This coin is one item from a collection built up by a detectorist. Alan Hewitt was thinking about buying the collection but he asked for my opinion on a coin, as he thought it could be a forgery.
The coin about which Alan was suspicious is illustrated here and is supposed to be a penny of Coenwulf, who was King of Mercia from AD 796 to 821. On the obverse is a diademed bust facing right and a legend reading +COENVVLF REX M. Within the inner circle on the reverse is a cross pommee with wedges in the angles and the legend on this side reads +EABA MONETA. Pennies of this type were struck at Canterbury between AD 805 and 810 and are listed as number 344 in J. J. North’s English Hammered Coinage.
Both sides of the coin are blurred and the surface is porous, so this is definitely a cast copy of Coenwulf penny. As a cast copy this ‘coin’ would be of minimal value.
There are two main reasons why you should never let someone make a mould of one your finds:
1. Damaging the original coin
Most moulds are made from a two-part substance, which is initially soft but hardens fairly quickly. Whilst the substance is still soft a coin or artefact is pressed half way into it, together with channels to let metal in and let air out. When it has hardened up more substance is placed on top and allowed to harden. The two part mould is then separated, the coin or artefact and the material that has formed channels removed, and the mould is then ready to start producing things. When pressing something into the first part of a mould a delicate item can easily break.
I remember seeing an extremely rare Scottish coin soon after it was found. The next time I saw it the edge was badly chipped. It turned out that the coin had been damaged whilst a mould was being made of it.
2. Devaluing the original coin
Reason number two why you should never let a con or artefact be reproduced relates to another extremely rare coin. The finder of this rarity had agreed with a leading London dealer a price of £1,000. However, just as the deal was being finalised the finder happened to mention that some copies had been made. On hearing this the dealer immediately withdrew the offer. You might ask why this happened. Well, if I was buying a rare coin I would not like to think that there were copies of it readily available on the internet.
Call them reproductions, copies, forgeries, clones or whatever you kike but at the end of the day they are not the real thing. The best place for them is a melting pot.