Well, I don't want to get wound up in discussions of this material or that material or the other material. In many cases, it doesn't matter what kind of material it is, you'll be able to see through it if you just slice it thin enough.
But your question can answer itself if we handle it carefully:
How do we "SEE" anything ? By light ! So if there's light coming through something, then you can see through it. And if there isn't, then you can't. I think it's just that simple.
That makes the statement false.
