H2O. It has varieties with tetragonal, orthorhombic or triclinic crystals.[5]

The mineral occurs within cavities in nepheline syenites, carbonatites, in hydrothermal veins and various mafic rocks. It occurs associated with thomsonite, analcime, natrolite, harmotome, brewsterite, prehnite and calcite.[4]

The mineral was first reported by and named for Scottish mineral collector James Edington (1787–1844).[3][4] Other sources (including the mineralogist Haidinger) credit Scottish geologist and mineralogist Thomas Edington (1814-1859).[6] However, as the mineral was named in 1825, the former accreditation must be the true one.[7]

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. ↑ Edingtonite mineral data from Webmineral
  3. 1 2 Edingtonite mineral data from Mindat.org
  4. 1 2 3 Handbook of Mineralogy
  5. ↑ Richard V. Gaines, H. Catherine W. Skinner, Eugene E. Foord, Brian Mason, and Abraham Rosenzweig: "Dana's new mineralogy", pp. 1683-1684. John Wiley & Sons, 1997
  6. ↑ Biographical Index of Former Fellows of the Royal Society of Edinburgh 1783–2002 (PDF). The Royal Society of Edinburgh. July 2006. ISBN 0-902-198-84-X.
  7. ↑ Wilhelm Karl von Haidinger, "Description of Edingtonite, a New Mineral Species", in The Edinburgh Journal of Science, V. iii, October 1825, pp. 316–320

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