Assaying and smelting noble metals in sixteenth-century Austria: a comparative analytical study.
Doctoral thesis, UCL (University College London).
This thesis aims primarily at furthering our understanding of the technologies involved in the metallurgy of precious metals during the Renaissance, by combining a critical evaluation of historical texts with the analytical study of contemporary archaeological remains. In particular, this work focuses on high-temperature processes performed in the fire assay and smelting of ores, by investigating two archaeological case studies from sixteenth-century Austria: the small-scale laboratory of Oberstockstall – the most complete Renaissance laboratory ever recovered –, and the contemporary large-scale gold smelting site of the Angertal. The analytical techniques used are optical microscopy, X-ray fluorescence, and scanning electron microscopy-energy and wavelength dispersive spectrometry. In the Oberstockstall laboratory, the study of high-temperature residues produced in triangular crucibles, scorifiers and cupels allows a detailed examination of fire assay practice. The main technical sequence identified is a three-step fusion-scorification-cupellation process, performed on fahlores for their precious metal content, together with a wider range of experimental chymical activities, testing the properties of new materials and illustrating approaches that would prove fundamental in the development of chemistry and modern science. The analyses of metallurgical remains from the contemporary gold smelting site in the Angertal indicate that silver and gold were extracted from a variety of sulphidic minerals characteristic of the regional mineralisation, employing a very standardised technological sequence. Smelting such ores created lead bullion at the bottom of the furnace, which collected most of the noble metals, fayalitic slag on top, and matte in between. The significant gold and silver losses in matte, documented through experimental cupellation of archaeological samples, suggest the possibility of matte being re-smelted, while it demonstrates in practice the links that would have existed between small- and large-scale metallurgical processes. The archaeological and historical contextualisation of these reconstructions, and comparison with contemporary technical treatises, allow a detailed insight into early modern gold and silver extraction and highlight the potential of future work.
|Title:||Assaying and smelting noble metals in sixteenth-century Austria: a comparative analytical study|
|Open access status:||An open access version is available from UCL Discovery|
|UCL classification:||UCL > School of Arts and Social Sciences > Faculty of Social and Historical Sciences > Institute of Archaeology|
Archive Staff Only