Someone posted this on the forum long ago, and it works a treat
You need a magnet and a file
1. Highly Magnetic? Yes. #2 No #3
2. It's ferrous (Iron)
3. Scratch or file it. Will it scratch? Yes #4 No. #7
4. Is it lightweight? Yes #5 No #6
5. Scratch easily? Yes It's aluminum. No. It's titanium.
6. Scratch easily? Yes It's lead. No It's zinc.
7. Is it copper colored? Yes It's copper. No #8
8. Is it gold colored and slightly magnetic? Yes it's bronze. No #9
9. it's brass
I copied that from a hand copied note I keep in my bag... I hope I got it correctly.
I'd be interested to hear what the jeweler says. It sounds like you've eliminated silver as a candidate since it's in the nickel range. I hope it's worth a lot either way!
I haven't found a stainless ring myself, so I can't confirm by firsthand experience. I see others in the post linked above saying it shows up in the foil range, which is typically below nickel.