A new mineral whose composition almost exactly matches that of Superman-felling kryptonite has been unearthed in Serbia by mining company Rio Tinto. The mineral was identified by researchers at the Natural History Museum, and Canada's National Research Council.

Mike Rumsey, mineral curator at the Natural History Museum, explains that when the team had worked out the structure of the mineral, sodium lithium boron silicate hydroxide, they typed it into Google to see whether anyone had classified it already.

The first link returned by the search engine was to a Wikipedia entry on kryptonite, specifically a label on a box of kryptonite in the movie Superman Returns.

He says it was very exciting because very few new minerals are discovered - between 30 and 40 every year.

However, because the mineral is actually nothing to do with Krypton, it can't be called kryptonite. International nomenclature rules are strict, and the substance will officially be called Jadarite. As well as missing out on its showbiz name, the mineral is not a radioactive green crystal, but a rather ordinary looking white powdery substance.

As for kryptonite's potentially superhero slaying powers, Rumsey is not worried: "It probably won't do superman, or us, any harm whatsoever," he said. ®