Hectorite
Hectorite | |
---|---|
General | |
Category | Phyllosilicates Smectite |
Formula (repeating unit) | Na0.3(Mg,Li)3Si4O10(OH)2 (empirical: Na3(Mg,Li)30Si40O100(OH)20) |
Strunz classification | 9.EC.45 |
Crystal system | Monoclinic |
Crystal class | Prismatic (2/m) H-M symbol: (2/m) |
Space group | C2/m |
Unit cell | a = 5.25 Å, b = 9.18 Å c = 16 Å; β = 99°; Z = 2 |
Identification | |
Color | White, cream, pale brown, mottled |
Crystal habit | Thin laths and aggregates |
Cleavage | [001] Perfect |
Fracture | Uneven |
Mohs scale hardness | 1 - 2 |
Luster | Earthy to waxy |
Streak | White |
Diaphaneity | Translucent to opaque |
Specific gravity | 2-3 |
Optical properties | Biaxial (-) - 2V small |
Refractive index | nα = 1.490 nβ = 1.500 nγ = 1.520 |
Birefringence | δ = 0.030 |
References | [1][2][3] |
Hectorite is a rare soft, greasy, white clay mineral with a chemical formula of Na0.3(Mg,Li)3Si4O10(OH)2.[1]
Hectorite was first described in 1941 and named for an occurrence in the United States near Hector (in San Bernardino County, California,[3] 30 miles east of Barstow.) Hectorite occurs with bentonite as an alteration product of clinoptilolite from volcanic ash and tuff with a high glass content.[1] Hectorite is also found in the beige/brown clay ghassoul, mined in the Atlas Mountains in Morocco.[4]
Despite its rarity, it is economically viable as the Hector mine sits over a large deposit of the mineral. Hectorite is mostly used in making cosmetics, but has uses in chemical and other industrial applications, and is a mineral source for refined lithium metal.[5]
References
- ^ a b c Handbook of Mineralogy
- ^ Hectorite data on Webmineral
- ^ a b Ralph, Jololyn and Ida (2007): Hectorite on Mindat.org
- ^ Benhammou,, Abdelaziz;; Tanouti,, Boumediene;; Nibou, Lahbib;; Yaacoubi, Abdelrani;; Bonnet, Jean-Pierre (2009). "Mineralogical and Physicochemical Investigation of Mg-Smectite from Jbel Ghassoul, Morocco". Clays and Clay Minerals. 57 (2): 264–270. Bibcode:2009CCM....57..264B. doi:10.1346/CCMN.2009.0570212.
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: CS1 maint: extra punctuation (link) CS1 maint: multiple names: authors list (link) - ^ Moores, Simon (2007) Between a rock and a salt lake; Industrial Minerals, June '07