For the most part unless you got a XRF you can't be totally sure, I got a sigma metalytics verifier it's not really meant for jewelry but it sometimes works and recently got the Kee gold tester it seems ok and was not too expensive will slowly start buying jewelry for spot from private sellers and testing with XRF at some shop to insure I don't get reckt too hard
RE: Metal verification the old fashion way/Reblog lottery