[Rockhounds] Help! Has anyone ever seen or heard of black Torbernite?

[Kreigh Tomaszewski]

Hey List,

I recently acquired two specimens of Torbernite from Bendada Quarry in 
Portugal. Both of the specimens are mostly beautifully formed, bright 
green, torbernite crystals, up to 6 mm, standing on edge, in a 
beautiful patchwork coating. I have absolutely no doubt about the 
Torbernite identification for the green crystals.

However, both specimens have a portion that is covered with what looks 
like black torbernite crystals. On both specimens there are a few 
crystals that are half green and half black.

I've never heard of black torbernite. I'm guessing a pseudomorph, but 
what the heck could it be? Torbernite without the Uranium? What would 
that be?

I did find one Torbernite specimen for sale from the quarry that 
included Nsutite (which is not listed by Mindat for the locality) as a 
black secondary mineral, but it doesn't make sense chemically to me.

Do any of you experts have a suggestion for what I have acquired in a 
trade? I want to make a good label, but I'm stumped.

Kreigh