Caratterizzazione e identificazione di alabastri calcarei usati in antico.

Calcareous alabasters from several areas of the ancient world have been frequently used for the manufacture of small precious objects such as vases (alàbastra), statuettes, etc., and for architectural elements. In spite of their importance, alabasters have been seldom studied archaeometrically, so that many problems connected to the accurate identification of many types, especially of those used in Roman times, are still existing. It is for this reason that we have started a systematic research on two alabasters used by the Romans: that of Thyatira (province of Akhisar, Turkey), and that of Iano di Montaione (Florence, Italy). The first may be easily macroscopically confused with the more famous Egyptian alabaster (alabastro cotognino) that is why we tried to differentiate it by using Sr-isotope determination. The second was for the first time characterised by laboratory analyses (OM, XRD, AA, Sr-isotopes) also to check if it was much used in the Renaissance and Baroque times by comparative analyses on archaeological artefacts. In both cases the more interesting and discriminant analysis resulted that of Sr-isotopes. This allows us to distinguish between the alabaster of Thyatira and the Egyptian alabaster, and to confirm that three aryballoi found in Greek Lydian tombs come from Egyptian quarries (whose values vary from 0.7070 to 0.7078), hence, the use of the first limited only to Roman times. The analyses of the alabaster from Iano gave values of Sr varying from 0.70798 to 0.70922. They allowed to establish that a slab facing a wall of the Veronese Capitolium came from that locality, thus proving the use of the alabaster from Iano di Montaione in Roman times.