October 27-28—SACRAMENTO, CALIFORNIA: 82nd Annual Gem, Jewelry, Mineral and Rock Show; Sacramento Mineral Society; Sat. 10-5, Sun. 10-4
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PostPosted: Wed Feb 28, 2007 7:05 pm 
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Oh my! I didn't mean to cause trouble :oops: . I was just hinting that some of us won't be able to have the instrument if it's priced beyond our means :( .

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PostPosted: Thu Mar 01, 2007 2:52 am 
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Maybe there wil be a stripped down, no frills "student model" that is less expensive, aimed at hooking all the new and soon-to-be gemologists on this instrument forever :wink:


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 Post subject: Reflectivity devices
PostPosted: Fri Mar 02, 2007 4:58 pm 
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Location: Louisville, KY
RE" It should not be affected by quality of polish... I think and would like it to be able to handle rough as well, but further testing will be required for that. "

Reflectivity {non contact liquid (critical angle)} devices will always be effected by quality of polish, in an absolute sense.

The Jemeter used normal reflectivity.. John Allaman and I had some ideas about modifications which never came to fruition.

Brewster Angle devices have inherent problems that could be solved with software null sensing, and thus use two (or more) monochromatic sources, which I surmise that is what you might be doing.

However the quality of polish may not effect an accurate null sensing system, although I don't know whether you would get 0.001 accuracy. Hats off to you if you can.

I have Connie Hurlbuts (rest his soul, one of the finest men I have known) prototype Brewster angle refractometer, and the first thing I did a long time ago, in the 90's, was replace his red LED with a yellow LED (~ Sodium line).. You actually need three sources to get the nominal RI and the dispersion.

Connie went to GIA Gem Instruments, and they wanted money from him to improve his device. All they did at the time is spend money to repackage the case (I also have that device). Bothe were analogue null sensing.

Note that there are two defined dispersions, Gemological and mineralogical based on different wavelengths of light, so five sources (or filters) might make it more acceptable to other communities.

My advice regarding working with GIA.. DON'T.. Sell yourself via the internet and keep the resellers margin they want for doing nothing except lending their slightly soiled name.

Send me an email and I'll be happy to talk to you..

Marty Haske
http://www.adamasgem.org

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PostPosted: Wed Mar 07, 2007 2:39 pm 
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These are the late Connie Hurlbut's Brewster Angle Refractmeters I was talking about in my last post.

Marty Haske

Image

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PostPosted: Sat Aug 18, 2007 9:03 pm 
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Location: Nepal
Hi Jleb,
is your product so called "digital refractometer" available in the market?If yes , where can i purchase it from? and what's its current market price?
Please mail me the updates at rishi@researchut.com


Thanks,
Rishi.

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 Post subject: Re: Digital Refractometer - Soliciting Input
PostPosted: Mon Jul 09, 2012 7:39 am 
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Location: Bangkok
jleb wrote:
We have just completed the optical design for our digital refractometer and I am writing the patent(s) right now. The core code for the microprocessor is being done, and we are now in the user interface, feature set specification. I thought I'd give folks a chance to input their desires in this type of instrument and tell me what features that they might like or think would be useful. We should have prototypes ready by the end of spring.

This will be a portable, battery and wall operated device with an LCD screen. It has an internal database of RI's and dispersion values which will be matched to probable candidates detected. The sensor has a .001 accuracy.

We have dual light sources so we'll be generating dispersion readings as well. A usb port is in the instrument that will allow you to export readings to a memory stick and import them into desktop programs like excel. Updates can be made via memory stick for both code and database.

I thought a feature that would allow you to set an RI, as for ruby, and then test each stone in a parcel would be useful. Then as you run each stone from the parcel through the unit, and it hits a spinel, it beeps, thus allowing fast verification and elimination of the "ringers". The range will be 1.50 - 3.0 in R.I. It should not be affected by quality of polish... I think and would like it to be able to handle rough as well, but further testing will be required for that.

I recall others wanting a nib like the jemmeter for stones with prongs.. would you want multiple readings with an average? Ability to input identifying information? Indicators for rotating the stone for bifringence and trifringence measurements?

We will price this between $700 - $950 retail at our current estimates.

Let me know what you'd like, and i'll see about putting it in.. thanks for all your help in advance..


I would love to have an update on this. If this is as you describe, it would be an invaluable gift to the entire gemological community. I'm sure many would support bringing it to market.

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 Post subject: Re: Digital Refractometer - Soliciting Input
PostPosted: Fri Jul 13, 2012 10:57 am 
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Mr Hughes, if nothing has happened in 5 years I guess the idea is buried or at least showed to be not economically viable...

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 Post subject: Re: Digital Refractometer - Soliciting Input
PostPosted: Tue Aug 07, 2012 7:30 am 
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Test results of digital refractometer, interesting link:

http://www.free-form.ch/tools/gemmetertest.html

pezzottait


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 Post subject: Re: Digital Refractometer - Soliciting Input
PostPosted: Tue Aug 07, 2012 1:50 pm 
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those are NOT digital refractometers, those are REFLECTOMETERS......
ciao
alberto

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