The Princess of Wales stunned royal-watchers this week with her spectacular five-ring stack, which includes a priceless piece that originally belonged to the late Princess Diana

The princess stunned onlookers with her jewellery choice

A whirlwind trip to Northern Ireland this week saw the Princess of Wales pleading to be allowed to drive a fire engine through Belfast’s streets “at full speed” complete with blazing lights and howling siren.

Yet, whilst Kate Middleton’s plea was courteously declined, she succeeded in capturing spectators’ focus through a more understated approach – displaying a piece of jewellery valued at more than most people’s properties.

The princess is celebrated for her budget-conscious wardrobe, and she maintained that for her Belfast outing, re-wearing a tailored green Alexander McQueen coat she was first seen in five years ago.

The complete collection, which specialists have estimated to be worth at least $527k (around £393,000) features the stunning 12-carat sapphire engagement ring that previously belonged to the late Princess Diana.

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The princess’s engagement ring is beyond price(Image: Max Mumby/Indigo, Getty Images)

Additional components of the extraordinary ring collection include Kate’s Welsh gold wedding ring, two eternity rings presented by her husband Prince William, and a fifth – currently unidentified – ring seemingly crafted from platinum.

Both of Kate’s eternity bands were reportedly created by high-society jewellers G. Collins and Sons.

Angie Kennedy, vice president of merchandising for luxury jewellery brand Zalles, revealed to Elle Magazine that Kate Middleton’s engagement ring is priceless due to its historical significance: “When Diana selected this ring herself back in 1981, she broke royal tradition-it wasn’t custom-made but chosen from a jeweller’s catalogue.

“That choice was very forward-thinking and in line with what we see brides doing today: picking a ring that reflects their personal taste. The bold Ceylon sapphire centre stone, paired with a halo of diamonds, made coloured gemstones and halo styles highly desirable.”

Kate’s engagement ring has a unique provenance(Image: Max Mumby/Indigo, Getty Images)

The ring was purchased from Royal jewellers Garrard and Co., who currently sell similar items for between £14,000 and £21,000. However, Angie Kennedy believes the value of Kate’s ring far exceeds that.

“Experts estimate the diamonds together weigh about six carats, with each stone close to half a carat,” she said, estimating its value at around $500,000 (£375k), before adding: “Of course, its history and royal connection make Kate’s specific ring truly priceless.”

The worth of Kate’s engagement ring significantly overshadows that of its accompanying eternity rings, which would likely retail for between £3750 and £11,000 each.

Some days Kate leaves her engagement ring at home(Image: Max Mumby/Indigo, Getty Images)

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She wears different jewellery from day to day(Image: YUI MOK, POOL/AFP via Getty Images)

During her appearance at Wimbledon in 2025, the princess was only wearing four of the rings, and she has been known to leave her hefty engagement ring at home on certain occasions as well.

Royal expert Christine Ross, co-host of The Royal Dress Code podcast, revealed to Town and Country Magazine that Princess Catherine appears to be adopting a more relaxed attitude towards her clothing choices following last year’s health battle.

She explained: “While she may have scrutinised and analysed every fashion decision in the past, one could assume that she is funnelling less energy into minute details and more energy into how she feels day to day.

“Some days she feels like wearing a more relaxed stack of rings, and other days she dons the iconic and historic sapphire engagement ring.”