The platinum and diamond engagement ring given to Camilla by the Prince of Wales belonged to Charles's grandmother, Queen Elizabeth the Queen Mother. It was not the Queen Mother’s wedding or engagement ring but one of many rings in her collection. Clarence House confirmed only that the ring was a precious royal heirloom. But a courtier said: “It was the Queen Mother’s. No doubt about it.”
The Times reported that the 1930s art deco ring, which has been reset to fit Camilla, was a favourite of the Queen Mother. At the time it was given to Camilla, it was valued around £100,000. It has been speculated that it may be part of the Greville inheritance, a gift to the future Queen Mother from the society hostess Mrs Ronald Greville at whose home, Polesden Lacey in Surrey the Queen Mother spent her honeymoon (as the then Duchess of York)
Dame Margaret Greville, the heiress to the McEwen brewing family and a close friend of Queen Mary, left most of her collection to the Queen Mother. Most of her jewels were set in platinum, reflecting the taste of the Queen Mother and the style of the period.
The choice of a ring owned by the Queen Mother is a little surprising, as it has been repeated broadcast that the Queen Mother deeply disapproved of Mrs Parker Bowles and opposed her grandson’s remarrying. And in addition Charles and Camilla spent their honeymoon at Birkhall, the Queen Mother's former on the Queen’s Balmoral estate which she willed to Prince Charles.
The engagement ring that Prince Charles gave to Diana, Princess of Wales, was bought by the Prince from Garrards (the royal jewellers) for £28,500 in 1981. It was an oval sapphire surrounded by 14 diamonds and set in 18-carat white gold. Before her death, Dians'a engagement ring had been valued at £250,000 - though it is not clear how much of this valuation is due to her ownership. Diana continued to wear it after her divorce and she needed to wear a second ring to stop it slipping off when her fingers shrivelled during her bulemic period. After her death his ring was the only heirloom that Prince William asked to keep.