Cinnabar: Discovered by Jabir ibn Hayyan.[14] Damascus steel: Damascus blades were first manufactured in the Near East from ingots of Wootz steel that were imported from India.[15] Geared gristmill: Geared gristmills were built in the medieval Near East and North Africa, which were used for grinding grain and other seeds to produce meals.[16] Hydrochloric acid: Discovered by Jabir ibn Hayyan.[8][17] Oud and lute: The Arabic oud in Islamic music was the direct ancestor of the European lute.[18] Paper mill: Scholars have identified paper mills in Abbasid-era Baghdad during 794–795.[19] Sulfur-mercury theory: Precursor of Acid-Base Theory, Discovered by Jabir ibn Hayyan.[20] Tin-glazing: The tin-glazing of ceramics was invented by Muslim[citation needed] potters in 8th-century Basra, Iraq.[21] The oldest fragments found to-date were excavated from the palace of Samarra about 80 kilometres (50 miles) north of Baghdad.[22] Panemone windmill: The earliest recorded windmill design found was Persian in origin, and was invented around the 7th-9th centuries.[23][24]