Burguillos "allanite-(La)" photos, cows and milk

Dear friends!
Visit on the allanite-(La) photo gallery [www.mindat.org] leave very strange impression of quiet idiocy...

All material from Burguillos really is composed by large crystals of epidote with very thin zones (~10-50 mkm) of allanite-(La). Summary REE2O3 content of brutto crystal from here don't exeed 1-2 wt%. Real allanites begin from 6-7 wt. % of REE2O3 - this are low-REE or calcian allanites.
Moreover allanite-(La) zones concentrated in core parts of epidote crystals and are INVISIBLE on photos.

It is simply ridiculous to read captions "Allanite- La. 35x33 mm", "A single Allanite-(La) crystal with small Magnetite crystals, all on a matrix of Hedenbergite. The upper tip of the crystal was broken and has then recrystallized ... Main crystal size: 0.9 x 0.5 cm", "Crystal size is 7mm", "Crystal with 1cm on top", etc. All these words belong to usual green epidote.

It would be ridiculous, if it wasn't sad.

All these captions should be improved. It is possible to speak about allanite-(La) from Burguillos only concerning with polish sections opening central parts of crystals or microprobe preparates photos. It is the same as to show a cow photo and to give the caption "milk". :)

Kind regards,
Pavel

I have uploaded what I hope to be a real image of allanite-(La), from Mochalin Log, Kyshtym, Chelyabinsk, Russia. Unfortunately, it is not much to look at, strictly a picture just for the record.

Dear Jeffrey!

It is strange, but your photo [www.mindat.org] hadn't appeared not in allanite-(La) gallery, not on Mochalin Log locality page.

By the way, it is very probably, that all black rim in upper part of your photo consist of allanite-(La) if it is black prismatic mineral and not optical effect. And promised by you the child photo of the specimen hasn't appear nowhere... Kash problems again?

I'll also try to photograph tomorrow some my allanites-(La).

I am admire your antoinite specimen!
And under which light had you photograph your belovite-(La) specimen? It is very impressive, but usually the mineral is more light coloured, and much more green.

Kind regards,
Pavel

Cleared Mochalin Log cache. Photo should be there now.

Thank you for the comments, Pavel; and Alfredo, thanks for clearing the cache. Since I don't have "automatic approval" status, there is a delay in when a photo gets uploaded and then linked to the appropriate pages.

With regards to the allanite-(La) photo, the black rim could be prismatic material, but I am relying on the arrow, appearance of similar specimens (as this was from a small lot), the description that came with the material (small 1-3 mm black aggregates, microprobe confirmed) and most likely what appears to be prismatic crystals is in fact just shadows.

The photograph of the antoinite is just a snap shot - these types of specimens, with no crystals and just earthy material are easy to photograph, but thanks for the admiration!

The belovite-(Ce) I don't recall the specifics, as I was in the midst of photographing 1000's of specimens. Judging from the picture, and my set-up at the time, I was using two hot-light, a 350W fill light and a 500W main light. The specimen is placed on glass, with a white reflector below. For this specimen, the effect is more-or-less even illumination, plus some back light to get the crystal to glow - I guess a bit of artistic license. I checked the color balance, and yellow with some green is correct.

Jeff

Hello,

it seems that Pavel is right.
One of the Photo is from me, so i'm interested in a correct description.
Maybe we can ad the term "La-dominant allanite/REE-rich epidote crystals" in the description of the photos, as used in the following link :

[findarticles.com]

(Min.Rec Nov/Dec 2002)

Best regards
Elmar



Edited 3 time(s). Last edit at 11/21/2007 08:03AM by Elmar Lackner.

I have a Franklin specimen consisting of calcite, franklinite, willemite, hardystonite, esperite, AND a medium brown mineral, that I was told was an alteration product of esperite. Any thoughts anyone?

And no. NJ is not a suburb of NY.

Please see the Mineralogical Record's article:

The Nueva Vizcaya Mine, Burguillos del Cerro, Badajoz, Spain (by J. Gonzalez del Tánago & B. Saínz de Baranda Graf) Volume 33: Pages 489-500.

Jordi Fabre

Dear Elmar!
the article, citing by you, was published before allanite-(La) approvement. Now allanite-(La) is valid mineral. So you can use the therm allanite-(La) in your caption.

What about your specimen, I would write the next caption for example, being on your place: "7 mm size crystal of green REE-bearing epidote with inner mkm-size zones of allanite-(La)", or something similar.

I obtained my own specimens of Burguillos epidote/allanite-(La) and information on its conditions from Jose Gonzalez del Tanago. He wrote article about them, but now I haven't it under my hands.

By the way, explanation of encreasing of La/Ce ratio in this specimens, given in the article, is slightly ridiculous. Magnetite haven't crystallochemical position, which able to incorporate REE, especially only single Ce. As I can to propose, fractionation of REE on the locality was connected with partial oxidation of Ce up to unsoluble tetravalent state and depletion of allanite-forming solutions with it. So this process was connected more likely with hematitization of magnetite or hematite formation rather than with formation of secondary magnetite. Analyses of Ce-enriched magnetites weren't given in article...

Best regards,
Pavel

I had in view the another Jose Gonzalez article in some Spanis scientific magazine in Spanish.

Forget to say, that one thing in the article [findarticles.com] is very important and right. Not EVRY epidote crystal from Burguillos is enriched with REE and contain allanite-(La) microzones. With this statement I am agree completely.

Thank's Pavel.

I fixed the description of my photo.

Best regards
Elmar

Dear Mr.Kartashov

I was quite surprised for the commentary about the allanite-(La) from Burguillos del Cerro.
Jordi Fabre placed already a quotation on a MR article about this subject.

I have now it in my hands, and as I remembered, the analysis showed from 9 to 22% REE oxides, that place them apart from an epidote.
Being you an expert in those minerals, sure you know Mr. Del Tánago and Mr. Saiz de Baranda.
They find that the REE oxides vary inside the crystal, but with a minimum of 9% in the poorer part. And that, qualifies the species to be named allanite.

Done the discrepancies between your analysis and those published in MR, and done also the mention you make about *green epidote crystals*, I would think that you are not analyzing the allanite-(La) from Burguillos del Cerro, that is jet black, without the faintest trace of green.

I would then think that you perhaps are analyzing an epidote from Burguillos del Cerro, that exists also and that are green.
But taking in account that the authors I quote, Mr. Del Tánago and Mr. Saiz de Baranda state clearly that this epidote is free of REE, I fear that perhaps you are analyzing any epidote from another occurrence.

If you want, I suppose that I could send you a sample for the pertinent analysis.

But I fear that I should disagree in that statement that "would be ridiculous if it was not sad".
I fear that you have analyzed God knows what, but not an Allanite-(La) from Burguillos

With best wishes

Lluís

P.D.: if you could read spanish, that could be interesting
[www.fabreminerals.com]
Dear Mr.Kartashov

I was quite surprised for the commentaire about the allanite-(La) from Burguillos del Cerro.
Jordi Fabre placed already a quoatation on a MR article abou this subject.

I have now it in my hands, and as I remembered, the analysis showed from 9 to 22% REE oxides, that place them apart from an epidote.
Being you an expert in those minerals, sure you know Mr. Del Tánago and Mr. Saiz de Baranda.
They find that the REE oxides vary inside the cristal, but with a minimum of 9% in the poorer part. And that, qualifies the species to be named allanite.

Done the discrepancies between your analysis and those published in MR, and done also the mention you make about *green epidote crystals*, I would think that you are not analyzing the allanite-(La) from Burguillos del Cerro, that is jet black, without the faintest trace of green.

I would then think that you perhaps are anlyzing an epidote from Burguillos del Cerro, that exists also and that are green.
But taking in account that the authors I quote, Mr. Del Tánago and Mr. Saiz de Baranda state clearly that this epidote is free of REE, I fear that perhaps you are analyzing any epidote from another occurrence.

If you want, I suppose that I could send you a sample for the pertinent analysis.

But I fear that I should disagree in that statement that "would be ridiculous if it was not sad".
I fear that you have analyzed God knows what, but not an Allanite-(La) from Burguillos

With best wishes

Lluís

P.D.: if you could read spanish, that could be interesting
[www.fabreminerals.com]

Dear Lluis!
I have two specimens of this material from Burguillas with crystals 5-10 mm size with magnetite and without it. Both labeled Nueva Vizcaya Mine. I obtained both them directly from Jose Gonzalez del Tanago. I don't analysed them personally, because was completely satisfied by explanations of Dr. Tanago about them. Mineral on both specimens is dark green epidote-like. As he explained me, this ares low-REE epidotes containing thin multiple inner zonation with allanite-(La) zones mkm-size.

Usually allanites are black due to presence of iron in different valent state in its structure. Epidote contain only trivalent iron, and it is green. So colour may be the feature, allowing to distinguish epidotes from allanites.

Colour may to depend of a surface condition. Mirror-smooth surface perceive by eye more darker than rough one of the same colour. Apparently you have crystals of better quality then me.

All crystals on the photos from allanite-(La) gallery (excludind uploaded for the last two days) have apparent greenish tint.

I am suppose, that for the past time more rich in REE contents specimens were found in Burguillos. But based on specimens in my collection and Dr. Tanago explanation I had wrote my initial comment.

Looking on my Burguillos specimens I haven't any wish to analyse them, because I not want to cut them to open their inner parts, containing allanite-(La). Outer parts looks not perspective for investigations due to their colour. Moreover I had allanite-(La) specimens long before.

In any case, I can to test your specimen if you are interested. Contact me by e-mail pkartashov@yandex.ru

Unfortunately I can't read in Spanish. Some time ago I'd want to learn it, because a third of the World speak on it, but hadn't succeed in this undertaking. I may to understand only in a general way scientific texts in Spanish.

And of course I haven't any negative to Spanish peoples, Spanish science or to Burguillas allanites. Only I am know, that some mineral sellers are ready to supply collectors (who aren't obliged to have special mineralogical cnovledge in common sence) uncheked, inauthentic, doubtfull material with very attractive labels. Such way epidote can become allanite-(La), or hornblende turn into ferripedrizite. And later photos of all these may to appear on the database.

Kind regards,
Pavel

P.S. Today I had upload photos of some allanites-(La) from Ural. You may to look them.



Edited 1 time(s). Last edit at 11/22/2007 09:23PM by Pavel Kartashov.

As explanation of my last words, this example is.

Strontiopiemontite was discovered, described and approved from Val Graveglia mines.

One can ask "Who has piemontite-(Sr) from Val Graveglia?", and many peoples may answer " I am have!". Some years ago I would add my voise to this chorus.
BUT when I'd check two my specimens of "piemontte-(Sr)" (obtained from respected Italian collectioners) I'd found, that in this mineral specimens absent even traces of Sr...
As I know, Nikita Chukanov had tested much more quontity of specimens (~7-8) labeled as "strontopiemontite" from Val Graveglia deposits, and found only usual piemontite.

So situation will be good, if only one from ten peoples, who THINK, that they have piemontite-(Sr), REALLY has it.

And situation with piemontite-(Sr) is quite different from the one with siderazot. In the difference from the later, piemontite-(Sr) really exist, at least in the holotype specimen, because it was investigated by modern analytical methods. Evrybody have it, but almost nobody in reality. And from this side, situation is the same as with siderazot.

Meanwhile evrybody able to buy now piemontite-(Sr) from different sellers, and to pay own money practicaly for nothing.

May be similar situation is and with Burguillas material. Who said, that radically black crystals mentioned by Lluis, aren't real black allanite, but ... usual allanite-(Ce) of the more earlyer generation, mentioned in the cited article? What we can say without analyses? In any case, abundance of "empty" epidote on the locality is much more wide, than allanite-(La) quontity here. Ratio between them may be about tons (or tens tons? or may be hundreds tons?) epidote against kilograms (or tens kg?) of allanite-(La) bearing specimens.

It is possible, that somebody visit the locality and collect the first met him epidote specimens, and decided that this is allanite-(La), because it is known from here. Some after he begin to spread this specimens labeled as allanite-(La). Is it unbelievable story? :)

Would somebody like to buy Khibinskite specimen collected according to the same principle? Only 20$ for tumbnail. 20-30 specimens available! :) :) :)

Dear Pavel,

I live close to the manganese deposits of Val Graveglia and I’m particularly focussed on its minerals.
Unfortunately I think you are right about piemontite and piemontite-(Sr) from that locality.
In these years I have personally checked by microprobe tens of “piemontites� self collected or traded, having various appearances and different occurrences, coming from the three main mines: Molinello, Cassagna and Gambatesa. No success.
Probably I am not lucky but so far I could not get any piemontite-(Sr) from Val Graveglia in my collection and I must be happy with that one from the Wessels (checked !).
Anyway also Prof. Andrea Palenzona which I know well, one of the authors of the original work, confirmed me the high rarity of the Sr term for the type locality.
Another good example from Val Graveglia are the clinochlore-pennantite solid solutions where both terms are present in undefined quantities but are always labelled by the collectors, without analysis, as the rare manganesiferous species!
Generally speaking I think that minerals in the collectibles field are frequently affected by arbitrary classifications and this problem increases proportionally with the rarity and complexity of the species involved. And typically when in dubt between two terms, the most “exotic� is chosen.

Ciao

Corrado Balestra