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Fakes & FraudsAnthropogenic silvers?

1st Sep 2008 09:42 UTCJOAN ABELLA CREUS

Hi,

I just wrote an article: "Anthropogenic silvers?" on my blog. I think that it could help to clarify and identify the real nature of the recent Imiter silvers. Unfortunately it is written only in Spanish language, I'm sorry for it. Hopefully it can be more or less comprehensible for the not Spanish speakers.

The link to see the article is:

http://www.mineralsabella.blogspot.com/

http(://)www(.)mineralsabella(.)blogspot(.)com(/)

Joan Abella

1st Sep 2008 11:05 UTCJolyon Ralph Founder

Would you be ok for someone to translate it to English and post on mindat?

Jolyon

1st Sep 2008 13:49 UTCPeter Seroka

Hi Jolyon and Joan

that's a lot of text . Would it be ok with Joan, if I write a brief summary of what he's going to tell us about his suspicions, related to silver wires from Imiter ?

Being in the middle of creating a silver mineral portrait on the German Mineralienatlas, I am sure, that Joan's experiments and his guesses and doubts might become a similar sensation like the fantastic man-made sulphurs a few years ago.

If Joan agrees, I would be prepared to do this translation from Spanish to English (though I'm German).

Regards

Peter

1st Sep 2008 14:40 UTCJoan Abella i Creus

Dear Sir.

Thank you very much for your offer.

For my part been charmed with, it is an honor.

A cordial greeting,

Joan Abella i Creus

1st Sep 2008 15:59 UTCDavid K. Joyce Expert

I would be very interested in the summary!

David K. Joyce

1st Sep 2008 18:52 UTCPeter Seroka

Summary of Joan's article, originally written in Spanish language.

Over the last years I have seen numerous specimen, labeled " Native Silver" from the Imiter silver mine, Boumalne-Dadès, Ouarzazate province, Sous-Massa-Draa region, Morocco. This is wiry silver, which usually has an intense metallic lustre and occurs on a matrix of Acantite.

Knowing the old metallurgical efforts to obtain silver wires from Acantite the polemics of the supposed unnatural silver specimen from Freiberg (Saxonia, Germany) and the massive Acantites from the Imiter mine were ringing my alarm-bell.

Brief history

The making of wiry silver from Acantite is a process known since centuries. To my knowledge, the first notice stems from the German mineralogist von Henckel (1678-1744), who, in the year 1732, established a large laboratory in Freiberg where he conducted innummerable metallurgical experiments.

A few years after Henckell's death, the postum work “Henckelius in Mineralogia Redivivu”,

was published in Dresden and, it's precisely in this book, where the experiments to obtain wiry silver from acantite has been described.

Years later, the same process had been described by the French mineralogist Balthazar Georges Sage (1740-1824), the one, who was the founder of the Paris School of Mines and the Public Mineralogical Museum. In his book “Elémens de minéralogie, docimastique” edited in the year 1772 in Paris, Sage explains exactly the same process (l’Argent vierge capillaire au en filets contournés) as it had been described by Henckel, 25 years earlier.

In 1784 the mining engineer Schreiber wrote an article in the "Journal de Physique" about silver minerals from the Allemont mines in the Chalanches Mts., and about the process to obtain silver from Acantite.

All the works by those mineralogists has been more or less fundamental. However, the relatively easy metallurgical process has become more popular through the famous French mineralogist René Haüy, the father of crystallography. In one of his major works, "Traité de Mineralogie", edited 1801 in Paris, Haüy describes the process, how to obtain wiry silver from Acantite, based on his own experiments and citing the above mentioned mining engineer Schreiber.

Experiments / Trials

Before the first wiry silver specimen from Imiter appeared on the market, I had the opportunity to examine some pieces of massive Acantite from this mine. The Acantite had an intense metallic lustre and was associated by brilliant iron sulfide; some pieces had a weight up to 2 kg. When I examined the matrix of the Imiter silver, which was Akantite, there had been some aspects, which made me become suspicious; precisely some white-bluish spots at the base, some iron oxides near the silver wires and a distinct and very accented lack of lustre on the Acantite.

Fortunately I disposed of diverse massive Acantite pieces, which I had collected at the (Spanish) Balcoll de Falset silver mine and whose characteristics have been very similar to those observed at those specimen from the Imiter mine. With those specimen I have made different experiments, applying various techniques, as : using (welding) torches of butane and acetilene, reducing and oxididizing flame, flow control , with and without porcelain and graphite crucibles, with and without additives. With those techniques I obtained small but magnificent wiry silver specimen on a matrix of Acantite. As I analyzed the loss of specific weight of the Acantite during each step, observed each reaction of the Acantite, its conductivity and specifically the growth of the silver and compared the final result with the natural wiry silver specimen from the Balcoll de Falset mine, I came to the following conclusion: If the experiment is done without a lot of precaution, there will be different characteristics which permit the differentiation from natural specimen. Opposite, if the whole process is done with utmost precaution, one will obtain specimen which are not easily distinguishable from natural ones

Results

The different aspects which I observed on the wiry silver specimen, which I had made from Acantite from the Balcoll mine coincide with the particual characteristics of some of the wiry silver specimen on Acantite which are said to come from the Imiter mine in Morocco. Due to this, the recognition may help us to be cautious, when it comes to the decision to buy one or the other of the Imiter specimen.

The main differences are:

Lack or loss of lustre of the Acantite may be the result of bad or unexperienced treatment. In this case we can observe concave protuberances and/or traces of scoria on the Acantite; limited to the the area, which has been in contact with the crucible (if it's done with caution).

It is by no means strange to observe a play of colors (iridescence) on the surface of the Acantite, with a dominance of the bluish colors .

.

Appearance of an aureole: When the treatment has been rough, there can be a yellow aureole at the point of strongest heat, which is white at the center and is greyish-blue at the borders; if the treatment has been well terminated, one may only observe a bluish-white aureole.

Other characteristics:

I have observed silver wires, obtained from Acantite, which have undergone a break during their growth, which certainly stems from oscillations of the temperature during the growth process. There are fine separation lines at the connecting points. At those points the silver wires can be easily divided. Naturally grown wire silver does not have these interruption marks .

In some cases unnatural silver wires contain irregular fragments of Acantite, some quite large ones, which had been loosened during the rapid process of growth.

As I had mentioned earlier, both the Acantite specimen from Imiter and from Balcoll are mechanically mixed with iron sulfides. This is the reason for small crusts and reddish masses between the man made silver wires and on other parts of the Acantite and is due to the toasting of the iron sulfides, which are exposed to the torch or a high temperature and which results in iron oxide and sulfur dioxide; e.g. the formation of Hematite between the wires and on the Acantite.

I have not observed this pseudo-paragenesis on natural specimen, which, however, can be associated with Goethite. The paragenesis of silver and hematite has been described from some meteorites. The intent to eliminate this oxide leads to the appearance of a yellowish patina on the silver, similar to a golden patina.

This association and the conspicuous breakages during the growth together with the particularities mentioned above could ring an alarm-bell, telling us, that the specimen which we hold in our hand, is an anthropogenic silver, obtained from Acantite.

Conclusions

The above mentioned results of the experiments are only useful to allow a simple empiric visual analysis; however, those results may be a help in doubting the origin of a specimen.

If we want to confirm, that a specimen is of anthropogenic nature, we have to do an exhaustive chemical analysis, use spectroscopic techniques and isotope analysis.

The doubts, which I have, refer to a certain silver specimen; it goes without saying that I do not pretend to say that all wiry silver specimen from Imiter are man made. However, I believe, that some of the specimen offered on the market are the result of manipulation.

(Translation from Spanish: Peter Seroka)

1st Sep 2008 19:17 UTCJoan Abella i Creus

Dear Peter Seroka,

Thank you very much for this brilliant summary, which I recommend to all the readers of the forum. Excellent work.

A cordial greeting,

Joan Abella i Creus

1st Sep 2008 20:20 UTCFred & Linda Elsnau

While the above summary is very useful, you miss the wonderful pictures in the original spanish article.

If you have the Google Toolbar on your computer, you have access to their translation program. The translation is not perfect, but you can get the meat of the information provided. It is a very long piece, but appears to be worth the read. And the silvers pictured are great!

Go to the blog link shown above, Once the page opens, enable the translation via the Google toolbar and enjoy!

Fred

3rd Sep 2008 19:41 UTCIan Jones Expert

Mindat readers might also like to look at the letter from Don Edwards in the January-February 2001 issue of Mineralogical Record. He describes how he grew wire silver from acanthite in his kitchen! They were so good that I recall people refusing to believe that they were man-made (although labelled as such) when he had some for sale in Denver a few years ago.

5th Sep 2008 13:23 UTCJolyon Ralph Founder

If it is OK with everyone, I'll take Peter's translation, edit the grammar slightly and add the original photos into a mindat article, which I will put on the front page.

5th Sep 2008 15:19 UTCPeter Seroka

Hi Jolyon,

OK with me - go ahead.

Regards

Peter

6th Sep 2008 23:14 UTCBarry Miller

Thank you all for making this useful information available. I had admired these specimens but I now know to be suspicious.

7th Sep 2008 12:40 UTCJeffrey Shallit

At Tucson last year, I was dealing with a Moroccan dealer who asked, "Do you want to see something really special?" He then pulled out a silver specimen that looked exactly like the ones on Joan Abella's page, and said, "How much?" He was very insistent, but something about it made me suspicious and I refused to make an offer.

9th Sep 2008 08:08 UTCJOAN ABELLA CREUS

Dear Jeffrey Shallit,

Your you did well, the prudence is the virtue of the reason!.

As in the diamond clubs. The persons been interested in minerals, we should create a space in Internet where to put the information and the merchants' photo that bandage falsified minerals.

A greeting

2nd Oct 2008 02:57 UTCRob Woodside 🌟 Manager

Thank you for a most interesting note. It makes me wonder what else is buried in those old 18th and 19th century mineralogies.

The problem with the characteristic habit of these anthropogenic silvers, is that I believe it can also occur naturally. I had a specimen from the Frotier Mine in Cobalt that had this habit with an acanthite base. I'm sure it was natural, but how can one be sure?

29th Mar 2009 02:04 UTCEdgars Endzelins

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=120397407795

What do you think about this one?

29th Mar 2009 02:22 UTCAlfredo Petrov Manager

I am of the opinion that there is no way to conclusively prove whether any native silver wires are natural or not, unless you mine it yourself or get it from a really really old museum collection with impeccable documentation. Certainly can't be judged by how clean it is (any dirty silver can be cleaned, and any clean silver can be exposed to sulphur to tarnish it again). Certainly not by chemical analysis either - Artificially inducing silver wires to grow on a natural acanthite-rich substrate will result in the same impurities Nature has when it "makes" a silver wire. Consequently, considerng our inability to give a definitive answer to the question of natural origins, it would seem that any purchase of alleged native silver is a rather "iffy" investment.

29th Mar 2009 03:08 UTCFrancis X Dzubeck

Alfredo:

I must respectfully disagree with you on one statement in your last post. "Artificially inducing silver wires to grow on a natural acanthite-rich substrate will result in the same impurities Nature has when it "makes" a silver wire." This will only occur if growth occurs under the same conditions (temp, humidity, and mineralization in the air/water/etc.) in all cases. Artificial induction of growth cannot be compared to the natural growth conditions from one mine or multiple locality mines. The impurities in native Silver and the associated matrix must be analyzed and compared to known reference samples to categorically define authenticity and locality. Native Silver from Imiter should contain a measurable Mercury content consistent with its growth environment. This will not be present in a wire Silver with induced artificially growth from an Acanthite matrix from Imiter. The same was true for the German Silvers a few years ago. Their purity without traces of Bismuth and Arsenic was impossible unless they grew in the laboratory or (as I believe) in the Smoke Stack walls of the Smelter. Unfortunately, I have seen no published research on the chemical analysis of the real or "fake" Imiter wires. Therefore, I will agree with your last statement: "Consequently, considerng our inability to give a definitive answer to the question of natural origins, it would seem that any purchase of alleged native silver is a rather "iffy" investment." My last words are Caveat emptor!

Frank

29th Mar 2009 03:43 UTCAlfredo Petrov Manager

Frank,

You are of course right that the impurities (or lack of them) will vary between different deposits and different growth conditions. Native silver is a widespread mineral and must grow under many different conditions, with different contaminants. Unfortunately, a lot of this can be duplicated in the laboratory. Adding a trace of mercury shouldn't be difficult either, even post growth. (I suppose one could scan a cross-section and detect that the Hg was concentrated on the surface, but who wants to do that to a nice specimen?) If I were an artist and lab technician, instead of a geologist, I'd try to duplicate nature in my creations as closely as possible. Eventually the required testing would cost far more than the potential value of the specimen. As you said, Frank, "caveat emptor" is the only good advice.

Cheers,

Alfredo

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