Inorganic. "Manganic hydroxide, Mn(OH), together with manganese manganite.", "Occurs naturally as manganite but the commercial product is usually synthetic." (Ref Inorganic Colouring Matters, Color Index 3rd Ed.)Manganese hydroxide and oxides, the natural form usually also contains iron oxides and clays. Manganic oxide. Manganic hydroxide. Making pigments: Umbers at webexhibits.org.
Colors by Brand for Manganese Brown
Mixed Colors that use the unique color Manganese Brown: