Jade

[Indylady]

I''ve seen a couple of threads out there about jade, but I''m still a little lost and would like to learn more. Can anyone help educate me about treatments and sources to find quality jade? I''ve read about dying and impregnation; Type A= untreated, Type B= impregnated, Type C= dyed. Is this the typical grading system? Does anyone have jade pieces they might do a little show and tell with?

Thanks in advance!

 

[babydoll_mini]

Hi IndyLady, I''m so happy that finally here is a question I do know a little about, yay~

You are right about the grading, but different from colored stones, NO treatment ever is acceptable with jade.

 

[Arkteia]

In Matlin''s book, I read that even big auction houses, like Sotheby''s, have been known to make mistakes re. treated vs. untreated jade. Is it difficult to find out whether jade has been treated?

 

[morecarats]

Before getting into treatments it''s worth mentioning that, strictly speaking, there is no such thing as jade. Or rather there are two quite different minerals called "jade" -- jadeite and nephrite. The distinction between them was only made in 1863.

Nephrite, the more common mineral, is a calcium magnesium iron silicate with a hardness of 6 to 6.5, and a density of 2.90 to 3.03. All of the traditional Chinese jade is nephrite, since there are no jadeite deposits in China.

Jadeite, the more valuable of the two, is a sodium aluminum silicate with a hardness of 6.5 to 7, and a density of 3.30 to 3.38. The most famous jadeite deposits are in Burma, with some more recent finds in Canada.

Jadeite and nephrite have different crystal structures as well as different chemical compositions.

Nephrite is quite inexpensive, while jadeite -- especially the rare imperial jadeite colored by chromium -- can be quite expensive in fine grades.

 

[morecarats]

I''m not really a jadeite expert, but I''ve had some dealings with it.

Usually all jadeite has been waxed after polishing. Type A jadeite has not been treated except for waxing. Type B has typically been soaked in some sort of chemical bleach and then impregnated with resin to improve the color and transparency. Type C has been dyed.

The treatments are not always easy to detect, even for experts. If you''re buying anything valuable it''s a good idea, as with all gemstones, to have them certified at a lab that has advanced instruments to do the analysis.

 

[morecarats]

I''m not really a jadeite expert, but I''ve had some dealings with it.

Usually all jadeite has been waxed after polishing. Type A jadeite has not been treated except for waxing. Type B has typically been soaked in some sort of chemical bleach and then impregnated with resin to improve the color and transparency. Type C has been dyed.

The treatments are not always easy to detect, even for experts. If you''re buying anything valuable it''s a good idea, as with all gemstones, to have them certified at a lab that has advanced instruments to do the analysis.

 

[Arkteia]

Can there be white jadeite from China? I once saw this vase in an antique shop. It was beautiful and antique, but had no certificate and they told me it was white chinese jadeite.