Sisters inherit rare 1975 dime worth a staggering $500,000 after it was locked away in a bank vault for 40 years

The siblings are now the proud owners of a rare dime (10 US cents), minted by the U.S. Mint in San Francisco in 1975 - a coin which had been locked away in a bank vault for some 40 years.

Three sisters from Ohio are set to receive a staggering financial surprise after discovering the true value of a coin they inherited from their late brother.

The siblings are now the proud owners of a rare dime (10 US cents), minted by the U.S. Mint in San Francisco in 1975 - a coin which had been gathering dust in a bank vault for some 40 years.

That year, the mint issued 2.8 million special uncirculated "proof" sets containing six coins, which retailed at $7 each.

It was only years later that collectors realised two dimes from these sets were missing the 'S' mint mark, making them incredibly rare.

Ian Russell, president of GreatCollections, has indicated that the sisters' dime could command an eye-watering $500,000 (around £384,000) at auction.

The coin, bearing the image of former US President Franklin D. Roosevelt, is especially valuable because of this omission. The other erroneous dime fetched $456,000 (about £350,000) when it went under the hammer five years ago, before later being sold on again to a private collector.

"They were hidden for decades," Russell disclosed to the Independent, noting that most major collectors and dealers have never even laid eyes on one.

He also shared that the sisters, who wish to remain anonymous, revealed their brother and mother acquired the coin back in 1978 for $18,200 - roughly equivalent to $90,000 (around £69,000) today.