A fine-grained stone mainly consisting of quartz sand originating from weathered rocks and then compressed into a compact whole again with the help of small amounts of clay, calcium carbonate, iron oxide or silica. Sandstone is principally found in the hills bordering the Nile valley south of Esna. The most important quarries are those at Silsila where there are inscriptions left by expeditions sent to quarry this stone from the 18th Dynasty on. Sandstone as a building material was already used in the 1st and 2nd Dynasties at Hierakonpolis. A few sandstone temples dating to the Middle Kingdom are also known. It was only after the middle of the 18th Dynasty, however, that sandstone became generally used as a building material, replacing limestone. Almost all of the great temples of Upper Egypt are thus entirely or partly built of sandstone, including parts of the temples of Karnak and Luxor, the Ramesseum, Medinet Habu, the temples of Dendera, Esna, Edfu, etc. Exceptions are the temple of Hatshepsut at Deir el-Bahari and the two temples at Abydos. Sandstone was of course also used to make statues and other objects.