Microelemental characterisation of Aboriginal Australian natural Fe oxide pigments

This manuscript presents the first comprehensive microcharacterisation of Fe oxide minerals used in Aboriginal Australian mineral pigments. The combination of X-ray fluorescence microscopy (XFM) and light microscopy provides a broad characterisation as well as the ability to spatially match visual observation with elemental composition. A novel method for casting pigment samples in a pattern on a slide was used for consistent elemental mapping. Semiquantitative bulk data was also collected and compared to the microscopic and microelemental data. These analyses demonstrate the ability to document the variability in ochre pigments in Australia, as well as which elements drive the variation within and between ochre source locations. The methods developed provide a more comprehensive understanding of other complex natural mineral pigments worldwide.