Hectorite
| Hectorite | |
|---|---|
|
Hectorite from California | |
| General | |
| Category |
Phyllosilicates Smectite |
| Formula (repeating unit) |
Na0.3(Mg,Li)3Si4O10(OH)2 (empirical: Na3(Mg,Li)30Si40O100(OH)20) |
| Strunz classification | 09.EC.45 |
| 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° |
| Identification | |
| Color | White, cream, pale brown, mottled |
| Crystal habit | Thin laths and aggregates |
| Crystal system | Monoclinic |
| 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
- 1 2 3 Handbook of Mineralogy
- ↑ Hectorite data on Webmineral
- 1 2 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