-Manganese dioxide exists only below 1080C, above which the dioxide form disassociates to release its oxygen (see MnO for more information).

-Manganese is a colorant using in bodies and glazes, producing blacks, browns, and purples.

-Manganese is a constituent in many igneous rocks, and thus occurs in many clays weathered from these parent rocks. In most cases it is a very minor oxide, but does occur in much greater amounts in some slip and highly stained materials. It is thus a color contributor in many traditional and historic slip glazes.

-Smaller amounts are easily dissolved in most glaze melts, however, around the 5% threshold, the manganese will precipitate and crystallize. In large amounts in a glaze (i.e. 20%), metallic surfaces are likely.

-In glazes below 1080C, it can give coffee color browns when used with tin.