Sarah Ferguson, the Duchess of York, is the former wife of Prince Andrew, the Queen’s youngest son.
She is also the mother of Princess Beatrice, 29, and Eugenie, 27.
The 58-year-old has a very valuable jewellery collection, courtesy of the Royal Family.
What are her gems worth? Grant Mobley, a gemologist and Director at Pluczenik, one of the world’s leading diamantaires gave Express.co.uk his exclusive evaluation.
The York Diamond Tiara $300,000 (£220,000)
The York Diamond Tiara, given to Sarah Ferguson by the Queen, is one of the few pieces given as a gift and not on loan from Her Majesty.
While Princess Diana and Camilla Parker Bowles wore their family tiaras when the married, Sarah’s was made especially for her courtesy of the Queen.
Grant said: “This picture-perfect classic is made entirely out of diamonds set in platinum with floral scrollwork and a large diamond of around 5 carats sitting on top.
“The value of such a piece is not easy to calculate without knowing details about the diamond sizes, qualities, and also the weight of the platinum.
“That being said, with the value of a top quality 5 carat stone like this tiara topper combined with the platinum and other diamonds, the value of this tiara would easily be more than $300,000 USD today. I am certain that whatever the Queen paid for this beautiful piece in 1986 is far less than the value today because of how significantly the value of diamonds and platinum have appreciated over the years, and continue to do so.”
Sarah Ferguson’s engagement ring $100,000 (£73,300)
Grant claims this unusual engagement ring would easily fetch tens of thousands of pounds.
The expert said: “This engagement ring features an unconventional and rare Burmese Ruby centre stone surrounded by a halo of 10 beautiful white diamonds in a classic yellow gold setting.
“The red centre stone was chosen to compliment her red hair and today would be worth upwards of $100,000 USD because of the colour and quality of a ruby of this size.
“As with all jewellery in the Royal collection, the true value would be even more considering its rich history.”
The York Diamond Demi-Parure $500,000 (£366,600)
This stunning demi-parure consists of a matching necklace, bracelet and pair of earrings.
Grant said: “The York Diamond Demi-Parure has a famously interesting story behind it. On a trip in 1996, this set was mistakenly put into a piece of checked luggage and was stolen by a baggage handler, which was later recovered by the FBI.
“The pieces are set in platinum with dazzling white diamonds.”
Grant explained the design of the jewellery is timeless and would not look out of place on the Hollywood red carpet today.
He added: “The necklace has stations of large diamonds surrounded by smaller diamonds in a floral pattern and hugs the neck. “Along with the perfectly matched bracelet and earrings, this is a stand out set in the Royal collection.
“The value is estimated at $500,000 USD, but because it belongs to the Royal collection the resale value is exponentially greater.”
Does Sarah still wear her engagement ring from Prince Andrew?
The pair had their wedding in 1986 but divorced 10 years later.