Abstract
In this study the authors focus on forgeries of Prague grossi struck under Wenceslaus II. They present a total of five coins which include both low quality fakes as well as almost perfect imitations of genuine Prague grossi and analyze their material composition using two non-destructive analytical techniques, the Energy-dispersive Xray spectroscopy and the hydrostatic assessment of density.
The results of the measurements confirm the assumption that all five are counterfeit coins and further provide information with respect to the production methods of the fakes. In case of one of the coins the material composition analysis indicates a tin-plated lead and in another case the most likely production method included the blanching of a coin flan made from a silver-copper alloy which had the effect of significantly increasing the silver content in the surface layer of the coin.
The most frequent production method confirmed in three of the analyzed coins was the silver-plating of a copper core by amalgamation. An interesting conclusion is drawn for the last of the presented coins which exhibits a striking similarity to untypical Prague grossi from a well known treasure excavated in the Polish city of Krakow.
The studies that have focused on the grossi from this treasure conclude that these are either genuine Prague grossi struck in the royal mint chamber in Kutna Hora (Kuttenberg) after the death of Wenceslaus II or contemporary copies (i.e. not fakes) produced in Poland during the reign of the Polish ruler Vladislav I Lokytek probably after 1306. The material composition analysis of the last coin however yields a different result.
Being one of the fakes produced by silver-plating of a copper core by amalgamation it is more likely a counterfeit rather than a genuine Prague grossi or its contemporary copy.