We are wondering about the origin of the "yellow colour" of glazed ceramics from Raqqada (Tunisia ; IXth - Xth centuries). The archaeologists gave several hypotheses : presence of antimony, iron or a mixture of lead antimonate and tin. Raqqada is an aghlabide capital based in 876 AD and abandoned in the middle of the XIth century. It is situated 9 km southwest of Kairouan (Tunisia). The archaeological excavations of the site unearthed yellow ceramics, with brown and green decorations. The study of 15 shards by optical absorption spectrometry on the bodies and on the glaze and body together shows that they have similar optical absorption spectra. Moreover, it reveals that the origin of the «yellow colour» of this ceramics is the presence of iron not only in the lead glaze but also in the body. The latter contributes weakly to the yellow colour because of the transparency of the glaze. The analysis by energy-dispersive X-ray confirms the presence of iron in the glaze (2,26 ± 0,73 % Fe2O3) and also in the body (5,27 ± 0,69 % Fe2OA We notice the absence of antimony and tin in detectable contents by the implemented method. Finally, the study by optical absorption spectrometry and energy-dispersive X-ray spectrometry allows to precise the nature of the colouring agents responsible for the green and brown decorations : respectively, as expected, copper Cu2+ and manganese Mn3+.

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Distinction de céramiques glaçurées aghlabides ou fatimides (IX e-XI e siècles, Ifriqiya) par la mise en évidence de différences de texture au niveau de l'interface glaçure-terre cuite

Metallic lustre decoration of glazed ceramics is a very special kind of ornament, because its colours change with the observational conditions. In diffused light, they can be green, brown or ochre–yellow. In specular reflection, they show an associated coloured metallic shine (blue, golden‐yellow or orange). The lustre tiles at the Sidi Oqba Mosque in Kairouan still have no defined origin (possibly Kairouan and/or Mesopotamia). Physicochemical analyses of eight Kairouan lustre tile samples and four Mesopotamian lustre pottery samples show that the Kairouan tiles probably came from Mesopotamia, from a major production centre, possibly Baghdad, Samarra or Basra.

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