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Questionable uranocircites from Assunçao mine (Portugal)
  
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Cesar M. Salvan
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PostPosted: Jul 05, 2008 08:14    Post subject: Questionable uranocircites from Assunçao mine (Portugal)  

Greetings to the members of this forum. This is my first contribution and I introduce myself: My name is Cesar, I am mineral collector from Madrid. Also, I am a chemist working in the geochemistry field.

Today, a friend asked me a question about several misidentified specimens of the north os Spain and I taken the case of uranocircites from Assunçao as an example in my response. After that, I revised the images on Mindat of uranocircite, where we can found several images of Assunçao specimens.
Now I am working in a project on radioactive minerals in Iberian peninsula and I analized several lots of, supposedly, uranocircite from Assunçao, presented in spanish fairs by several dealers. In all cases the specimens turned out to be autunite. Also, I analyzed several samples collected in situ by some collectors. Again, in all cases autunite is the species.

Some dealers and collectors are reluctant to this finding ("who is this f... young unknown nerd, that come here to speak me about wrong labelling??? may be the thought...) and persist the misidentification in the market.

My question for now is, anybody found actually uranocircite in Assunçao? and Is geochemically possible the existence of species, due to the barium content? as far as I know the presence of barium is negligible and the probability of a barium/uranyl secondary mineral, low, but I need to confirm this idea, because I haven´t solid reference (i did not found anything in published papers), just a conversation with a geologist that worked in the quarry.


Thank you very much



autunito asuncion2.JPG
 Description:
typical autunite from Assunçao. Part of a lot presented as uranocircite in a spanish mineral fair.
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autunito asuncion2.JPG


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Cesar M. Salvan
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PostPosted: Jul 05, 2008 08:18    Post subject: Re: Questionable uranocircites from Assunçao mine (Portugal)  

Sorry, I forget to clarify the procedence:
Assunçao mine, in Aldeia Nova, Viseu (Portugal). A famous locality for phosphate minerals
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PostPosted: Jul 06, 2008 04:32    Post subject: Re: Questionable uranocircites from Assunçao mine (Portugal)  

César,

I have no idea if some Uranocircites were ever mined in Assunçao Mine, but for sure, the guys selling Uranocircite on Shows have also been warned by other people (not just you) about this material and that after being analyzed it gave as a result the same that you mention: Autunite (and also Metaautunite). Why they don't changed their labels? I don't know, but I can easily imagine why.

Jordi
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Gail




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PostPosted: Jul 06, 2008 10:22    Post subject: Re: Questionable uranocircites from Assunçao mine (Portugal)  

Welcome Cesar, and thanks for your contributions!
_________________
Minerals you say? Why yes, I'll take a dozen or so...
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Cesar M. Salvan
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PostPosted: Jul 06, 2008 14:59    Post subject: Re: Questionable uranocircites from Assunçao mine (Portugal)  

Thanks, Gail, for your welcome!. I hope to contribute frequently in the future.

Jordi, it is not surprising that other guys analyzed the autunite. Also, is not a surprise that certain dealers insist in the mistake. I think is due not only they doubted the words of a unknown guy in the field. I can imagine they belief that if they sell the specimens as uranocircite, the material could yield more profits...In personal view, I think this is quite absurd and unethical.
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Les Presmyk




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PostPosted: Jul 08, 2008 09:29    Post subject: Re: Questionable uranocircites from Assunçao mine (Portugal)  

Cesar,

I appreciate your humor. You are right. The only reason a dealer knowingly mislabels a specimen is for marketability. To your point about a dealer's reaction I will relate a story I witnessed first hand. At a Tucson Show, probably 1968 or 1969, a dealer (just starting out but very prominent today) had a quartz on chrysocolla labeled Bisbee, Arizona. A collector, in his late 20's or early 30's walked through the booth and informed the dealer that the specimen probably came from Miami, Arizona. After the collector left the booth, the dealer turned to one of his associates and made some comment about "who the heck was that and why should I pay any attention to what he just said?" The language was a bit more colorful but you get the point.

The collector was correct. Chrysocolla is an uncommon mineral from Bisbee and quartz on chrysocolla is almost unknown from there. However, it is well known from Miami, Arizona, which is where this piece was from. By the way, the collector was Richard Graeme, whom I had just met at that particular Tucson Show.

Keep up the good work and I look forward to hearing more from you.
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PostPosted: Jul 08, 2008 21:06    Post subject: Re: Questionable uranocircites from Assunçao mine (Portugal)  

Les,

It has been a pleasure to read your post. I enjoyed your story and it cheered me up :) (and added colour to my language. I´ll try to do my best with my English and I apologize for mistakes or inadequate expressions on sucessive contributions).

Your story and my own experience points out a fact: the prevalence of aristotelic authority principle in the modern practice. Of course, the authority of experts is a natural reaction: we place our trust in people devoted to a field of knowledge. And, as a consequence, if we are on the outside of an "expertise club", we must to justify all our statements with references and data. But, worrying, in some cases the prevalence of the truth is a secondary factor, after the perception of authority or certain personal interests (here, speaking about the natural sciences at all level and tangent activities. In other fields, this is the rule as we know).

Getting back to the "specimen-directed" mineralogy, both the expertise dictatorship and the marketability, plus the unavoidable mislabellings, forces to do a lot of analytical work, otherwise unnecessary, as in the case of autunite from Assunçao. And my original questions remains unanswered, but after your comments (and the absence of other comments or opinions) and after thinking about it, my suspect of marketing ploy now is above the accidental mislabelling.
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PostPosted: Jul 09, 2008 02:07    Post subject: Re: Questionable uranocircites from Assunçao mine (Portugal)  

Some Portuguese are frequent visitors to this Forum, maybe they can let us know their opinions about these dubious Uranocircites?

Jordi
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Maxxedison




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PostPosted: Jul 15, 2008 07:02    Post subject: Re: Questionable uranocircites from Assunçao mine (Portugal)  

Hello Jordi, i am Portuguese, and i heard many story's about these "dubious Uranocircites", i have a friend of mine that is a phosphate lover (and his my master in mineralogy in Portugal), and usually is going to Viseu (Assunção Mine) to gather some phosphates and the only thing that he discover is autunite and some uranophane, but NEVER discovered uranocircite!
I never went to Assunção Mine, but i believe it never existed uranocircite in that place!
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