Post subject: Re: Instrumental methods or what to choose for a small lab?
Posted: Sat Oct 14, 2017 11:26 am
Site Admin
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
Morning Neo-alchimic. I have the greatest respect for Moscow State University . The University has been responsible for some of the most impressive spectrographic developments in the world. I had the opportunity to visit several years ago and took a diamond class. You are absolutely correct that GIA, DGemG, Gem-A do not offer classes on understanding sophisticated instrumentation.
As you point out Cr is very easy to recognize with PL....copper not. Now that I know you have studied with the most forward thinking gemological institution in the world, I would like you to ask their gemology department the same questions you've posed here.
In my opinion, your expectations are far greater than your budget.
Post subject: Re: Instrumental methods or what to choose for a small lab?
Posted: Sat Oct 14, 2017 12:53 pm
Established Member
Joined: Sat Oct 25, 2014 3:17 am Posts: 47
Hi, You missed the point of discussion: there is no problem to train, the problem is your expected budget- 5000 will be enough for UV-VIS, but definitely not for FTIR or Raman... even good condition second hand will cost well over 10000 eur...
Your remark about Cr - yes, we see it many of stones, but it didn't help much in case of synthetic sapphire... so didn't catch your remark
About XRF and phone - most probably you think about ARM has driven built-in micro PC with small LCD... yes, have seen them, even we have one on the table... your expectation about it is to optimistic - there are many minerals with very similar chemical composition - Al, Si, Ca - in many cases it just not enough to identify stone... but it helps in many other cases... but we have 5 different XRF systems, mostly used for metal testing...
MAGI EXA - as soon it will be possible Alberto will reveal more, just be patient... but you will be able to differentiate synthetic and natural diamonds... what is not a trivial task in modern times.
Post subject: Re: Instrumental methods or what to choose for a small lab?
Posted: Mon Oct 16, 2017 12:33 pm
Site Admin
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
For everyone's information, Alberto and Mikko have an article featured in the current issue of Rivista Italiana di Gemmologia #2 entitled "-Raman spectroscopy: technique and its gemological application".
Post subject: Re: Instrumental methods or what to choose for a small lab?
Posted: Thu Feb 11, 2021 5:15 pm
New to the Forum or The Quiet Type
Joined: Thu Feb 11, 2021 4:05 pm Posts: 4
Neo-alchimic wrote:
Hi, Peters! Thank for advises and taking part in the dissuasion. Could you tell me, please, is it true for Raman (if we use a PL data too), that it can separate cu tourmaline from usual, synthetic Ruby from natural (for different color agents), confirm Rubellite and catch x-heated amethyst or not? As for your questions, Alberto, I like to work with colored stones more, but the reality is that people mostly come to check their "diamonds", so I need to have an opportunity to work with different stones. Now, according to my budget, I have choice between GL Gem spectrometer and ultra low cost Raman from thunder optics,... could you tell me, whichone can open more horizonts for me (don't take the manufacturiers, please, I write you them, just you to know the level of the equipment I can afford. My general question is about technic of these devices, which will be more helpful for me on yours opinion? ) As for X-ray, it isn't in use in the lab, it's my friend's machine, but if is very satisfied with it, because it gives all the composition of the material on the phone directly! I asked him about the price, because it seemed to be very easy to use and helpful for me, but it costs a lot..I have a picture of it how it works, but have the problems with the attachment....
Hi Neo-alchimic! Any news or feed backs about ThunderOptics Raman system? i see that they have now a Gurzil Raman Microscope that seems terrific for the price they offer : https://thunderoptics.fr/product/gurzil ... aedd0e4327 I am in contact with them, they send me some spectra, they realluy seem good. i have jusyt some doubts, that it can be such efficient instrument for this price. Please, share your opinions. Civ
Post subject: Re: Instrumental methods or what to choose for a small lab?
Posted: Fri Feb 12, 2021 9:41 am
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Joined: Thu Feb 11, 2021 4:05 pm Posts: 4
Barbra Voltaire, FGG wrote:
Hi Civ. Please share with us what you believe this microscopic raman can do. What can it identify, determine, etc?
Barbra Voltaire, Yes, for sure, I will do But in the same time, I would like to know if someone has already purchased such Microscope, their brochire seems awsome .. and the spectra they published are also impressive for such cost. I will search and I may buy it in a week or two. and I will make tests and share. But please, let me know if any one has any information.
Post subject: Re: Instrumental methods or what to choose for a small lab?
Posted: Fri Feb 12, 2021 1:19 pm
Established Member
Joined: Sat Oct 25, 2014 3:17 am Posts: 47
Hi,
The system could be fine, but it's not what we usually understand with Raman microscope (confocal microscope), but just used a microscope to focus the beam on the surface. There are many systems in price range 20 k USD. Don't see anything to call it special!
Post subject: Re: Instrumental methods or what to choose for a small lab?
Posted: Fri Feb 12, 2021 3:25 pm
New to the Forum or The Quiet Type
Joined: Thu Feb 11, 2021 4:05 pm Posts: 4
Peters wrote:
Hi,
The system could be fine, but it's not what we usually understand with Raman microscope (confocal microscope), but just used a microscope to focus the beam on the surface. There are many systems in price range 20 k USD. Don't see anything to call it special!
Peters
Thank you Peter, Yes, but confocal microscopes cost usually more than 50k US$. And the non confocal are all of them higher than 20k US$, it is why i am very intersted in the Thunder Optics Raman Microscope; i want to focus on tiny microscopic parts of my gems and stones, and I think. Please, can you send me the other suppliers / manufacturers that are bellow 20k or even 20k. I am very interested. Thank you Civ
Post subject: Re: Instrumental methods or what to choose for a small lab?
Posted: Sat Feb 13, 2021 12:11 am
Site Admin
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
It's not the $$$, it is what it can add to a lab. Spanish proverb: Words I live by: Lo barato sale caro Microscopic raman usually aids in determining the identification of an inclusion. Perhaps we can get Alberto or Mikko to weigh in.
Post subject: Re: Instrumental methods or what to choose for a small lab?
Posted: Sat Feb 13, 2021 10:25 am
New to the Forum or The Quiet Type
Joined: Thu Feb 11, 2021 4:05 pm Posts: 4
Barbra Voltaire, FGG wrote:
It's not the $$$, it is what it can add to a lab. Spanish proverb: Words I live by: Lo barato sale caro Microscopic raman usually aids in determining the identification of an inclusion. Perhaps we can get Alberto or Mikko to weigh in.
Yes, I definitely agree, I want to ask them to send them a sample and they will send me what they can do and if they can see and analyze inclusions. They promised that their Gurzil Model can do this. I am excited to have such an instrument. I will keep you informed, but I want mostly that I get help from the community if someone has any experience or business with Thunder Optics. 17k US$ is still a big investment for me. Cheers
Post subject: Re: Instrumental methods or what to choose for a small lab?
Posted: Sat Feb 20, 2021 4:18 am
Site Admin
Joined: Fri May 12, 2006 11:24 am Posts: 7523 Location: Rome, Italy
Hi, i did not check this particular model so i cant comment about its capabilities....BUT......i had a demo in Singapore at a manufacturer's lab, they were featuring a VERY similar setup and claiming their unit could do the job. we brought our samples to test and......it did not work. There are a couple of things worth to mention here in a matter of identification of inclusions. You NEED to have a CONFOCAL Raman for spatial resolution AND..........an adequate software is critical as well..... the signal you get by shooting an inclusion is a mix of 2 raman spectra, one coming from the host material and the other from the inclusion. you NEED to have a software in order to "clean up" the spectrum of the inclusion from the host one...this is not secondary AT ALL. The only way to know if this unit works is to send them a sample previously tested with a serious unit (Thermo DXR or Renishaw InVia) and ask them the scan. but i am not optimistic AT ALL..... I understand 17 k are a big investment for you, really i can. but they are too few for an effective tool for doing what you are asking for.....there is a reason why a confocal costs 70k or more.......its not about manufacturer's greediness.... just my 2 cents only.......
Post subject: Re: Instrumental methods or what to choose for a small lab?
Posted: Sat Feb 20, 2021 2:32 pm
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Joined: Mon May 26, 2014 9:42 pm Posts: 1033
Very good explanation! I wonder if you do a "side sample" to get the Raman spectra of the base material, and subtract out those peaks before doing a Raman match against what is leftover? That seems like it would be the easiest way. That would almost demand doing a "peak match" as opposed to a curve match.
Post subject: Re: Instrumental methods or what to choose for a small lab?
Posted: Sat Feb 20, 2021 2:52 pm
Site Admin
Joined: Fri May 12, 2006 11:24 am Posts: 7523 Location: Rome, Italy
Thanks, i have a bit of experience with confocal DXR by Thermo and their OMNIC software. I have to say its not very intuitive and being able to isolate peaks from the inclusion requires some tricky operations. That said, the real issue occcurs when host and inclusion feature peaks in the same area.........and this raise another point i forgot to mention in my previous post: resolution of the spectrometer. Ramans like the one sold for 17k simply don't have enough resolution for the task, especially in case of overlapping peaks between the 2 materials...............
I keep meaning to try doing a simple coaxial microscope arrangement like this with my raman--if I do I'll definitely post results, though it's hard to imagine it could be that easy, especially after reading Alberto's post above, but I'll report back when I get around to trying it.
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