Hectorite from California
|Crystal symmetry||Monoclinic prismatic
H-M symbol: (2/m)
Space group: C 2/m
|Unit cell||a = 5.25 Å, b = 9.18 Å, c = 16 Å; β = 99°|
|Color||White, cream, pale brown, mottled|
|Crystal habit||Thin laths and aggregates|
|Mohs scale hardness||1 - 2|
|Luster||Earthy to waxy|
|Diaphaneity||Translucent to opaque|
|Optical properties||Biaxial (-) - 2V small|
|Refractive index||nα = 1.490 nβ = 1.500 nγ = 1.520|
|Birefringence||δ = 0.030|
Hectorite was first described in 1941 and named for an occurrence in the United States near Hector (in San Bernardino County, California, 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. Hectorite is also found in the beige/brown clay ghassoul, mined in the Atlas Mountains in Morocco.
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.
- Handbook of Mineralogy
- Hectorite data on Webmineral
- 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.
- Moores, Simon (2007) Between a rock and a salt lake; Industrial Minerals, June '07
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