Edingtonite
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.[4]
| Edingtonite | |
|---|---|
 Edingtonite from Ice River Alkaline Complex, Golden Mining Division, British Columbia, Canada | |
| General | |
| Category | Tectosilicate |
| Formula (repeating unit) | BaAl2Si3O10·4H2O |
| Strunz classification | 9.GA.15 |
| Crystal system | Orthorhombic |
| Identification | |
| Color | White, gray, pink |
| Crystal habit | Prismatic pseudotetragonal crystals; massive. |
| Twinning | On [110] and [001] |
| Cleavage | Perfect on [110] |
| Mohs scale hardness | 4 - 4.5 |
| Specific gravity | 2.73 - 2.78 |
| Optical properties | Biaxial (-) |
| Refractive index | nα = 1.538 nβ = 1.549 nγ = 1.554 |
| Birefringence | δ = 0.016 |
| 2V angle | 54 - 62° |
| Dispersion | r < v; strong |
| Other characteristics | Pyroelectric and piezoelectric |
| References | [1][2][3] |
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.[3]
The mineral was first reported by and named for Scottish mineral collector James Edington (1787–1844).[2][3] Other sources (including the mineralogist Haidinger) credit Scottish geologist and mineralogist Thomas Edington (1814-1859).[5] However, as the mineral was named in 1825, the former accreditation must be the true one.[6]
References
- Edingtonite mineral data from Webmineral
- Edingtonite mineral data from Mindat.org
- Handbook of Mineralogy
- 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
- 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.
- 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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