The Path of Diffusion
-Lisa Brooks-Pike
When I began looking seriously at Andesine in early 2006, the thought that anything other than sapphire could be diffused was considered ridiculous, and impossible. By the Tucson Gem Show in 2008, I had collected enough samples, information, and evidence suggesting not only that it was possible, but it was happening. I turned the information, evidence and samples over to Robert James of the International School of Gemology for testing, and the rest, as it were, is history.
By summer of 2008, I had a theory; Isomorphous replacement series gemstones could surely be diffused. But that didn’t explain Sapphire, which had been diffused for years. Could it really be possible to diffuse almost any gemstone? I consulted an expert who said, “of course it’s possible”. The oversimplified explanation was that no crystal is perfect, they contain natural vacancies, more importantly; gemstones that are diffused are not the perfect crystals, but rather the less than perfect that need help to become beautiful.
There were some that still insisted it wasn’t possible; too much heat, too much time, not profitable. We already knew it had been VERY profitable with early estimates suggesting over $100 million dollars of diffused andesine had been sold. But what about the heat and time?
I turned my search to the process of diffusion, and found some very interesting patents.
Richard Pollak of United Radiant Applications held the following patents:
Submitted in 1990 coloring gems with irradiation
Submitted in 1997 coloring gems with cobalt surface diffusion
Submitted in 2000 Coloring gems with cobalt surface diffusion less time lower temps
Submitted in 2001 Coloring gems with copper surface diffusion
Samples of Pollak’s stones were examined by GIA in late 1992 as stated on page 749 of “Gems: Their Sources, Descriptions and Identification” where it says, “In late 1992, Richard Pollack[sic], of United Radiant Applications, a major producer of diffusion-treated sapphire…” and also stated in the Spring 1993 edition of Gems and Gemology.
Although the patents and articles refer to a “surface diffusion”, there was awareness that the process had improved. “Gems” states diffusion coating was present in the early 1980’s, with the presence of “deep diffusion” appearing in the early 1990’s. Additionally, on page 750 under “Be-Diffused Corundum” “Gems” states, “According to Coldham(2002), since late 2001 a new method of colour enhancement, which involves the diffusion of beryllium…….first appeared undisclosed in the Thai gemstone market.” On page 751: “beryllium and other light elements, such as lithium” were being diffused. Click for Terry Coldham’s must read article.
John Emmett is credited by many sources as having written the most comprehensive paper on Be-diffusion.
By November 2008, Emmett had done the “impossible”, he successfully diffused copper into feldspar, turning it red.
November 12, 2008 JCK Article
August 21, 2009 GIA report.
With Emmett’s success, many thought the “Andesine” scandal would end. That was not to be.
Recently, a JEA member (wishing to remain anonymous) contacted me with some information I had not seen before. This revived my search and additional investigations have turned up some interesting information.
In the following patents submitted by inventors Ram Pratap and Samir Gupta it would appear they have managed to significantly reduce the time and temperature necessary for diffusion.
published 10-2009
published 06-2010
The patents describe “A method for producing color in a crystal, comprising the steps of: (a) depositing onto the crystal an atomically mixed single film comprising atoms of two or more metals by physical or chemical vapor deposition, one of the metals selected to impart color to the crystal, and the other one or more selected for color shading effect; and (b) heating the film-coated crystal to cause atoms in the film to diffuse into the crystal simultaneously from the single atomically mixed film” and “…thin film makes intimate contact to the crystal surface for efficient diffusion of coloring atoms in the crystal body”
Whereby, “The method of claim 1, wherein the metals diffused into the crystal are incorporated into the lattice structure of the crystal” using temperatures as low as 700C in a period of 30 to 90 minutes. “Examples of suitable crystals (useful as gemstones/decorative articles) contemplated for uses herein include (but not limited to) gemstones such as corundum, silicates olivine, topaz, garnet, aluminum silicates as dalusites, disthene or mullites, cubic zirconia, quartz, sapphire, beryl, decorative objects (all colorless/transparent) and the like.
All of this is achieved using the following color imparting/toner elements: “…cobalt, iron, chromium, nickel, titanium, praseodymium, iridium, platinum, tin, vanadium, antimony, cadmium, silicon, zirconium, magnesium, zinc, palladium, erbium, neodymium, silver, copper, germanium, molybdenum, or any combination thereof”.
You will note that molybdenum is listed as a color imparting/toner element in the diffusion patents being discussed. Is it a surprise then to find this unlikely element appearing in the SEM testing of “natural Tibetan sunstone”?
Continuing with the naïve belief that the only gemstones capable of being diffused are sapphire and feldspar is akin to burying ones head in the sand. As an industry we must change our thinking from, “just because it is possible, doesn’t mean it is happening” to “where there is a will, there is a way”.
"Those who cannot remember the past are condemned to repeat it." - George Santayana
Throughout my Andesine investigation I have had immense help and support. Thank you to Robert James of the ISG for believing and being willing to go to the front lines, spending a great deal of his time and money, and to those of you who wished to remain anonymous, trusting me with your secrets, facts and expert information, often putting yourselves at risk. Thanks also to David Federman for listening, confirming and writing the story and to all of the Oregon miners for their time, education, information and samples. Thanks and appreciation to Mariana Photiou, whose own long time investigation finally caused us to cross paths, compare notes, and work together. To all of the consumers and ISG members, thank you for your assistance, support and patience. I am forever grateful to my husband, family, Pamela and Veronica for being there for me, through it all.
Member Spotlight: Dust Devil Mine
Ask anyone who has visited the sunstone mines in south central Oregon of their experience, and they will say that it is singular. To spend time in that arid, open expanse while digging in the hard earth could never be described as easy. When the earth yields its treasures however, the sweat and aching muscles are forgotten. For the owners of the Dust Devil Mining Co., this has been a way of life for many years.
Rock hounds as children, Don and Patsy Buford never stopped loving stones. When their children were young and part of The Boy and Girl Scouts of America, Don and Patsy formed a Lapidary Explorer Post, and taught the teenagers in their group the lapidary arts. It was also while involved with the scouts that the couple met Terry and Jude Clark, fellow gem enthusiasts.
Together, the two couples decided to take their hobby to the next level, and searched Oregon’s Bureau of Land Management records for any open mining claims in the state. They found 3 abandoned claims in the high desert, and in the winter of 1992 (when the desert is at its coldest) Don and Terry, along with Don’s son Clay staked their claims. Thus was Dust Devil Mining Co. incorporated, and the lives of the Bufords and Clarks changed. For three years, the couples spent weekends and vacation time making the eight hour drive out to their claims. After the hard work of digging, breaking and screening by hand, the sunstone was faceted, set in gold, and sold to friends and colleagues. As demand for sunstone grew, the Bufords and Clarks came to see a future in the mine. They met Steve Hackler, equipment operator extraordinaire, and after converting an old bus into a processing plant and purchasing an “ancient” D9 backhoe, the now five owners put everything into making a living in the sunstone business.
As the mine grew, so did the community of friends that formed around it. Dust Devils claims have increased over the years, and they now hold twenty five, including opal, varicite and fire agate claims in other parts of the country. The mine attracted many artists, and for years Dust Devil held nine day “dig-ins”, where artists were allowed to keep the best 300 carats of what they brought out of the mine free of charge. Stones from Dust Devil have been crafted into works of art, and have resulted in over 15 AGTA Cutting Edge Awards. Many have found a sort of family in the collection of fellow rock hounds and sunstone lovers, and visit the mine several times over a season. In the evenings, Patsy works miracles from her small but efficient kitchen and anyone at the mine is invited to join for supper.
Sunstone has had much exposure over the years, and many times has been named as the next big thing in the gemstone trade; it has also experienced more than its share of setbacks. From earthquakes and market crashes in Asia to the flooding of the market by the now infamous “Andesine/Tibetan Sunstone”, Oregon Sunstone and the lives of its miners have seen fortunes wax and wane. This year, Dust Devil looks forward to the use of a sorting method that will increase daily production tenfold.
Since 1996, Dust Devil has had a presence at the Tucson Gem & Mineral shows. For several years Dust Devil has been located near the group from Idar-Oberstein. Now located at the GJX show, Don is proud that he and the other owners have been appointed honorary Germans.
The miners favorite cut? To Don, the round brilliant and trillion cuts show the true depth and beauty of sunstone over others. The biggest piece of sunstone to come from Dust Devil was a whopping 1092 carats of bi-colored material heavy with the unmistakable Oregon schiller, and was fashioned into a rose by award winning gemstone artist Dalan Hargrave.
 Click to visit Dust Devil
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