Antiques Roadshow viewers were left stunned as a guest was left speechless upon discovering the 'true' value of her inherited gold brooch.

The BBC show, filmed at Ebrington Square in Derry, saw expert Joanna Hardy examining an array of fascinating items brought in by visitors.

One item that particularly caught her eye was a brooch brought in by a woman who had inherited it from her grandmother in 2003.

"There's nothing better to brighten up a rainy day than by bringing me a beautiful brooch", Hardy remarked.

The guest explained: "I inherited it from my grandmother in 2003 when she passed away.

"Gran had had a gold ring, a Roman ring, which had been unfortunately stolen from her house in Dublin in the mid 1960s and she had received some insurance money."

"And, at the time, my mum was in school with a girl called Madeleine Grima.

"So she suggested to Granny that why doesn't she think about perhaps buying a piece of Grima jewellery.

"Granny bought this piece and wore it often and then when she died, she left it to me."

Hardy stated that Grima was a "very important person in the 1960s", often referred to as the "godfather of the modern jewellery world".

"Up until 1960, jewellery had been quite sort of tired, there was no innovation, it was very samey, it was very dull", she said.

Andrew Grima, who joined his father-in-law's workshop HJ and Company in the late 1940s, was inspired by a visit from Brazilian gemstone dealers in the early 1960s.

"These dealers came into the workshop and opened their suitcases to reveal these amazing big rocks from Brazil, all sort of natural stones," explained Hardy.

Grima was struck by the beauty of the raw stones and decided to incorporate them into his designs as they were, rather than cutting them into traditional shapes. This led to the creation of his unique, "free-spirited jewellery designs".

The item under discussion was an exquisite 18-carat yellow gold brooch with platinum down the centre and brilliant-cut diamonds. The back of the piece bore the hallmarks of HJ and Company, dating back to 1965.

Hardy admired the piece, saying: "It is really, really quite stunning. It's very beautiful and it's always such a thrill to be able to see a Grima jewel."

She estimated its auction value at around £5,000 to £7,000, causing a stir among the crowd. The owner of the piece was taken aback, commenting: "OK. Wow."

Hardy concluded: "Well, thank you so much for brightening up this day by bringing me a Grima jewel."

Antiques Roadshow is available to watch on BBC One and BBC iPlayer.