I thought I would post these images showing Lady Mary Stuart Walker wearing other jewels, which I have not positively identified as yet. Unfortunately, Lady Mary seemed to avoid the cameras, so there aren't many images.
1937. At the Anglo-Finnish Ball
These may be her mother's emeralds.
Detail
1937
Detail
1937
1955 at her daughter's engagement party
1935. Gown was described as geranium red.