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Gem Testing In Jewelry


#1

Hi Everyone,
I am trying to find out your thoughts on effective testing of gems already set in jewelry. If you were to travel to different jewelry stores to value jewelry for insurance purposes, what equipment would you use to test the gems given they are set. For example would you use thermal and RI tests and or others? Just want to see what your thoughts are.


#2

Hi I am not a valuer, but if you are talking about coloured gemstone then you may be able to get an RI if the stone is set high enough. Certainly use the trusty 10 X lens and use a Spectroscope. if it was set low then the valuer may need to take the gem out of the setting… Most Valuers I know of in Australia would use a Microscope say X 60 to look at inclusions to validate Natural from Synthetic.

I am sure other forum followers would have more info

thanks.


#3

There are a couple of things that you can use with gemstones that are set.

If its high enough in a rub-over setting / bezel set you can use a refractometer.

Its always easier if the stone is not in a closed backed setting.

You can use a spectroscope, dichroscope, microscope and the UV light. to a lesser extent you can use the the polariscope, but thats all you might have at your disposal anyway.


#4

Yes I agree with that, however in relation to a polarascope and Refractometer if the gemstone is a double refractive gem say sapphire and the table is cut 90degrees to the C Axis and you take a reading from the table you would get a single refractive reading which obviously would be false. hence the reason why you take more than just the reading from the table, when you are identifying a gem with these instruments
thanks.