Example of two crawling glazes. Both have magnesium carbonate added to make this happen (around 10%). On the left at cone 04 on a terra cotta body, on the right at cone 6 on a porcelain. Magnesium carbonate also mattes glazes.
A ceramic glaze fault that occurs during firing of the ware, islands of glaze form as it crawls, leaving bare patches of body.
|Materials||Light Magnesium Carbonate|