Very interesting, thank you Janet!
I wonder which of Edith Londonderry's descendants is selling the earrings?
When she married, Edith's father-in-law, the then Marquess of Londonderry, gave her a complete parure of rubies and diamonds.
The only member of the family I have seen wearing a ruby parure is Edith's daughter, Helen.
She was definitely not wearing the earrings for auction in the photo below.