X-Ray Powder Diffraction Investigation of the Monumental Stone of the Gastel dell'Ovo, Naples Italy

Abstract

The Castel dell'Ovo on the Bay of Naples, Italy, is an important historic structure dating from the 12th century. It is composed of a soft, volcanic tuff that was employed because it was locally available and easy to quarry and work. The exposed stone of this monument shows extensive decay, principally in the form of the crumbling away of the surface, and this has progressed to the greatest extent in the lower parts of the structure. Restoration and preservative intervention are now being considered. The essential prerequisites to the formulation of a safe and effective strategy of treatment of the monument are the understanding of the nature and properties of the stone, and of the factors responsible for its decay. The present investigation was undertaken to provide that information. In the course of these studies certain novel and significant features of the crystal chemistry of one of the common zeolite minerals have been observed, and are reported here.