Figure 3
From: Shedding New Light on Ancient Glass Beads by Synchrotron, SEM-EDS, and Raman Spectroscopy Techniques
Glass samples divided into two groups according to average Fe oxidation state: (a) Group I: BLALL5-1, BLALL5-3, and BLALL5-4, black, show that Fe is found in the form of FeO or Fe2+; and Group II: samples with other colours (yellow, green, and blue) demonstrate that their peaks were all matched with the Fe2O3 or Fe3+ peak (all peaks are shown in Supplementary Information); (b) The plot shows a summary of the average values for the Fe oxidation states plotted against the K-edge energy derived from the experiments, corresponding to the marks in (a). The values were not in integer form, showing that the Fe-atom was affected by the surrounding atoms of other elements. The line shows a linear fit with the reference compounds.
