Terra-Sigillata is a slip made of clays whose particles are extremely fine. Like slip or engobe, which it basically is, Terra Sigillata appeals to those who wish to develop an intimate relationship between the surface of their work and its form. Terra-Sigillata becomes an integral part of the clay body rather than coating the surface like a glaze. After the final firing the forms are hand-polished with Tung Oil to achieve a more durable surface. Terra-Sigillata means "sealed earth." The Greeks and Romans used it before the invention of glaze. These are non-functional forms and need to be appreciated and valued only for their being here.