Well, besides those two lines from the "Big Important Book on Life and Ethics", there is what the law says:
At least in my State (California) the law is written in such a way that an item is declared 'lost' when an owner misplaces it accidently. It legally still belongs to that person so long as that person believes he/she can hope to recover it and makes a reasonable effort toward such a recovery. If that person gives up, and the item is found subsequently, then it belongs to the finder.
So it seems that if a ring is lost today and that person walks away, and I find it tonight, I can legally claim it. Gray areas start to show up if that person hangs around waiting for someone with a detector to show up, or comes back the next day with a detector of his/her own. But if we never meet, who can prove which way it should go?
Years ago I heard in a detecting club that the suggested moral code was this: If you find something, run an ad in the 'Lost and Found' section of the newspaper. This can usually be done for free to the finder for an ad that runs 3 days. If someone can describe it, its theirs. If not, its yours.
Police have told me that if you find something worth $100 or more, it should be turned in to them. If after 90 days nobody claims it, its yours and you get it back. If an item is worth less than $100, it isn't worth worrying about.
So Coinshooter, you seem hazy on determining when -exactly- ownership of an item shifts from the loser to the finder, if ever. Which of these (if any) do you think is reasonable, and why? If others are unreasonable, why is that? I'm not accusing you or chastizing your opinion. I'd really just like to understand why you might think something I found 5 years ago, for which I've tried and couldn't find the original owner, might in your mind still belong to him/her, and contradictorially why you think that returning a ring you found with someone's name on it shouldn't be pursued? It seems to me that one needs to decide for himself what is 'fair' or 'ethical', and just be consistent with it and let it rest at that.
BTW-- I don't base my own sense of morality or ethics on how proud my parents may or may not be. That comes directly from my own conscience and nowhere else. You are free to disagree with the values I've chosen, but you should know I've given a lot of thought to them and won't dismiss them easily. Where I have 'drawn the line' is arrived at after careful consideration, and all I have to do is see where any particular item falls in regard to that line. Hopefully this will help you decide where you should draw yours.