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Have the reverse-skeletal Madan galenas been faked?

Posted by Patrick Haynes (2)  
Re: Have the reverse-skeletal Madan galenas been faked?
November 18, 2009 03:32AM
You're right, Ken, those are bizarre; but I don't see any similarity to the "hollow" skeletons this thread is about.
avatar Re: Have the reverse-skeletal Madan galenas been faked?
November 18, 2009 08:02PM
Alfredo, there are dimples in the center of some of the cube faces. That could show an early stage of a development leading to hollowed out cubes.
Re: Have the reverse-skeletal Madan galenas been faked?
November 18, 2009 10:09PM
    
Yes, as Dominik notes, seeing the dimples and other surface defects made me think these could represent early stages of the dissolution process. --Ken
avatar Re: Have the reverse-skeletal Madan galenas been faked?
March 01, 2010 01:26AM
    
I recently had the oportunity to loop some of these cavernous galenas at Tucson. The pock marking from the air abrasive is quite noticeable at 10x!!! I'm told that Mike Rumsey is going to get some backscatter SEM photos of this material that should put this matter to rest.
Re: Have the reverse-skeletal Madan galenas been faked?
March 01, 2010 02:02AM
    
Thank you Rob, I have been wondering what was going on with these galenas. Lyla
avatar Re: Have the reverse-skeletal Madan galenas been faked?
March 01, 2010 03:26AM
    
Jessica found this in Tucson this year. She photographed it specifically for this discussion. It shows one of these galenas with quartz poking through the hole. I am not saying this solves the mystery.

©



Edited 3 time(s). Last edit at 03/01/2010 03:55AM by Jessica and Robert Simonoff.
avatar Re: Have the reverse-skeletal Madan galenas been faked?
March 04, 2010 07:00PM
    
Im new to the debate, but these specemines look highly etched with some type of acid. Could someone have"painted" on a sealant to protect the galena edges early before etching,with the purpose of cleaning them up and removing the oxides and such. In doing this they possibly inadvertantly dissovled away the centers of the galena cubes and just went with it. It does look like a byproduct of acid cleaning. What sealant would protect the edges of the galena to acid but later be able to be removed after with another chemical?

Ariel
Re: Have the reverse-skeletal Madan galenas been faked?
March 04, 2010 09:17PM
If it looks like a fake...then it is a fake.
Re: Have the reverse-skeletal Madan galenas been faked?
March 04, 2010 09:42PM
Thanks for the photo, Jessica!

What the quartz shows us is that the galena is younger, in other words the galena grew over the quartz crystals, which were then hidden inside the galena as inclusions, to be revealed again after the galena was etched away. Whatever etched away the galena, whether mechanical or chemical, natural or artificial, did not attack the quartz. So, unfortunately, the quartz doesn't help to answer the question of whether the peculiar holes in the galena are natural or artificial. If you can find a less tough mineral inside the galena, like calcite or sphalerite, that would pretty much destroy the "manufactured by microabrasive" theory. Keep looking!
avatar Re: Have the reverse-skeletal Madan galenas been faked?
March 05, 2010 06:13PM
    
There could well be damage to the quartz from the air abrasion, if they used anything hard like glass beads.. What has been frustrating about this thread is that there are no photo micrographs of this material. They would clearly show the pitting I saw with a 10x loup on the several specimens I saw at Tucson.
avatar Re: Have the reverse-skeletal Madan galenas been faked?
March 05, 2010 09:00PM
    
When we met in Tucson Alfredo mentioned seeing a specimen of these Bulgarian galenas with remnants of "clay" inside the hollow galena-cubes. A SEM-picture should be able to tell if there was remnants of a abrasive material in the "clay". Any news on this, Alfredo ?
Knut
Re: Have the reverse-skeletal Madan galenas been faked?
March 07, 2010 05:42AM
No, Knut, no analyses done yet on the white residue, as far as I'm aware.

And Rob, I've seen lots of quartz crystals cleaned with glass beads and they don't show any damage. The 5 - 7 hardness difference is significant. Perhaps impact by glass beads would leave marks visible by SEM?
Re: Have the reverse-skeletal Madan galenas been faked?
March 07, 2010 07:40AM
att: Jolyon - if you have some suitable material I suggest you can bring them up here to the NHM and ill book some time on the SEM to take a look.....
Re: Have the reverse-skeletal Madan galenas been faked?
March 07, 2010 09:55AM
Hello,

The last 10 years I specialized in collecting bulgarian Minerals.

I saw a lot of interesting Specimen,mostly from the Madan-Laki Region in the Rhodopi Mountain.

"Mother Nature" is the best artist on this Planet, but in my opinion ,in this case we have a good hand-made job!

A "normal" salary in Bulgaria is between 200-400€. Its too much to die and too little for Life.

Maybe this year I have the chance to meet the artists of this ......and here goes my respect to this very talented bulgarian people.!

Cheers

Marcus
avatar Re: Have the reverse-skeletal Madan galenas been faked?
March 10, 2010 10:02PM
    
So it seems that some pictures or a video of these being found in the mine from which they came from would lay to rest any uncertanty about these being naturally formed or not.

Ariel
avatar Re: Have the reverse-skeletal Madan galenas been faked?
March 10, 2010 10:17PM
Not really, Ariel. It would help, of course, but it's not impossible to fake.

The real test will be microscopic examination of the surfaces to see if it shows abrasive marks.

Jolyon
Re: Have the reverse-skeletal Madan galenas been faked?
March 10, 2010 10:19PM
....then we'd be discussing digital alteration of video instead of alterations of minerals winking smiley)

And as for SEM analysis of surfaces to check for abrasive marks, I'd think it would be easy to remove those by etching with HNO3 after the mechanical treatment. There really isn't much that Nature can do that humans can't duplicate. (Although the reverse is not true, at least not on this planet.)



Edited 1 time(s). Last edit at 03/10/2010 10:24PM by Alfredo Petrov.
avatar Re: Have the reverse-skeletal Madan galenas been faked?
March 11, 2010 05:40AM
    
Well like I asked before is, could someone paint on some type of selant to protect the edges of the galenas then chemicaly etch them? Then remove the sealant off later with something else preserving the terminated edges? No mechanical just chemical etching.

Ariel
avatar Re: Have the reverse-skeletal Madan galenas been faked?
March 11, 2010 03:45PM
Take a look at [www.mindat.org] for an example of a naturally etched mineral, albeit in this case pyromorphite microcrystals. Clearly these crystals are chemically zoned as revealed by distinct variations in color, with a layered structure, better seen in [www.mindat.org]. It is my belief that slight differences in solubility, due to this chemical zoning, resulted in selective etching of these pyromorphite crystals, resulting in the unusual shell/tubular morphology due to the outermost layer, by chance, being the least soluble. (btw, softness of images due to just getting acclimated to using image stacking, may remake these images in the future). Same behavior in vanadinite, from the same locality: [www.mindat.org]

As suggested in prior posts, selective etching of chemically differing zones, in the galena, could result in the observed morphology. However, subsequent cleaning of these specimens have unfortunately removed any indications of a natural origin.

Or, someone with too much time on their hands, and access to a portfolio of M. C. Escher prints for inspiration, has made these. You can etch with sand blasting, or using a microsyringe, apply liquid drop-by-drop, on each face, with a suitable liquid with wax coatings in areas to be protected.

I have read nothing in any of the prior posts that is conclusive one way or the other. I would prefer that the source supplier bear the burdon of proof - show us one that has not been cleaned and clearly indicates its natural origin.



Edited 2 time(s). Last edit at 03/11/2010 03:49PM by Jeffrey Weissman.
avatar Re: Have the reverse-skeletal Madan galenas been faked?
April 24, 2010 06:23AM
    
Just to keep this discussion rolling, I have a little more information to add.

I was able to purchase the specimen highlighted by Ken Doxsee earlier in this thread with the galena crystals with the dimples shown in the centre of the crystals.

Even though most of the crystals showed dimples, one was hollow as the photographs show. Interestingly the hollow crystal continues under a solid galena crystal. This would be very difficult to produce mechanically and why only do one when the rest are dimpled. It can be noted that in one point a crystal has a small hole that opens into a larger cavity within the centre of the crystal. I think that the dimples are the last stage of growth not the first stage.

Closer investigation does not show any mechanical making under magnification. Another interesting aspect are the growth layers on the galena crystals, also shown on the photographs. Similar growth structure is noticeable on the chalcopyrite and Sphalerite crystals on the same specimen.

I can not speak for the other skeletal examples discussed but I would strongly suggest this specimen has naturally developed.

I am surprised at some comments that imply that when a specimen looks like a fake then it must be a fake, sorry but nature does not work that way. I have spent enough time field collecting to know when unusual elements combine with out of the ordinary environments then very unusual mineralogical outcomes sometimes occur. I suspect this is the situation at Madan ore field with some of these galenas'.

© Andrew Tuma
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