Everything to Know About Kate Middleton's Engagement Ring

Kate Middleton’s engagement ring is arguably one of the most well-known, influential pieces of jewelry of all time. To this day, the Princess of Wales’ royal bauble, a 12-carat sapphire stone encircled with 14 diamonds, is still a source of inspiration for many modern designs. Of course, the striking-yet-timeless appearance definitely contributes to the enduring and widespread popularity of the ring, but the accessory’s rich history and sentimental value are also responsible for its everlasting appeal.

When Kate and her then-fiancé, Prince William, announced their engagement on November 16, 2010, the sparkler was instantly recognized as the same engagement ring that William’s mother, the late Princess Diana, received from Prince Charles (now King Charles III) when he proposed. According to Kate and William’s ITV interview, selecting the heirloom jewel was a way for the couple to keep Diana close to the them.

Yet, the origin story of the diamond-and-sapphire gemstone starts even before both princesses had their turn wearing it. To learn more about the notable rock’s interesting past, in addition to its design features, estimated value, symbolic meaning, and evolution, we've created a complete guide to the Princess of Wales' heirloom gemstone. Ahead, everything you need to know about Kate Middleton’s engagement ring.

The History of Kate Middleton's Engagement Ring

Although Princess Diana was the first one to own and wear the original engagement ring, the inspiration for the diamond-and-sapphire design actually dates back to the 19th century. Learn all about the history of Kate Middleton's bauble below.

1840: The inspiration behind the design was born.

The inspiration behind the royal bauble’s beginnings dates back to 1840: Ahead of his nuptials to his future wife, Queen Victoria, Prince Albert asked British jeweler Garrard to create a special brooch made of diamonds and sapphires for her. Immediately after the former monarch received the gift, it became a staple in her wardrobe. “She found she loved it so much that she decided to wear it on her wedding day as her something blue on the front of her dress," Garrad’s Creative Director Sara Prentice shared with Vogue.

Victoria continued to don the jewel up until her death in 1861, which is when the royal accessory became a crown heirloom—meaning it would always be in the possession of the reigning British monarch. Subsequent British rulers also sported the brooch, including the late Queen Elizabeth II.

1981: Prince Charles picked an engagement ring inspired by the brooch.

Before Prince Charles got down on one knee, he reportedly presented his future wife, Princess Diana, with multiple engagement rings to choose from—one of which was a diamond-and-sapphire ring from Garrard that reminded him of his mother’s brooch. Lady Di ended up selecting the large sapphire because it was allegedly reminiscent of her mother’s engagement ring, but some said she chose the piece because it matched her blue eyes.

The bright blue stone actually broke royal tradition, however. Since the ring was a stock piece in Garrard’s catalog, not a bespoke design like previous royal engagement rings, non-royals could own it—which didn’t go over well with the royal family.

1997: Princess Diana's sons inherited the ring.

After Diana tragically died in 1997, her two sons, Prince William and Prince Harry, inherited their mother's engagement ring. Publications reported that Harry chose the sparkly bauble from Diana's collection, but when William was getting ready to propose to Kate, Harry reportedly gave it to his brother. However, Harry refuted this claim in his memoir, Spare, asserting that William had always been the rightful owner. Yet, Diana's former royal butler, Paul Burrell, confirmed that the original story was true: Harry inherited the ring.

2010: Kate debuted the sparkler.

Regardless of how William got his hands on Diana's engagement ring, he proposed to his girlfriend with the meaningful bauble while they were on a trip in Kenya in 2010. On November 16, 2010, the Princess of Wales debuted the rock for the first time (which perfectly coordinated with her royal blue Issa dress) when the couple announced their engagement at St. James' Palace.

During their interview with ITV, William explained that he proposed with the ring to honor his mother's legacy. “It’s my mother’s engagement ring, so I thought it was quite nice because, obviously, she’s not going to be around to share in any of the fun and excitement of all this,” he said. “This is my way of keeping her sort of close to it all.”

The Details Behind Kate Middleton's Engagement Ring

Kate Middleton's engagement ring is a 12-carat, oval-cut Ceylon blue sapphire from Sri Lanka, surrounded by 14 round-cut solitaire diamonds and set in 18-karat white gold. When Charles proposed to Diana with the original design in 1981, it had an estimated value that fell between $37,500 to $60,000. Now, however, due to inflation and its meaningful history, Kate's ring is said to be worth up to $520,000.

The Symbolism Behind Kate Middleton's Engagement Ring

In addition to its sentimental and monetary value, the gleaming gemstone also has symbolic meaning. Sapphires have long been associated with love, commitment, loyalty, truth, protection, abundance, and good fortune—all qualities that are hallmarks of a successful partnership. Kate’s ring also represents tradition, given its royal history, and remembrance, a way for the couple to feel connected to Diana.

The Evolution of Kate Middleton's Engagement Ring and Growing Ring Stack

Since 2010, the Princess of Wales' engagement ring has gone through some changes, both in terms of its physical appearance and its accompanying accessories. Learn more about its evolution here.

A Different Size

When Kate first slipped the sparkler on her left ring finger, it was reportedly too big, so the couple took it to royal jeweler G. Collins & Sons to get it resized. To fix the loose fit without altering the original design, the jeweler added platinum beads to the inside of the band to retain the initial size.

A Gold Wedding Band

Once Kate and William tied the knot on April 29, 2011, her ring collection grew: In addition to her engagement ring, she also added a thin gold wedding band to her left ring finger, a band that she and William allegedly designed with Bristol jewelry company Wartski. The wedding ring was made of Welsh gold, which was an engagement gift to the couple from Queen Elizabeth.

A Diamond Eternity Band

In 2013, the Princess of Wales' ring stack continued to expand. After she gave birth to Prince William, the couple's first son, William gave his wife a white gold and diamond eternity band from Annoushka as a gift.

A Promise Ring

Another bauble of Kate's came to the public's attention following the 2024 Paris Olympic Games. In a congratulatory video to Team Britain, which the royal couple shared on social media, Kate donned another ring: the promise ring that Prince William gave her while dating. The accessory features each of the couple's respective birthstones, garnet and pearl, and is set on a rose gold Victorian-inspired band.

A Sapphire-and-Diamond Eternity Band

When Kate announced the end of her chemotherapy treatment in September 2024, following news of her cancer diagnosis in March 2024, she uploaded a video where another rock appeared on her left hand. In addition to her normal stack (with the exception of her engagement ring), she included an eternity band made of sapphires and diamonds. The following month, during Kate's first public outing since she finished chemotherapy, she was seen wearing the eternity band once again.