Imogolite
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.