Notice the inside of this large transparent glazed cone 6 stoneware bowl. There is a concentration of specks on one part because that area was sponged at the leather hard and dry stages to smooth surface problems that happened during the jiggering process. These specks are normally driven below the surface during forming.
Jiggering is a process of forming pottery that employs a spinning plaster mold and a tapered template to press soft clay or porcelain against it.
To potters, stonewares are simply high temperature, non-white bodies fired to sufficient density to make functional ware that is strong and durable.
Specking is a fault in fired ceramic ware where speckles of ion bearing contaminants are visible and mar the appearance of the surface.