The Sevso Silver treasure, shown above, is the largest ever find of roman silver. It was the subject of much media attention and a large legal dispute when the owner, Lord Northampton, put it to auction in 1990 and three countries immediately claimed rightful ownership. Dr Anna Bennett of the Conservation and Technical Services formally at Birkbeck College (and at that time at the Institute of Archaeology) used evidence from various analytical techniques and diverse science disciplines to show that there were no grounds for these claims. The claims were subsequently rejected by the court in 1993. Together with Marlia Mango, she published her findings in the Journal of Roman Archaeology
PXRD is traditionally a phase identification tool so we concentrated on identifying the mineral assemblages included in the corrosion material adhering to the silver. PXRD patterns of the samples were measured on the Applied Chemical Crystallography's Siemens powder diffractometer. Despite the fact that samples weighed just a few milligrams, the data was of sufficient quality to positively identify 10 phases. Even with the aid of computerized search/matching, this was a very challenging problem to solve.
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