I an not quite sure, but I would say male. How old is it? I am not sure if its old enough to be sexed.
How big is it? If it's under 8" you might have to wait a while to sex it.
Looks like a male, possibly who is just starting to show? My males have somewhat more rounded-out bumps. Yours looks like he's just getting through puberty.
Also, don't worry about your substrate; it seems good. (they don't live on glass in the wild, either)