Glass and sand are both made of silicon dum-dum.
Sand and glass are essentially the same thing, just in different forms. Shatterbird can affect all forms of silicon from glass to quartz sand.
I mean, yeah, I know that glass is made from sand and is essentially just another form of it, but it’s a superpower we’re talking about. Magic by another name. Without testing/exposition, you never really know what sort of limits there are going to be, at what point the power is going to say “no, this is similar but it isn’t in my job description”.
So I’m absolutely fine with Shatterbird being able to control sand – I only questioned it in the sense of “oh, it extends to this form too?” – but I don’t think it would be any weirder for someone to have a power over glass and not have it extend to sand.
Hell, in most other settings, I would consider that more likely because magic doesn’t usually care about chemical composition and stuff like that, or include crabs and such alongside insects. Worm’s powers are a little different from the norm of magic in fiction because it doesn’t quite follow human categorizations and ideas.
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