Cone 6: Opal Lustre is a glossy, semi-opaque glaze that displays variegated shades of blues, greens, and purples. Breaks warm brown over texture. Cone 10: Color flattens, and warm undertones come through. TIP: This glaze is semi-fluid at 3 coats. Additional coats or increased application thickness may result in movement. Can be used in oxidation or reduction firings. Results may vary. The choice of clay body, thickness of application, firing process, and temperature will greatly affect the fired results. Always test your application on your clay body in your kiln environment.