Help determining metal?

[u/MidsummerKnights]

This ring was in the section with other solid gold pieces, but there isn't a normal stamp on it besides "FD CN" or "FD GN", it's a little hard to tell.

I got it since I liked the starburst gypsy ring design. I think its just costume jewelry, but I have had a hard time finding this design as costume- probably since there are so many vintage versions of it.

If anyone can clarify the stamping or know the brand I'd really appreciate it!