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Authenticating Ancient Chinese Jades Using Scientific Methods

by Sandra Lee Stuart (01/24/09).

By Janet G. Douglas

Many collectors and museums have questions relating to the authentication of ancient Chinese jades in light of the current market where forgeries are commonplace. Today’s forgers are producing convincing fakes, and it is becoming increasingly difficult to rely on one’s eye and knowledge.

It is only natural that people are looking to science for help.

In 1999, the catalog for a German auction of Chinese jades included scientific reports of authenticity of the items for sale. To the best of my knowledge, this was the first time
This was done. While this approach is a step in the right direction, jade collectors should know what science provides beyond a piece of paper deemed a certificate of authenticity.

Science can’t give definitive answers

At the risk of chipping at the pedestal on which some place the “scientific method,” jade collectors need to understand that scientific investigation cannot always provide black-and-white answers to jade authentication questions. The first, and probably most important, step in the authentication of a jade object should always be the thoughtful consideration of its art-historical context, as well as comparison with similar, preferably excavated, jades.

Nephrite jade incense burner

Nephrite jade incense burner

This incense burner is from the Tang Dynasty (circa 618-907).

This step is analogous to what a museum curator does when considering whether to purchase a piece. It is important to bear in mind, however, that this is also done by those in the lucrative business of jade forgery.

The challenge for the collector, then, is to look longer and more carefully than the forgers.

How does the jade compare in shape and decoration to those in excavated contexts and in well-documented museum collections? How does it compare, under close scrutiny, in workmanship? It is surprising how many forgeries can be uncovered by close examination and careful research. An educated jade collector is more likely to make good collecting decisions and avoid forgeries.

Lab work’s expensive

It is only after this first step that scientific investigation should be considered. Given the significant expense, the collector must feel comfortable with the validity of the results. Does the laboratory have a demonstrated history in the study and analysis of ancient Chinese jades? What is the specific question to be answered by the analysis? Is there data to support a given scientific technique showing that it is the most appropriate tool to answer a given question? Is there an opportunity to talk to the analyst to ensure that specific questions are answered?

Scientific methods to analyze and authenticate jades require a little ingenuity. For instance, no one will argue that ancient jades were worked using modern tools and techniques. But what does the presence of tool marks produced by hand tell you? It does not necessarily prove that the jade is ancient because it is entirely possible that a jade could be worked by hand today.

Similarly, we have to think carefully about surface accretions. Although a laboratory can identify residues of a mineral abrasive on the surface of a jade, it is far more difficult to determine when it was applied. Natural mineral abrasives used in ancient times are still readily available today, so their presence proves nothing.

Forgers able to fake jade’s appearance

The same is true of earthy accretions such as soil and calcareous encrustations. The clever forger, intending to simulate the appearance of burial and/or significant age, could easily add these to the surface of a jade.

White jade Buddha

White jade Buddha

This seated Buddha is from the Tang Dynasty (circa 618-907).

The use of natural alteration or “weathering” as proof of age is also difficult. Some scientists contend a jade with a weathered surface is at least a thousand years old because it takes this long for such a surface to develop. I’m not sure that research has been done to back that up. Any such research would need to take into account a variety of factors, such as porosity of the jade surface and the presence of deleterious substances in the burial environment, as well as water content and acidity (measured as pH).

A particular type of alteration known to occur on ancient Chinese jades, called “burial alteration,” consists of a selective dissolution (leaching) on a microscopic scale along mineral grain boundaries of solutions of high pH (pH> 9). This type of high pH environment can occur during decay of the corpse(s) with which the jades were buried.

Natural burial alteration may not take long

In one study, a piece of jade was placed in a bath of pH 10 for three months, after which the same type of alteration found on jades from ancient burials was seen to have occurred. Showed that “burial alteration” can take place within a relatively short time, and in the case of jades in ancient tombs, probably occurred during the months immediately after burial when the corpse(s) decomposed. Thus, it is entirely possible that this type of alteration can be achieved quite easily over a few months by a forger using a variety of artificial means.

There are other methods of treating the surfaces of jade artificially. Many of these treatments may elude detection by scientific method. This means the jade collector cannot rely solely on science to answer questions of authenticity. Nevertheless, scientific investigation can help by supplying additional information such as the identification and structure of materials on the surface of a jade, which can assist in the assessment of authenticity.

Green jade seal

Green jade seal

A nephrite green-jade seal made between 1736 and 1795 during the Qinglong Period.

Nonetheless, clear-cut answers to questions of authenticity are still few and far between. Jade collectors must concern themselves with the serious study of excavated and other well-documented jades, and grapple with multiple explanations for what they observe. Yet that is partially what makes jade collecting so rewarding.

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5 Responses to “Authenticating Ancient Chinese Jades Using Scientific Methods”

  1. NINA says:

    I AM INTERESTED IN SELLING 2 LION FOO DOGS THAT ARE FROM THE QING DYNASTY THEY COME W CERT. OF REGISTRATION BUT I DNT KNOW MUCH ABOUT THIS TYPE OF ART. THEY ARE WHITE JADE AND 33 CMS TALL THE 2 OF THEM WIEGH 100 PDS.

  2. Jon says:

    As a collector for over 30 years, I’m saddened to see such a meaningless and misleading article written. Until a scientific method is perfected, possibly with Artificially-generated radio waves, to detect measurable data from surface crystal disassociation, experience, experience, experience with handling and seeing genuine pieces, knowing the stone absolutely, the authentic elements of style of the carving, and bearing in mind that “best stones are trusted with best carvers”… and finally, nephrite jade doesn’t calcify or degrade easily, when it does, there is depth as well as breadth. Most great pieces were placed as guardian figures or sumptuary ware in dry tombs; they look quite quite unchanged by time. The first piece in this article attributed to Tang appears to be an obvious fake. And Guanyins like the one shown are all over the internet, usually made from white marble. Relatively little jade was produced during the Tang dynasty, as gold and silver ware from Persian influence was in vogue for the first time. And the seal said to be Qing is just too awful with stone and carving to consider. The writer needs a lot more experience before publishing such misleading dribble.

    • diana says:

      Apparently you know a lot more about antique jade than I ever will. Please let me know if you are available for discussion concerning a “collection” about to come to market

      • Jon says:

        Diana,

        Methinks you reply with a bit of sarcastic self deprecation. I am, however, available; and I admit that I let the photos override my reading of your article if, as Zhang Dahai wrote, they were added separately and apparently without the writer of the article’s agreement. To be sure, if you are with the Freer, you surely know better. There is a bottom line for all the endless chatter about fakes. One that top dealers and most knowledgable collectors have long known: best quality jade along with best quality carving = no mistakes. Regardless of “age.” Only a fool would deface a piece of jade that is selling by the gram for, at best, the price of gold, whether by poor carving or surface alteration. Especially when there is so much suspicion to the point of paranoia, when it comes to attributions earlier than Qing. Besides, like new pieces with an easy Qianglong attribution are bringing the world record prices, if you are an expert “faker” with a beautiful piece of nephrite, where would you direct your efforts?

  3. Zhang Dahai says:

    This is a good article written by Janet Douglas of the Freer Gallery, originally published in Orientations magazine.

    However, the photos of supposed antique jades that accompany the article were added by someone else. They are not even high-end forgeries, but the kind of trash available on eBay and in tourist markets for a few dollars.

    These photos undermine an otherwise good article, and readers would do well to ignore them.

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