I think by 'zircon' you mean 'cubic zirconia'. There is a difference: Zircon is a naturally occuring mineral, and gem quality zircons can run up to hundreds of dollars a carat. Not as rich as diamond, but valuable. Cubic zirconia (CZ) is a man-made material that is frequently used as faux diamond, but is virtually worthless. I suspect in a plated ring you have the latter. Still, even if just plated, you can say you found gold which is always a good thing! Polish it up and put it in your show case-- nobody will be the wiser!