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 Post subject: Best light setup to see color zoning?
PostPosted: Mon Mar 01, 2021 10:33 pm 
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Hello guys,
I am a complete newbie to this and am now trying to learn to identify natural vs synthetic amethysts.

I have a question about color zoning - what is the best light setup to spot the differences? I have been getting different results under different light conditions, and possibly some color bleeding or refracted light is throwing me off. This is especially true for complex faceted stones.

I assume diffuse light is best, bu front or back? Does light temperature matter? Would you bother building a black box for evaluation or is this already going too far?


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 Post subject: Re: Best light setup to see color zoning?
PostPosted: Tue Mar 02, 2021 1:43 am 
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Soft transmitted light while stone is immersed in a liquid with RI similar to quartz is the best way to see zoning.

However, I don't think zoning is the key to separating natural from synthetic quartz.


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 Post subject: Re: Best light setup to see color zoning?
PostPosted: Tue Mar 02, 2021 2:03 am 
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Thank you! I will look for breadcrumb inclusions once the microscope arrives :)
Is there anything else to look for to separate synthetic quartz from natural besides natural inclusions, breadcrumbs, bubbles and color zoning? Especially in very clean stones?


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 Post subject: Re: Best light setup to see color zoning?
PostPosted: Tue Mar 02, 2021 11:15 pm 
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 Post subject: Re: Best light setup to see color zoning?
PostPosted: Wed Mar 03, 2021 8:33 pm 
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Thank you for the suggestions.
I have found some pale color zoning on the stone with bars of color going at a 90 degree angle to each other, as well as a feather-like inclusion that goes all the way to the surface.
I haven't found any twinning on a home-made polariscope, which does not necessarily mean it is not there - since I could not see the color banding of synthetic stones as shown in the article photos either.

I assumed presence of color zoning means the quartz is natural, is this not quite the case?


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 Post subject: Re: Best light setup to see color zoning?
PostPosted: Tue Mar 30, 2021 6:16 am 
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Straight colour zoning would be an indicator of it being a natural stone, yes. You can get curved colour zoning in some other types of synthetic stones but quartz are mainly made using hydrothermal so you would be looking for either breadcrumbs, heat haze/chevron effect or the nail head type inclusions. You shouldn't be finding much in the way of bubbles or curves as those are more common in Flame Fusion or Crystal pulled synthetics.

The article Barbra posted though would go much further in depth than I would so I'd recommend going through it for what you'd be looking for between the two.

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