This small shard is covered with a thick bluish green toned glaze. The first layer of glaze was applied and then the bowl was biscuit fired. This was followed by the application of several layers of glaze before the bowl was again fired in a reducing atmosphere. Varying amounts of iron oxide in the glaze can result in varying tones from blue-green to sea-green. Biscuit fired refers to a process where a ceramic object is fired to temperatures of at least 1000°C to harden the body.