New evidence about the use of serpentinite in the Minoan architecture. A ?-Raman based study of the “House of the High Priest” drain in Knossos

Serpentinites have been widely used as a raw material in a huge repertoire of shapes during the Minoan period, for the construction of artifacts both for domestic use as well as for religious purposes. However, the utilization of serpentinites is extremely limited in the Minoan palatial architecture. In all the cases where the use of serpentinite is documented, it has been for the construction of column bases. The aim of this study is the investigation of the material used for the construction of the drain located under the stair leading to the adyton (sanctuary) of the “House of the High Priest” one of the peripheral monuments of the Palace of Knossos.

Despite the fact that Sir A. Evans documented the stone drain and described the raw material as stone, no further comments were made regarding the exact type of stone used by the Minoans. Furthermore, the fact that a rather unusual material was used for the construction of a drain instead of a more typical material such as limestone or sandstone, enhances the ill-defined and controversial character of the “House of the High Priest”.

The initial mineralogical characterization of the drain material was carried out by means of X-ray powder Diffraction leading to the identification of several minerals and polymorphs. Further examination of the sample in terms of microstructural and chemical analysis of the different inclusions was implemented by means of confocal ?-Raman spectroscopy. Within the concept of this study emphasis is given to the application of this nondestructive and noninvasive technique that can be applied in situ for the analysis and characterization of objects of archaeological significance made out of serpentinite minerals, where often sample acquisition is not possible.

The choice of Raman spectroscopy as the main non-destructive analytical tool consists a strategic decision for two main reasons: (a) There are several other architectural elements implemented in the Minoan palatial architecture allegedly made out of serpentinite that macroscopically bear different characteristics and have to be examined, and (b) the majority of the Minoan stone vases corpus is consisted of artifacts made out of serpentinite but in both cases sampling is not possible. Lastly, the correlation of the data acquired from the analysis of the serpentinite outcrops on the island of Crete, with those from the archaeological objects might augment the development of knowledge regarding the cultural networks among the agricultural areas, where the serpentinite sources are located towards the centers of the Minoan civilization.