This ribbed jar excavated at Nishapur speaks to the technical and decorative innovations that transformed pottery production in Iran during the eleventh century. First is the body fabric of the vessel itself. Whereas up to this point an earthenware body was standard for local production, this jar is made primarily of ground quartz with an admixture of clay. Known as fritware or stonepaste, this fabric allowed for a sturdier and whiter body than earthenware. This new fabric in turn led to further developments in shape and decoration. Being especially sturdy, stonepaste allows for vessels with thinner walls and more intricate shapes. The ribbed sides of this jar, for example, had not been common in earthenware before. Stonepaste also allowed the potter to use a new type of glaze that employed alkali (e.g. borax) as a fluxing agent. Alkali-based glazes, such as the fine turquoise glaze on this jar, remain transparent longer than the lead-based glazes used in Nishapur before the introduction of stonepaste.Archaeological evidence suggests that in the Middle East, stonepaste was first made in Egypt and then spread to Syria and Iran where it flourished at multiple centers of production. The excavations at Nishapur uncovered not only many fine examples of stonepaste vessels but also a set of kilns where they were made, proving that it was one of these centers.