Kryptonite on earth?

Came across this article today and found it interesting.

Apparently they've found a mineral on earth that has "virtually" the same composition as Kryptonite.

"The new mineral does not contain fluorine and is white rather than green, but in all other respects the chemistry matches that for the rock containing kryptonite."

I love how at the end they say they'll have to be careful with it as they don't want to "deprive" Earth of our favourite superhero.

Okay, so how long before I sound like a complete Superman nerd? I'm already there? Alrighty then.