The PietraAlberese is a marly limestone belonging to the Ligurian series (Monte Morello Formation of Eocene age). It is a material rarely mentioned in the historical Florentine architecture because the Pietraforte, the stone of the Medieval Florence and the Pietra Serena, the stone of the Renaissance, were the main lithotypes commonly used in those periods. Nevertheless, the Pietra Alberese has been widely utilized to build the town, because it is the only limestone cropping out in this part of Tuscany allowing the production of lime. In Prato and Pistoia, the Pietra Alberese was also used as stone (e.g., ashlars) in the structures and façades of many public and religious buildings. In this work, the geological setting and a mineralogical, petrographic and physical characterization of Pietra Alberese used as building stone are proposed together with a discussion about its durability. Moreover, the different compositional and macroscopic characteristics of two lithotypes (namely the sasso alberese and sasso porcino) utilized to produce the two types of lime used in the local traditional architecture (calcina dolce and calcina forte) are highlighted.

Elena Pecchioni, Fabio Fratini, Enrico Pandeli, Emma Cantisani, and Silvia Vettori . Episodes 1999;0:. https://doi.org/10.18814/epiiugs/2020/020087

Red stains are a common discolouration on stone cultural heritage all over the world.

After the cleaning procedures carried out during a recent restoration work, the Matera Cathedral’s (UNESCO World Heritage Site) façade needed the application of a water repellent treatment. Aqueous emulsions of silanes/siloxanes, also in a mixture with acrylic polymer and an alkyl/alkoxysilanic resin (by BEL CHIMICA S.r.l. and PHASE restauro S.r.l), have been tested as representative of the most used formulations in the restoration of buildings in Italy, especially in the last decade. This paper focuses on the best practices to be adopted for the identification of the suitable protective product in terms of effectiveness, harmfulness and durability, in particular respect to photo-aging and thermo-hygrometrical aging. The conservation materials have been tested in situ and in laboratory on a stone block expressly extracted from the monument. The chemical composition of the products and their degradation processes were characterized by means of FT-IR and PY-GC-MS. The performance of the treatments was evaluated, both in laboratory by permeability, color and capillarity measurements and in situ by non-destructive techniques (IR reflectance spectroscopy, color measurements, water absorption tests by contact sponge). Silane/siloxane emulsion presented more pronounced degradation phenomena after artificial aging, while the mixture of silanes/siloxanes and acrylic polymers decreased the permeability to water vapour.