Abstract:

A total of 13 thresholds composed of one or more blocks of alabaster (calcitic onyx alabaster) survive in situ at Villa A at Oplontis. They decorate the elegantly Second-Style painted rooms, such as atrium (5), triclinium (14), salone (15) and cubiculum (11), as well as (surprisingly) some service areas. The thresholds, which belong to Villa A’s original phase of construction in the middle of the first century BC, arguably represent the most spectacular example of alabaster use to survive from the villas and houses preserved by the eruption on Mt. Vesuvius in AD 79. Visual characteristics – dark beige to light gray with wavy patches and no banding, coarse to very coarse compact crystalline calcite – point to a number of potential sources for the alabaster. Due to the difficulty of positive identification via visual analysis, a total of seven samples from six thresholds have been subjected to laboratory analysis with the aim of determining the source of the stone. This article presents the results of the minero-petrographic (XRD and microscopic study of thin section) and isotopic studies (Sr and Pb isotope analyses by mass spectrometry), conducted by LAMA (Laboratorio di Analisi dei Materiali Antichi) and the Institut für Geologie at the Universität Bern, respectively, that were carried out on the alabaster thresholds of Villa A, Oplontis. While a number of quarry sources can now be ruled out – Egypt, Circeo (province of Latina, Italy), Jano di Montaione (province of Florence, Italy), Castelnuovo dell’Abate (province of Siena, Italy) and Hierapolis (now Pamukkale (province of Denizli in Turkey)) – the actual quarry source still remains uncertain. The results reiterate the need for a thorough investigation and re-examination of the sources of alabaster used in the Roman period in order to provide a comprehensive database of the alabaster quarries that may have been operating during Antiquity.