Common opacifier, often used in place of the more expensive tin oxide. Sold as Opax, Superpax, Ultrox, etc., use 7% in a slip and 10 to 12% in a clear glaze to get pure opaque white. Zirconium particles are extremely refractory and remain as inert inclusions in the glaze-melt. They will not affect mattness or gloss, but will increase viscosity. Source: Clay: A Studio Handbook


Back to Glossary