Todorokite (Mn,Ca,Mg)Mn3O7.H2O Monoclinic

Description: Todorokite is soft sooty brown, gray to black mineral formed as a result of the alteration of other manganese minerals or as a precipitate from surficial waters.

Todorokite is reported as a component of the small manganese nodules found at various sites in Lake Michigan, particularly in Green Bay. (Rossman, et. al., 1972).