A ring originally bought for $13 in the 1980s sold for more than $800,000 at Sotheby's Fine Jewels auction Wednesday, June 7 in London, England.

The auction writes on its website that the ring was originally purchased at a car boot sale "under the assumption it was a decorative costume jewel."

"It was only in the past few months that the owner decided to see if the ring had any value and asked Sotheby's to appraise it," the sale report reads.

"Much to the owner's surprise, the ring turned out to be a genuine cushion-shaped diamond weighing 26.29 carats with an attractive colour grade of I and impressive clarity grade of VVS2"

The seller of the ring asked to remain anonymous through the auction process. CNN reports after seeking out an appraisal, the ring was identified as a "cushion-shaped diamond set in a 19th century mount."

On Monday, the ring was estimated to be worth between $325,000 and $456,000, so the sale of $847,667 was quite the jump in value. The head of Sotheby's jewelry department, Jessica Wyndham, told CNN that the ring's value was surprising because its mount and cut are unrecognizable to modern jewelry wearers.