London: Playboy founder Hugh Hefner's ex-fiance has put her engagement ring from Hefner up for sale between USD 20,000 and USD 30,000.

The blonde beauty called off her marriage to the 85-year-old just days before it was due to take place in June, and has since listed her 3.39 carat circular-cut diamond up in market at Christie's auction house in New York, according to reports.

"She couldn't bear to look at the ring anymore because it brought back bad memories," a source said.

The description on the website read, "A diamond ring. Set with a circular-cut diamond, weighing approximately 3.39 carats, to the circular-cut diamond hoop, mounted in platinum."

Hefner who has been married twice previously had let his former fiancee keep the engagement ring, because he doesn't believe she was faking her feelings for him.

"I truly didn't see it coming. I think an argument could be made that she took me for a ride, but I must say, quite frankly, it was a pretty nice ride. If she was faking it, she did it very well. If you're looking for an explanation about Crystal, I don't have a clue. I don't really feel bitterness," Hefner said.