Britain's Duchess Catherine's engagement ring has increased over tenfold in value.
The 32-year-old royal's 12-carat blue sapphire ring, which was handed down from the late Princess Diana, is estimated to be worth a whopping £272,000 more than it was when Catherine wed Prince William in April 2011 at London's Westminster Abbey.
The precious jewel was first given to the Princess of Wales by Prince Charles in 1981 after he purchased it for £28,000, but is now valued at a staggering £300,000.
The heirloom - which also boasts 14 diamonds encircling the sapphire - is worth three times more than the Queen's own engagement ring, which came in second place on a list of the world's top 20 most famous rings, ranked according to how much their value has increased.
Vashi Dominguez, the ITV 'This Morning' jewellery expert who compiled the list, commented: "The Duchess of Cambridge's ring has appreciated more quickly than any other ring in the list.
'It's Kate's style icon status that makes the ring so special."
The second most expensive of the royals' rings actually belongs to the Duchess of Cornwall, Prince Charles' second wife.
The Art Deco bling, valued at £100,000 at the time of their 2004 wedding, is worth £250,000 today and placed ninth on the list.
As for Queen Elizabeth's three-carat diamond solitaire engagement ring, it has increased in value from £10,000 to £100,000 since Prince Philip got down on one knee in 1947.
Tagged in Princess Diana Prince William Duchess Catherine