Nice Find indeed, and glad you noticed the detail, sometimes it's easy to miss.
I had a ring for a while that sat with my other 'scrap' til I noticed
some faint markings on the inside edge, with some talcum powder applied
I could make out 'liberte égalité, fraternité' and what I think is 1916,
it's a two Franc coin, possibly WWI trench art. Good eye and Congrats on the ring !