In the below link, if one looks closely at the necklace with its appendages worn by Queen Alexandra, one would notice the heart shaped one at the base of her neck and the resemblance it has in size and shape to the one worn by Queen Camilla at the Commonwealth day service this year.

https://pin.it/2NhbbZLhR

I've always wondered what the appendages are though but the heart shaped one sure does cuts a match with the one seen recently.

Regards,

Dave.