How to bond wood and slate?

If the piece of wood is small, I would use epoxy, but if it's a bit larger, I'd definitely use a stainless steel screw just to screw it in (or even several screws)
 
I've had luck using some aquarium silicone to attach smaller (10" x 6") pieces of driftwood to slate bases. Most of the bases I see commercially use a single stainless steel screw; I just happened to have a bunch of extra silicone lying around.
 
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