[X] Truth
If we're able to do this, it would be a MAJOR weapon to protect the empire. Being able to test some artifact, or magical effect, and be able to conclusively say that it is or is not from a proscribed god would revolutionize the work of the witch hunters and their ilk. Look at Kragg's dilemma with the Axe of Unknown Origin - one of the big worries in Warhammer is always "Is this a blessing of friendly gods, or a deception of chaos?", and this might be able to provide a way to demonstratively prove "Yes, this think is OK/No, this thing is not OK".