Which "allegedly" unique item would you find in the Cathedral of Valencia, Spain?

Duneboy, I don't think that you can carbon date agate because it's a stone and stones are as old as the Earth. But you can date an artifact by the style.

How come anybody thought at the last supper hey I will take this cup and make a legend everyone will search for centuries for I was more than likely it was washed up with the plates put in a cupboard and that was that.

this is awesome if true! have they tried carbon dating it?