The Black Rock Paradox

If magic can craft everything, can magic then craft something, which cannot be affected by magic?

One of my players raised this paradox, as he wanted to craft a black rock item with the use of magic. As is known, black rock is a substance in the Ultima universe, which blocks the ether and thus cannot be affected by magic. Yet, when magic can craft everything can magic then craft black rock, which cannot be affected by magic?

If we answer yes, then it cannot be black rock we craft, because black rock cannot be affected by magic. And something, which has been magically crafted, cannot be considered unaffected by magic.

If we answer no, then magic cannot craft everything and we started out by saying, that magic actually can craft everything.

This problem reminds me of the very similar and classical question: "Can an all powerful God create a stone so heavy that He cannot move it?"

It is always a pleasure to encounter old questions in new places.