Now it’s true that the same village blacksmith could smelt his own raw
material from bog iron – that’s the technical name for the iron sulfide deposits laid down in most temperate zone
wetlands by chemosynthetic bacteria. There’s a lot of bog iron to be had, since it hasn’t been used commercially
in centuries and most North American deposits away from the Atlantic coast have never been worked at all. It’s easy
to smelt bog iron into workable form – people in Dark Age Europe and early colonial America did it with simple charcoal
fires – and it’s also quite easy to do the same thing with rust, which is iron oxide, the standard commercially
worked iron ore in the days before huge fossil fuel subsidies made it possible to use low-grade ores like taconite.