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 | |
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. 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.
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