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 Post subject: Old discoloured oil in emerald?
PostPosted: Tue May 09, 2023 6:29 am 
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I have a clearly dyed emerald submitted. In some fissures a brown discoularation is visible. Can this be the remnants of old discoloured oil? I have seen this once or twice, but am not sure. The brown inclusions are only in the fissures near the surface. No raman, so microscope and common sense only. I searched for some images of these kind of old oils, but could not find them... Attached one from this stone.


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vulling-gemmology-online.jpg
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 Post subject: Re: Old discoloured oil in emerald?
PostPosted: Tue May 09, 2023 3:15 pm 
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typical dried oil, and probably traditional aka (Cedarwood oil), Don't know about the other part of your claim about the stone being dyed, which I don't see any patched of dye in the attached picture. but Emeralds, specially Colombian they get oil treatment rather than Dye!

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 Post subject: Re: Old discoloured oil in emerald?
PostPosted: Wed May 10, 2023 2:55 am 
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Thank you. There are some two phase inclusions in the stone, but not 3-phase. Don't know its origin. I can see colored patches (not on this picture). Always difficult to capture. See the attached pictures. One is dye in a fissure (you can also see veils in the lower right), and a filled fissure (always a lot clearer through a microscope, this is a stack of 13 images.

Still strange I can not find any other pictures of degraded oil in emeralds.


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export-dyed-fissures.jpg
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export-dye-inclusion.jpg
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 Post subject: Re: Old discoloured oil in emerald?
PostPosted: Wed May 10, 2023 5:28 pm 
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If it's just right at the surface (hard to tell in a stacked photo ofc) that could be chrome oxide polish remnants. Which is not to say they couldn't affect the color.

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 Post subject: Re: Old discoloured oil in emerald?
PostPosted: Thu May 11, 2023 4:26 am 
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Stephen Challener wrote:
If it's just right at the surface (hard to tell in a stacked photo ofc) that could be chrome oxide polish remnants. Which is not to say they couldn't affect the color.


Thank you. For the second picture it did cross my mind, will re-evaluate. I didn't take into account that polishing powder can also be emerald green. The second picture was not stacked. The upper one is stacked, and near the surface. For me it seems like a colored substance.


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 Post subject: Re: Old discoloured oil in emerald?
PostPosted: Thu May 11, 2023 5:50 am 
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The stone has a lot of fissures where dye has entered. I think it is intentional, although maybe they used a polishing powder as colouring agent. It has entered the fissures with a kind of oil (with a stereo microscope it is very clearly visible that it is inside the emerald).

For me, apart from evaluating the stone, it is also of some academically interest to understand what happened, and how "they" did it. I had some remarks the brown inclusions are an ironoxide, but to me that seems somewhat far-fetched. It is remarkable I have heard a lot that brown staining inside an emerald is normally degrade oil, but how difficult it is (for me), to find images of examples. So I have to make the example pictures myself.


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File comment: Dye in fissure of emerald. It has clearly entered from the fissures and going deeper.
dye-in-fissure.jpg
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