The first line in the Wikipedia article for "Glass" reads:
Glass is a non-crystalline amorphous solid that is often transparent and has widespread practical, technological, and decorative usage in, for example, window panes, tableware, and optoelectronics.
Emphasis, mine.
From what I've been taught at school, if a solid is amorphous then it is necessarily non-crystalline and vice versa. (Of course, you could convert a given sample of an amorphous solid to some crystalline form...but it would no longer be amorphous now would it?).
The "non-crystalline amorphous" pleonasm adopted by Wikipedia seems to suggest the existence of (yes, I know this sounds stupid) crystalline amorphous solids.
Can something (I'm using glass as an example) be both "crystalline" and "amorphous?"
If not (as I suspect is the case), then why does Wikipedia use the pleonasm "non-crystalline amorphous" when describing glass? Is it purely for emphasis?
Yes, I've already seen this question here, and no, my question's not a dupe of that.
Sure, it's possible to convert an amorphous solid to a crystalline solid (proper melting and cooling should do it), I'm not questioning that.
What I am questioning, is whether a crystalline amorphous solid can exist. For example, glass has both (non-crystalline) amorphous and crystalline (non-amorphous) phases.... but does it have crystalline amorphous phases? Yes? No? Why?
