The Cartier Halo tiara, which was loaned to Princess Kate from Queen Elizabeth II, will be on display at the National Gallery of Australia from March 30 through July 22 — meaning it won’t be available for Markle and Prince Harry‘s May 19 nuptials.
According to the official website for the jewelry show, titled “Cartier: The Exhibition,” the Cartier Halo tiara will be one of 300 tiaras, necklaces, brooches and earrings featured. The piece is on loan from the Royal Collection Trust and the Queen, who received the tiara as an 18th birthday gift from her mother (the Queen Mother herself was given the tiara by Elizabeth’s father King George VI in 1936).
Other items in the collection include Dame Nellie Melba’s diamond stomacher brooch, Princess Grace of Monaco’s 10.48-carat diamond engagement ring, and Dame Elizabeth Taylor’s diamond and ruby necklace.
So what tiara will Markle be wearing instead?
Leslie Field, author of The Queen’s Jewels: The Personal Collection of Elizabeth II, told PEOPLE she thinks Markle will try something new.
“I don’t think it will be a traditional diamond tiara but it could be one loaned to her by the Queen,” she said. “My feeling is that Meghan and Harry have a new way of working events.
“It wont be a traditional headdress, meaning a diamond tiara,” she added. “It may be that it is a headdress as opposed to a tiara. It could be her American heritage and could be made with fabric flowers, set with fake jewels.”
“I’m sure she will go for something that is true to her style and I’m sure it is going to be refined and elegant,” Eva Hartling, vice president of Maison Birks, Meghan’s go-to jewelry brand, told PEOPLE, adding: “It will probably involve a simple pair of earrings that will bring out her natural beauty, she won’t overdo it.”
Founded in 1879 by silversmith Henry Birks, who was originally from Sheffield in the U.K., the Canadian brand’s heritage is a perfect example in diplomatic dressing for Meghan. And they have their own ties with the British royal family, too. Not only have Queen Elizabeth, Princess Margaret and Princess Grace of Monaco all worn pieces from Birks over the years, but the brand was also granted a Royal Warrant by the Duke of Windsor in 1935. While they no longer hold a royal warrant, Hartling says with pride: “It’s the continuation of a beautiful tradition – we’ve officially come full circle with Meghan so it’s been quite a nice story for the brand.”
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In the end, it’s likely Markle will wear a tiara on loan from the Queen to complete her wedding day look.
Still, Hartling can’t hide her excitement that she just might wear Birks, too. “We would be very happy if she chose to wear Birks and we know she has some nice pieces so we will have to wait and see!”
- With reporting by SIMON PERRY