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Glued Dioptase ?

Posted by Andrea Sansoni  
Glued Dioptase ?
June 06, 2011 12:56PM
    
I recently bought a dioptase specimen from Congo, it is a nice single crystal about one inch tall, on a small piece of pale blue matrix, probably plancheite. The piece has a strange look, the crystal sticks out of the matrix in a strange unnatural way, so I have put it under long-wave UV light and there is a ring of blue fluorescence on the matrix all around the crystal, everything else is not fluorescent. I also tried to scratch the matrix with an sharp iron tool, and the fluorescent ring is much harder than the bulk of the matrix, in fact I almost cant scratch it. There are other smaller crystals on the piece nested in a small vug, looking perfectly natural and showing no fluorescence nearby. I suspect the big crystal was planted on the matrix with with a mixture of glue/cement and powder from the matrix but I have no experience with glues. Are glues or cements likely to be used for this kind of fakes supposed to be fluorescent ?
avatar Re: Glued Dioptase ?
June 06, 2011 01:30PM
    
Hi Andrea - from what I've read elsewhere, yes, the glue used to attach crystals is often (but not always) fluorescent.
avatar Re: Glued Dioptase ?
June 06, 2011 03:06PM
Perhaps we can give a more concrete opinion if you can post pictures of the specimen under white, and also under UV, light, so we can see the fluorescence.
Re: Glued Dioptase ?
June 06, 2011 04:55PM
    
Andrea

If you don't mind the crystal comming off , , you can try soaking it in acetone.
Then you will know for sure, you can always re epoxy it back on.

Wayne
Re: Glued Dioptase ?
June 06, 2011 08:34PM
hi .are you sure it's a dioptase cause recently i buy a large dioptase crystals but when i receive it i fasten discover than the crystal was in fact a manmade emerald green zircon stick on a matrix of quartzite coated by blue shattuckite.the first clues than lead to discover the scam was the cheap price for a large crystal like that(4inches long for 40$)and the shape of this crystals who's look like the manmade zircon than i see in the vug special fakes minerals.that's been very hard to find than the crystals was glue to the matrix cause they really do a great job.i never check if the glue was fluorescent but i think they use a kind of epoxy cause the glue had begin to turn yellow.bye. i hope it's not the same problem with your crystal and sorry for my bad english.
Re: Glued Dioptase ?
June 07, 2011 08:28AM
    
Yes, I will try to take photos and post them.
Anyway, yes it is Dioptase not Zircon, and I don't want to soak it acetone because I want to send it back to the dealer if it is glued.
Re: Glued Dioptase ?
June 08, 2011 01:13PM
    
Ok here are the photos in normal light and UV 360nm



Edited 1 time(s). Last edit at 06/08/2011 01:16PM by Andrea Sansoni.
Attachments:
open | download - Diopta1.jpg (342.1 KB)
open | download - Diopta3.jpg (343.5 KB)
avatar Re: Glued Dioptase ?
June 08, 2011 03:01PM
Glued. A fake, or at least a repair. Definitely.
Re: Glued Dioptase ?
June 08, 2011 03:30PM
Dear Andrea;

Only the xl w/the fluorescent ring is glued on; the rest are authentic. I don't think it's simply a repair; the piece looks a LOT better (to an unsuspecting buyer), with that xl standing up, when nonje fp the others are doing so. I say THAT xl makes it a "fake".

Your friend, Steve
avatar Re: Glued Dioptase ?
June 08, 2011 03:30PM
Thank you for the excellent photos Andrea - they show exactly how the fake (or reconstruction) is perpetrated. Glue mixed with powdered rock is set into a cavity in the specimen, and a loose crystal is pushed into it. Under UV light you can clearly see how it has been constructed.

Would it be possible for us to use these photos in future on this site to help educate other people how to spot such fakes? I'd be very grateful!

Jolyon
avatar Re: Glued Dioptase ?
June 08, 2011 09:05PM
    
I recently came across a specimen in my collection that may be faked or repaired, though I can't be certain what exactly was done. The piece is Chinese, of a type that had a rash of fakes some years ago, from what I have now read. I was inspecting it under a loupe shortly after I got it, and the primary crystal looked good. However, as I looked closer, I saw a tiny gap between one edge of the crystal and the matrix.

There was a larger crystal of a secondary mineral on the back of the piece, but nothing looked out of place with it. Finally there was a small spot along the matrix that was shinier than the rest of the matrix around it, like dried glue. I took it under UV, and sure enough, the shiny spot glowed bright. However, nothing at all glowed around the main crystal, or the secondary crystal.

So, I am at a loss as to what exactly was done. Perhaps a stabilized matrix, and a very artfully attached main crystal? I really don't want to say much about it or post photos, so I realize that not much of an opinion can be given. I just wanted to relate my own story and see if anyone had any type of opinion at all. I know the dealer that I bought it from, and I know for a fact that he would not willingly sell something like that. I do know however that dealers have a lot of stock to deal with, and don't honestly have the time to check everything as good as I checked that piece. Also, I can't be 100% certain that something has been done. I guess I could soak it in acetone, but I like the look of the piece whether it is real or fake (the minerals are most likely real, just possibly an enhanced assemblage). Luckily, I didn't pay much for the piece (less than $40 USD), so it is not much of a loss.

Since I am relatively new to collecting, this was my first experience with something like this, and I was a little upset at first, and unsure of how to proceed. I thought perhaps leaving it alone and just labeling the piece as possibly repaired would be fine.
avatar Re: Glued Dioptase ?
June 08, 2011 09:34PM
    
Reattached xls can be impossible to prove without long baths in solvents. Any separation of xl and matrix is a warning sign. I don't have a problem with repairs and stabilizations clearly labelled, but constructions are something else.

Most Spanish pyrites are reattached as the tiny white layer between the pyrite and matrix is water soluble (gypsum?). The cubic corners left in the matrix are an open invitation to "improve" the specimen by reattaching a better or bigger xl.

Edit: At the Mindat conference I learned that the white rind on Spanish pyrite is Talc!!! It swells under water and allows the cube to fall out



Edited 1 time(s). Last edit at 08/29/2011 10:54PM by Rob Woodside.
Re: Glued Dioptase ?
June 09, 2011 08:06AM
    
Of course you can use the photos in any way you like, please do it !
I have looked at it with a good microscope and I can clearly see the glue in some spots, I will try to take photos and post them too.
avatar Re: Glued Dioptase ?
June 09, 2011 11:44AM
    
Excellent photo's Andrea, thanks for sharing. It reminds me a lot of the Namibian Dioptase from the Kaokoveld plateau in Kunene Region. I hope you have no problems getting a refund.

:)
Re: Glued Dioptase ?
June 09, 2011 12:37PM
    
Here are some photos taken with a good microscope. The matrix near the crystal (the fluorescent area) has a wet resinous yellowish look.
Attachments:
open | download - Matrix1.JPG (239.2 KB)
open | download - Matrix2.JPG (445.4 KB)
Re: Glued Dioptase ?
June 09, 2011 12:42PM
    
... and these are a couple of spots where the glue is clearly seen on the crystal, in the second photo the layer of glue is detached from the surface of the crystal. Thank you all for the comments !
Attachments:
open | download - Glue1.jpg (217.3 KB)
open | download - Glue2.jpg (220.4 KB)
avatar Re: Glued Dioptase ?
June 09, 2011 02:17PM
    
This is not a new phenomenon! The enclosed pictures show a crystal of apatite from Carrock Fell attached to an authentic 'gilbertite' matrix. I can't manage UV photos of any quality unfortunately, but the attachment points glow brightly blue-white. The apatite has a nice green fluorescence, and the matrix is inert. The label in the photo in the next message was originally glued to the specimen but became detached on cleaning. I got this from a dealer in Manchester in the early 1980s. Butler dealt at Brompton road from 1884 to 1927, I believe. The style of the label suggests the earlier period - perhaps up to the 1914-18 war ...

Caveat Emptor - but I treasure the specimen for the story it tells!

Cheers

Tim
Attachments:
open | download - Carrock apatite0.jpg (396.1 KB)
open | download - Carrock apatite1.jpg (352.1 KB)
open | download - Carrock apatite2.jpg (348.8 KB)
avatar Re: Glued Dioptase ?
June 09, 2011 02:18PM
    
Label:
Attachments:
open | download - Carrock apatite4.jpg (340.6 KB)
Re: Glued Dioptase ?
June 09, 2011 11:09PM
hi. personally i have no problem with buy a glue specimen to is real matrix if the sellers inform me before i buy it.i buy recently a glue cinnabar for a well know sellers from tucson than many peoples here know and appreciate.i pay less than 10$ for this gemmy blood red large specimens of cinnabar .im sure it's the real matrix cause i can found inside tiny inclusions of the same kind of cinnabar.if i can save money with a repaired specimens.anyway my cats push over the edge the shelf many specimens each years and i must repair them myself.i search for cinnabar with the same size and quality and i found nothing under 100$-300$ .if i had never found this repair specimens i think than i never had something like this in my collection.bye
Re: Glued Dioptase ?
June 10, 2011 11:29AM
    
The dealer agreed on a refund or exchange, he is a nice person and was also deceived, he imported a big stock, I can imagine that it is difficult to check everything. A good lesson learned anyway, and I wont forget my UV flashlight for my next buy.
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