According to written accounts confirmed by archaeological finds, imported Chinese ceramics were widely available throughout the Abbasid period (749–1055). Potters in Iraq and Iran imitated Chinese white stoneware by covering their 9th–10th century buff or red earthenware with white slip. During the 12th–14th century, potters in Iran rediscovered or revived an ancient Egyptian process of making a ceramic body predominantly of silica-rich quartz rather than clay as used in China. This material, called fritware or stonepaste, produced a harder and more durable ceramic body compared to the earthenwares. Slip continued to be used as a ground which was decorated with underglaze painted motifs—usually blue or black. Arabic inscriptions remained popular choices for ornament. Patterns imitating script (13) also persisted. As Dr. Richard Ettinghausen noted, “...inscriptions ...more often observed and admired than read... [had] a symbolic function, asserting the power and rectitude of Islam simply by their presence.”