Magnesium Carbonate

Available from Seattle Pottery Supply when we last checked. Sold from the shop’s own store; the price there is the one that counts.

Magnesium Carbonate (MgCO₃) is a white, powdery material used in ceramics as a flux and matting agent in glazes. During firing, it decomposes to release carbon dioxide, which can create matte surfaces, textured finishes, or crawling effects in glazes. It is particularly useful for controlling glaze flow and adding subtle surface texture. Magnesium Carbonate can be irritating if inhaled as dust. Always wear a dust mask or respirator and work in a well-ventilated area. Learn more about Magnesium C