Glazeless (top) and with glaze (bottom): A1 (bentonitic), A2 (ball clay), A3 (stoneware), 3B (porcelains), 3C (lignitic ball clay), 3D (silt). The bottom row has also shows soluble salts (SOLU test).
|Materials||A1 Ball Clay|
|Materials||A3 Stoneware Clay|
|Materials||A2 Ball Clay|
|Materials||3C White Ball Clay|
A sought-after visual effect that occurs in reduction fired stoneware. Particles of iron pyrite that occur naturally in the clay melt and blossom up through the glaze
A common problem with dry and fired ceramic. It is evident by the presence of a light or dark colored scum on the dry or fired surface.