Is this Jade Nephrite or Jadeite?

[JadeEmperor]

Hey all!

First off, I would like to thank you for visiting this thread. I appreciate it! Alright now to cut down to the chase...long story short my dad bought it a couple decades ago, I was wondering if it's Jade Nephrite or Jadeite...I have a sneaky suspicion that it's Nephrite but it would be nice to get a second opinion since I don't know too much about Jade in general.



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Thanks!

 

[Harriet]

Hi,

It's hard to tell, especially from a photograph. I've been taught that the 'easiest' way to distinguish jadeite and nephrite (without using lab equipment) is by luster. The former's is vitreous (glassy) whereas the latter's is greasy. That said, serpentine, another lookalike, can also be greasy.

 

[VapidLapid]

It also might not be a true jade at all. the jade of california is actually a compacted form of vesuvianite, or idocrase, aka californite.
DO you know where the block came from?

 

[JadeEmperor]

Thanks for the responses! I appreciate it!

The Jade was purchased from somewhere in San Francisco if I remember correctly.

 

[innerkitten]

I thought they were both forms of jade?

 

[innerkitten]

Oh I see you want to figure out which it is. I wish I knew more. I'm sure there are a few jade experts around here.

 

[Pandora II]

You really need top get an expert to look at this for you. As well as nephrite jade there are a number of substitutes to consider: bowentite, steatite, marble, quartzite etc .

There are differences that you can look for - jadeite often has an orange-peel like effect and a fiborous 'sugary' looking structure. Nephrite tends to be more organised with parallel fibres.

More difficult tests would be to establish the SG, the RI and check for a spectrum: -

SG:
Jadeite - 3.30 - 3.36
Nephrite - 2.90 - 3.02

RI:
Jadeite - 1.660 (spot) DR 0.013
Nephrite -1.610 (spot) DR. 0.026

Spectrum -
Jadeite - band at 437.5nm, doublet at 690nm and possibly lines at 630nm and/or 650nm
Nephrite - not characteristic

I find them a total nightmare - it's not something I would be thrilled to have to ID! Luckily there are lots of true experts out there, especially the Chinese dealers who can tell at 20 paces with extreme accuracy!