COLEMANITE

A naturally occurring insoluble source of boron in glazes.

A powerful primary or secondary flux, it intensifies the effect of colouring oxides and increases craze resistance of glazes.

Formula: 43.9% B2O3, 26% CaO, 4.5% SiO2

Acts as a powerful flux it can intensify the effect of colouring oxides and can increase craze resistance in glazes.

Screen out any materials coarser than 200s mesh, or ball mill the glaze.