I'm not sure there's enough to say that'd really satisfy the the sub's rules, but for the sake of an answer anyway, it's just a signet ring with a coat-of-arms on it. The arms are reversed (per tradition) so the ring could also be used as a seal for wax seals. That's not very common these days but signet rings with coats of arms aren't entirely uncommon here in European countries with past-or-present tradition of people with coats-of-arms (whether nobility or not).

Although seals back in the Middle Ages had legal significance (like a signature) and were usually broken after their owner's death, these rings from more recent centuries don't and aren't.

So anyway, new ones are made today, like any other jewelry they sometimes get lost or sold. They're not that uncommon at jewelry auctions in Europe at least; but they're not usually worth much more than the metal value though. As with jewelry with specific engravings on them, there's not much interest in wearing something that was clearly made for someone else. To the extetnt that around here engraved signets are sold simply as gold scrap. With the rare exception of items which belonged to a celebrity. (e.g. Friedrich Nietzsche's signet ring sold here some years back for 190k SEK - far above the auction house estimate)

How this particular ring relates to your family is something you'd be in a better position to find out than a historian would be. But odds are that if you don't know, it has no relation and is just a ring your grandmother found or bought somewhere. You haven't posted any pictures of actual stamps on it which could say when/where it's made. Style wise (and given the lack of patina) I'd wager mid-20th century though.

If you were expecting this to have some special significance, like being some royal ring out of a medieval fantasy novel handed down to the heir to the throne or some such, I'm afraid I have to disappoint you; bottom line is It's just jewelry with a family logo on it.