Chemistry:Efremovite
From HandWiki
Short description: Rare ammonium sulfate mineral
| Efremovite | |
|---|---|
| General | |
| Category | Sulfate minerals |
| Formula (repeating unit) | (NH4)2Mg2(SO4)3 |
| Strunz classification | 7.AC.10 |
| Crystal system | Cubic |
| Crystal class | Tetartoidal (23) H-M symbol: (23) |
| Unit cell | a = 9.99 Å; Z = 2 |
| Identification | |
| Color | White to gray |
| Crystal habit | Equant grains and crusts |
| Cleavage | None |
| Fracture | Uneven |
| Mohs scale hardness | 2 |
| |re|er}} | Vitreous |
| Diaphaneity | Transparent to nearly opaque |
| Specific gravity | 2.52 (calculated) |
| Optical properties | Isotropic |
| Refractive index | n = 1.550 |
| Alters to | Readily hygroscopic |
| References | [1][2][3] |
Efremovite is a rare ammonium sulfate mineral with the chemical formula: (NH4)2Mg2(SO4)3. It is a white to gray cubic mineral.[3] This anhydrous sulfate occurs as constituent in sulfate crusts of burning coal dumps. It is hygroscopic and when exposed to humid air it slowly converts to the hydrate form, boussingaultite.[5][6]
It was first described in 1989 for an occurrence in the Chelyabinsk coal basin, Southern Urals, Russia . It was named for Russian geologist Ivan Antonovich Yefremov (1907–1972). It has also been reported from several coal mining areas across Europe.[2] It occurs in association with native sulfur, kladnoite, mascagnite, and boussingaultite.[3]
References
- ↑ Efremovite, Webmineral.com
- ↑ 2.0 2.1 Efremovite, MinDat.org, http://www.mindat.org/show.php?id=1355
- ↑ 3.0 3.1 3.2 Handbook of Mineralogy
- ↑ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine 85 (3): 291–320. doi:10.1180/mgm.2021.43. Bibcode: 2021MinM...85..291W.
- ↑ Chesnokov B. V. and Shcherbakova E. P. 1991: Mineralogiya gorelykh otvalov Chelyabinskogo ugolnogo basseina - opyt mineralogii tekhnogenesa. Nauka, Moscow
- ↑ Jambor J. L. and Grew E. S. 1991: New mineral names. American Mineralogist, 76, pp. 299-305
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