Have the reverse-skeletal Madan galenas been faked?

well while there are ways to have "proof" I think any absolute proof would only come in a video of the discover. Without it we are only lead to believe that this old, one time find is real. There is proof and then there is proof.

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A buena hambre no hay pan duro

James,

I assure you this, as I can tell you it can be done. Here is a photo of a galena from the Blanchard Mine in New Mexico, great etching patterns, done in 10 minutes.

Joe, you make a good point about softer minerals inside the cavity, although I have yet to see this occurance.

Jolyon,

Here is an example that I have an issue with, if there is solution etching in the pocket or distorted growth, why do some of these galena crystals on the piece have little distortion?

Regards,

Ryan



Edited 2 time(s). Last edit at 11/07/2009 05:43PM by Ryan L. Bowling.

Ok Ryan,

Thanks for taking the time to do the experiment - this is exactly what we needed to see - proof that similar material can be created artificially.

While it's impossible to say for certain right now, your experiment has swung things firmly back towards the possibility that they are faked.

What an exciting thread this is turning out to be.

Jolyon

Ryan, I love your first photo with the inserted quartz xl that proves these are real!!! The next step is to insert one with non fluorescent glue!!! Your observation of the paragenesis in your earlier post is quite telling. Now I am more puzzled by Joyon's photo than these cavernous Galenas, but I suspect the luck of a fracture produced it.

Other minerals within the cavities could have developed before the galena, and been subsequently freed by whatever process created the cavity.

Good point Dominik. Ryan please replace the quartz xl with a calcite crystal, then it will be real. As with my allusion to non flourescent glues, the danger here, as with any fakes, is that once the faker knows of an objection specimens will appear that meet the objection. I think these are great mineral art!!!



Edited 1 time(s). Last edit at 11/07/2009 07:40PM by Rob Woodside.

Rob,

I did not insert any quartz crystal in any of the photos, I think that what you see is the hollowing out of the crystal, or your comment is in jest. The matrix is classic Blanchard Mine quartz crystals.

Ryan



Edited 1 time(s). Last edit at 11/07/2009 08:46PM by Ryan L. Bowling.

Sorry Ryan, I got the impression from your posting and photos that the quartz xl in the first had been inserted in a xl of your second photo. In the absence of any soft xl overgrowing the caverns, one has to look at photomicrographs to see if these are cleavages or dissolution features.

edit. The first two photos look like Banchard material and thinking the quartz was inserted the fakery seemed obvious and when that happens I get sarcastic. At least your experiment vitiated the claim than any quartz would be blown away in the cavities. Until something soft is found in the Bulgarian cavities, one could assume that the paragenesis was Galena, quartz, dissolution. Still the difference between cleavage and dissolution should be obvious under the scope.



Edited 1 time(s). Last edit at 11/07/2009 08:56PM by Rob Woodside.

Very interesting, Ryan. Thanks for posting the pictures!

I have been following this thread with interest having seen some of these at Springfield. Jolyon's photo reminded me of some micro specimens I have in my collection. These are from Cornwall, England, and date back to at least the late 1800's (having been part of John Frederick Calvert's collection - he died in 1897). The crystals are about 3 mm, and the material associated is Sphalerite (no photo) and Baryte. In DSCN 6136, the Baryte is visible on the side. It is in perfect condition - no scratches, etc. I suppose something harder than Galens and softer than Baryte could have been used to abrade the crystals, but it seems bizarre to do so with micro material.

Bob

Bob:

I think one of the differences between your specimens and the skeletal Galena is that there is a more rounded form to your specimens than what I have seen so far with the skeletal Galena.

Your specimens just look 'Right'.

I think if we got quite good shots of the stepping patterns in the skeletal Galena, it would show that the 'steps' are actually of a much more ragged appearance than your specimens.

Bob, your crystals show growth hillocks and possible hopper development (these are growth features). The Mandan specimens would have had to develop by dissolution.

Thanks so much Robert. As Bri and David say these are honest growth features, quite different than the Bulgarian caverns. Could some please post photomicrographs of the Bulgarian material?

I believe the faked galenas are easily identified with a good microscope. The skeletal crystals that have been microabraded very clearly show rounded, dull surfaces the result of abrasive action. The genuine (I believe) show distinct growth-layers that are sharp and well defined.

One idea that seems to be absent from this thread is this: just because the appearance of these galenas can be mimicked by man (or woman or air blaster) does not mean the Bulgarian specimens are or are not fakes. Metaphor: I can grow diamonds in the lab, so all 'natural' diamonds are fakes?

Because no one I know of has the photographic equipment (or lifetime) to actually observe the galena growth or etching it situ, I believe the most definitive evidence will be a photo of the specimens in question in situ.

Until such a photo surfaces, I'm inclined to believe these specimens to be fakes. And I suspect because we've shown the world how easily they can be made, they will appear in quantity at Tucson, perhaps with a Chinese locality label.

Hi,

As I stated in an earlier post, when I see some calcite, dolomite, siderite, barite or other fragile minerals nesting in those voids, I will cast aside my doubts and accept that they are natural.

Best,

Joe

Steve, as I pointed out earlier in this thread some of these galenas may be real and some faked, like the stringy wire silvers. As I and others have pointed out, a good microscope will tell if the lines in the galena are due to growth or cleavage. An in situ photo can be easily faked by mere careful placement of well carved galenas. Air abrasion will not produce micros and the remnants of growth hillocks. The presence of bas relief or the presence of soft minerals in the caverns would prove reality as well as. The fact that none of the Bulgarian galenas show any bas relief should raise a lot of red flags.

I suspect the appearance of this thread will decrease the further appearance of such specimens giving credence to those who claimed this is an old one time find.

I find it odd that dissolution would favour the center of the cube faces. Seems to me that dissolution would be more rapid at the edges and corners resulting in a round crystal rather than a hollow one.

I agree, Reiner. That's one of the reasons I was first suspicious too. But Jolyon has come up with a possible mechanism to explain it: Imagine a hopper-faced galena that changed composition as it grew, with the older growth (the center of the crystal) being less resistant to dissolution than the younger growth (the skeletal edges). This might be theoretically possible, but personally I'm still skeptical. I'll believe in the natural origin when I see one that has its "tunnel" entrances blocked by quartz or other minerals making it difficult to point a microabrasive pen through it, or a specimen with younger and softer minerals growing in the cavities, but I'm trying to keep an open mind (although a friend told me our brains will fall out if our minds are too open). :)

I cannot understand the concept of "older" and "younger" when it comes to skeltal growth, only slower and faster. Seems to me that the more rapidly growing edges would also be the least stable and more likely to dissolve than the slower growing centre.