I'm surprised the article doesn't have any details about speculation or research into why it's such a unique mine for extremely rare natural elements.

Surely some geologist has been having serious fun figuring that out right?

Or am I totally off base, and mines all over the world are full of "rare" elements like that but we just don't notice or care?

I think the close proximity to the Swedish capital with easy access to educated geologists might be a factor.

If you are off base, I'd love to read details on why, because I agree that it would be quite surprising!