According to Islamic laws of inheritance, at least by Twelver Shia laws, a father's personal belongings are passed down to his oldest son. The laws explicitly mention finger rings as a personal belonging that must be passed down to the first son.
The turquoise ring (left) belonged to my great grand father some day. It always reminds me of my grandfather, and grate grand father (Yes I was lucky enough to see them both). The agate one is my father's.
- Nikon D7000