Yesterday, Princess Margaretha of Sweden celebrated a major milestone: her eightieth birthday. Expressen reports that her four siblings — King Carl XVI Gustaf, Princess Birgitta, Princess Désirée, and Princess Christina — organized a surprise birthday party for her in Stockholm. But we’re extending the celebrations for her here by marveling at her tiara: the aquamarine kokoshnik that has been worn by generations of Swedish princesses.

It’s said that this tiara originally belonged to Margaretha’s grandmother, Margaret of Connaught. To my knowledge, she was never photographed in the tiara, which also has a coordinating aquamarine and diamond brooch. But Margaret’s collection was absolutely lousy with jewels, so it’s certainly possible that she acquired the piece somewhere along the line. The maker of the tiara is unknown. Both the tiara and the brooch feature absolutely enormous aquamarines;
the tiara places delicate lattice-like diamond elements in between the
large blue stones to form the traditional kokoshnik shape.

We’re all familiar with the tragic story of Margaret of Connaught’s death, which led to the division of her jewels among her children. If this piece was indeed a part of her collection, it was inherited by her eldest son, Gustaf Adolf, who was expected one day to become king. His wife, Princess Sibylla of Saxe-Coburg and Gotha, was possibly the first person to be photographed wearing
the aquamarines. She debuted the tiara at a ball ahead of their civil wedding in Coburg in 1932. Sibylla wore the aquamarines throughout her lifetime, even after the untimely death of her husband in a 1947 plane crash. She was the de facto first lady of Sweden following the death of Queen Louise, and she was regularly bedecked in jewels.