Post subject: Re: Relatively low cost hand held Raman Spectrometers
Posted: Thu Oct 01, 2020 1:22 pm
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Joined: Mon May 26, 2014 9:42 pm Posts: 1033
Yes, RRUFF (Free on line) is available for basically ALL minerals.
I put in something like 500 spectra in the Ahura's Stephen sells, and that covers all the gemstones. It also comes with software that allows IDing a large number of minerals using either an Android phone or a Windows machine.
I didn't see the previous question. Depending on which Ahura you got, one of them puts out an ascii representation of the spectra, which you can use CrystalSleuth to match. (I don't much like CrystalSleuth, myself, but it is FREE!) However many of the old Ahuras seem to have had the calibration be off a bit. I correct for that in my software, by first matching the spectra peak of quartz and diamond and doing a calculation of the shift and magnification of the spectra, and then correcting for it when I load spectra into the Ahura, or when matching outside the Ahura.
I also do resampling and normalization of spectra that I match outside the Ahura (I imagine they use peak matching inside - I use spectra matching outside.)
I just retired, so I may have time to try to analyze chemistry of some gems based on peak movement. I hope so - it sounds like a lot of fun.
Post subject: Re: Relatively low cost hand held Raman Spectrometers
Posted: Thu May 13, 2021 3:38 pm
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Joined: Fri Aug 28, 2020 12:16 am Posts: 2
Hi Stephen, I'm keen to try to do the same thing with an ahura that I have. Is there any chance you could post some instructions, or if I could pick you brains on how you did this?
Post subject: Re: Relatively low cost hand held Raman Spectrometers
Posted: Sat Mar 05, 2022 12:18 am
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Joined: Fri Mar 04, 2022 6:29 pm Posts: 2
Sorry to bring this thread up yet again. Can anyone who can help me setup a first gen 2007 date FirstDefender hit me up. I'm missing the original system SD card.
Post subject: Re: Relatively low cost hand held Raman Spectrometers
Posted: Sat Mar 05, 2022 10:36 am
New to the Forum or The Quiet Type
Joined: Fri Mar 04, 2022 6:29 pm Posts: 2
Likewise I'm trying to setup a Ahura First Defender which is missing it's libraries. This seems to be the biggest collection of people who own/know about them. I'd be extremely appreciative if anyone who can help would reach out to me here.
Post subject: Re: Relatively low cost hand held Raman Spectrometers
Posted: Wed Nov 22, 2023 11:28 am
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Joined: Tue Jul 02, 2013 9:00 am Posts: 1322 Location: Wylie Texas but in Alaska for a while
dchallener wrote:
Well I *finally* have managed to port gem and mineral spectra *into* the Ahura Spectrometer. So now it is point and shoot (or put it in a bottle and shoot) and have it display the answer.
Post subject: Re: Relatively low cost hand held Raman Spectrometers
Posted: Wed Nov 22, 2023 3:04 pm
Gold Member
Joined: Mon May 26, 2014 9:42 pm Posts: 1033
Hi - it was pretty complicated. I "cracked" the .spc files that they have. Then I re-wrote it into a from crystalsleuth would use. I didn't like that program, so I wrote my own. The background removal was a bit of a problem, but I finally got that to work and then I wrote a subroutine that did matches. (Had to download a lot of data from RRUFF and process it to get that to work. Additionally, it appears some of the spectra in RRUFF are bad (there is even one that is a straight line - guess the grad student forgot to turn on the machine for that sample.) Once I had "good" spectra, it took a few months to figure out how to put those spectra into the ahura itself. Stephen sells the program by itself, so you can contact him if you have a Raman you would like to use it with.
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