Surface orange patinas on the limestone of the Batalha Monastery (Portugal): characterization and decay patterns

Orange patinas on the limestone of Batalha Monastery, Portugal, exhibit distinct compositions and decay patterns, suggesting diverse formation pathways. Analysis via μ-XRD and LV-SEM+EDS revealed that the ornament's patina primarily consists of gypsum with minor hematite, indicating possible intentional application as a tint plaster mixture of ochre and lime, while the window tracery's patina contains Ca-oxalates (weddellite and whewellite) with minor hematite, likely formed naturally due to atmospheric pollutants or bacterial activity. The ornament shows decay and delamination, whereas the window tracery exhibits granular decohesion without delamination. This study highlights the complexity of patina formation on limestone monuments and their susceptibility to degradation.

Ding, Y., Redol, P., Angelini, E., Mirão, J., & Schiavon, N. (2021). Surface orange patinas on the limestone of the Batalha Monastery (Portugal): characterization and decay patterns. Environmental Science and Pollution Research, 29(20), 29467–29477. https://doi.org/10.1007/s11356-021-15490-1