Gold-leaf glass mosaic tesserae (Umayyad)

Gold-leaf tesserae are small glass cubes carrying a leaf of gold (or silver), used to decorate the Great Umayyad Mosque of Damascus and other Umayyad buildings. ³ The mosque was commissioned by al-Walid I in 705/706 and completed by 715, its walls covered inside and out with glass mosaic; the author estimates its mosaics needed about 170 tons of glass. ^{4 3} Tenth-century Arab sources, she notes, say the tesserae and workmen came from the Byzantine empire. ³

Nadine Schibille analysed the gold leaf of tesserae from Damascus (21) and Khirbat al-Minya (9) alongside earlier ones from the Roman villa of Noheda in Spain, St Mary's at Ephesus and Hagia Sophia. ¹ The Damascus and Khirbat al-Minya tesserae contain 77% to 97% gold, considerably less than Byzantine and early Umayyad gold coins of Syria, with more silver. ¹

Platinum and palladium ratios to gold show that the gold of the Damascus, Khirbat al-Minya and Hagia Sophia tesserae came from a common stock different from that of Byzantine and Umayyad coinage, ruling out a direct material link between tesserae gold and the coinage of the sixth to eighth centuries. ² The author suggests craftsmen used unrefined native gold, since tesserae did not need the purity of coin gold and native gold was presumably cheaper. ²