Kryptonite It Exists!

In article ,
says...
"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.



I can understand to this guy his amazement that his material is the same
as Kyptonite but why should this material not exist.