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 Post subject: methylene iodide vs water
PostPosted: Wed Feb 27, 2013 10:13 pm 
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Joined: Thu Sep 20, 2012 10:45 pm
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Location: Pittsburgh, PA
Specifically looking at the issue of examining a stone for growth lines and color banding, I've heard that using methylene iodide immersion is the way to go. I understand its better than water, but by how much? With stones like corundum and chrysoberyl, is water going to help at all?


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 Post subject: Re: methylene iodide vs water
PostPosted: Wed Feb 27, 2013 11:54 pm 
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Joined: Sun Oct 16, 2005 12:22 pm
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Location: San Francisco
The purpose of immersing something in a liquid is to limit reflection and make inclusions and internal characteristics more apparent.
Methylene Iodide is a preferable liquid for corundum and chrysoberyl because its refractive index is very close to those materials. When you submerge these gems in methylene iodide they essentially disappear so that all you see are internal characteristics such as inclusions or growth features.
For emerald, benzyl benzoate is the liquid of choice as its RI is very close to beryl.

I have never used water, but I have used baby oil in a pinch.


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 Post subject: Re: methylene iodide vs water
PostPosted: Mon Mar 04, 2013 3:43 pm 
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Joined: Sun Jun 28, 2009 9:56 am
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the idea is to use a liquid which RI is as close as possible to the stone RI range

immersion liquids discussion: http://gemologyonline.com/Forum/phpBB2/ ... =methylene


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