La Pietra di Cusano nell'architettura della Campania: qualità tecniche e prospettive di valorizzazione della risorsa

The present study brings some information on the geological-stratigraphical, mineralogicalpetrographical and physico-mechanical characters of the Pietra di Cusano or Bryozoan and Lithothamnion limestones (BLL), commercially known as Perlato Royal Coreno.The stone crops out over vast areas in central and southern Italy (Campania, Lazio and Abruzzo regions) ad has been widely employed from Roman times (as demonstrated by several findings in the archaeological sites of Minturno, Cassino and Pompei), through the Medieval period (e.g., the bell tower of the Santa Chiara monastery in Naples) to modern times (e.g., the XIX century Bourbon Bridge on the Garigliano river, near Minturno). BLL are appreciated as a valuable building stone today as well (e.g., the Montecassino Abbey, rebuilt in the 1950s).A field survey of the main BLL outcrops allowed a lithostratigraphic reconstruction to be drawn and the eight main lithotypes presently used as dimension stones to be recognized.Mineralogical and petrographical characterization was performed by means of X-ray powder diffraction and fluorescence and optical and electron microscopy.The physico-mechanical characterization was carried out according to the European-suggested standards (UNI EN, Normal) and ISRM suggestions. Ageing tests were also performed.A detailed study on the facades of the bell tower of the Santa Chiara monastery in Naples allowed to recognise the main weathering phenomena involving the stone when used outdoor.