My brother says to bite it to find out if its really silver. If it is, there will be bite marks in the ring (if you don’t want big teeth marks, bite lightly!). He said even the slightest mark means it could very well be real silver. You could also take it into a jewelers and see if they will give you their opinion. I think they’ll do it for free, but I’m not sure. As for the blue gems…aren’t sapphires blue? Otherwise, it could be sterling sliver or just sliver paint and paste gems.

I’d say you two got a good deal anyway!