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

[Axel Emmermann]

Kreigh,

I found a reference that may make sense:
http://www.uraniumminerals.com/UTh/M-Torbernite.htm

Meta-torbernite is sometimes nearly black and occurs as a pseudomorph after
torbernite. There are several degrees of dehidratation and it appears that
the color (pale green to almost black) is greatly influenced by formation
process.

Axel



> -----Oorspronkelijk bericht-----
> Van: rockhounds-bounces at lists.drizzle.com
[mailto:rockhounds-bounces at lists.drizzle.com]
> Namens Kreigh Tomaszewski
> Verzonden: zondag 15 maart 2009 4:39
> Aan: Rockhounds at drizzle.com: A mailing list for rock and gem collectors
> Onderwerp: [Rockhounds] Help! Has anyone ever seen or heard of
blackTorbernite?
> 
> 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
> 
> 
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