In the 1st below link is a real picture of the late Queen Mary wearing the reported station necklace of very large diamonds. I have only ever seen paintings of Queen Mary in this said necklace. The necklace stands out.

https://pin.it/1vmGujm

In the 2nd link below is a picture of said Queen Mary in another necklace, but I'm unsure as to the large stones in that necklace. Can anyone define the necklace better. Queen Mary was known for her love of diamonds so I don't expect the that the necklace is of costume make.

https://pin.it/5vP3h8r

Regards,

Dave.