Panchina Calcarenite: A Building Material from Tuscany Coast

The “Panchina” calcarenite widely outcrops along the Tuscan coastline from Livorno to Baratti (western Tuscany). It is a stone, highly porous with medium sized grains rich in organogenic carbonate fragments, mainly consisting in shells of bivalves, gastropods, and echinoderms visible to the naked eye or by using a lens. In the framework of the ongoing research on the building stones and mortars used throughout the Middle Ages in and surrounding the Pisa’s city (western Tuscany), this study focuses on the determination of the main physical and mechanical properties of “Panchina” stone samples from Livorno coast (Tuscany, Italy). The “Panchina” stone is no longer quarried and data is collected from unweathered rocks sampled from currently accessible outcrops. The data collected on twenty-eight samples from six outcrops of the Tuscan coast showed that the analysed specimens are made up of abundant calcite, subordinate quartz and feldspars, and traces of phyllosilicates. The analysed samples are characterized by medium-high porosity, highly variable water absorption by both capillarity and total immersion at atmospheric pressure, low uniaxial compressive resistance. Thanks to the good physical and mechanical properties that characterize the stone, the “Panchina” calcarenite is easy to work and extensively used in the necropolis of the Gulf of Baratti since Etruscan times and, in medieval times, in various public and religious buildings in the city of Pisa.