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Fake pyrite concretion?

Posted by Reiner Mielke  
avatar Re: Fake pyrite concretion?
December 14, 2010 02:51AM
Much better :)

The natural world continues to throw amazingly odd things at us, and it would be totally wrong for us to discount such things out of hand.
Re: Fake pyrite concretion?
December 14, 2010 02:52AM
Apart from matrix-free specimens like alluvial nuggets, meteorites, etc, I suppose almost all mineral specimens have been "enhanced" by judicious removal of some matrix, cleaning off of unwanted films and crusts, etc. They don't look the same as they did when still embedded in the wall of the mine! But the word "enhance" seems to have acquired undesirable connotations among collectors (despite the fact that most of their specimens have been "enhanced" in this sense). So we are faced more with a semantic problem than a mineralogical problem. Perhaps we need two different words, one for desirable enhancements and another for undesirable enhancements, bearing in mind that "desirable" and "undesirable" are going to be frequently endlessly debatable and that the boundaries change with the fashion of the times and with the culture.

Asians do tend to like to give matrix an artistically sculptured appearance - as for example with the chipping of the white marble matrix of the pink Vietnam spinels. I don't particularly appreciate that technique myself, but we mineralogically scientific Westerners are only a small segment of the market for such stuff, so we can avoid buying them, but that's not going to have much influence on the custom.
avatar Re: Fake pyrite concretion?
December 14, 2010 05:45PM
    
The "enhancements" on most specimens are otherwise known as trimming and cleaning.
avatar Re: Fake pyrite concretion?
December 14, 2010 06:50PM
    
I don't see a problem with a natural evolution of these pyrite concretions. I have seen numerous concretions (Kettle Point, Ontario, Colorado River, Utah) with layers of hematite stains. As these weather out of their matrix, they are often concentrated by natural processes (such as rolling down hill).
If you bury these in an organic rich, reducing environment for a million years, the chemical reaction produces pyrite, just as it does for the pyrite "dollars" found in the midwest U.S. coal mines.
-Dean Allum
Re: Fake pyrite concretion?
December 14, 2010 07:00PM
    
I'm looking forward to perhaps picking up one of these "new" Chinese pyrites in Tuscon this year.

Because this type of nodule is formed in sedimentary deposits, the banding could be explained by the differences in the makeup of the individual layers of the sediments.

I have in my collection a "spherical" pyrite in black shale matrix from China, that is entirely made up of cubic crystals. Sorry no photos, but it is 3cm big(the nodule) with the individual crystal face of 2mm.


Bob
Re: Fake pyrite concretion?
December 15, 2010 12:48AM
    
"Because this type of nodule is formed in sedimentary deposits, the banding could be explained by the differences in the makeup of the individual layers of the sediments. " If that were the case then the banding would not be resticted to round spheres ( concretions) but extend into the matrix. Also concretions are not a product of sedimentation but later crystallization of minerals around a nucleus be that a fossil or mineral grain.
Re: Fake pyrite concretion?
December 15, 2010 04:40AM
    
A close examination of a sliced surface through a big piece of this shale with still embedded pyrite concretions would help. Is any out there?



Edited 2 time(s). Last edit at 12/15/2010 04:42AM by Franz Bernhard.
avatar Re: Fake pyrite concretion?
December 15, 2010 08:33AM
    
Folks,
IMHO they are all natural .. i have had some of those in my hands and i have seen a picture of them in situ in a mudstone/shale (but do not remeber who showed me the picture). To me they are nothing unusual re formation ...
There are single "balls" as well as "bread leafs" and double "eggs" etc.

Cheers
Roger
avatar Re: Fake pyrite concretion?
December 16, 2010 04:13AM
    
Looks natural to me as well, certainly within the realm of pyrite concretions in sedimentary rocks.
Re: Fake pyrite concretion?
December 16, 2010 10:19PM
Hi All,

for me these Pyrite concretions are natural.

I imagine, the Pyrite grow in mud at the borderline of two stata of fluid with different O2 content, Fe content ore other chemical/physical conditions. And this borderline sink and go up by the time; maybe with the rainfall, summer heat ore other climatic conditions.

My wife comes from Shanghai. Since I met her, I say (, if she can not hear it): "If You have to do with Chinese, think like Chinese." - But in this case, I think, the P. concretions are natural.

And an other important point, which has nothing to do with mineral collecting: If China is econmically developed like the Western World, the economy of the Western World will not break down! Like the British economy broke not down at the end of the 19th century, when Germany and Austria became technical and economical developed like England!

Inhonest dealers You find all over the world. - There are many fakes of and fraudulent Trilobites from Morocco. The Morocco people learnt it from white dealers, how the make a trilobite fake!

Greetings from Thale near Goslar

Georg
Re: Fake pyrite concretion?
March 21, 2012 01:40PM
Does anyone have any information on whether the pyrite in these balls is going to succumb to pyrite disease (rot)?
Re: Fake pyrite concretion?
March 21, 2012 10:38PM
Great question Eric,

Unfortunately, my initial observations is that some are going to be problematic. A little over two and a half years ago Mike New, of Top Gem in Tucson, imported thousands of Chinese pyrite concretions. Solid pyrite concretions, with no shale banding, and the appearance of crystalized surfaces. (Top Gem had been importing them for a number of years prior to this, but not anything like this shipment for quantity.) The bulk of the pyrite concretions that I chose from were round, with a sizable percentage flattened discoid shaped. I was careful, sorting through hundreds, and picked out ones with minimal flaws, and specifically no cracks.

Now several years later a number are starting to have issues. Out of 12 flattened discs, ranging in diameter from 4cm up to 6.5cm, 5 now have radial cracks with one severely cracked. All of the spherical pyrite concretions that I picked out, under 5cm in diameter and showing prominent crystal faces surrounding the exterior surface, are fine. They show no cracks, discoloration, nor do they 'smell'. Now I cant say the same thing for the large ones that I chose. I picked out several exceeding 10 cm in diameter. Out of three, two are starting to turn. They are developing a darker patina, and have several areas with lighter discoloration appearing. Picking them up, and smelling them, they are developing a noticable odor. I have removed the big ones from display and storage with other pyrites. What I did notice, is that the larger diameter pyrite concretions have smaller crystal faces showing on the surface, and more resemble 'scales' instead of cubic faces.

Upon close inspection, with a hand lenses, I can find remnents of shale matrix down in crevices between crystal faces on most of the Chinese pyrite concretions. It has only been recently, in the last two years, that I started noticing the shale banded pyrite concretions. I did pick up two feeling that they were legitimate natural specimens, similar in occurence to those I already had. I have not yet had any issue with those.

Sorting through so many pyrite concretions, I was fortunate to see several which had been broken in half. The interior showed bright 'pyrite' colored material with a fibrous radial pattern. It was similar in appearance to the interior sections that I have seen in French marcasite concretions. I am not sure if that type of structure has any relevance, since crystalized pyrite, when broken, has a semi-concoidal fracture.

Phil
Re: Fake pyrite concretion?
March 22, 2012 07:25AM
Hi Phil,
It is quite common in many of the occurrences of these spherical or spheroidal pyrite concretions that the internal structure includes zones which are pyrite intergrown with some marcasite. Examples I've looked at under the reflected light microscope were from Dover, England and several places in the Goldfields and Pilbara province in Western Australia. This marcasite component is quite distinctive in reflected light and I suspect this mineral is the main culprit responsible for the concretions falling apart in a damp atmosphere.
Cheers,
Ben.
Re: Fake pyrite concretion?
April 11, 2012 07:47PM
    
I happened to come across a Sino-American couple that import these concretions from family in China. This was at one of the outlying venues at Tuscon this year. They informed me that these things are NOT completely natural. They had dozens of both spherical and egg shaped nodules with rings, spirals, even diagonally patterned ones. They did state that they have been decorated and shaped by man. Even though they were VERY cheap, I did not buy one.
Re: Fake pyrite concretion?
May 31, 2012 04:15PM
HA! The plot thickens. Anybody who has studied up on how concretions form could see some problems here, as Reiner has outlined.

Now I really want one of these things, to put to the saw.
Re: Fake pyrite concretion?
June 01, 2012 09:15PM
    
Hi all,

This thread has been going on so long that an entire research project on similar iron-sulfide shale concretions in central Ohio has been completed (since I last posted) by an undergraduate student in our department. The project was presented at a GSA meeting a month or so back, and the abstract is below. The link goes to a GSA page with a big PDF download with information and data for the geologically inclined. The research focused on the stages of development of the concretions, their organic origins, and their mineral composition (pyrite and marcasite - which develop in a complicated manner - see the PDF at the GSA link below). Eric's plans to continue studying the geomicrobiology of the concretions in graduate school. I'm not a geologist (I work with them) but this was a fun project to follow.

Marcasite and pyrite in the concretions (reflected light microscopy (RLM)):



Some SEM images from one of the concretions:



Below is an image of one of the flatter concretions cut in half. A spherical specimen was cut, but I don't have a picture at the moment.



GSA Abstract & PDF download: [gsa.confex.com]

IRON-SULFIDE CONCRETIONS OF THE OHIO SHALE: GLIMPSES OF DEEP SUBSEAFLOOR MICROBIAL ECOSYSTEMS OF THE LATE DEVONIAN
MUMPER, Eric, Department of Geology and Geography, Ohio Wesleyan University, Delaware, OH 43015, mumperman@gmail.com and FRYER, Karen H., Department of Geology and Geography, Ohio Wesleyan University, Department of Geology and Geography, Ohio Wesleyan University, Delaware, OH 43015
Recent interest in black Devonian shales for natural gas exploitation has brought shale research into new importance. At the same time, advances in the understanding of deep subseafloor microbial ecosystems have revealed that microbes play a more pivotal role in geologic processes than ever imagined. The convergence of these two areas provides an excellent opportunity to reexamine enigmatic concretions of the Ohio Shale. The Huron member of the Ohio Shale is distinguished by the presence of carbonate concretions. These concretions vary considerably in size and differ in composition from the host rock. Their origins have been questioned since they were first described in 1873. Current models attribute concretion formation to abiotic mineral replacement of organic substances. However, smaller, iron-sulfide concretions inhabit the same horizons and are less well studied. Iron-sulfide mineralization has been attributed to biotic processes and may be connected to the presence of the larger carbonate concretions. Iron-sulfide concretions have been collected from three sites in Delaware and Franklin Counties in Ohio. These samples were investigated using reflected light microscopy, scanning electron microscopy, and energy dispersive x-ray spectroscopy. Based on morphology, composition and size, the iron-sulfide concretions have been categorized into four different stages of paragenesis. These stages correlate well with known microbial zonations of deep subseafloor environments. Understanding the microbiological processes at work in the creation of black Devonian shales may shed light on how to exploit modern microbial systems to develop sustainable sources for carbon fuels in the future. GSA North-Central Section - 46th Annual Meeting (23–24 April 2012)




John K.
Re: Fake pyrite concretion?
July 06, 2012 12:25AM
    
I'm puzzled by the decription of Fig. 8&9. It says that "the anisotropism is indicative of pyrite crystals"? But isn't pyrite isotropic?
Re: Fake pyrite concretion?
July 21, 2012 06:31PM
How about this one? Given the asking price I am assuming this is real.

Ebay "Volleyball" from Kansas?
Re: Fake pyrite concretion?
July 21, 2012 08:00PM
Howard, if that is museum quality, what museum already has one?? To me, tho I'm a novice, comparatively at this, hollow means fake. Slag has air bubbles, rocks are solid, except for geodes. I thought of a basketball dipped in clay. Where in Kansas? Are there more? Jsome ideas for you...ust
avatar Re: Fake pyrite concretion?
July 21, 2012 11:53PM
I don't see any pyrite, but it looks to be real and a pretty cool concretion.

Rock Currier
Crystals not pistols.
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