Hectorite
Hectorite is a rare soft, greasy, white clay mineral with a chemical formula of Na
0.3(Mg,Li)
3Si
4O
10(OH)
2.[1]
| 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 | 9.EC.45 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| 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 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] A large deposit of hectorite is also found at the Thacker Pass lithium deposit, located within the McDermitt Caldera in Nevada. The Thacker Pass lithium deposit could be a significant source of lithium.[5]
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.[6]
See also
- Classification of minerals
- List of minerals
- Saponite – Trioctahedral (Mg2+, Fe2+) calcium smectite, phyllosilicate mineral
References
- Anthony JW, Bideaux RA, Bladh KW, et al. (1995). "Hectorite" (PDF). Handbook of mineralogy. Tucson, Ariz.: Mineral Data Publishing. ISBN 9780962209734. OCLC 20759166.
- "Hectorite Mineral Data". webmineral.com. Retrieved 3 Apr 2019.
- Jololyn R (2007). "Hectorite: Mineral information, data and localities". www.mindat.org. Retrieved 3 Apr 2019.
- Benhammou A, Tanouti B, Nibou L, et al. (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.
- Bradley, Dwight C.; Stillings, Lisa L.; Jaskula, Brian W.; Munk, LeeAnn; McCauley, Andrew D. (2017). Lithium, Chapter K of Critical Mineral Resources of the United States—Economic and Environmental Geology and Prospects for Future Supply (PDF) (Report). United States Geological Survey.
- Moores S (2007). "Between a rock and a salt lake". Industrial Minerals. 477: 58–69.