Possibly a grille gate key, might be bronze, difficult to tell without seeing it. Like a mortice type key (with collar and symmetrical cuts) for operating from both sides of a lock, but with a weight of 60 grammes and only 3 inches long it’s heavier build suggests a grille gate key to me. Hobb’s made all sorts of heavy mortice locks, mortice latches and banking equipment.
The VR crown is the Royal cypher mark for Victoria’s reign, (Victoria Regina)so narrows it down to 1837-1901.
