an off-white, grayish, brown, yellow, or reddish-brown rock composed of a mixture of various amorphous or crystalline hydrous aluminum oxides and aluminum hydroxides (principally gibbsite, some boehmite and diaspore), along with free silica, silt, iron hydroxides, and especially clay minerals, pms alumiiniumhüdroksiididest koosnev punane või pruun kivim, sisaldab lisandina raudoksiide ja -hüdroksiide, savimineraale jm... Boksiit on tähtis alumiiniumimaak, mida tarvitatakse värvide tootmisel, sorbendina, elektrokorundi saamiseks jm.