Gold is malleable, portable, nontoxic, beautiful and rare. Those qualities have made it an excellent currency over the centuries.

But there’s another metal with all those properties and more—and it’s much more valuable.

It’s called rhodium, part of the platinum group of metals. The name comes from the Greek rhodon, meaning rose, for the rosy color of rhodium compounds.

It’s abundant in other parts of the universe but vanishingly rare in Earth’s crust—just one part in 200 million. We mine 100 times more gold each year.

Eighty percent of the world’s rhodium comes from South Africa. And 80 percent of annual supply is consumed by the auto industry.

That’s because, like all metals in the platinum group, rhodium is an excellent catalyst: it controls and encourages chemical reactions.

In your car, that means it’s used in the catalytic converter.

Exhaust flows through a metal honeycomb lightly spattered with rhodium and other platinum group metals. They turn dangerous nitrogen oxides and carbon monoxide into nontoxic nitrogen gas, carbon dioxide and water vapor.

Rhodium’s catalytic properties are in demand in other industries too.

There’s even an experimental technology that uses solar energy to turn carbon dioxide and water into high energy fuels using rhodium as a catalyst.