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 Post subject: Re: NIR absorbance spectra of tourmaline
PostPosted: Tue Oct 19, 2010 6:39 pm 
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Very interesting Bruce. Standing by for results. :D


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 Post subject: Re: NIR absorbance spectra of tourmaline
PostPosted: Tue Nov 02, 2010 10:58 am 
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Last night, I had a dream.

I envisioned a small (inexpensive) portable pocket size instrument which could almost instantly characterize Paraiba tourmaline. I think I shall make one. However, I have a problem, I have no samples to test.

Therefore, I would like to make this offer. If someone can supply me with a number of unidentified samples of tourmaline (Paraiba and other) which I can use to test my instrument, and if it works, I will return your stones and send you an instrument. If it doesn't, I shall chalk it up to a bad dream and still return your samples.

I can use any tourmaline, stone or rough, which is at least one carat in size—flaws are not a problem. If anyone is interested, please PM me.


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PostPosted: Thu Oct 20, 2011 7:50 am 
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Alberto wrote:
Neat report Dr. Brian, thank you! :D
i hope to have my HR4000 online (sooner or later) to start playing with spectras too....
ciao
alberto


around 1 and 1/2 year had passed but, well, here's my first UV-VIS-NIR abs spectra of a cool, little, turquoise color paraiba cab.

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ciao
alberto

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 Post subject: Re: NIR absorbance spectra of tourmaline
PostPosted: Thu Oct 20, 2011 9:39 am 
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Glade you're making progress.

When I looked at the curve something looked different. I have not find that about 770nm peak in any of my 1000 plus tourmalines in my collection with my set up. I then did a quick double check and did not see it in a curve generated by a Swiss lab on my best neon blue cuprian tourmaline. I then check some curves that a Japanese lab did on cuprians and it does show an about 770nm peak, but to a much less degree than the700 nm peak.

Do you know any history of the cab? Have you had any analysis of it performed? It is rather unnerving to see a peak in a tourmaline that I have not found. My spectrometer does go up to 849nm and should see it.

Bruce


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 Post subject: Re: NIR absorbance spectra of tourmaline
PostPosted: Thu Oct 20, 2011 10:18 am 
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bruce_tourm wrote:
Glade you're making progress.


thx, i'm really glad too.... :D

Quote:
Do you know any history of the cab?


i purchased it as a sample from Wild & Petsch, pulled it out from a misc color parcel of Mozambique copper bearing tourm cabs.

Quote:
Have you had any analysis of it performed?


purchased it yesterday...... :wink:

ciao
albé

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 Post subject: Re: NIR absorbance spectra of tourmaline
PostPosted: Thu Oct 20, 2011 11:36 am 
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I hope yesterday was a good day for purchasing cuprian. Now you have the tool to see deeply into the soul of your new tribe please test them. I would expect you to observe the same general layout of absorption curves as you got with your first try. I would like to know if you get indications of the same 770nm absorption curve. Especially in any blue/purple cabs you might have.

Let understanding rain down on the fields of imagination in the world of tourmaline.

Bruce


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 Post subject: Re: NIR absorbance spectra of tourmaline
PostPosted: Wed Oct 26, 2011 7:57 am 
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bruce_tourm wrote:
I hope yesterday was a good day for purchasing cuprian.


nope, i purchased only that sample for my collection... :lol:

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I would like to know if you get indications of the same 770nm absorption curve.


as suggested by Brian it seems that curve is an artifact due to the light source.... :? , i'm actually working on that, i'll post another spectra once i'll have time to get rid of it.
ciao
albé

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 Post subject: Re: NIR absorbance spectra of tourmaline
PostPosted: Wed Oct 26, 2011 9:32 am 
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I mentioned that it may be an artefact of the light source, as I had seen something similar when first collecting spectra of Bruce's tourmalines. So this still leaves open the possibility that it may not be an artefact.


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 Post subject: Re: NIR absorbance spectra of tourmaline
PostPosted: Wed Oct 26, 2011 9:43 am 
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Brian wrote:
I mentioned that it may be an artefact of the light source, as I had seen something similar when first collecting spectra of Bruce's tourmalines. So this still leaves open the possibility that it may not be an artefact.


sorry if i didn't reported your impressions correctly, Brian. I guess it is an artefact... :wink:

ciao
albé

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 Post subject: Re: NIR absorbance spectra of tourmaline
PostPosted: Wed Oct 26, 2011 10:25 am 
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Terrific.

Is this the unit you have?
HR4000?

How do you have it set up?
Exactly what is involved in getting results?

You could use this unit to determine polymer impregnation of jadeite, no?


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 Post subject: Re: NIR absorbance spectra of tourmaline
PostPosted: Wed Oct 26, 2011 1:54 pm 
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Alberto wrote:
sorry if i didn't reported your impressions correctly, Brian. I guess it is an artefact...


Actually, you probably reported my initial reaction correctly. But until further testing, one does need to leave the door open to the slight possibility that it was a real phenomenon. Now you've done the testing and slammed that door closed. Good job. :D


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 Post subject: Re: NIR absorbance spectra of tourmaline
PostPosted: Wed Oct 26, 2011 2:00 pm 
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Brian wrote:
Now you've done the testing and slammed that door closed. Good job. :D


yup, thank you very much for the precious advice!!! :D =D> =D> =D>
still some work left to fix it as i would...... :-|

ciao
albé

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 Post subject: Re: NIR absorbance spectra of tourmaline
PostPosted: Fri Oct 28, 2011 8:13 am 
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this one should be better..... purple > new lamp - light blue > old lamp

Image

ciao
albé

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 Post subject: Re: NIR absorbance spectra of tourmaline
PostPosted: Fri Oct 28, 2011 10:28 am 
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OK, so now have we lost the copper absorption?


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 Post subject: Re: NIR absorbance spectra of tourmaline
PostPosted: Fri Oct 28, 2011 10:40 am 
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the 900 nm peak seems very clear to me.... :roll:

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