The historical glazed tiles from Nossa Senhora da Soledade Cemetery, Northern Brazil: microstructural, physical and mineralogical characterization

Abstract During the nineteenth century, historical glazed tiles were used in the mortuary architecture of Nossa Senhora da Soledade Cemetery, in Belém. These ceramic pieces are an extraordinary part of Brazilian cultural heritage but are at a high deterioration stage due to conditions to which they are subjected. The aim of this research was the microstructural, physical and mineralogical characterization of glazed tiles from Nossa Senhora da Soledade Cemetery. The samples consisted of Portuguese fragments from the nineteenth century, decorated by stamping. The characterization was performed by optical microscopy, scanning electron microscopy with energy dispersive spectroscopy, water absorption test, and X-ray diffractometry. The results indicated that glazed and ceramic layers have manufacturing defects and a heterogeneous character due to the handmade production process. The porosities vary from 13.3% to 22.9%. The ceramics are composed of quartz, gehlenite, calcite, rutile, cristobalite, diopside, anorthite, hematite and wollastonite. According to the results, despite many similarities (country of origin, century of production, decorative technique), the samples have variations in their microstructure and mineralogy. Information regarding the compositions of the tiles and their variation is important to support future restorative interventions.