Why not iron?

Whenever a fantasy setting gets some form of innately magic-resistant material it almost always ends up being something strange and exotic. Sometimes a super-rare metal. Sometimes a spooky crystal of some kind. Sometimes a fancy rock. Petrified trees are certainly a new one (wouldn't mind hearing a why on the magic-sucking property some day).

But almost inevitably, the oldest standby for anti-magical material gets passed over.

Good old fashioned iron.

So I'm curious as a result. Did the topic of iron's anti-magic properties in folklore ever come up in the discussion? Was it seen as just too mundane a foil for magic? Because, honestly, its mundaness is exactly why it's such a great foil for magic. You could pretty easily take it a step further and say that while all iron has some degree of magic resistance this one special type of iron (sun-steel?) is extra special.

Iron has a few thousand years of narrative power behind its magic-thwarting properties, why not take advantage of that?