Yesterday, I read an item about the Timur ruby necklace on the Royal Collection site; however, today I cannot access that site, so the following is from memory. The necklace containing 4 'rubies', including the 'Timur ruby', was set for Queen Victoria. The necklace was altered for Queen Mary. To me that suggests that QM wore the necklace at some time but, of course, it does not necessarily follow that the Timur ruby necklace is what HM was referring to in the entry Nellie has mentioned above.