She may have thought that her jewels would be best tp be seen worn by Royalty.
And (am I being uncharitable here ?) it is a way of ensuring her being known after her death.
--Previous Message-- : I am learning about Dame Margaret Helen : Greville. She and her husband Ronald : Greville, who died in 1908, had no children. : From what I glean from on-line references, : she was an only child. Besides the jewels : bequeathed to Queen Elizabeth, she left : £20,000 to Princess Margaret and £25,000 to : Queen Victoria Eugenia of Spain. She left : her property Polesdon Lacey to the National : Trust. She had been friends with both Queen : Mary and Queen Elizabeth. [Wikipedia] :