Fire-gilding is a historic technique for the application of golden layers on a number of different base materials, identifiable by the Hg content of these layers. Considering recent findings, the previously accepted lower limit for Hg content comes into scrutiny, motivating the development of a new, destruction-free identification method independent of the absolute Hg content. During the course of development, we identified a characteristic Hg profile in fire-gildings on Ag substrates and gathered evidence to further corroborate the accept lower limit.

The dataset was gathered at the BAMline of BESSY II at the Helmholtz-Zentrum Berlin and processed with the AXIL code to give the intensities of the relevant elements in the spectra. [B. Vekemans et al. Analysis of X-ray spectra by iterative least squares (AXIL): New developments. X-Ray Spectrometry 23.6 (1994), pp. 278285.]