An Antiques Roadshow guest was left stunned to learn the true value of her item. The lady appeared on the American version of the BBC show, as she took a family heirloom to be evaluated by an antiques expert.

She had inherited a diamond ring from her mother, and while the guest said that the sparkler was evaluated once in 1973 and given a value of $20,500 (£15,100), she added that she had no idea what it was worth today. She explained to the show hosts: "This was my mother's ring from her second marriage. I think it was around 1971 or 1972 is what I'm guessing, probably closer to 1972." The show guest continued as she shared how sentimental the piece was to her mum, who she explained had nicknamed it the "Denning diamond" in a nod to her partner's name.

"This diamond, it stayed on her finger and she refused to take it off," the woman added. "She was very sentimental about it."

The show's jewellery expert, Kaitlin Shinnick, was visibly impressed by the shiny diamond, noting that it was a high-quality emerald cut. She said: "It really shows off the clarity of the stone, and that was one of the first things I noticed about this stone was its incredible clarity, and that means its lack of inclusions, diamonds."

In terms of the size of the jewel, Shinnick deduced that it was approximately five carats. "Again, it's a very, very clean stone, it's a relatively white stone, it's probably about an eye color," she said.

"This has a classic setting for an emerald-cut diamond, which is a four-prong setting, and then at the side are two tapered baguettes, and I know it's platinum."

Leaving the ring owner speechless, the expert then offered a valuation of the piece. She predicted that the clean-cut ring would fetch between $80,000 (£50,000) and $120,000 (£89,000) at auction.

However, due to insurance reasons, Shinnick added that the value of the piece would actually be $140,000 (£103,000).