The ornamental stones of Caserta province: the Campanian Ignimbrite in the medieval architecture of Casertavecchia

A detailed mineralogical and petro-physical characterization was carried out on Campanian Ignimbrite (CI) formation, a volcaniclastic rock widespread over the Campania region. This stone represented and still is an important building material since historical times. Given the huge extension of this formation (about 30 000 km 2 ) the attention was mainly focused on the historical exploitation areas that provided building materials for the medieval village of Casertavecchia. Building stones (different facies of CI) used facciavista in some relevant monuments of this village were also characterized to carry out a comparison with the in situ corresponding rock. At the same time a complete survey of all the lithotypes used for the facades of the village as well as their state of conservation and weathering phenomena was also performed. As expected, CI in its different facies resulted the most common building stone, also affected by severe weathering such as lacks, alveolization and biological patinae, decay forms likely related to the high textural heterogeneity of the rock. Mineralogical and petro-physical characterization allowed to distinguish, within the investigated outcrop area, three different facies: dark, light and earthy grey tuff (DGT, LGT and EGT, respectively). Differences in mineralogical data mainly consist in the presence of clay minerals in the EGT facies only. K-feldspar always occurs in very high amounts (80–90%). As far as geomechanical parameters are concerned, the most pronounced differences are recorded in water absorption capacity, ultrasonic velocities and UCS values. These tests evidenced a substantial homogeneity of DGT and LGT facies and an overall worse behavior of EGT. Tests performed on CI samples from both monuments and outcrops gave similar results. This evidence strengthened the former hypothesis of a location of CI historical quarrying sites close to Casertavecchia. The only exception is the tuff used for the Mastio of the castle, whose chemical features are definitely referable to a different volcaniclastic formation. © 2004 Elsevier SAS. All rights reserved.