An early mortar used in ancient Egypt for limestone construction (Lucas and Harris 1962). The gypsum was burnt and slaked then applied in thin layers between the heavy stones.
Museum of Fine Arts, Boston (2000). [J. Cassar, R. de Angelis]
note: Antonio De Vecchi, Giovanni Fatta, Glossario per rivestimenti ad intonaco, Palermo, Arti Grafiche Siciliane 1992.