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Lecture held by Elise Morero, OxfordThe Fatimid caliphs of the 10th- to 12th-century C.E. are well known for their patronage of luxury arts, especially carved rock crystal vessels, although the manufacturing techniques employed in their production remain largely unknown. The processes of Fatimid rock crystal carving were investigated using a multidisciplinary method based largely on: the observation at various scales of the manufacturing traces on the surface of the objects; tribological analysis; the analysis of archaeological and ethnographic data; and also experimental reconstructions of ancient techniques.These complementary methods enabled us to identify the techniques and tool-kit used by Fatimid craftsmen. The hardness of rock crystal (Mohs scale 7.0), together with its homogenous crystalline structure, makes the use of percussive tools inefficient. Instead, the crystal must be ground away using an abrasive powder and a lubricant. The mixture was carried to the surface of the crystal using different tools put in motion by a horizontal bow-lathe. It was determined that a particularly famous group of seven ewers was produced by a few specialised workshops, probably located at Fustat (Old Cairo), in about the year 1000 C.E. 11 Lecture held during the conference "Gemstones in the first Millennium AD. Mines, Trade, Workshops and Symbolism." October 21st, 2015 at the Roemisch-Germanisches Zentralmuseum, Mainz (Germany).Foto: Fatimid rock crystal ewer (Francis Mills ewer – Keir Collection, Dallas Museum of Art)