Silvia Vettori

Pietra Serena: the stone of the Renaissance

Abstract The most frequently used material in Florentine Renaissance architecture was Pietra Serena, a sandstone that nowadays is found in a quite satisfactory state of conservation. The reason for this is that architects and stone cutters in the past made careful selections of the materials they employed. This conscientious picking out was very important because most sandstone layers have a composition that is not always suitable for assuring an acceptable durability. This paper deals with the mineralogical, chemical, petrographical and physical characteristics of the Pietra Serena sandstone quarried in the hills near Florence in order to verify what was affirmed by Vasari (1568), Tuscan painter, architect and historian of art of the 16th century, and other Tuscan naturalists regarding the quality of this sandstone. As a matter of fact, analyses demonstrate that the Pietra Serena sandstones quarried in the hills of Settignano (to the northeast of Florence) and in the Gonfolina area (Lastra a Signa, to the west of Florence), are composed of layers particularly rich in calcite present mainly as sparitic cement. This calcitic cement gives great durability to the stone as is demonstrated by the good state of conservation of some Florentine monuments realized with Pietra Serena.

Quantitative mapping of clay minerals using airborne imaging spectroscopy: New data on mugello (Italy) from SIM-GA prototypal sensor

Abstract The possibility of using high spectral and spatial resolution remote sensing technologies is becoming increasingly important in the monitoring of soil degradation processes. A high spatial resolution hyperspectral dataset was acquired with the airborne Hyper SIM-GA sensor from Selex Galileo, simultaneously with ground soil spectral signatures and samples collection. A complete mapping procedure was developed using the 2000–2450 nm spectral region, demonstrating that the 2200 absorption band allows the obtainment of reliable maps of the clay content. The correlation achieved between the observed and the predicted values is encouraging for the extensive application of this technique in soil conservation planning and protection actions.

Environmental impact assessment on the stone decay in the archaeological site of Hierapolis (Denizli, Turkey)

The archaeological site of Hierapolis (Denizli province, Turkey) is unique in terms of the conservation of marbles and travertines. Environmental factors (i.e. interaction with thermal waters, high thermal stress, CO2 degassing) and geological aspects (presence of seismic faults, frequent earthquakes, formation of travertine) play a fundamental role in the durability and conservation state of the stone materials. This paper presents a multi-analytical approach aimed to identify the phenomena and causes of stone decay related to environmental conditions. The analyses of alteration and decay phenomena are discussed together with the monitoring of the main environmental parameters and with analyses of waters and gases present in the archaeological site. Finally, the need of a continuous monitoring of the environmental parameters affecting the archaeological site is stressed.

Production of the Roman Cement in Italy: characterization of a raw material used in Tuscany between 19th and 20th century and its comparison with a commercialized French stone material

ABSTRACT An experimental approach in order to investigate the possibility that some Italian limestones were used for the production of Roman Cement is proposed. Three types of Pietra Alberese, a marly limestone used since Roman times for the production of “lime” in Tuscany (Italy), were selected. By burning of these stones, specimens of binders were realized. The characteristics of these binders were compared with the binder obtained by burning a French marly limestone commercially used for the production of Roman Cement. All samples of carbonate stones were preliminarily characterized from the chemical, mineralogical, and petrographic point of view. The colorimetric coordinates were measured on both rock samples and hardened binder samples. The analysis carried out shows that Pietra Alberese with an high content of clay minerals develops a similar microstructure with respect to that developed by the French marly limestone used for the production of Roman Cement.