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GG help
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Author:  mariana1 [ Thu Jul 14, 2011 10:35 am ]
Post subject:  GG help

Hi all

I am takong the GG correspondence courses and I am having a hard time doing the gem ID course.I tryed to get some help from the Gem Labs in the city,unfortunatly people do not have time.
I am wondering i there would be some instruments that would make my life easier?
Any thoughts?
Thank you
MM

Author:  Truffaut [ Mon Jul 18, 2011 1:29 pm ]
Post subject:  Re: GG help

How far are you into the course? When you say you're having problems, do you mean with the reading assignments/questionnaires or the stone boxes? What equipment do you already have?

Author:  amommj [ Sat Jul 30, 2011 4:53 am ]
Post subject:  Re: GG help

I learned very quickly my cheap refractometer was not up to par which would have affected my readings greatly. I decided to pay the big bucks for GIAs and it's made a HUGE difference. I'm having trouble with my spectroscope and am not sure if it's because mine is cheaply made or if I'm doing something wrong but am getting ready to order a new one. Fortunately my other equipment has been well functioning.

Have you not been able to reach your instructor? Yes, let us know specifically where you're having trouble. I'm doing Gem ID right now too.

Author:  Kerensky [ Sat Jul 30, 2011 10:14 am ]
Post subject:  Re: GG help

amommj wrote:
..... I'm having trouble with my spectroscope and am not sure if it's because mine is cheaply made or if I'm doing something wrong but am getting ready to order a new one........


They are not the easiest bits of kit to use with confidence, are they?

In addition to a spectroscope that works, the following are important to the most effective use:
- The quality of your light. This should be an incandescent light source, quite powerful, putting out a collimated beam and mounted on a stable and adjustable stand, so that the angle of light incidence to the stone can be adjusted correctly and maintained throughout the observation.
- Similarly, the angle between your spectroscope and the stone is important to optimise and then needs to be maintained steadily.
- It helps to have a rotating platform on which to place the stone so it rests securely and steadily whilst one adjusts the aspect of the stone relative to the light source and spectroscope for the optimal spectral display.

There are a number of 'big buck' desktop spectroscopes about (including from GIA) that make provision for all of the above and more. I use a cheaper option which is the OPL teaching spectroscope c/w stand and an OPL Hylite. I bought the Hylite before I bought a cold light source with goosenecks. If one has a cold light box, then there's no need for anything like the Hylite as well.

Its worth, too, experimenting with colour-filtering your light source. This is usually simple when using a cold-light box, Else one may be having to mess about with a flask of Copper Sulphate solution (etc).

Author:  Barbra Voltaire, FGG [ Sat Jul 30, 2011 10:39 am ]
Post subject:  Re: GG help

What kind of spectroscope do you have?
I always recommend the OPL Desk Model....quite reasonably priced as well.

And, I would also suggest starting with some gems where the spectrum will be a slam dunk, so you will learn what to look for and how to bob your head around appropriately to see absorption bands.

Get a large synthetic flame fusion ruby, a big faceted almandine garnet and a zircon.

Once you learn proper positioning of the light source, spectroscope and head with these easy peasy gems, you can set up the harder ones in the same manner.
And you know what? It works. :wink:

Author:  amommj [ Sat Jul 30, 2011 2:06 pm ]
Post subject:  Re: GG help

Awesome tips! Thank you. I have a cheap diffraction spectroscope. I'm able to make out the bands in most garnets, corundum and zircon--sometimes. If the stone is smaller I have a heck of a time seeing anything. I've been using a maglite and just purchased a nifty tripod to stablize it.

GIA's diffraction spectroscope looks just like mine but is twice what I paid. I'm ready to pay the money as it may provide peace of mind that it's not the equipment that's the problem.

Author:  Alberto [ Sat Jul 30, 2011 2:16 pm ]
Post subject:  Re: GG help

amommj wrote:
GIA's diffraction spectroscope looks just like mine but is twice what I paid. I'm ready to pay the money as it may provide peace of mind that it's not the equipment that's the problem.


follow Barbra's advice then and buy an OPL teaching spectroscope :wink:
ciao and good luck!
alberto

Author:  Lisa Elser [ Sat Jul 30, 2011 3:54 pm ]
Post subject:  Re: GG help

Alberto wrote:
amommj wrote:
GIA's diffraction spectroscope looks just like mine but is twice what I paid. I'm ready to pay the money as it may provide peace of mind that it's not the equipment that's the problem.


follow Barbra's advice then and buy an OPL teaching spectroscope :wink:
ciao and good luck!
alberto


I wanted the one with training wheels and a big sign saying "spectral lines here!" Sadly, that's not the one I got, but the OPL is a great little spectroscope.

Author:  Kerensky [ Sat Jul 30, 2011 4:27 pm ]
Post subject:  Re: GG help

Lisa Elser wrote:
Alberto wrote:
amommj wrote:
GIA's diffraction spectroscope looks just like mine but is twice what I paid. I'm ready to pay the money as it may provide peace of mind that it's not the equipment that's the problem.


I wanted the one with training wheels and a big sign saying "spectral lines here!" Sadly, that's not the one I got, but the OPL is a great little spectroscope.


But we know that *none* of them come with training wheels, Lisa. One has to learn to balance by pushing oneself along with one's feet :lol:

@amomm, you now have a 4/4 recommend to the OPL teaching spectroscope. What are you waiting for? :lol: And *do* get the stand and - unless you already have something as good/better - ask Colin Winter if he has a re-conditioned 'Hylite' that he can let you have cheap.

In conclusion, if you do buy from OPL, invest just a very few more dollars in their 'Students Guide to Spectroscopy'. If you are like me, it will be only after six months of struggling along that you will come to appreciate just how good that cheap little guide is.

Author:  amommj [ Sun Jul 31, 2011 4:31 am ]
Post subject:  Re: GG help

You all are the best! I'm all over it. I'm just looking for a US vendor now who sells the OPL "Teaching" Diffraction Grating Spectroscope. I'll grab the book too.

And thanks also for sharing your own frustrations with the spectroscope. More than half the time I can see the lines. Unfortunately there are some gems where GIA requires spectrum tests for confirmation and I just can't see any lines.

Thanks again!

Author:  Barbra Voltaire, FGG [ Sun Jul 31, 2011 10:38 am ]
Post subject:  Re: GG help

Not all gems will cooperate.
I'm pretty good with a spectroscope and on many occasions I'll set up a gem with the OPL, bob my head around for a hell of a time before I accept that there is nothing there to see. :(

Author:  amommj [ Sat Aug 06, 2011 1:09 am ]
Post subject:  Re: GG help

I did order the OPL and look forward to receiving it.

I wonder how GIA would react to the explanation that I just can't get a reading with the spectroscope? Has anyone experienced this? I really am glad to hear there are stones out there where even trained professionals can't seem to get a reading.

Author:  Barbra Voltaire, FGG [ Sat Aug 06, 2011 10:11 am ]
Post subject:  Re: GG help

I can't speak for the GIA (you might want to call them and ask the question) but I think with some gems, they KNOW there will be an observable absorption pattern and in others, perhaps not.

Author:  mariana1 [ Fri Sep 30, 2011 12:47 pm ]
Post subject:  Re: GG help

Hi Trufaout,I am at my last course,colored stone grading.Thank you for asking

Author:  mariana1 [ Fri Sep 30, 2011 12:50 pm ]
Post subject:  Re: GG help

Hi Trufau,I do have all the instrents.Thank you

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