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PostPosted: Fri Oct 09, 2009 5:25 pm 
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there is at least one german seller on net , who sells hayne, even rough,at afordable prices, very litle stones like 8 stones 1.1 caract at total. 30 euro for a colector stone parcel i think isn´t expensive , he have 0.99 caract sone very prety, price on request i think that one isn´t for my small pockets.


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PostPosted: Fri Oct 09, 2009 5:26 pm 
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Pedro, how about a link. ;)


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PostPosted: Fri Oct 09, 2009 6:36 pm 
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well since i´m not thinking in buying this :)
some nice afordable gems site and a lot of variety
here
Click HERE


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PostPosted: Fri Oct 09, 2009 9:11 pm 
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Thanks Pedro, more eye candy :mrgreen:

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PostPosted: Sun Oct 18, 2009 6:04 pm 
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Hauyne- Image

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PostPosted: Sun Oct 18, 2009 8:00 pm 
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Oh that Huayne, tiny but packs a punch :P

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PostPosted: Mon Dec 07, 2009 3:30 pm 
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Seriously-gemented sent some specimens of green hauyne from afghanistan, and so it seems like a good time to re-visit this topic, collect some new spectra, and combine it with new information from this thread.

This GIA article on hauyne describes the spectrum of hauyne as arising from two absorption bands due to multi-atom negative ions of sulfur.

The article identifies the broad 600nm absorption band that arises from a color center associated with negative-charged sulfur trimers (S3-). Note that this is three sulfur atoms that together manage to capture an electron to create a negative ion. These sulfur trimer anions might result from some kind of radiation damage.

And the article also identifies a 380nm absorption band that arises from negative-charged sulfur dimers (S2-). Note that this is two sulfur atoms that together manage to capture an electron to create a negative ion. This same absorption band is also the source for the fluorescence observed in some hauyne. Based on previous studies in this thread, where luminescence spectra are produced using both 360nm and 400nm LEDs, I would suggest the center of the broad absorption band is located closer to 400nm than to 360nm. So I tend to pin it at 400nm rather than 380nm.

My general thinking is that the dimer anion and trimer anion are located at the same defect site in the hauyne crystal. So I tend to think that maybe an increase in concentration of one type of anion will correspond to a decrease in concentration of the other anion type.

So here we are going to compare three pieces of hauyne. The first is a very blue piece from Eiffel that Tim first sent me. The color in this piece is like "wow!" The second is a less-saturated blue-green piece from Eiffel that Tim sent in a later batch. The color in this piece is like "eh." The third is a saturated green piece from Afghanistand that Mark sent recently. The color in this piece is like "not too bad at all!" These rough pieces are generally in the size range 0.06g to 0.12g, no problem to collect spectra from. Mark sent some less-saturated green pieces as well, but those were very small.

Now let's have a look at the transmission spectra (recall that absorptions results in "dips" in these spectra) of three pieces of hauyne:

Image

The vertical scale for these spectra is matched somewhat arbitrarily so that they have the same counts at 500nm. Comparing absorption dips, we can guess that the very blue has the larger concentration of (S3-) ions, with the blue-green having less, and the very green having the least concentration. In contrast, we can guess that the very green has the larger concentration of (S2-) ions, with the blue-green having less, and the very blue having the least concentration.

A quick note about the very green hauyne spectrum; it is reminiscent of an emerald spectrum, just not quite as pure green. But the extra blue and yellow just add up to green in the eye anyways, and so the very green hauyne does have a definite resemblance to emerald in color.

From these spectra, we can guess the spectra and thus relative concentrations of anions in the newly discovered yellow hauyne and in colorless (or white) hauyne. Probably the yellow stuff has no (S3-) ions and a large concentration of (S2-) ions. Then the colorless stuff probably has small to no concentration of either type anion.

Next, since the (S2-) ions are responsible for fluorescence, we can guess that the very green fluoresces brightest, the blue-green fluoresces less brightly, and the very blue fluoresces least. Here then is the luminescence spectra of the three, collected using a 400 nm LED as excitation source:

Image

Here, the vertical scale is as recorded. Note in particular that the fluorescence signal for the very blue hauyne has been multiplied by a factor of five! I tried to set up the same collection conditions for the three pieces, but of course they are slightly different shapes and sizes and that has some effect. Also note that the excitation light is scattered throughout the rough pieces, which leads to a large background... so roughly, the signal at wavelengths less than 500nm should be ignored.

The evenly-spaced peaks in the luminescence spectra are pretty cool. I mentioned in an earlier post that it reminds me of a vibrational progression, but I was thinking that the wavelength spread between peaks was too large for vibrational progression in a neutral atom or positive ion. Well, now that I learn that it is a negative ion that is fluorescing, this sort of spread makes sense... and the fact that it is a negative dimer makes even better sense why we'd be able to see it so clearly. So I like it.


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PostPosted: Mon Dec 07, 2009 3:40 pm 
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Has anyone found a colorless Sulfur free example of hauyne or is it a theoretical situation?

By the way, this report is brilliant! Thanks Brian.


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PostPosted: Mon Dec 07, 2009 3:45 pm 
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Brian, you should think about submitting a version of your report to a journal. I'll bet few (if any) people have done similar work.


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PostPosted: Mon Dec 07, 2009 4:02 pm 
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Colorless hauyne... scroll to the bottom of the page.

Oh, some more information on fluorescence that I forgot to mention. The very blue fluorescence is so small, it looks essentially inert under LWUV lamp. It is even hard to see with the 400nm LED. Also, we can guess that the new yellow to yellow-green stuff will fluoresce like mad, and the colorless stuff probably also looks inert.

Thanks Karim, but this is just a hobby. All these speculations would require more work for a journal write-up.


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PostPosted: Tue Dec 08, 2009 1:23 pm 
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:smt023

perfect! Thanks Brian, extremely cool how you make it all come together!

Now... this calls for testing the suspicion of yellow stuff fluorescing like mad... It was ze Germans who collected the yellow material if I'm not mistaking... perhaps wir sollen mal ein bischen rundfragen... :wink:

It started in Germany and it will end there too... ghe...


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PostPosted: Tue Dec 08, 2009 1:51 pm 
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Was?
Ich verstehe das nicht. Was bedeutet rundfragen?


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PostPosted: Tue Dec 08, 2009 1:54 pm 
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ghehe... that would be my peasant German for asking around...


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PostPosted: Tue Dec 08, 2009 2:22 pm 
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In the article "Gem-Quality Yellow-Green Haüyne from Oldoinyo Lengai Volcano, Northern Tanzania " in the latest G&G, there is a mention of fluorescence:
LWUV: light orange
SWUV: inert

But no mention of "knock your socks off" intensity.

Also, of note, is the geologic environment of the find described as the only active carbonatite volcano in the world. That's an awesome concept. How is that similar to the geologic environments of the Eifel or source in Afghanistan?


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PostPosted: Tue Dec 08, 2009 2:31 pm 
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Also, of note, is the geologic environment of the find described as the only active carbonatite volcano in the world.


carbonatite volcano?

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That's an awesome concept


why?


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