Abstract
The potential of laser-induced breakdown spectroscopy (LIBS) in differentiating between types of genuine and fake Ushabtis was studied. For this goal, the present study was initiated by a comprehensive spectrochemical analytical study of four archeological Ushabti statues, dated back to the late Ptolemaic period (332-330 B.C), which have been excavated south of El-Shawaf pyramid in Saqqara, Giza, Egypt. This study was followed by performing the same investigations on several imitated Ushabtis, which were purchased from the touristic marketplace in the region of the pyramids. For the archeological samples, optimization of LIBS experimental parameters in terms of temporal detection conditions along with laser wavelengths and their corresponding ablation rate was performed. The spectrochemical analyses of the genuine archaeological samples were carried out both superficially and stratigraphically. Main surface elements such as Ca, Na, Al, Si, Cu, Fe, and Mn were detected while large amounts of Ca and Sr represent their bulk elements. The LIBS results were validated by results obtained by SEM-EDX technique, which provided complementary information such as surface morphological images and quantitative composition of the samples' constituents. Under the optimum experimental conditions, LIBS spectral emission of the imitated samples was acquired and compared to those for true archeological ones for the sake of possible discrimination between them. Successful utilization of LIBS in examining the authenticity of suspect Ushabtis has been accomplished and presented. This study may suggest the need for archeologists to be equipped with portable LIBS systems in the excavation sites or museums, which facilitate the immediate discrimination process when LIBS data of genuine samples are initially available. (c) 2019 Elsevier Masson SAS. All rights reserved.