A tin-glaze provides a surface to lay a painted decoration on a baked piece of ceramic.
Tin oxide is a colorant that makes glaze opaque, thus enabling it to cover a fired piece of ceramic ( also known as biscuit). It was the interaction between the Islamic world and China around 850 A.D. that led to the development of tin-glaze in Persia, as a result of the the Persians’ desire to imitate white Chinese porcelain. The formula of stannic oxide is SnO2.