People spend too much time worrying and not enough time enjoying life.
Like Joe said, they're glass.
Annealed or no, if it hits a cement floor it's likely to break. Even annealed, with that thin constriction it's a potential breaking point, but it's small and thin enough overall that it's likely fine.
I like them, by the way.
I tried doing that with paper once, it didn't go well
