How a dusty old envelope led to discovery of one of world’s rarest minerals

Humboldtine doesn’t look like much, but these yellow lumps are highly prized (Picture: Prögler/LfU)

When Roland Eichhorn popped open the dusty cardboard box, he couldn’t believe it.

There, in the basement of a stuffy government office in Germany, was a pile of six yellow lumps.

But these old rocks were one of the rarest minerals found on Earth.

Until the discovery, only about a snowball-sized amount of the mineral, called humboldtine, had ever been found, Roland Eichhorn...