ISG: The Limitations of K/Ar in Gemstone Treatment Testing

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1 Like Share this Page: a publication of the International School of Gemology...28 April ISG: The Limitations of K/Ar in Gemstone Treatment Testing Over the past couple of years the jewelry industry has been razzle-dazzled by some rock star famous PhD scientists regarding the claimed use of potassium/argon testing (K/Ar) to identify gemstone treatment. The sheer weight of credentials and initials after these folk s names has invoked shock and awe in the hearts of consumer and professional alike. There is, of course, just one problem..k/ar cannot disprove that a gemstone has been treated. What K/Ar does do is simply show a presence of argon gas inside a crystal as a result of deterioration of potassium to argon over millions of years. High heating will allow this gas to escape leaving the void to demonstrate the result of the heating. While this test can use the absence of argon gas to show that a stone has been subjected to high heating treatment, it cannot prove or disprove that a gemstone has been treated by a variety of other methods. Mainly because there are myriads of treatments out there that do not require high temperatures. In fact, with the latest reports from Ted Themelis, low temperature diffusion of gemstones is a reality. This creates a one way street for K/Ar dating: The absence of argon gas can prove heating, but the presence of argon gas does not disprove other possible treatments. This gives K/Ar testing only a single value purpose in gemology: to identify gemstones that have been subjected to high heating. K/Ar cannot be used to show that a gemstone has not been treated. But a recent report by Dr. Philip Ganz, expert witness in defense of Direct Shopping Network in the DSN v- Robert James legal action, recently issued a report that attempted to use K/Ar to prove a negative in the matter of andesine treatment. The concept put forth by Ganz was that a green andesine supplied by Andegem and sold by DSN was all natural based solely on the positive reaction of argon to K/Ar testing. The problem is that Ganz made erroneous conclusions based on simple math. We can demonstrate this by using the simply math equation: If A=C and B=C then A=B. In the case of this green andesine. A=C but B C therefore A B. This situation can be demonstrated by the copper bearing feldspar that has become quite famous. In this case A = red feldspar color source B = green feldspar color source and C = copper. And since copper has distinct and verifiable absorption spectra in feldspar, we are able to verify the equation by use of the VIS-NIR Spectrometer. For our purposes we used our GL Gem Spectrometer from the CIG, the Challenger Vis-NIR, and our own OPL optical diffraction grating spectroscope. You can see the copper absorption spectra in the visible range below. This is a specimen that obtained direct from the miners of the Outback Sunstone Mine from Oregon while at the Tucson Pueblo Show last February. The absorption band is where the red and green meet. Notice that the absorption area in the 577nm green/red meeting section is an actual digital image taken through our OPL diffraction grating spectroscope of this specimen. This clearly shows the copper absorption area in this stone. This becomes the control spectrum for our testing. The Math of Oregon Sunstone In the case of Oregon sunstone A= Red Sunstone B = Green Sunstone and C=Copper. Notice the rough crystal of Plush Oregon Sunstone from the Double Eagle #16 mine shown at left. We have a distinct red color and green color within this crystal. This is a first test specimen.

2 We also used the specimen you see below that was designed and cut by the world famous John Dyer. Note that this Plush Oregon Sunstone from the Dust Devil Mine demonstrates a pronounced green color, although in our Dixie Cup immersion cell it is clear to see that this stone is of a red and green coloration from the copper. Based on our spectroscopic evaluation of this feldspar dating back to 2008, we know that the red and green areas of Oregon Sunstone result in the diagnostic absorption lines that are known to show copper as the source. This is repeatable and predictable for Oregon Sunstone. As a result of the above we find that our equation works quite well: A=C B=C therefore A=B. The red color is due to copper. The green is due to copper. Therefore the red and green are both due to copper. The spectral analysis positively supports this equation as true. Then.we have Tibet andesine supplied by Andegem, sold by Direct Shopping Network, and tested by Dr. Ganz. The Math of claimed "Tibet Andesine" from Andegem and Direct Shopping Netork As you can see above, we have known that we had a problem with the math on this claimed Tibet andesine since the very early stages of testing. Why? The spectra does not match for the red and green. The math does not work. Jewelry Television also had Andegem as their supplier. JTV now discloses all of their andesine as diffusion treated. The spectral images above are direct digital images taken through our OPL diffraction grating spectroscope of JTV stones from Andegem in Note that while the red has the distinct copper absorption band, the green does not. The green Andegem stone shows no copper absorption spectra. That is the

3 problem with the math of the Andegem andesine sold by JTV: A=C B C therefore A B. Which (we would find out), the green color is not due to copper but instead due to a reported radiation pre-treatment that is done on the stone to prepare it for the copper diffusion, to make the diffusion work better. That radiation treatment has been reported as the cause of the green color in this claimed "Tibet" andesine. The JTV stones had a preliminary treatment that K/Ar simply cannot identify or dispute. Below are three stones sold by DSN and tested by the ISG in 2008 and The dark red stone below right has an extremely strong absorption line in the 577nm region that is known for the copper absorption. But the stone cut in half with light pink color is weak in the absorption. Most important.the green stone shows no copper absorption at all! Once again, this stone shows the results of pre-treatment but very little of the copper diffusion treatment. You can see that results in the image below right. The red coloring is only barely penetrating the stone. And yet the green color is dominant throughout the stone. A(red color source)=c(copper) B(green color source) C(copper) therefore.a(red color source) B(green color source). These stones have different sources for their color. And yet, based solely on his findings that K/Ar testing showed no heating to 1100 C of the green stone above right, Dr. Ganz and DSN reported the stone to be all natural and without treatment. In truth, the above explains a lot of what we have been seeing in this Andegem supplied Tibet andesine for years. The green is not due to copper, and not due to diffusion. The specimens support the reports that a radiation pre-treatment is done on the stones before the high heat diffusion process is performed. The result is that the stones are green first from pre-treatment, and then red after diffusion. Below are a few images to demonstrate this. Consider these images along with the question about why the Andegem andesine was green inside and red outside, while the natural Oregon Sunstone is just the opposite. The Oregon Sunstone is due to copper green and red. The Andegem / DSN andesine color is due to reported radiation treatment induced green, followed by the copper diffusion treated red. A=C B C therefore A B. Check out the images below and consider this equation. The rough specimen below right was tested by OPL Spectroscope specifically in the red and green areas and the above equation was demonstrated in this rough along with many others. The faceted Andegem stone below left shows the green interior color with the red diffused color that was done later.

4 Below are two specimens from the ISG study collection. Below left is a radiation treated green andesine that shows very little diffusion of red copper color, while below right this stone also shows the radiation induced green color with a greater degree of red diffusion coloration. This also explains the very unusual piece of rough andesine claimed to be from Tibet and supplied to us by Chinese supplier Litto Gems (below left). Notice the green coloring with the red being diffused from the outside in. And the round faceted stone purchased direct from Andegem at the GJX show in It should be noted that AGTA member Andegem sold this stone to us without any disclosure, a violation of AGTA published directives for this stone. Perhaps most profound on this issue is the image below from the ISG archives. This image clearly demonstrates that the green color is a body color of the andesine. The red color shows the diffusion process that occurred at some later time. Again in this image A=C B C therefore A B. The green color does not equal a copper source. It was not due to diffusion. Not identifiable by K/Ar testing.

5 Let s take this whole thing one step further and look at the actual gemstone tested by Dr. Ganz on behalf of Direct Shopping Network. When the DSN lawyers asked for specimens for destructive testing, my recommendation was to not agree to the request on its face. A destructive test precludes any ability to evaluate and/or verify Dr. Ganz test results. My recommendation was to cut the stone in half, allowing for half to be preserved for verification of any findings by Ganz. Therefore the stone you see at left is one half of the original stone belonging to the class action member in the Class v- DSN litigation. We originally tested this stone in Dr. George Rossman of Caltech did the cutting of this stone in half and forwarded a half to us and half to DSN representative. The gemstone in its original condition is seen below. At left is the original ISG image of Ms. Johnson s DSN andesine taken in the ISG office in This is the entire stone seen in 2008 that was cut by Dr. Rossman and seen above in its cut state currently. Dr. Ganz and DSN has declared this stone to be all natural based on K/Ar testing showing argon. But we now know that the green color of this stone is not due to natural copper in fact not to copper at all. And the pre-treatment that imparts this color does not require heating. A point that Ganz s K/Ar testing could not address. Remember the images above showing the green half stone that showed no copper absorption line.that is this very stone. To review, below is the red DSN andesine sold to Ms. Johnson in our Challenger VIS-NIR spectrometer, below right is the green DSN stone sold to Ms. Johnson and cut in half by Dr. Rossman. Both at 577nm where the copper absorption should be located. The green.shows none. No copper. A=C but B C. Let s go back to our Dixie cup immersion cell and see if our original findings support this conclusion. Remember the images with the triangle cut andesine showing different levels of diffusion of the red copper diffusion into the green radiation treated andesine. Here they are again:

6 Now, look at the DSN andesine sold to Ms. Johnson and now cut in half. Clearly this stone shows the green color that we have seen shows no copper absorption, and the very partial red color due to failed or stopped diffusion treatment. The failed or stopped diffusion treatment means that the stone was not subjected to high temperature. Result: K/Ar testing would indicate no heating due to the presence of argon gas. Ganz and DSN therefore said: No heat...no treatment. This was an incorrect conclusion since K/Ar cannot deny all possible treatments. The depth of the red copper diffusion material into the stone can easily be seen in the 90x microphotograph seen at left. Here is our question for DSN and Dr. Ganz,. Of all of the DSN red andesine in question, including all (100%) of the DSN 2008 Beijing Olympic Andesine that are red.why did you pick a green stone to test using K/Ar? With the overwhelming majority of the Tibet andesine colored red, including the DSN 2008 Beijing Olympic Andesine, why pick a green stone to test for the court? Was Dr. Ganz and DSN aware that the green stone would give them the results they needed for this litigation purposes? We don t know. But.. The two stones below were both part of the litigation group sold by DSN and supplied to them by Andegem. Why not pick the stone below right? This stone was also sold by DSN to Ms. Johnson and photographed as you see below right in Both have green centers but one has only very slight red diffusion. That is the stone that DSN and Ganz picked for K/Ar testing. Why?

7 We believe we know the answer: They knew that the green stone had not been subjected to high heat, and that K/Ar testing would allow them to claim: No Heat = No Treatment. Unfortunately, that equation did not work, and does not work today. There are a myriad of treatments out there that do not require high heat, which makes K/Ar testing for gemstone treatments to be invalid for anything other than high heat. All of the other treatments can and are missed if only the K/Ar testing is used. Want to test this theory? Ask Dr. Ganz and DSN to run that same K/Ar test on the Johnson stone seen above right, or this DSN 2008 Beijing Olympic Andesine at left. Of course, Dr. George Rossman and his team at Caltech have already done this and found the red stones from Andegem to all have been subjected to high heating. This supports our equation that the red and green colors in the Andegem claimed Tibet andesine are due to treatments, but does not dispute our equation that the colors are due to separate treatments. However, this does leave us with one more equation that is critical based on Art Garabedian's own declaration that Andegem is the supplier of andesine to DSN: A represents andesine supplied by Andegem. B represents andesine sold by DSN. C represents treated andesine as verified by Dr. Rossman and the ISG above. The equation: If A=B and A=C then B=C True! There is nothing in the Ganz report that can dispute this equation. There are serious limitations to K/Ar testing. It cannot be used to disprove a gemstone treatment. In the case of the Oregon Sunstone v- the claimed Tibet Andesine where A is red color source, B is green color source and C is copper. Oregon Sunstone: A=C B=C therefore A=B Tibet Andesine: A=C B C therefore A B There is no K/Ar testing that can refute this. DSN cannot claim that the green andesine sold to Ms. Johnson is natural and without treatment based on K/Ar testing. K/Ar testing cannot prove that a gemstone has not been treated. Robert James President, International School of Gemology To obtain this report in PDF format please click here: The Limitations of K/Ar Testing Contact the ISG by clicking on this icon: