A black powder which gives red, brown, purple or black tones to clay bodies and glazes. A strong flux when added in large amounts to clay bodies. In ceramics, it is used primarily in clay and glaze to achieve dark brown or black fired speckle. This is the same material as manganese dioxide powder, it is simply not ground as fine.Typically a 60-80 mesh material is used in amounts around 0.2-0.3%.