Alkaline Massif of Poços de Caldas, Poços de Caldas (Osamu Utsami mine), Tocantins Province, MG, Brazil.
Genesis: a gray, yellow, or reddish-brown sedimentary rock composed of a mixture of various aluminium oxides and hydroxides (principally gibbsite, böhmite, and diaspore), along with free silica, silt, iron hydroxides, and clay minerals; ...