Check your change because you might have a 50 pence piece that’s worth more than 50p. The Royal Mint reckon that the Kew Gardens 50p coin will disappear pretty quickly now that they’ve called it the “rarest coin in general circulation”.

The coin was produced in 2009 to mark the Royal Botanic Gardens 250th anniversary. What makes it rare is that just 210,000 examples were created. Compared to the 22.7million Royal Arms coins produced in 2008, and the 2010 Girlguiding coin, of which 7.5million were produced, this is a very small amount so you shouldn’t be surprised to read that you could get up to £24 for one.

If you find one in your pocket, eBay buyers are looking to take them off your hands. While £24 isn’t a lot of money, it’s far more than the coin’s monetary value. The numbers suggest that one in every 300 people will have a Kew Gardens coin so dig around your wallet or purse to have a look. The Royal Mint is making a big noise about this in an effort to get them out of circulation. A spokesman told us that they’re “urging everyone to check their change to see whether they could have one of these exceptional coins in their pockets.”

The Royal Botanic Gardens pagoda is featured on the coin along with the dates 1759 and 2009. The word “Kew” is also present, so it shouldn’t be too hard to spot among your other silver coins. If you’ve got an uncirculated example in its commemorative plastic box, The London Coin Company are currently offering £54.95 for it through their eBay page.

If you find one of these Kew Gardens coins, holding onto it for a while could be the prudent thing to do as you might find that it’s worth more as the years go by.