The Catholic church requires gold, not silver, to be in contact with the elements of communion.
From the Catholic Encyclopedia:
"It should be either of gold, or of silver with the cup gilt on the inside or it may have a cup only of silver, gilt on the inside; in which case the base and stem may be of any metal, provided it be solid, clean, and becoming."
I have no Catholic Digest reference. I just know what I was told by my former Episcopal priest who is also a Roman Catholic monk and became a Bishop and took all his Episcopal Diocese to the Anglican Communion worldwide. He told me God would not kill me for taking communion. I guess I listened.