The Timur Ruby Necklace was a 1853 gift to Queen Victoria from the East India Company. One question: did Queen Elizabeth II ever wear it in public? I don't think I ever see any picture showing Queen Victoria, Queen Alexandra, Queen Mary or the Queen Mother wearing it, do you?
(By the way, I already pre-checked the Royal Collection which does not show a picture of this necklace or any story about it except the year of the gift and which jewelers had created it on behalf of the East India Company.)