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Old Yuma Mine ID help

Posted by Andrew Tuma  
Old Yuma Mine ID help
November 11, 2009 09:16AM
All you AZ wulfenite experts out there I need a little ID assistance,

I picked up the wulfenite specimen as pictured below that has what appears to be calcite. However this "calcite" has a stunning lime green fluorescence. Does the calcite from OD Yuma Mine fluoresce green or is this an inclusion of another mineral?

Scattered around the Wulfenites are small barrel shaped yellow/orange crystals with rounded terminations (doesn't look like vanadinite) - could this be Mimetite?

On the side there is a pale green matting/smudges of some finely crystalline mineral - what could this be?


© Andrew Tuma

Any ideas what the other minerals are would be greatly appreciated

Andrew Tuma
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avatar Re: Old Yuma Mine ID help
November 11, 2009 01:44PM
au    
Hi Andrew
You get some yellow vanadinite from this site - I dont think mimetite has been recorded here.
I think the whitish mineral may be willemite.

Ralph
avatar Re: Old Yuma Mine ID help
November 11, 2009 05:23PM
us    
Hi Andrew,

Agree with Ralph, mimetite is unlikely here. Either Wulfenite or Vanadinite. You of course know how to test for Calcite (carbonate) with dilute HCl (muriatic acid). You can use a very small piece and if it is Calcite it will fizz, if no reaction it's like Ralph says, perhaps Willemite (nesosilicate). Willemite will most always fluoresce I believe some sort of green/yellow. If the white material fluoresces another color say red, probably calcite. Good luck Andrew.

Ron
avatar Re: Old Yuma Mine ID help
November 11, 2009 05:35PM
us    
*Additional thought, I can't really tell from your image but the white material (when enlarged) looks as though it might be a bit "sheaf-like", this habit would be typical of some hemimorphite (somewhat unlikely at Old Yuma Mine). Like Willemite, it would be non-reactive with dilute HCl and may be bluish under SW UV only.
Re: Old Yuma Mine ID help
November 11, 2009 06:16PM
us    
Lime green fluorescent coatings often make me think of hyalite, though your unknown appears to show crystal form. Just a thought. --Ken
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