Stone Chemıcal and Mineralogical Research in Hercules Laboratory, Portugal

Abstract

Created in 2009, the HERCULES Laboratory (HERançaCULtural, Estudos e Salvaguarda / Cultural Heritage Studies and Safeguard) is a research infrastructure form Evora University devoted to the study and valorization of cultural heritage and endogenous natural resources, focusing on the integration of physical and material sciences methodologies and tools in interdisciplinary approaches. HERCULES Lab is based in Évora, a UNESCO World Heritage town, and is supported by both a strong analytic infrastructure. The Lab is currently comprised by a team of 33 PhD researchers from different areas of knowledge, namely chemistry, biochemistry, geology, geochemistry, materials science, conservation science and archaeology/archaeometry enabling a truly interdisciplinary approach and scrolling through multiple paths at the level of research, teaching and dissemination of cultural heritage and natural resources. In this communication, several case studies will be presented with examples on the use of several analytical technics and methods from the biochemistry, inorganic and organic chemistry fields to the preservation and valorization of Cultural Heritage, as testimony of ancient societies. More important, in the last years the HERCULES Laboratory is developing intense research in the chemical and mineralogical characterization of stone materials and in the modelling degradation processes. The process of stone degradation at the world heritage Alcobaça monastery will be presented as an example of multi approach research. The used methodology included optical microscopy, scanning electron microscopy with X-ray microanalysis (SEMEDS) and X-Ray diffraction (XRD) and Raman spectroscopy. The results point out to several deleterious processes and sources and highlight the harmful role of salts as halite and sylvite. More recently, stone research at HERCULES Labis focused in the color of economically important marbles and limestones. This characteristic is a major argument that drives the decision making of architects and the worth of an ornamental stone. Therefore, research is being carried out to understand how the color of each limestone and marble is naturally achieved, the mechanism of color alteration and discoloration and strategies for its mitigation.