Pottery represents one of the earliest complex technologies—that of changing a plastic material, clay, into an aplastic material, ceramic, more colloquially known as pottery. In order to produce pottery it is necessary to obtain clay, either from a water course or sometimes by mining, and to process it by adding “opening materials” (“temper”) to improve its working properties, or by removing materials such as calcite. Egyptologists recognize two broad types of clay, that containing silt from the Nile River and the calcareous marl clays obtained from the desert. The clay, or mixture of clay and other materials, is then shaped either by hand-forming, using the potter’s wheel, or by molding. The finished form is then dried. This is the last point at which the potter could rework the material by simply adding water to it. Once dry, the material is fired either in the open or in a kiln. Firing leads to the fusion of the clay platelets, which renders the material aplastic. It is the sherds of this aplastic material that are most commonly encountered in the archaeological record.