[card_zero]

They found ancient inhabitants of Georgia using iron ore as flux for copper smelting, so it's a theory of how they went from one to the other. It's not terribly exciting but it beats "they tried smelting rocks at random to see if anything good would happen".

[GreenWatermelon]

Smelting random rocks (with fairly distinct appearances) sounds like a very logical thing to do. I would say it's a natural human impulse to experiment with random stuff and see what happens, that's curiosity.

What sound highly improbable is someone having access to this obviously different ore (used as a flux) but never thinking of smelting it.