The Royal women follow the etiquette wearing black and white. The State Opening of Parliament used to be a very formal event with tiaras and gowns and big jewels. It was revamped in the 70's, however, the women and men still follow the color code.



https://www.thecourtjeweller.com/2026/09/the-queen-and-princesses-of-sweden-wear-parliamentary-pearls-and-diamonds.html