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 Post subject: Gem ID machines (1) Jewelers Eye (2) Presidium Gem Tester
PostPosted: Sun Nov 20, 2016 4:06 pm 
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Gem Identification Machines;

(1) The Jewelers Eye by Hanneman

(2) The Presidium Gem Tester


It seems to me that these type of machines are the quickest and
easiest test that you could do to quickly identify unknown gemstones.

Do these two different machines work on the same principle?
I's guessing Thermal conductivity and or Thermal Inertia

Do any companies sell " The Jewelers Eye by Hanneman "

Note: The Presidium Gem Tester is for sale on Amazon.

Has anyone here used the Presidium Gem Tester?

If so would you please tell us how well it works
and what experiences you have had with it.

Also I would love to here from anyone who uses and or owns
The Jewelers Eye by Hanneman


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 Post subject: Re: Gem ID machines (1) Jewelers Eye (2) Presidium Gem Test
PostPosted: Sun Nov 20, 2016 7:26 pm 
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Calldoug, if you do some searches on this platform, you will see that both the methods you list are unreliable at best.

If you are a professional in this business, or hope to be, your gem identifications must be completely accurate. There is no room for error or speculation. In order to achieve that you can't use thermal testers and pin hole refractometers.

Gem identification is a function of ruling out possibilities. In order to do that you will need a polariscope, very accurate refractometer, microscope, scale with SG capability, LW/SW UV light, and a hand held spectroscope, minimally. Oh yes, and a rare earth magnet.
Also, one needs the ability to properly interpret the results of their instrumentation and recognize when the results of certain tests need to be repeated or disregarded.

Quick and easy may be acceptable for a frozen dinner but not for gem ID. There is no ONE instrument which qualifies as an "end all".


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 Post subject: Re: Gem ID machines (1) Jewelers Eye (2) Presidium Gem Test
PostPosted: Sun Nov 20, 2016 11:38 pm 
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I should have worded that last post a little better.

I mean a Quick and easy test to get an idea of what a gem is initially.

And, if they are fairly accurate to rule out what the stone is not.

I think that If they are accurate ( I have not used them, that's why I asked )
they could rule out a number of things initially, especially in mounted stones.


The pinhole refractometer and many other things that I am interested in are for fun
and to get a better visual picture, etc of the different aspects of Gemology.


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 Post subject: Re: Gem ID machines (1) Jewelers Eye (2) Presidium Gem Test
PostPosted: Mon Nov 21, 2016 8:19 am 
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The Presidium meter works on thermal conductivity. The problem with conductivity is that it is hardly precise enough to give anything like an accurate result.
The "Jewellers eye" works on reflectivity, which is related to refractive index. Again, hardly accurate enough for precision gemmology. It is interesting to note that early models had a scale of R.I. but later models were marked with bands showing expected values. That said, the Jewellers eye was rated the best of this class of instrument by a very respected gemmologist.
If you seek an approximate idea of what a gem is I cannot do better than recommend viewing as many different gems as possible and getting a feel for them, then you can refine your opinion with use of the instruments.


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 Post subject: Re: Gem ID machines (1) Jewelers Eye (2) Presidium Gem Test
PostPosted: Mon Nov 21, 2016 12:38 pm 
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Hi Alan. A sound post. Thanks.

When I was a student in Germany I was taught to hit the instruments BEFORE looking at a gem.
Why? Because if one does a cursory site ID, they tend to bob their heads in every direction until the instruments agree with them. :wink:

I have a reflectometer in my graveyard of useless tools. Did I mention it was a useless tool?

Even with a sophisticated GemmoRaman, which is now the first instrument I turn to, results are not always 100%. I always back up a raman scan ID with a spin on the polariscope and an RI and a look with the scope and then an SG top off followed by "I wonder if this fluoresces".


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 Post subject: Re: Gem ID machines (1) Jewelers Eye (2) Presidium Gem Test
PostPosted: Mon Nov 21, 2016 12:51 pm 
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Interesting, I was taught (possibly a good many years before you), to use one's instruments to confirm what one already knew, but like I say, that takes a terrific degree of familiarity with stones (and the ability to let go of an opinion if proved wrong!).


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 Post subject: Re: Gem ID machines (1) Jewelers Eye (2) Presidium Gem Test
PostPosted: Mon Nov 21, 2016 3:52 pm 
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Presidium Gem Testers can be either thermal conductivity or relative reflectivity or BOTH depending on the price. Further options are the presence or absence of the optional set of test stones which would probably greatly increase the accuracy of the relative reflectometer. Another recent option that presidium provides at a rather high price is connectivity to their gem ID program.

Unfortunately none of this is a substitute for gemological training and using "real"instruments. I have been tempted to buy their thermal conductivity set because the meter has some readout arcs which they claim correspond to various gemstones. This may make the thermal conductivity tester somewhat more useful than a diamond or no led light or buzzer. But the arcs overlap over the entire range so that limits the usefulness.

The Presidium Relative Reflectometers don't attempt to readout in RI units nor in gemstone names but just in arbitrary reflectivity units. You then go to a table and look for your stone.

Reflectometers have a lot of spots where they can give erogenous readings. All these have been beaten to death in previous posts which I suggest you review before spending your money.


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 Post subject: Re: Gem ID machines (1) Jewelers Eye (2) Presidium Gem Test
PostPosted: Mon Nov 21, 2016 5:22 pm 
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G4Lab: Wow! Reflectometers give erogenous readings? I think I'll dig mine out to see if my erogenous zones are up to snuff. :)

But I'll probably just get erroneous results. Just kidding with you.

_________________
Rick Martin

www.artcutgems.com


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 Post subject: Re: Gem ID machines (1) Jewelers Eye (2) Presidium Gem Test
PostPosted: Mon Nov 21, 2016 5:37 pm 
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:lol: :lol:


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