When a costume ring caught one shopper's eye at flea market, they never imagined it could change their life.
Bought for ten pounds, or around $17, 30 years ago, the stone turned out to be a 26 carat white diamond.
The gem was cut on the 1800s, before diamonds were cut to make the most of their clarity and sparkle, meaning the true value was only recently discovered.
The lucky owner even wore the ring every day believing it to be fake.
London auction house Sotheby's have described it as an 'amazing find' and the jewel is expected to sell for more than $600,000 when it goes under the hammer in July.
Now, that's a bargain!