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Hectorite

Hectorite
Hectorite from California
General
Category	Mineral
Chemical formula	Na_0.4Mg_2.7Li_0.3Si₄O₁₀(OH)₂
Identification
Color	White
Crystal habit	Thin laths and aggregates
Crystal system	Monoclinic
Cleavage	[001] Perfect
Fracture	Uneven
Mohs Scale hardness	1 - 2
Luster	Earthy (dull)
Refractive index	nα = 1.490 nβ = 1.500 nγ = 1.520
Optical Properties	Biaxial - 2V small
Birefringence	δ = 0.030 max.
Pleochroism	Colorless
Streak	White
Specific gravity	2-3 (Avg 2.5)
Diaphaneity	Translucent to Opaque
References	^[1]^[2]^[3]

Hectorite is a soft, greasy clay mineral that forms near Hector, California (in San Bernardino County). The mineral is rare in that it is found primarily in one mine. The chemical composition of hectorite includes: sodium, lithium, magnesium, silicon, hydrogen and oxygen. Hectorite is mostly used in the manufacturing of cosmetics, but has uses in chemical and other industrial applications.

Additional recommended knowledge

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Hectorite occurs with bentonite as an alteration product of clinoptilolite from volcanic ash and tuff with a high glass content.^[1]

References

^ ^a ^b http://rruff.geo.arizona.edu/doclib/hom/hectorite.pdf Handbook of Mineralogy
^ "Hectorite Mineral Data" Mineralology Database.
^ Ralph, Jololyn and Ida (2007): "Hectorite" Mineral information and data. Mineralology Database. http://www.mindat.org/min-1841.html