A few weeks ago GO was asked for an opinion on a few medieval hammered silver coins. One piece was a Henry IV light coinage half groat from 1412. From DG’s book Obv. 1. Rev. 4. A unique coin in the British Museum.
This note presents XRF analysis of the piece along with eight genuine half groats of the same period. The metal is silver, but trace elements always present in genuine medieval hammered silver (typically Gold ranging 0.3-0.5% and Bismuth 0.01-0.05%) were completely absent from the piece in question.
This prompted a much closer inspection that revealed features of the surface that are “not quite right” and eventually traces of where a countermark R had been erased.
The piece has been traced to a group of modern replicas, being sold quite openly and correctly as such with the identifying R countermark. However when the replica is damaged, scratched, has its edge filed, the R erased, and is artificially toned, it becomes a very deceptive and dangerous counterfeit. Pennies of William II and Henry I have also been seen that have received the same treatment and been offered for sale as genuine.
There will be more.
BNS Research Blog 