All colors in the Opalescent Series are LEAD FREE. CL glazes restricted from use K-6 (ASTM D-4236/LHAMA) Although AMACO® Opalescent Glazes may be used on any AMACO® clay, they develop their greatest opalescence and most interesting textures when applied over red clay like ABFE. Most of the AMACO® Opalescent Glazes have a high gloss similar to mother-of-pearl. Best results are achieved with three or four applications of glaze. On textured ware, the glaze flows thin on relief and thick in incised areas, giving an added dimension on the surface. AMACO® Opalescent Glazes can be used very effectively in Raku firing. We suggest controlled experimentation with Opalescent glazes (for example O-42, O-23 at Cone 5, 2205°F, 1207°C). When fired at this temperature on the inside of a stoneware bowl, the glaze flows to produce a variegated bottom and thins at the rim to expose more of the clay body. AMACO® Opalescent Glazes are supplied in liquid, ready-to-use form in pint jars. They are applied on a mature Cone 04 (1971°F, 1077°C) bisque by brushing, dipping, or pouring. On red bisque, these glazes should be applied rather heavily, and a slow rather than fast firing is best. Recommended temperature is Cone 05 (1911°F, 1044°C).