Five-day countdown towards end of the year, five #bestof2017 in jewellery...
Who would have known that car boot sale is the best place to find the surprise diamond. The 26.27 carat diamond ring now named "Tenner" was originally purchased in the 1980s from a car boot sale.
The owner assumed it was merely a costume jewel, had no idea of its value and bought this cushion-shaped jewel for £10 in the 80s. This assumed costume jewel was then sold via Sotheby's for £656,750.
Watch how this beau sold in just about two minutes
Video taken by Tsai x Tsai founder Patricia Tsai who was at the auction when the hammer came down this June.