What is "coaltan" ?

The other day I was listening to a story on NPR radio about the Congo. They were talking about the many natural resources in that country, including something called “coaltan.” What is this?

I’ve proibably spelled it wrong, but I tried googling and found a few scattered sites saying it’s some kind of dirt, but I couldn’t find anything scientific or anything in Wikipedia, etc.

It’s coltan, or columbite-tantalite. You can get tantalum from this mineral - a key component of electronic parts.

The irony of actually being able to obtain something called “tantalum” notwithstanding…