Return to main page of Gemology WorldIn September, 1995, I was at the Jade market in Hong Kong. While walking by a lady in a jade-hawkers stall, I saw she was sorting a beautiful strand of bright, translucent, apple-green jade beads. Next to it I noticed another bagged strand of beads the same size. These were more opaque and marred by yellow-brownish stains yet were from the same strand as the fine beads. That was my first encounter with the new treatment called "bleached" jade or "B" jade. I managed to get "before and after" samples of these beads and took them back to California for further analysis.
The "B" samples were uniform in colour, quite translucent and had a light, apple-green body colour. Using the normal gemmlogical procedures, this stone was jadeite jade and not colour-enhanced. The refractive index indicated clearly in the jadeite range, and spectroscopic analysis did not indicate dyes. These three tests are what the average jeweller or appraiser uses to verify that a stone is jade and that its colour is natural. These may no longer be enough though because "B" jade can pass these tests.
The actual process of treating jade to be "B" jade is two-staged. Starting with a sample of green jade with brown or black stains, the sample is immersed in a powerful acid, usually hydrochloric or sulphuric, and some times the acid is warm. Repeated applications are usually necessary. The fumes are quite toxic and this procedure is not without some danger. The resulting stone has had its structure changed; the sodium in the sodium-silicate of jade's infrastructure has been leached out and the internal stains with them. This new stone is not as durable as it was and, since the impuritites removed area largely metallic, its specific gravity is marginally lower. The next step is to impregnate this new stone with a polymer and fill those interstices just created in the bleaching process. An excellent filling agent would be a polymer of refractive index equal or close to that of jade. So far, several different polymers have been identified (among them, Opticon by GIA).
There is now a new lexicon in the jade world: "A" jade indicates natural jadeite jade without colour enhancement. "B" jade indicates bleached, polymer-impregnated jadeite jade. "C" jade indicates colour-enhanced jadeite jade (either bleached or not).
How can you be really sure that what you are seeing is natural jadeite and not "B" jade? Under a microscope you can sometimes see an edge of the polymer flow, or floating "platelets" or concentrations of impregnating substance in the fractures and cavities visible under magnification. Or you can get lucky and discover a surface point that reacts to a thermal tester. The result will have a very distinctive odour. If you have a thermal testing point and are checking out a carved piece, look in deeply recessed areas for evidence of this "epoxy-like" resin.
When "B" jade was first identified and word of this new process spread, there was a loss of confidence in the jade market. Exports of jade material declined as much as 50% from Hong Kong during the years 1989-1991. They have since bounced back. Two markets are emerging: the "A" market and the "B" market. Much of the "B" market is in Asia itself (Taiwan, China,Vietnam, the Philippines and Malaysia). Dealers are becoming more careful of the provenance of their stock and are dealing more with prime cutters.
COLOURS:
Green "B" jade can be almost any tone, but be especially wary of light, bright apple-green that's slightly on the lemon-green side. Recently, we have begun to see "B" jade in lavender which is extremely translucent and very light in body colour ("pink" hues). We are told that red and yellow jade are now treated also. As the process is perfected and made cheaper, it is reasonable to assume that bleaching may be applied to all colours of jade.
STABILITY:
No one is sure of what happens to polymers after a decade or more of exposure to W light. We have some samples now over 10 years old that exhibit slight yellowing with impaired translucence while others become brittle after bleaching and no amount of impregnation can ever stabilise them. We have been told of mild cases of "acid burn" on the skin in places at close contact to acid-bleached jade. Durability or toughness, in its gemmological definition, is lowered.
COMBINATION OF TREATMENTS:
A piece of jade can be treated in the "B" manner and, thereafter, dyed or restained, to give the illusion of being natural. Pieces exhibiting two or even three colours may still be "B" jade.
In reality,"B" jade is here to stay. Chemistry has the ability to change the nature of the materials with which we live, including our precious stones. After all, diamonds are treated, filled and synthesised, corundum (ruby and sapphire) are heated to enhance colour, emeralds are oiled and "grown" and star-stones are now routinely lab-grown. It would be naive to think that jade is somehow not amenable to sophisticated treatment. The emerging middle class in China is a huge potential market.The real issue is one of disclosure.