Clay mineral associations in sandstone of Arezzo (Italy): A reliable tool for discrimination in architecture

Some of the sandstone utilized in the monumental Florentine architecture are difficult to recognize; the key to identification is based on the presence of different clay mineral association; this methodology has proved to be a reliable tool in the discrimintaion of the different varieties of sandstones used for monumental buildings and extracted from different quarries. This paper reports the preliminary results of the applications of this study to the sandstone of Arezzo. This sandstones is mineralogically similar to the Florentine Pietra Serena and it was extracted from different outcrops throughout the past centuries. The analyses allowed the recognition of four different clays mineral association characterising several quarrying zones in the Arezzo territory, but the anlyses did not permit the identification of the location of specific ancient quarries, now unfortunately completely destroyed and unrecognisable.