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Happy St. Patrick’s Day, everyone! To celebrate, we’ve got a fantastic and unusual piece of royal jewelry to enjoy: the diamond and turquoise shamrock brooch worn by the Duchess of Cornwall.

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The petite brooch features smooth Persian turquoises set in the center of each of the three leaves of a diamond shamrock. A larger diamond sits where the leaves are joined, and another tiny diamond trefoil springs from the stem of the brooch.

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One of Camilla’s most prominent appearances in the brooch came in the autumn of 2014, when she wore the jewel for the funeral of the Dowager Duchess of Devonshire.

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Following that occasion, Arthur, one of the posters at the Royal Jewels of the World Message Board, raised an intriguing possibility: that the brooch could be the diamond and turquoise brooch listed among the Queen’s wedding gifts in 1947. That brooch was a gift from the Dowager Duchess of Portland.

There’s definitely a connection between the Devonshires and the Portlands. The Devonshire dukedom is held by the Cavendish family, while the Portland dukedom was held (until the 1990s) by the Cavendish-Bentinck family. As their surnames suggest, the families are distant cousins: Lady Dorothy Cavendish, daughter of the 4th Duke of Devonshire, married the 3rd Duke of Portland in 1766. The Dowager Duchess of Portland who gave the Queen a turquoise shamrock brooch was the widow of the 6th Duke of Portland. (The 6th Duke also happened to be the first cousin of Nina Cavendish-Bentinck, the Queen’s maternal grandmother.)

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To my knowledge, no official comment has been made on the provenance of the shamrock brooch worn by Camilla. But we know that the fascinating jewel is still in her jewelry box, as she wore it recently (in February 2019) to officially open a remodeled play area at the Barnardo’s WellBeing Hub in Ilford.