halloysite
noun
hal·loy·site
həˈlȯiˌsīt,
haˈ-,
-ˌzīt
plural -s
: a clay mineral Al2Si2O5(OH)4.n H2O occurring in soft white or light-colored masses and in at least two states of hydration n =2, n =4
Word History
Etymology
French, from Omalius d'Halloy †1875 Belgian geologist + French -ite