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 Post subject: cat's eye : enstatite vs kornerupine vs diopside
PostPosted: Sun Jul 14, 2013 1:14 pm 
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hi,
What is the most simple methods to separate chatoyant variants of enstatite, diopside and kornerupine?

Thanks in advance


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 Post subject: Re: cat's eye : enstatite vs kornerupine vs diopside
PostPosted: Mon Jul 15, 2013 2:22 am 
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Enstatite DR B+; RI: 1.673-1.663; Hardness 5-6
Diopside DR B+; RI: 1.701-1.675; Hardness 5-6
Kornerupine DR B-; RI: 1.667-1.680; Hardness 6-7

Basically a refractometer should be enough for you to make the difference.

John

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 Post subject: Re: cat's eye : enstatite vs kornerupine vs diopside
PostPosted: Mon Jul 15, 2013 3:46 am 
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Since they are in cabochon form, it is quite hard to determine their birefringence. In case of opaque stones, it is impossible to see their dichroism.

- What is the best visual clue to separate them?
- What is the best test (without spectroscope) to separate them? Thanks


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 Post subject: Re: cat's eye : enstatite vs kornerupine vs diopside
PostPosted: Mon Jul 15, 2013 12:39 pm 
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To start, this is a very difficult separation.
The SGs and RIs overlap.
If the bottom of the cab is flat and polished, one can often get a good RI reading.
One can also often determine birefringence with a spot reading if the polarized plate is left on the refractometer.

OK..what's the color of the stone?
Is the gem opaque or can you backlight it and get any light peaking through?
Any observations with magnification?


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 Post subject: Re: cat's eye : enstatite vs kornerupine vs diopside
PostPosted: Tue Jul 16, 2013 11:13 am 
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A raman scan with the GemmoRaman would find out in a moment :)

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 Post subject: Re: cat's eye : enstatite vs kornerupine vs diopside
PostPosted: Sat Aug 03, 2013 7:57 am 
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try to measure birefringence

...and leave the Raman to beautiful rich happier people :mrgreen:


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 Post subject: Re: cat's eye : enstatite vs kornerupine vs diopside
PostPosted: Sat Aug 03, 2013 11:24 am 
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cascaillou wrote:
...and leave the Raman to beautiful rich happier people :mrgreen:


i'm everything but rich........... :lol:

ciao
alberto

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 Post subject: Re: cat's eye : enstatite vs kornerupine vs diopside
PostPosted: Mon Jan 12, 2015 3:42 am 
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Pic's would be nice!
Good hint might be that Kornerupine is normally found as very small stones. average rough gem weight is 0.25ct up to 3.50ct. larger stones are extremely rare. I have only seen one large Kornerupine in my life and it was 8ct's. just one!

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 Post subject: Re: cat's eye : enstatite vs kornerupine vs diopside
PostPosted: Fri Jun 12, 2015 4:49 pm 
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Maybe we could start with the color of the stones ? Diopside is often of a typical green.
Enstatite would be rather more brownish.
Of course color can only suggest, not determine.

Cascaillou how can you find out birefringence with cabochons ? Most of the time you have to be content with a RI zone.


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 Post subject: Re: cat's eye : enstatite vs kornerupine vs diopside
PostPosted: Fri Jun 12, 2015 5:32 pm 
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I do have a green enstatite cat's eye as well as brownish yellow enstatite star so color can for sure vary.

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 Post subject: Re: cat's eye : enstatite vs kornerupine vs diopside
PostPosted: Sat Jun 13, 2015 11:01 am 
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Of course, enstatite and diopside are in solid solution. So realistically the stones could also be in-between forms like augite or pigeonite depending on how precise you're being. But of course I would not reccomend it, given the somewhat unexciting nature of those names.

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