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 Post subject: gemological instruments on ebay
PostPosted: Sun Apr 08, 2018 10:33 am 
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I'm thinking of getting some id instruments and wondering if these are worth buying.

https://www.ebay.com/itm/Pocket-Diffrac ... %7Ciid%3A1

https://www.ebay.com/itm/Portable-Optic ... %7Ciid%3A1

https://www.ebay.com/itm/External-Monoc ... xyFrNRqWuf

Any opinions of these tools?
I'm on the injured list so not much spare cash at all, trying to get started as cheaply as possible.

Thanks, Jim


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 Post subject: Re: gemological instruments on ebay
PostPosted: Sun Apr 08, 2018 12:13 pm 
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Hi Jim.
I'd stretch a bit on the spectroscope and go with the OPL Teaching Model with stand.

The polariscope may be useful. Hard to screw that up.

I have no experience with that refractometer.


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 Post subject: Re: gemological instruments on ebay
PostPosted: Sun Apr 08, 2018 4:34 pm 
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I susoect that refractometer is similar to the various cheap Chinese ones I have used through the years (a couple JTV branded, a couple that looked thr same but weren't). They have all been perfectly fine and given me accurate readings.

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 Post subject: Re: gemological instruments on ebay
PostPosted: Sun Apr 08, 2018 7:47 pm 
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I agree that the OPL should be the spectroscope. The cheap ones are all but worthless. Since spectroscopes are one of the hardest instruments for most people to master, having a good one is a big advantage.

The inexpensive Chinese Polariscopes seem to work just fine.

I find that the inexpensive chinese refractometers seem to work fine on the flat surfaces of faceted stones, but are not good for spot readings. Since the refractometer is one of the most important tools on a gem lab, I would go ahead and try to get a used G.I.A one that has been well taken care of. If the glass is scratched, I have had very good results polishing them on my faceting machine.

The light source for your refractometer is almost as important as the the refractometer. You should have white light and a proper monochromatic source. I find that many of the inexpensive Chinese lights work just fine.

An inexpensive dichroscope should be fine for your lab. I often use my polariscope for that purpose as well.

Easy to make your own specific gravity setup for your digital scale.

A couple of inexpensive color filters can be a big help.

Also nice to have a LW/SW light box, these can be very affordable used.

Since most of the really financially consequential separations these days are based on magnification, I suggest you get a very good microscope. Do not waste your time with off brand scopes. Try and get a used Gemolite in good shape.

This year I have put together three labs for offices in Africa. I find I am able to get a decent lab together for between 1,200 - 1,500 dependending on how lucky I get on Ebay.


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 Post subject: Re: gemological instruments on ebay
PostPosted: Mon Apr 09, 2018 12:37 am 
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The refractometer looks exactly like my bought from Mueller company including the bottle for RI liquid..

Works fine but I always check it with the same sapphire and spinel before working with new stone...

Only problem I had was buying a cheap liquid in St. Marie. Here you need a good one.

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 Post subject: Re: gemological instruments on ebay
PostPosted: Mon Apr 09, 2018 5:59 am 
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Thanks for the opinions/experiences, I'm glad I can get by with the cheap refractometer and polariscope, the opl looks good but steep for me as money is extremely tight being injured and unable to hold a regular job, but don't need a cheap tool that won't work.

I guess I'll have to sell some more of the things I can no longer use to fund the tools.

Thanks, Jim


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 Post subject: Re: gemological instruments on ebay
PostPosted: Mon Jun 04, 2018 9:47 am 
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I always recommend that you get a prism spectroscope as well as a diffraction grating one. The diffraction grating instrument has the advantage that the spectrum is evenly dispersed, but because they have a fixed slit they can be dim. Prism instruments tend to bunch the spectrum up at the red end, but as they usually are fitted with an adjustable slit the brightness can (within limits) be adjusted. Beck instruments often come up on ebay and are usually good value and very well made. I can recommend them.


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