Please could you suggest a beautiful, timeless diamond ring or couple of rings that stack together to buy with inheritance to remember a special grandparent with 
Open to yellow gold or white gold- more dainty than bold but not too nothingy as i have fairly big hands 
no specific budget. Thanks so much
This is a lovely idea. Have you looked at Otiumberg?
I really love the brand for dainty and delicate stackable rings. The designs are so pretty, I’ve linked below a few of my favourites that I think would layer so nicely together, they would work separately too.
I have one from the brand that I wear everyday, I love it and always think about getting another!