Analytical study of an 1899 Peruvian dinero: unveiling the mystery of a coin that wasn’t officially minted

The present paper presents the analytical study of an unusual Peruvian 1899 dinero coin whose authenticity has been questioned since the 1970’s. This coin, which is present in some numismatic collections although there is no record of having been minted officially, has been characterized using non-destructive techniques such as X-ray fluorescence (XRF), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM–EDS), and X-ray diffraction (XRD). Results are consistent with a cast counterfeit coin made at the turn of the 19th and 20th using a copper base alloy that was silver-platted to pass unnoticed among the public. The alloy used, generally known as german silver, was common for counterfeits in North America and Europe in that period. The historical reasons for the appearance of this unexpected coin in Peru during a time of economic difficulties, where the public experienced a shortage of small-change coins, are briefly outlined.