Imogolite

Imogolite
General
Category Clay mineral
Formula
(repeating unit)		 Al2SiO3(OH)4
Strunz classification 9.ED.20
Crystal system Tetragonal
Unknown space group
Identification
Color White, blue, green, brown, black
Crystal habit Conchoidal to earthy masses of microscopic threadlike particles and bundles of fine tubes, each about 20 Å in diameter
Mohs scale hardness 2-3
Luster Vitreous, resinous, waxy
Diaphaneity Transparent to translucent
Specific gravity 2.7
Optical properties Isotropic
Refractive index n=1.47-1.51
References [1][2][3]

Imogolite is an aluminium silicate clay mineral with formula: Al2SiO3(OH)4. It occurs in soils formed from volcanic ash and was first described in 1962 for an occurrence in Uemura, Kumamoto prefecture, Kyushu Region, Japan.[1] Its name is derived from the Japanese imogo for the brownish yellow soil derived from volcanic ash. It occurs with allophane, quartz, cristobalite, gibbsite, vermiculite and limonite.[2]

Further reading

  • Wada, Koji; Yoshinaga, Naganori (January–February 1969). "The structure of "Imogolite"" (PDF). The American Mineralogist. 54: 50–71. Retrieved 13 March 2012.
  • Gabriel, Jean-Christophe P.; Davidson, Patrick (2003). "Mineral Liquid Crystals from Self-Assembly of Anisotropic Nanosystems" (PDF). Top Curr Chem. 226: 126–127. Archived from the original (PDF) on 2011-07-26. |chapter= ignored (help) (Contains structure illustration)

References

  1. 1 2 Imogolite on Mindat.org
  2. 1 2 Handbook of Mineralogy
  3. ↑ Webmineral data
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