So it's all true then.

London (UK) - A mineral matching the composition of Superman’s feared Kryptonite has been discovered in a mine in Serbia.

A research team in the mine at Jadar discovered the unusual mineral, and when they could not identify it they called in Dr Chris Stanley, a mineralogist at London's Natural History Museum.

“Towards the end of my research I searched the web using the mineral's chemical formula - sodium lithium boron silicate hydroxide - and was amazed to discover that same scientific name, written on a case of rock containing kryptonite stolen by Lex Luther from a museum in the film Superman Returns,” he told the BBC.

Link: TG Daily - “Kryptonite” discovered in Serbian mine