Chemical, physical and mineralogical characterisation of the Hispano- Moresque tile collection from Lisbon Roman Theatre Museum

Abstract

This work intends to study a set of Hispano-Moresque tile fragments from the Lisbon Roman Theatre Museum collection. The chemical and morphological characterization of the glazes and the ceramic body was presented and also the mineralogical characterization of the latter. The glazes are plumbic, being the opacity of the white and blue colors due to SnO2 (4-11 %). The other colors present amounts of SnO2 lower than 2 %. The ceramic body is typical of calcite-based pastes with CaO between 16-28 % and Fe2O3 between 4-5 %, the latter being responsible for the cream/ rose color. The mineralogical study identified wollastonite, calcite, diopside and calcic plagioclases. The results indicate that the firing temperature was generally around 1000 ºC while in some cases it was probably closer to 900 ºC. Physical characterization revealed values of 30-42 % for open porosity, a bimodal pore size distribution, a maximum water absorption of 16-26 % and a water absorption coefficient by capillarity of 1,5-6,1 kg·m-2·h-1/2.