Tags: Chemical Substance, Mineral.
Nontronite is the iron(III) rich member of the smectite group of clay minerals. Nontronites typically have a chemical composition consisting of more than ~30% Fe2O3 and less than ~12% Al2O3 (ignited basis). Nontronite generally does not exist in economic deposits like montmorillonite although it is not an uncommon clay mineral.
