I'm pretty sure loch is right. It's a type of gneiss. Granite doesn't have a glittery type surface like that.
Actually it can. depends on how much mica it has in it. Mica is the glittery part in granite.
Anyway, not to hijack, but what do you all think these rocks are? I'm most interested in the BROWN rusty rock. The person I got that one from was a aquascaper.
I'm not sure what you call it but it looks very similar to a rock we quarry on my property. Can't help you with a name but it looks rich in iron. Same with the red soil here.
Some of them (the flat ones) look a lot like slate.
First row of rocks matches the OP's.