Bowl, Chinese Ceramics, Rijksmuseum.

Iranian potters admired the porcelain imported from China. From the 12th century they began using a new material, quartz paste fritware: white clay ground with fine quartz and glass powder. It allowed them to throw much thinner walls. They were trying to approximate
the translucency of Chinese porcelain. Sometimes, as with this bowl, they made perforations and used a transparent glaze to enhance this effect.