A diamond ring, originally found on sale at a car boot sale and purchased for a mere £10 three decades ago, has now been estimated to reach a sizable £350,000 at auction.
The owner thought that the jewel was a piece of costume jewellery when she first picked it up at West Middlesex Hospital in Isleworth, west London, in the 1980s.
Blissfully unaware that her purchase was, in fact, a 26 carat cushion-shaped white diamond from the 19th century, she happily wore it as day-to-day jewellery for 30 years!
The stone is set to go under the hammer at world-renowned auctioneers Sotheby’s in July.
The head of the auction house’s London jewellery department, Jessica Wyndham, said: “The owner would wear it out shopping, wear it day-to-day. It’s a good-looking ring.
“But it was bought as a costume jewel. No-one had any idea it had any intrinsic value at all. They enjoyed it all this time.
“They’d been to quite a few car boot sales over the years. But they don’t have any history of collecting antiques and they don’t have any history of collecting diamonds. This is a one-off windfall, an amazing find.”
Ms Wyndham said the owner – who has wished to remain anonymous – presumed it was not a genuine gemstone because it was in a “filthy” mount and it did not possess the sparkle that is so often seen from a genuine diamond.
She added that because the older style of diamond cutting was “slightly duller and deeper” than nowadays “it could trick people into thinking it’s not a genuine stone”.
“With an old style of cutting, an antique cushion shape, the light doesn’t reflect back as much as it would from a modern stone cutting. Cutters worked more with the natural shape of the crystal, to conserve as much weight rather than make it as brilliant as possible.”
After about 30 years of wearing the ring, the owners took it to Sotheby’s when a jeweller told them it may be valuable.
“They came in with the idea that it might be real and they had no idea of its value,” Ms Wyndham said.
“We had a look and… got it tested at the Gemological Institute of America.”
She added: “The majority of us can’t even begin to dream of owning a diamond that large.”