The study of stone for conservation purposes: Lecce stone

Lecce stone is a fine bio-calcarenite, widely used in the Salento region (southern Italy) as a constituent material of the large-scale built cultural heritage. This stone is affected by serious deterioration problems, such as alveolization and biological attack. The extensive conservation work carried out over the last few decades has promoted large-scale studies of various aspects related to the stone's characteristics, its resources, and associated decay and conservation problems. The paper reviews the main features of 'Lecce stone', addressing the following points: distribution of the quarries, including quarrying and carving techniques; mineralogical-petrographical and physical-mechanical characteristics of the extracted materials; use of the stone from antiquity until modern times; morphology of decay and, most importantly, decay factors; conservation treatments (products, tools and techniques), with particular reference to case studies of Baroque monuments; and systematic monitoring of monuments treated in the last 20 years. Given the wide spectrum of activities conducted in connection with Lecce monuments, and the stone from which they are built, they may be regarded as a suitable model for the study and management of monumental heritage in terms of its preservation.