A RARE 50p with a peculiar fault has sold on eBay for almost 300 times its face value.
The 50p sold for £140 last month after 15 bidders jostled to claim it for their own.
The fault means the coin has ultimately been stamped twice, so eagle eyed coin hunters can spot a faint duplicate of the design that appears slightly off centre of the original.
The coin is a 1982 produced copy of the 50p which features the Second Portrait of Queen Elizabeth II on the obverse, and a a figure of Britannia on the reverse.
The coin itself isn't even legal tender anymore as its slightly larger diameter and design was demonetised in 1998 to make way for the modern 50ps we know today.
But that doesn't mean it won't continue to pass through hands today, and if you do come across one in your change, you could also try selling it on to make a mint.
Why is the coin rare?
This particular coin looks the way it does because of a process called machine doubling, explains the seller in the listing's description.
It's what causes the error and usually happens when the coin is being minted.
The Royal Mint manufactures between three million and four million coins a day, so it's common for things to go wrong.
Machine doubling will happen when an aging die reverberates or shifts during the strike, that means the coin gets hit twice and we see that twin or drop shadow-like look on the design - you're not seeing double, it's just a mistake!
Machine doubling is usually isolated to a relatively small number of coins as it's a fault with the mechanism so it won't necessarily affect all coins made from a particular die.
It might only make the error on one coin or a handful.
That's music to the ears of avid collectors though, as the low mintage means the coin is very rare and hard to come by.
That will often mean sellers on auction sites like eBay will hike up the price, or bidders will battle it out to get their hands on the coin, rocketing the value all the while.
Could I make a mint from other rare error coins?
Most error coins are still legal tender so you could easily come across one in your change too and sell it on.
One rare £1 error coin sold on eBay in October for £156, because it was missing a part of the design.
Meanwhile another coin in April sold for £155 because it had upside down writing on its side.
So often the coins, while faulty, will sell for hundreds of pounds and hundreds more than their face value.
If you're thinking of selling one yourself, get an imperfect coin verified by the Royal Mint to help place a value on it.
Online tools from change experts like Coin Hunter are helpful to see how much it could be worth too.
You'll also get an idea if it's legitimate or not as unfortunately there are many fake coins in circulation.
Normally when you're comparing others that have sold on eBay, a good indication it's the real deal is the number of bids on the listing.
The error 50p that we found had 25 bids placed over the 10 days that it was live, so we can see that coin collectors were keen to cash-in.
But remember, a buyer could pull out of the sale which means it won't have sold for the price that it says it has.
Rare coins and valuable notes - is yours worth a mint?
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