Craze, Crackle, Crawl
Glaze surfaces may have surface variations which might be seen as a flaw or, if intentional, might be an aesthetic choice. Crawling is when the glaze pulls away from the clay, and beads on the surface, either due to the bisque not being sufficiently cleaned before glazing, or a defect of the glaze composition. Crackle is the intentional development of a network of fine cracks in the glaze, often seen in Raku ware. Crazing is the unintentional forming of cracks in glaze surface, sometimes due to rapid cooling of glazed ware, or a poor fit between clay and glaze. All of these glaze surfaces, whether intentional or not, are not considered food-safe.