New pXRF Calibration for Emeralds
Back at the beginning of 2024, Agnese took a trip to UCL Institute of Archaeology to prepare pellets of geological reference standards, with varying levels of chromium, vanadium and iron. Rosie and Agnese then spent many hours analysing these standards with hand-held x-ray fluorescence, developing a new calibration suitable for the analysis of emeralds. With the calibration made, the pair then set off to the stores of the Sedgewick Museum of Earth Sciences, to undertake analyses of their full reference collection of emeralds and other Beryl gemstones. These analyses were a success, and will enable us to now create a protocol for evaluating the correlation between the chemical composition and provenance of emeralds, using a non-invasive, fast and portable method. >Next, Agnese will select a subsample to be analysed with LA-ICP-MS, to assess and refine the XRF calibration. In the future, we hope to use this calibration for the analysis of emeralds in Colombia.
