“…During most steps of ancient metallurgy and glass working heat is applied, which can be accompanied by partial evaporation and/or oxidation of some elements, which in turn can induce fractionation. This has been studied in detail for Cu (Asael et al 2007;Mathur et al 2009), Cd (Wombacher et al 2003), Sn (Berger et al 2018), Ni (Ratié et al 2016) and Zn (Mattielli et al 2009) where fractionation occurs and must be accounted for, and for Pb, where fractionation is within the experimental error of the analysis tools used and much smaller than the natural variation within one ore field, hence not influencing provenance issues (Cui, Wu, and Huang 2011). In other metals, such as Fe, the metal phase did not indicate any isotope fractionation relative to the starting material during smelting.…”