About 30+ years ago, some poor sap in London made a very, very foolish move by accidentally hocking a 26-carat diamond ring out of the back of his car at a boot sale (think of it as a marketplace where people sell their personal stuff from their vehicles).

The diamond, which was originally sold for the 1980s pound equivalent of $13, is actually worth up to 35,000+ times that, as it was recently valued at anywhere from $325,000 to $456,000. The current owner of this precious stone, who has wisely chosen to remain anonymous, says that she just bought it thinking it was costume jewelry.

The non-anonymous Jessica Wyndham, who's heading up the auction house where the ring will be sold, and has likely inspected boatloads of worthless crap from optimistic vendors, was understandably shocked at the discovery. "This is an extremely rare find," she said. "We're used to people coming in with pieces from their personal collections but this was exceptional."

Wyndham told CNN that the diamond's sparkle was likely obfuscated, so we guess if the original seller's still alive then they can feel a little less dumb. "When we think of diamonds, we think of modern cuts, of brilliance," she said. "This wouldn't have looked like that. The silver had tarnished and there was probably some dirt. These diamonds were made for candlelight, not our white artificial light, so it was all about trying to bring out its fire."

The ring is set to be sold at a Sotheby's auction 15 days down the road on June 7. If you've got deep pockets it could be a romantic gift to get *looks up June holidays* your old man for Father's Day.