And history experts now believe that the one-of-a-kind coin may even rewrite the entire history of coinage!
The silver penny dates back 850 years when Britain was under the reign of King Stephen and the country was enduring a traumatic civil war.
History buffs say that the coin was issued by the Earl of Derby in the early 1140s – a time when central authorities were not producing sufficient coinage for the country.
It's believed that the penny was formed at the Earl of Derby's home, Tutbury Castle, near Burton upon Trent.
A Sheffield joiner, who wishes to remain anonymous, found the coin in a Nottingham field back in November. The historical find is due to be auctioned this April in London and is expected to go for a hefty £10,000.
The metal detecting fan was quoted in the Sheffield Telegraph saying: "It still hasn't sunk in – it's the find of a lifetime."
Christopher Webb, head of the coins department at specialist auctioneers Di Noonan Webb added: "This is an extraordinary discovery. It is tremendously exciting."
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