nontronite
noun
non·tron·ite
ˈnän‧trəˌnīt
plural -s
: a pale yellow or greenish clay mineral that consists chiefly of hydrous iron silicate and is classed as montmorillonite in which iron has replaced more or less of the aluminum
Word History
Etymology
French nontronite, from Nontron, town in southwest France + French -ite