It takes a lady with serious tiara hair to pull off one of the biggest sparklers in Britain: the Greville Tiara, which was a favorite of the late Queen Mother and is now worn by her granddaughter-in-law, the Duchess of Cornwall.

The tiara was originally not a royal piece at all. It was made in 1921 by Boucheron — hence it’s often called the “Boucheron Honeycomb Tiara” — for the Hon. Mrs. Greville, a society hostess who was a friend of King George VI and Queen Elizabeth. The piece was constructed using diamonds from jewels already owned by the Grevilles. When Mrs. Greville died in 1942, she left a boatload of jewels to Queen Elizabeth, including this tiara. The tiara originally lacked the diamond clusters that sit atop the piece — those were one of the Queen Mum’s later additions, made possible by Cartier. (In older books on British royal jewels, including Suzy Menkes’s book, you’ll sometimes read that this tiara was an entirely new creation, ordered by the Queen Mother and made with South African diamonds. That’s incorrect; Hugh Roberts’s book offers a correct, updated provenance for the piece.)

Elizabeth’s term as the nation’s queen consort was relatively short; she was widowed at 51, and she lived for another half century afterwards. Even though her daughter was now queen, the Queen Mother continued to conduct a large number of royal engagements, and she still had reason to wear some of her elaborate jewels. She wore the Boucheron tiara up until her death in 2002, when the sparkler was inherited by the current queen.

Elizabeth II has never worn this particular tiara in public, however. In 2005, when Camilla Parker Bowles married Prince Charles, the queen gave her three tiaras as long-term loans, and the Boucheron tiara was among the collection. (The other two, per Hugh Roberts’s The Queen’s Diamonds, are the Delhi Durbar Tiara and the Teck Crescent Tiara.) The Greville Tiara is now frequently sported by the Duchess of Cornwall at white-tie events, including state banquets and the state opening of parliament.

Camilla garnered major public attention when she wore the tiara at a pre-inauguration reception for the new king of the Netherlands, Willem-Alexander, in the spring of 2013. Like the Queen Mum before her, Camilla has made the Greville Tiara something of a signature diadem, wearing it more times than all of her other tiaras combined.