Manganese Dioxide – MnO2 (m.p. 3000oF/1650oF) is a source of MnO in glazes or clay bodies, and is used to develop reds, blues, purples, and black. It is a strong flux (cone 5-10) in glaze and clay bodies when added in large amounts. Available in 200 mesh for glazes and 60/90 mesh for clay bodies.