Alchemists in the Middle Ages were fixated on turning lead into gold.

Both are soft, heavy metals. If they could make the dull one into the shiny one, they’d be rich. Right?

Maybe not.

Thousands of years before them, another metal, iron, was eight times more valuable than gold. It could only be found in its pure metal form in iron meteorites. Assyrians and Egyptians made prized iron jewelry, which we find in ancient tombs.

Then some alchemist of their time figured out how to smelt iron from common iron ore, like hematite and magnetite.

When supply boomed, the price plummeted. Iron eventually became the least expensive metal on Earth.

That’s because iron, as found in ores, is our most plentiful element by mass.

Iron makes up most of Earth’s core, which produces Earth’s magnetic field, protecting us from cosmic rays and solar wind.

Iron is the main ingredient in steel, an alloy of iron and carbon. We make a billion tons a year, and use it in everything, especially large buildings—which might be impossible without steel.

Iron is also abundant in the human body; it carries oxygen in the blood and gives blood its signature color…along with many other red things on Earth, from rocks and soil to farmers’ barns, painted with iron oxide pigments.

Iron is common and cheap and incredibly useful, so in some ways, that still makes it a lot more valuable than gold.