The Glaze Technology of Hispano-Moresque Ceramic Tiles: A Comparison Between Portuguese and Spanish Collections

For the first time, Hispano-Moresque glazed tiles from Portuguese and Spanish collections were studied together and compared. This work is included in a wider study tackling the technology of Hispano-Moresque tile production from several collections in the Iberian Peninsula. While showing many similarities, differences were identified between collections, regarding both chemical and morphological characteristics. The collection from the Mosteiro de Santa Clara-a-Velha (Coimbra) stands out from the other collections, with higher SnO₂ content (up to 14 wt%), the highest Fe₂O₃ contents in amber glazes and a Ca-rich interface layer (mostly comprised of wollastonite, CaSiO₃). Samples from Palácio Nacional de Sintra (near Lisbon) and Seville-attributed samples (from the Instituto Valencia de Don Juan) are chemically similar, except that most Sintra's samples display a K-rich glaze/ceramic interface, whereas the ones from Seville exhibit both K-rich and Ca-rich inclusions. The samples attributed to Toledo show glazes with many inclusions, contrasting with the homogeneous glazes in most Hispano-Moresque tiles. From these results, we identify differences that can be used as markers in future studies on Hispano-Moresque tiles.