• Kate Middleton doesn’t always wear her famous sapphire and diamond engagement ring, which once belonged to her late mother-in-law, Princess Diana.
  • Prince William proposed with the ring as a way to keep his mother close to it all in 2010; Diana died 13 years prior in 1997.
  • When she opts to not wear her engagement ring, the Princess of Wales wears a stack of eternity rings loaded with sentimentality.

While Kate Middleton has famously worn the heirloom jewelry piece from Princess Diana’s collection—her sapphire and diamond engagement ring—since Prince William proposed in 2010, sometimes she swaps it out for less formal royal engagements.

For the more formal royal occasions—Trooping the Colour, the Commonwealth Day service, and the like—the Princess of Wales will wear her engagement ring that her late mother-in-law once wore. That piece, according to The Daily Mail, is a 12-carat oval blue Ceylon sapphire encircled by 14 solitaire diamonds, designed by the London jeweller Garrard and estimated to cost over $400,000 (up from £28,000 when Prince Charles purchased it for his bride-to-be in 1981).

Kate Middleton and her engagement ring.

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Princess Diana and her engagement ring.

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But for more casual appearances or appearances where she wants her jewelry to be less in-your-face—like a recent Scouts promotional video or for hospital visits—she has lately been opting for a stack of eternity rings “that express her personal style and love for her family,” The Daily Mail reported.

The outlet cited jewelry experts at Steven Stone as estimating the stack to be worth close to £10,000, which translates to $13,530. “Kate’s choice of rings suggests that she values subtlety and meaning over grandeur, while still maintaining an air of elegance and sophistication,” Maxwell Stone told the publication.

Kate Middleton’s eternity ring stack.

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“Though her engagement ring has been seen less frequently, her continued display of commitment to Prince William through her eternity rings speaks to her desire for personal and understated expressions of love,” he added.

While royal jewelry is often heirloom pieces—Kate’s engagement ring being a prime example of this—royal jewelry often reflects tradition, like Kate’s Welsh gold wedding band, which almost all royal brides opt for. But her eternity stack represents “a quiet evolution in royal jewelry, favoring modern, personal symbolism over formality,” The Daily Mail reported.

Kate Middleton wearing her eternity stack in Southport, England on October 10, 2024.

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“The rings showcase her affinity for classic, timeless pieces that reflect her role as both a mother and wife,” Stone said. “They’ve been carefully chosen to be meaningful rather than overtly luxurious, which aligns with her image of grace, modesty, and a strong connection to family.”

Included in the eternity stack is a sapphire and diamond band with an estimated value of $6,359; this Cartier Etincelle band features 19 brilliant-cut diamonds alongside 19 matching sapphires. It was first seen last year and was believed to have been a wedding anniversary gift from William celebrating 13 years of marriage—and given to her at a poignant time, as she had been diagnosed with cancer months prior. (She is now in remission, she announced in January.)

Kate Middleton wearing her eternity ring stack on January 14, 2025 while visiting the Royal Marsden Hospital.

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“The more subtle alternative to her engagement ring, it reflects Kate’s enduring love for sapphire jewelry,” according to The Daily Mail.

The eternity stack also includes a white diamond band estimated at $1,353, which Stone said is “a thoughtfully chosen piece, complementing her other rings while maintaining a refined simplicity.” Also included is a diamond eternity ring with an estimated value of $2,029, given to her by William following the 2013 birth of Prince George. Her Welsh gold wedding band, with an estimated value of $3,112, also makes the stack. It is sourced from the same nugget that brides like Queen Elizabeth’s wedding bands were sourced from.

Kate Middleton wearing her wedding band.
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“Considering the nugget of gold it was made from and the legacy of the lady who wears it, it is likely to be worth a lot more in the coming years,” Stone said.