Emerald Greville Tiara

Summary
It was never seen in public, not in a single painting, nor photograph, until the 12th of October, 2018. Princess Eugenie of York wore it as a bride to wed her longtime, and only ever, boyfriend, Jack Brooksbank, at St. George's Chapel, Windsor. But for 75 years it sat in the mysterious vaults of the British monarchy. The wealthy Mrs. Greville commissioned it from Boucheron, the Paris jewellers, in 1919. She died in 1942 and, though her Will bequeathed it to Queen Elizabeth, later the Queen Mother, that queen never wore it. (Apparently, she wore other emeralds inherited from the Greville bounty.) Nor did the next owner, Elizabeth II, after inheriting it from the Queen Mother in 2002. The kokoshnik-style tiara is thought to be worth £10 million.