Avalas the 1st layer, there's a realm called Resounding Thunder that's related to some OA 5 Elements thing. Only in that realm would Metal =/= Earth under all circumstances. 99.9% probably No everywhere else, 'cept for tricky maybes. Could force the PCs into a rationalizing or philosophy discussion about the concentrated earth nature of metals ... while the rust monster sneaks closer and closer.
Thuldanin the 2nd layer, almost everything is petrified and/or turning to stone = yes, totally yes.
Tintibulus the 3rd layer, is volcanic basalt ... stone but wait, it might actually be cooling Magma. Yes , or maybe-oughta-be-yes. Lots of dust around, dust of what?
Ocanthus the 4th layer, is "black ice" if you have a clarification on what/why it's not ice proper, still 99.9% no.