Among the treasures in the Royal Treasury, Catherine hopes to inherit the Queen Mary Fringe Tiara. First created in 1919 for Queen Mary, the tiara is a favourite of the Queen. She famously wore it on her wedding day to Prince Philip in 1947. The unique French design of the tiara, reminiscent of Russian style, symbolizes continuity and strength in the monarchy. It also made a memorable appearance when Princess Anne wore it at her wedding to Captain Mark Phillips in 1973, further tying it to the family's bridal heritage.

As Princess Charlotte grows up, many in the royal family believe that the iconic tiara will eventually belong to her, following in the footsteps of her great-grandmother and great-aunt. The tiara represents a connection between generations of royal women, making it fitting that the next princess royal would continue this tradition. While Catherine may not have inherited the tiara, she is still tied to the Queen’s legacy through other pieces in the late Queen’s personal collection. Catherine has worn these exquisite pieces on many important occasions.

One notable moment was during the 2022 Platinum Jubilee, when she honored the Queen by wearing the Queen’s drop pearl earrings, a wedding gift from 1947. The earrings complemented Katherine’s elegant gold dress, symbolizing the strong bond within the royal family. Catherine also wore the famous Cambridge Lover's Knot Tiara, a beloved piece originally made for Queen Mary in 1914. The tiara was closely associated with Princess Diana, who wore it frequently as Princess Catherine.

Queen Elizabeth passed it down to Catherine, who used it for state receptions and diplomatic events. Its intricate design symbolizes the grandeur of the British monarchy and Catherine's role as a senior royal. During her 2019 tour of Pakistan, Katherine honored the Queen by wearing the Nizam of Hyderabad necklace, another stunning piece from the Queen's collection. The necklace, which was given to Queen Elizabeth on her wedding day, features an exquisite floral diamond design and highlights Caherine's respect.

At the 2017 State Reception for the King and Queen of Spain, Catherine wore the Queen’s Quatrefoil Diamond Bracelet, a timeless piece previously worn by the Queen. The bracelet’s sparkling design added elegance to Katherine’s pale pink dress, demonstrating its versatility. Catherine chose to wear the Japanese four-row necklace, which holds special significance for both the Queen and Princess Diana. The necklace was a gift from the Japanese government and was worn by Catherine on the Queen’s 70th wedding anniversary. Wearing it at such an important moment underscored Katherine’s deep connection to her late grandmother-in-law.