I wasn't going to comment on the "finder's" character - most of you have done so already. However - I am very superstitious about rings. I would never try on someone else's ring, and I would never

let anyone else try my rings on.

This will only bring him wafeti bokt. What kind of piker would give the ring of another to his future missis, as an engagement ring ? It defies understanding, for me.

In England & Wales (and for all I know, the other two Jurisdictions of the UK) this is stealing by finding, a section 1 Theft Act 1968 offence.

Were the artefact to be handed over to the bogies - and a receipt obtained - then, if the ring were not claimed within a given period of time, ownership would vest in the finder.