nephrite or jadeite using standard gemo tools/equip?

[dendufau]

I can't believe I haven't found concise and explicit information on how to tell the difference between nephrite and jadeite!!!
I know they are mineralogically different but look essentially the same and have the same refractive index. But how without guessing.
The only info on the internet is - "Ask an experienced jade trader, they can tell from 20 yards away" or "one is vitreous and one is greasy" or "one has a fibrous ,felt like structure and jadeite a more blocky cryptocrystalline structure". Well I don't have an electron microscope and I left my EDXRF, LA-ICP-MS and infrared spectrometer in the other car.

Somebody give me a link!!!

 

[chrono]

You can also do a specific gravity test, which the two are quite different. The refractive index is also slightly different.

Nephrite
Density 2.90-3.02, RI 1.60-1.63

Jadeite
Density 3.34, RI 1.660-1.680

 

[minousbijoux]

This question comes up from time to time here, and I think it is often fraught with frustration. There is another website geared towards those in the trade that has the word "Gemology" in the title (we are not allowed to link to it). I see jadeite questions raised there - with specificity in responses - fairly frequently so it is your best bet for the comprehensive response you seek. Good luck - and come back and let us know what you discover, as it certainly beats carrying around your LA-ICP-MS in your car

 

[dendufau]

Thanks to you all and a special thanks to Chrono.

I can't believe it.

I have two different reference sheets that I use saying jadeite like nephrite ha a RI of 1.6 - 1.627
Here is one of them. http://www.szfable.com/pic/2011041720494899238.pdf.. The other is a nice print out from another source.

But of course there is http://gemologyonline.com/jadeite.html which gives 1.66-1.668 and a bunch of sources every where else on the net.

Now you know the source of my frustration. RI is straight forward. Universally the same. How in the heck can two sources get it wrong and I happen to be using these two sources. What, am I going to check different places? Like H2O is water. Well I better check a few more sources to see if that's correct.

Unbelievable

Thanks again everyone

 

[treasurehunter]

Appearance generally is easy to tell but if not.

Jadeite RI
1.666 to 1.680 ( plus or minus 0.008 )

Nephrite
1.606 to 1.632

If you can't get an RI , then you can do SG or look at the spectra, in exception nephrite you may see a vague line at 500 nm or vague lines at the end of the spectrum , with jadeite you generally see a line at 437.5 and jade coloured by chromium might have lines at 630,655,691