SEM-EDS, EMP, ICP-MS, ICP-OES and XAS at the Cu-K, Fe-Kand Mn-K edge were applied to the study of green, marbled (green and yellow), blue andblackish (deep greyish olive green) glass slabs decorating three sectiliapanels from the archaeological site of Faragola. Results indicate that all slabs were made by mixing siliceous sand with natron, sometimes likely mixed with small percentages of plant ash. Cu2+and Pb antimonates should be responsible for the opaque green colours. The dark green and yellow portions of the marbled slabs are respectively comparable to the slabs comprising only one of these colours. Cu2+together with Ca antimonates likely produced light blue slabs, whereas cobalt was used to produce dark blue ones. We consider it to be possible that the abundance ratio of Fe2+/Fe3+and the complex Fe3+S2-would have an effect on the blackish slabs. The contribution of Mn cannot be ascertained even if it could have played a role in darkening glass colour. The comparison between the chemical composition of Faragola samples and several glass reference groups provided no conclusive evidence of provenance; whereas, the presence of a secondary local workshop can be hypothesised.
THE SECTILIA PANELS OF FARAGOLA (ASCOLI SATRIANO, SOUTHERN ITALY): A MULTI-ANALYTICAL STUDY OF THE GREEN, MARBLED, BLUE AND BLACKISH GLASS SLABS
F D'ACAPITO;
2010
Abstract
SEM-EDS, EMP, ICP-MS, ICP-OES and XAS at the Cu-K, Fe-Kand Mn-K edge were applied to the study of green, marbled (green and yellow), blue andblackish (deep greyish olive green) glass slabs decorating three sectiliapanels from the archaeological site of Faragola. Results indicate that all slabs were made by mixing siliceous sand with natron, sometimes likely mixed with small percentages of plant ash. Cu2+and Pb antimonates should be responsible for the opaque green colours. The dark green and yellow portions of the marbled slabs are respectively comparable to the slabs comprising only one of these colours. Cu2+together with Ca antimonates likely produced light blue slabs, whereas cobalt was used to produce dark blue ones. We consider it to be possible that the abundance ratio of Fe2+/Fe3+and the complex Fe3+S2-would have an effect on the blackish slabs. The contribution of Mn cannot be ascertained even if it could have played a role in darkening glass colour. The comparison between the chemical composition of Faragola samples and several glass reference groups provided no conclusive evidence of provenance; whereas, the presence of a secondary local workshop can be hypothesised.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
