An impure titanium dioxide tan colorant which contains a small amount of iron. Used for its tan color and its ability to give mottled effects to glazes. Blues and oranges are possible in reduction. In ceramic glazes rutile is more often considered a variegator than a colorant. As little as 2% can impart significant effects in stoneware glazes. Its normally used in combination with a wide range of oxides and stain colorants to produce surfaces that are much more visually interesting. Rutile encourages the development of micro-crystals and also contains significant iron content, so its use in combination with other colorants will often muddy the color that they would otherwise have or alter it if they are sensitive to the presence of iron.