1820 Rundell Bridge & Rundell The Diamond Diadem made for George IV, openwork silver frame lined w gold, set transparent w 1,333 diamonds including a 4 carat pale yellow brilliant in the centre front cross. It has been worn regularly by queens regnant and consort from Queen Adelaide onwards since George IV's use in 1821. Her Majesty now wears it when travelling to and from the State Opening of Parliament
Queen Elizabeth I’s Ring. Gold, mother-of-pearl, rubies, and enamel, c.1560. According to tradition this ring was dedicated to James I (James VI of Scotland) as evidence of the Queen’s death and given by him to 1st Earl of Home in 1603.
Strathmore Rose Tiara. Lady Elizabeth Bowes-Lyon (the future Queen Elizabeth, the Queen Mother) received it as a gift from her father, the Earl of Strathmore, for her wedding in 1923, though the piece itself dates from before that. The tiara features a garland of wild roses in diamonds mounted in silver and gold. The individual elements can be dismantled and worn as brooches, and according to Hugh Roberts were originally able to be substituted by single sapphires.
The Maple Leaf brooch, gift from king George VI to Queen Elizabeth (later the Queen Mother) in 1939 for their tour of Canada. Today it's worn by Queen Elizabeth II. It was also worn by the duchess of Cornwall and the duchess of Cambridge during state visits to Canada.