Kate Middleton was as stylish as ever in a bright red coat from Boden worn over a custom-made peach dress during an official outing Wednesday, but she was missing one key accessory: her engagement ring.
The royal mum is rarely seen without her iconic sapphire and diamond engagement band, which once belonged to Princess Diana. But during a visit with young patients at Great Ormond Street Hospital on Wednesday morning, she was only wearing her simple gold wedding band.
Kate, who was on hand to open the hospital’s Mittal Children’s Medical Centre, which provides accommodation for young patients and their families, left her sparkler behind in adherence with the hospital’s policy on minimal jewellery.
Since she would have to cleanse her hands thoroughly before touring the hospital’s wards and treatment areas, it is recommended to remove jewellery before entering.
Her stunning engagement ring is a sight to behold, consisting of 14 solitaire diamonds surrounding a 12-carat oval blue Ceylon sapphire set in 18-karat white gold. Her gold wedding band, however, which she usually wears along with her engagement ring, is much more simple.
The Welsh gold wedding ring is an 88-year-old royal tradition, dating back to Elizabeth Bowes Lyon and the future George VI. In 1923, the royal ring was fashioned from a gift of Clogau gold with enough left over for the weddings of the Queen in 1947 as well as those of the late Princess Margaret, Princess Anne and Princess Diana. And just before Kate’s royal wedding to Prince William, the palace announced that her wedding ring would also be made of Welsh gold.
This article originally appeared on PEOPLE.