Not exactly.
If the item is expensive you can put it in to be valued and that will tell you.
Otherwise you can have the item serviced, so sent away for a full buff and polish and the jewellerys should let you know.
It's no good putting an item in just for the free clean as they have been known to not pick up its fake and clean it anyway.
Otherwise try an authentication service. I don't have recommendations but maybe google some ideas.