Secondary phases in historical materials: a microstructural approach for interpreting correct sequences of crystallization

This paper reports on a number of case studies of post-depositional alteration of ceramic materials and concretes, from various environments, for which SEM analysis was crucial for defining the crystallization sequence of secondary phases. More in detail, it focuses on the study of secondary phases formed in some ancient potsherds from both terrestrial (Frattesina – North-Eastern Italy) and lagoon-like environments (Olbia – Sardinia, Italy), and in recent cement conglomerates from a heavily polluted industrial area (Porto Marghera near Venice – North-Eastern Italy).