Author Archives: Harry Bernard

Color-change Garnet from Kenya

Mgama Ridge: Probably the source of the alluvial garnets found in the plain below. Photo Raja Shah, Color First

As Raja Shah tells us, it is a story typical of gem strikes from the plains of Kenya to the Australian outback. While digging an outdoor privy, a ranch hand working in the gem rich region of Taita Tavita happened upon some unusual looking stones just a few feet under the surface and showed them to a local gem dealer.

Garnet Mining: Photo: Raja Shah, Color First

Late last November I received an email from a budding young gem dealer living in Voi, a town near Tsavo National Park, half way between Nairobi and Mombasa. He had a copy of my book Secrets and wanted to order more. Further he wrote excitedly of a find of Alexandrite somewhere nearby. “It looks just like the picture in your book.” Well, sometimes where there is smoke, there can be fire.

Once the word got out, thousands of independent miners descended on the area and began excavating private land and even a section of adjacent road where according to Shah a number of fine stones were located. The material is alluvial and appears to be spread out along a just south of Mgama Ridge (pictured above left)

1.83 carat color-change garnet sporting its daytime color

The strike turned out to be color change garnet, the best of which is similar to a find in the late 90s near the village of Bekily in southern Madagascar. Small amounts of color change garnet of this description has been showing up in East Africa for years. The first example I saw was in Kenya in early 1995. A Nairobi dealer had a 1/2 carat oval that bore an uncanny resemblance to Brazilian Alexandrite—the same teal blue peacock color that the Brazilian garimpeiros call peacock blue or pavão.

The same stone by night

Color change garnets have been found previously in Umba and Tunduru, Tanzania and in Embilipitiya and Athiliwewa, Sri Lanka and most recently on the island of Madagascar, in the southern part of the island near the village of Bekily.

Although some of the garnets from the aforementioned location do have the much desired “Alexandrite like” color change, it was the discovery of the Madagascar location that brought reasonably large amounts of alexandrite like garnet into the marketplace.

The range of color in garnet rough material from the new Kenya strike. All photos courtesy of Raja Shah, ColorFirst

According to Shah, the material comes in a range of hues with a predomince of brownish stones, only about 5% of the material has the most desired red/purple to teal blue change and only about 5% of that material is suitable for faceting.

The Madagascar material has been described as pyrope-spessartite with small percentages of almandine and grossular. This description is not particularly useful, relying as it does on a classification system that has been out of date for years. Apparently the garnet for the new Kenyan strike, described as pyrope-spessartite with grossular, is chemically similar. Again, like the Madagacar material, the color change is most likely associated with Chromium/Vanadium.

Book Review: Emeralds, A Passionate Guide by Ronald Ringsrud

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by Richard W. Wise

The subtitle of Ronald Ringsrud’s new book, A Passionate Guide, The Emeralds, The People, their Secrets has been well selected. The book is not just about emerald, most specifically Colombian emerald, it is about a country, its people and one man’s love affair with it all.

I first met Ron Ringsrud about a year and a half ago. I had never been to Colombia and as is my custom whenever I go into a new market, I was looking for a guide to the country and its emeralds. Ron Ringsrud was an inspired choice.

He is fluent in Spanish and has been involved in the trade and traveling to Colombia for over twenty years. He is a true aficionado and knows whereof he speaks.

The book begins with an excellent summary of the history of emerald mining in Colombia coupled with a history of the Mogul Empire and more specifically the Indian princes whose love affair with the Colombian emerald began, almost as soon as the Spanish conquered the mines in the 16th Century. Continue reading →

Grain Boundary Diffusion in Tourmaline; The Epochal Crisis, Part II; A Tempest in a Tabloid:

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An Open Letter to David Federman, Editor-in-chief, Colored Stone.

by Richard W. Wise, G.G.

David Federman, I just finished reading Joel Arem’s article Ending Diffusion Confusion in the current issue of Colored Stone together with your editorial titled Some Badly Needed Science. You have written so many open letters to the gemstone industry I thought I would try my hand at writing one to you. Given your reception of my January letter to the editor, I decided that the wisest course was to publish my opinion here.

First question; who is confused? For over a year you have repeatedly published your claims that tourmaline, topaz and tsavorite are being diffusion treated with little backup up of those claims other than your “long simmering suspicions” and the unsupported evidence of one man while many experts in the gemological community have been saying that the evidence presented to support those claims is just plain wrong. You state:

“Was there a better way to test James’ conjecture? I think so…It’s called experimental gemology.”

I find it ironic that you are suddenly calling for “experimental gemology.” I agree with your call, but let’s, just for a change, accurately define our terms. Continue reading →

Investing in Gemstones, Part II; A Strategy:

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Avoiding the Con:

There were a number of phony gemstone investment schemes in operation during the hard asset investment craze of the late 1970s and early 1980s. Until Congress put a stop to it, investors were purchasing, gems, antiques and Shaker rocking chairs as part of their IRA portfolios.

To avoid prosecution many gem investment scammers set up boiler room operations in Canada, but sold mostly to gullible U. S. investors. The pitch was simple and ingenious. To keep buyers from seeking an outside appraisal, the gems arrived in sealed packets with a microfilmed “certificate of authenticity”. Buyers were warned that breaking the seal would invalidate the certificate and negate affect potential resale.

Over the years, several victims have sought me out to appraise their purchases. In all cases, the gems were wildly overpriced stones and of a quality best described as Continue reading →

Investing In Gemstones, Part I: The Market

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Richard W. Wise, G.G.
© 2009

Bye, Bye Bling:

Perhaps it’s the tenor of the times. Increasingly I find myself fielding questions about gems as an investment. With government printing presses working 24/7, many people are concerned that deficit spending, coupled with Government stimulation of the credit markets in the U. S., Europe, China and Japan, will eventually lead to hyperinflation. With stocks, bonds and real estate in the tank and currencies at risk, people are thrashing about looking to find a safe financial haven. In uncertain times, investors turn increasingly to hard assets. Luxury per se is out, but investment is definitely in. (pictured above left a 1.01 vivid pink diamond from the 2008 Argyle tender)

The Problem:

Stocks and bonds trade in an orderly market. One share of General Electric common stock is just like another. Stock Exchanges guarantee that their members can trade stocks at the going price anytime the exchange is open. This gives stocks the advantage of liquidity. Stocks and bonds trade at established prices and these prices are Continue reading →

Drama In The Desert: ISG Seminar—A Dry Hole!

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Drama In The Desert: ISG Seminar–A Dry Hole:

The much ballyhooed "Epochal Crisis" never quite materialized at the International School of Gemology's "Let the Science Speak" seminar held February 6th at the Arizona Hotel. In a rambling presentation, ISG President Robert James back-pedaled on some of his previous statements and presented the results of advanced tests that contradicted his own theories.

The silence was eerie. It was painful to watch. Thanks to Colored Stone Magazine's drum beating, the talk was attended by a who's who of gem scientists. James' attempts at folksy humor fell flat. The scientists sat quietly and listened to the presentation of evidence. After the presentation, they politely applauded, asked few questions and filed out, leaving Robert James' reputation as a gemologist in a heap of smoldering ruins.

In a series of internet broadsides last September, James made sweeping claims that large amounts of Mozambique cuprian, as well as other tourmaline, were being subjected to copper diffusion treatment. Recently he cast his net wider, suggesting that what he now calls Grain Boundary Diffusion, is being used to improve the color of not only tourmaline, but garnet and topaz as well.

Goop In The Tubes:

The presentation centered on what James called "crud in the tubes." Hollow growth tubes are a characteristic tourmaline inclusion. What James finds telling is the fact that in some Mozambique tourmaline, these tubes are filled with a yellow-red substance that James cannot identify. In a previous GemWise blog, serious questions concerning these claims were raised by John Koivula and Christopher Smith, questions that James failed to address. In a significant variation on last September's theme, James has now backed away from his claim that the filling material is copper. In fact, he carefully avoided using the term copper diffusion throughout the lengthy talk.

James showed slides showing what he calls diagnostic "footprints" which prove treatment. However the footprints he finds in topaz do not in the least resemble the "footprints" he finds in tourmaline. His tourmaline slides showed straight growth tubes; his topaz slides showed a spider web of tiny lines. He presented absolutely no proof of diffusion in tsavorite garnet; he simply suggested that the appearance, in the past decade, of tsavorite over two carats is ominous. He never explains how that relates to his diffusion theory. Last September, he claimed he discovered that undisclosed amounts of synthetic tourmaline were being sold, but now admits that he was wrong. (image right: large chunks of tsavorite rough from a 2007 strike at the Scorpion Mine, Voi, Kenya, that yielded several stones above 10 carats. Courtesy: Tsavorite USA)

The conclusions drawn from the advanced testing promised last September conclusively demonstrated that James understands neither the characteristics of his test material, nor the diffusion process itself. According to James, LA-ICP-MS testing (commonly called laser ablation) conducted by Evans Analytical showed differing concentrations of manganese and iron in the tourmaline samples tested, with higher concentrations toward the center of the specimens. James suggests that this is another "footprint" left by the treatment process, and fails to note that the characteristic color zoning in tourmaline is the result of compositional differences within the stone. For example, higher concentrations of manganese produce richer pink zones in tourmaline.

In a later Q&A session, when the soft-spoken Dr. Adolf Peretti, former head of the Gueblin Lab and President of the GRS Lab in Bangkok, told him flat out that varying concentrations of elements are characteristic of natural tourmaline, James suggested that Peretti's test samples had been altered by diffusion. (photo left: Gemology 101, a natural "footprint" crystal cross-section: pink color zone caused by concentrations of Mg. in the center of the crystal. Similar images exist in the literature going back 150 years)

How Diffusion Works:

Diffusion is the word currently bandied about, but what is it, what does the term mean? Let me share with you an analogy suggested to me by one of the world's leading authorities on the use of diffusion treatment in gemstones:

Consider a dollop of blue ink dropped into a glass of water. The ink will slowly diffuse throughout the water, eventually turning the water a uniform light blue. Ion diffusion, or deep diffusion, works exactly the same way. Diffusion moves from higher to lower concentrations. Just as the ink does not remain concentrated, outside substances such as Beryllium and copper, when introduced into gem material, spread out and diffuse throughout the material. The ions do not concentrate as James suggests–concentration is the result of slow natural crystal growth and results in zones of color, a common trait in tourmaline. Thus, James' advanced testing proves, as Dr. Piretti and Dr. Kiefert have pointed out, exactly the opposite of James' contention. Concentrations of manganese and iron in tourmaline prove that the color is natural.

Industry writer and James acolyte David Federman has been warning for months that James' presentation would spark what he terms as an "epochal crisis" in the gem trade. Abandoning any pretense of objective journalism, he has written three articles praising James and ignoring prominent scientists such as John Kiovula, Richard Hughes, Christopher Smith and Ted Themelis who profoundly disagree with James' methods and conclusions. In the current Colored Stone, Federman says we are living in "gemological end-times." What did all this apocalyptic rhetoric amount to? What James actually presented was mostly old, largely discredited information that although full of sound and fury, flies in the face of science and logic and proves his own theory to be totally false.

AGTA and GJX:

There was definitely more action at the gem shows, but then gems are the major reason most people are here in Tucson during this two-week period. Most dealers I interviewed said that sales exceeded their expectations, though they didn't say what those expectations were. All signs point to a tough year ahead. As dealer Chris Johnston pointed out, its a Darwinian crisis, and as usual, the strong will survive.

Visit Burma's Valley of the Serpents and learn how sapphire is mined and graded. Follow me on gem buying adventures in Burma, Thailand and Sri lanka. Visit the gem fields of Australia and Brazil. 120 carefully selected photographs showing examples of the highest quality gems to educate the eye, including the Rockefeller Sapphire and many more of the world's most famous gems. Consider my book: Secrets Of The Gem Trade, The Connoisseur's Guide To Precious Gemstones.

“Wise is a renowned author… He’s done a marvelous job of this first book, monumental work, a tour de force…My recommendation: Buy this book”.
Charles Lewton-Brain, Orchid

whether you like to know what the best colour is in Tanzanite, or how to grade a Diamond, you will find it in this book. No other book I read before dealt with this topic is such detail as Richard Wise's masterpiece."
A. Van Acker, FGA Amazon June 2005

"Secrets Of The Gem Trade: The Connoisseurs Guide To Precious Gemstones by Richard W. Wise is an impressive new reference for dedicated dealers and collectors of gems, gemstones, and … pearls. Introducing and descriptively exploring each and every gem covered in the easy-to-use reference, Secrets Of The Gem Trade contains an illustrated summary of each stone inclusive of its history and general information, hue and tone, saturation, which may be noticed as the finest, an understanding of the particular gems rarity, and the caution for synthetics and how to depict them, however depending upon the stone there may be description of clarity, color fading, multi-color effect, etc. Secrets Of The Gem Trade is very highly recommended to anyone interested in gemology as a superbly organized, authoritative, comprehensive, and easy-to-follow reference."

Midwest Book Review April 2006

Only $39.95 in paperback. Read a couple of chapters online an order: We recently discovered about a dozen copies of the out of print hardcover: $79.95 signed by the author www.secretsofthegemtrade.com.

Buy it on Amazon: www.amazon.com

Copper Diffusion; Is It Gemology's Worst Nightmare?

Wednesday, September 24, 2008

Copper Diffusion; Is It Gemology’s New Worst Nightmare? Part I

The Latest From Bangkok?

Rumors are reverberating through the gem trade that gem alchemists in Thailand have developed a method to diffuse copper into tourmaline. This method converts low-end pale blue tourmaline into highly saturated material similar to the high priced cuprian tourmaline currently coming out of Mozambique. The first salvo was fired by Ted Themelis a well known expert on gem treatments and repeated in an article by David Federman in Colored Stone Magazine. One of my sources, a dealer active in Bangkok, wrote me two weeks ago claiming that some of this material had actually been certified as cuprian or “Paraiba” type tourmaline by an unnamed gem laboratory. (image above left; gemologist John Koivula lectures at the World of Gems Conference, Chicago)

Adding more fuel to the fire, just as I was about to leave for the World of Gems Conference (WOG) in Chicago, Robert James, FGA, President of The International School of Gemology (ISG) released a study that suggests that tourmaline, even some of the pricey Mozambique cuprian tourmaline is deep-diffused with copper to improve its color. The conference was abuzz with Mr. James’ contentions. Though deep diffusion was not on the agenda, everyone seemed aware of the article and James conclusions were much discussed. Unfortunately, James, who had planned to attend, was unable to due to Hurricane Ike.

This is James’ second broadside in a series. In the first installment he published a study that he says proves that Andesine is being bulk diffused with copper. Many of the gemologists I spoke to in Chicago expressed admiration for the James chutzpah while at the same time questioning both his methodology and conclusions. Stuart Robertson, Research Director of Gemworld International summed up the views of many of the gemologists attending the WOG Conference: “his conclusions on andesine may be right, but his science is flawed. He is way off base on tourmaline.”

Andesine Diffusion Has Arrived:
“Ive been able to turn it red in the lab.”
Dr. John L. Emmett

“I’ve done it” said Dr. John Emmett said in an interview just yesterday when I asked about copper diffusion in andesine. “I’ve been able to turn it red in the lab and made some that look like a good ruby.” The real issue says the former associate director of the Lawrence Livermore Laboratory is differentiation. Emmett, whose firm, Crystal Research, specialized in heat treating Montana sapphire, has tested labradorite from all the major sources, including Oregon sunstone and Mexican material from the Casa Grande mine. “There is natural labradorite, heated labradorite and copper diffused labradorite.” The question now is how do you tell the difference? Emmett prefers the term labradorite to andesine because, he says, the demarcation between the two is completely arbitrary.

Studies of this kind are normally done in well equipped gemological laboratories and subjected to a long process of peer review. Preliminary findings are submitted to colleagues, methods and are minutely scrutinized and conclusions challenged. This time consuming process works to the benefit of the scam artists. Gemologists are put in the position of always playing catch up. Why is this the case?

“Gem labs are sitting there fat, dumb and happy.”
Dr. John L. Emmett

“The problem is, gemology is an observational science not an experimental science”, Dr. Emmett stated. “Gem labs are sitting there fat, dumb and happy.” No one is doing the research. If GIA had put together a small research team in the 80s when surface diffusion first became an issue they would have discovered all the possibilities and would have been able to identify the possible diffusion treatments before the Japanese bought 100 million dollars worth of Beryllium diffused padparadascha sapphire.

Peer Review Goes Public:

James decided to shortcut the review process and has courageously or foolishly, depending upon your point of view, chosen to go public before completing his research, opening himself to a potentially painful process of public review. As luck would have it, several of the world’s leading gemologists; John I. Koivula, Chief Gemologist at The Gemological Institute of America (GIA), Dr. Lore Kiefert, head of the AGTA lab were in attendance and I took the opportunity to raise the issue of tourmaline diffusion with them and a few others. Stay tuned!

Rough Roulette; Colombian Emerald Part II

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By Richard W. Wise, G.G.

“Round and round she goes and where she stops, nobody knows.”

I have heard it said that each time you put an emerald on the wheel the chances of breaking the stone are about 50/50. I recall one hot and dusty afternoon in the late 1980s I was sitting with some friends at a cafe in Teofilo Otoni, a town which was, at that time, the gemstone capital of Brazil. A ragged looking garempiero rode by on a motorbike, turned around and rode back to the cafe. He knew my friend, a Brazilian cutter, so he pulled a dirty scap of cloth from his shirt pocket and let us have a look. The cloth contained an emerald crystal from the mines ant Santa Terezinha de Goiás. The miner had rode all through the night to bring his find to Teofilo. During the 80s Goiás produced emerald that rivaled some of the better gems Colombia had to offer. (pictured left: Entrance to the shaft at La Pita Emerald Mine. Guacharos wait for the tailings. Photo Richard W. Wise)

The perfectly formed hexagonal crystal showed a verdant medium-dark green color that looked exceptionally fine. I don’t recall the actual weight (somewhere in the 25 carat range) but the crystal was about the size of my index finger. This crystal lacked the jewel-like transparency of the Colombian crystals pictured in Part I and was difficult to evaluate. I could see the pepper like inclusions typical of of Goiás emerald but little else.

The asking price of the Brazilian crystal was a quarter of a million dollars. Long story short, I didn’t make an offer. I thought the crystal lacked the transparency necessary to evaluate it and I wasn’t prepared for a quarter of a million dollar spin of the wheel. I later heard that the crystal had been sold for something close to the asking price and that when it was put on the wheel it had literally exploded leaving the buyer with nothing to show for his purchase.

High Rollers:

Hurry, hurry, hurry and welcome to the high stakes world of the rough buyer where every parcel is a gambol. In this world, where a single bet may exceed a million dollars, the dealer across the table from me is a high roller. The parcel so casually scattered across the desk in front of me is a big time rise. Perhaps 1400 carats, it is from the new mine, La Pita, a complex of adjacent shafts in the Colombian state of Boyaca. One mine actually bears the name La Pita, the others are Consorcio, Cunas, Totumos and Polveros. In a country where the old mines have been producing since before the Conquistadors conquered their local owners in the mid Sixteenth Century, serious commercial mining only began at La Pita in 1997. (Pictured left: the author works his way through a half mile tunnel to the surface. Foreground, miner pushes cart full of mine tailings, these will be given to guacheros waiting at mine entrance for further sorting: Photo: Ron Ringsrud)

We are about to watch the fashioning of two of these crystals into gemstones. In this high stakes world a dealer needs an edge. Having a lapidary with the skill of Adolpho Argotty is just such an edge. According to Argotty, in his workshop, loss on the cutting wheel is perhaps 4% and that is perhaps why Argotty is rated the best. He is presently traiing the second generaltion, his niece, Fernanda, who sits at a wheel at his side (see image above right).

Argotty doesn’t just pre-form the stone he supervises the entire process:

“Would you ask an architect to just put up the bones of a structure and let others finish it?” he asks.

(images: above: Adolpho Argotty, holds forth: Picture Richard W. Wise) It takes just about a half an hour. Argotty works away the emerald held between his thumb and forefinger. He grinds a bit then holds the stone up and squints at it in the sunlight all the time carrying on an animated conversation in Spanish with my partner Ron Ringsrud. Ron loves Colombia. He deals exclusively in Colombian Emeralds, has been coming to Bogotá for twenty-five years and speaks fluent Spanish.

The workshop is surrounded by windows on three sides. The light is good. The two crystals have been blocked out, that is to say, they are now the size and shape of the finished gem. Argotty decided to cut the best crystal into a standard rectangular emerald cut. The stone started out at 7.17 carats it now weighs 4.77 carats and it is ready for the faceting wheel. Argotty is excited about this gem. He hands it to Maria Fernanda to polish the table, he wants a closer look.

She hands it back.

“This one”, he says, “will be worth at least $10,000 per carat.”

The second stone which began at 8.53 carats has been shaped into what Argotty is calling a rose cut. I am confused because the stone obviously has a pavilion and looks very much like an antique style emerald cut with overly large corners. Later we figure out the problem is in translation, Argotty means an old style cut which this stone obviously is. Even before polishing commences we see visible inclusions in the stone. It now weighs 6.44 carats.

Step #1 Sealing & Certification:

In Adolpho Argotty’s workshop, preformed stones are dipped into hot paraffin. The objective is to seal any surface breaking fissures to insure that no residue of the polishing compound makes its way inside the stone.

Colombian cutters become a bit testy when the subject of lab grading is raised. If you love emerald you must be prepared to accept some surface breaking fissures and yes, cedar oil is universally used as a treatment to hide these fissures. However, both dealers and cutters feel that they are getting a bad rap from some American and European Gem Labs. Most labs use a uniform four step grading process to grade the level of enhancement: none, minor, moderate and heavy. Gubelin adds insignificant between none and minor and AGL (American Gemological Laboratories) uses its own proprietary scale. Columbian Esmeraldaros believe that this system lacks consistency. The labs, they contend, are afraid to use the term none. According to Argotty, he has delivered emeralds that he personally cut and knows to be totally without enhancement, to major European labs which in turned issued reports claiming these emerald contained a filler. The reader should bear in mind that a certificate grade of none is in no sense a clarity grade,the stone can still look like a broken coke bottle. It just contains no filler, no clarity enhancement.

I examined hundreds of finer stones in the course of my week in the Bogata market and with but a single exception, every stone I saw had some surface breaking fissures. Taking Ron Ringsrud’s advise I rejected any stone with fissures on the crown or girdle or those with fissures on the pavilion that I felt might n anyway compromised the durability of the stone. This, by the way, would make a good definition of the term minor enhancement.

Next, Dopping, Faceting and Polishing. Stay Tuned.

Learn the truth about how Emeralds and other fine gems are graded and priced!

Follow me on gem buying adventures in the pearl farms of Tahiti. Visit the gem fields of Australia and Brazil. 1
20 carefully selected photographs showing examples of the highest quality gems to educate the eye, including the Rockefeller Sapphire and many more of the world’s most famous gems. Consider my book: Secrets Of The Gem Trade, The Connoisseur’s Guide To Precious Gemstones.

“Wise is a renowned author… He’s
done a marvelous job of this first book, monumental work, a tour de force…My recommendation: Buy this book”.

Charles Lewton-Brain, Orchid

A. Van Acker, FGA
Amazon June 2005

“Secrets Of The Gem Trade: The Connoisseurs Guide To Precious Gemstones by Richard W. Wise is an impressive new reference for dedicated dealers and collectors of gems, gemstones, and … pearls. Introducing and descriptively exploring each and every gem covered in the easy-to-use reference, Secrets Of The Gem Trade contains an illustrated summary of each stone inclusive of its history and general information, hue and tone, saturation, which may be noticed as the finest, an understanding of the particular gems rarity, and the caution for synthetics and how to depict them, however depending upon the stone there may be description of clarity, color fading, multi-color effect, etc. Secrets Of The Gem Trade is very highly recommended to anyone interested in gemology as a superbly organized, authoritative, comprehensive, and easy-to-follow reference.”

Midwest Book Review
April 2006

Only $31.95. Read a couple of chapters online: www.secretsofthegemtrade.com.

Buy it on Amazon: www.amazon.com

Emeralds; The God's Shed Green Tears

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The Emerald of Colombia Part I

By Richard W. Wise, G.G.

Green Gold:

There they sat, scattered like match sticks across the white desk blotter, glowing a rich cool green in the late afternoon sun. My breath catches in my throat. I do my best to maintain my cool, to politely keep my eyes on those of my host, a suave youngish Colombian businessman in a white dress shirt, the jacket of an expensive pin-striped suit thrown over the back of his desk chair. “Youngish” is, of course, a relative term when you’re pushing 63. The dealer smiles and motions me to a seat and there they were right in front of me, a king’s ransom of emerald crystals. I try not to dwell on the four tough looking guys with the semi-automatic rifle in the room we passed though on the way into the office. They too wore nice suits.

This was a sight I never expected to see. I have traveled all over the world and seen a number of exceptional gemstones but never have I seen a rough parcel of such high quality of anything, anywhere, never mind gem emerald. I pick up one crystal, it is a bit distorted in form but it is clean and the size of my thumb. I hold it up to the light. Completely clean a medium dark slightly bluish green. I do notice an interesting pattern of zoning, several thin dark lines, almost black, that run perpendicular to the length of the crystal.

“That one cost me $35,000”, the dealer volunteers.

“How much does it weigh”, I ask.

He places the crystal on a scale. I do a quick calculation. The price comes to $1, 411.00 per carat.

The dealer, perhaps regretting his candor with the inquisitive American author, hastens to add that the average yield in cut stones is only about 25%.

Point taken!, that means the average cost of the parcel after cutting works out to $5,644.00 per carat. This is beginning to sound like a multi-million dollar crap shoot because, as we are about to witness, this parcel contains a range of qualities.

Columbia’s Top Cutter:

Senor Adolpho Argotty is considered Columbia’s top emerald cutter. Now 55 he began cutting when he was 15 years old. His father wanted to be a cutter but was not very good at it. Argotty laughs, “so he became a teacher.”

We have been invited to watch Senor Argotty cut two rough crystals from the big La Pita parcel; one weighs 7.17 carats the other 8.53 carats. Argotty works by hand, literally! After examining the two crystals for a few minutes he takes one and casually puts it to the wheel. I see no scales, no calipers, no jam-peg, no measuring devices of any kind, not even a ruler.

The first step is called pre-forming; it is the most important step and requires the highest degree of skill. The wheel is charged with diamond grit mixed with water. The pre-former decides what to keep and what to cut out and that determines the shape and weight of the finished gem. The facets will be added later.

Next: Argotty puts it to the wheel! Stay tuned.

Learn the truth about how Emeralds and other fine gems are graded and priced!

Follow me on gem buying adventures in the pearl farms of Tahiti. Visit the gem fields of Australia and Brazil. 120 carefully selected photographs showing examples of the highest quality gems to educate the eye, including the Rockefeller Sapphire and many more of the world’s most famous gems. Consider my book: Secrets Of The Gem Trade, The Connoisseur’s Guide To Precious Gemstones.

“Wise is a renowned author… He’s
done a marvelous job of this first book, monumental work, a tour de force…My recommendation: Buy this book”.

Charles Lewton-Brain, Orchid

A. Van Acker, FGA
Amazon June 2005

Midwest Book Review
April 2006

Only $37.95. Read a couple of chapters online: www.secretsofthegemtrade.com.

Buy it on Amazon: www.amazon.com

Asking to see the Pigeon’s blood is like asking to see the face of God"

1 Reply

About once a month on one of the gem forums someone asks the question:

"What color is pigeon's blood."

by Richard W. Wise, G.G.

The real question is, of course, "what is the best color in ruby." Although I cover the question in some depth in my book; Secrets of The Gem Trade, The Connoisseur's Guide to Precious Gemstones, it appears that a few people have yet to read the book. (pictured above a gem quality 2.09 carat natural old mine Burma ruby with a GRS "pigeon's blood certificate)

The short answer is simply that rubies should be red. Problem is there are almost no visually pure color in nature so, we speak of a mixture of colors. In gems, we normally speak of a primary and a secondary color or hue. Gems may have more than two hues but it it is difficult for even the most discerning connoisseur to see more than two. Still a ruby must be predominantly red, that is, have a primary red hue. Put another way in the color mix, red must be at least 51% of the hue mixture. If its not red its not a ruby. Any member of the gem family corundum that is any color other than red we call sapphire.

Ruby may exhibit one of a few possible secondary hues. These are: pink, purple and orange. Purple and orange are the hues immediately adjacent to red on the color wheel. You will never find a ruby with a green secondary hue. Pink, a paler less saturated red is also possible. The finest color or pigeon's blood exhibits a purple secondary hue. Why purple, there are two good reasons; one historical and the other based upon color science.

This historical explanation I owe to Vincent Pardieu. Vincent began by studying gemology in Burma and he found a dealer who explained "pigeon blood" to him. The Burmese coined the term. Purple is a hue that falls between blue and red on the color wheel. It is known scientifically as a modified spectral hue.

The Burmese set gems in pure gold which is a a very rich yellow color. Blue is the compliment of red. Complimentary colors are those that cancel each other out. So when a purplish red ruby is set in yellow, the yellow of the metal cancels out the blue in the purple leaving behind, guess what an almost visually pure red.(pictured above a 1.63 carat gem quality old mine Burma ruby with a GRS "pigeon's blood certificate). So the goal for the Burmese is red, pure red! See more!

I wrote my book several years before I met Vincent in Bangkok. However, I reached the same conclusion by applying a logical analysis. My reasoning goes something like this. Color Science teaches that the color red reaches its optimum saturation (brightness) at a fairly dark tone, somewhere about 80%. This is not opinion, it is measurable scientific fact. If you consider that 100% tone would be pure black, 80% is pretty dark. Pink and orange on the other hand reach their optimum saturation at fairly light tones. Pink obviously as it is by definition paler (less bright). Orange reaches its optimum saturation at between 30-40% tone.

Purple reaches its optimum saturation at around 60% tone. Now, if you add a light pigment to a dark paint you would obviously lighten the overall effect. Same is true in transparent media. The optimum tones of red and purple mix fairly well both being both dark in tone. The purple unlike the pink does not dilute the red. Pink and orange would lighten the red thus reducing the overall saturation of the pinkish-red or orangy-red color. Purple reinforces the red, orange and pink dilute. Make sense? Not everyone agrees. Some connoisseurs like a bit or orange. They feel it frames and pumps up the red hue. A good point if you consider the effect of orange in red spinel. Be that as it may, for good historical as well as scientifically verifiable reasons, orangy red is not pigeon's blood.

The first image above is of a 2.09 carat Burmese natural ruby from the old min at Mogok. This stone has a bit purer red, exhibits less purple than the second stone, a 1.63 carat gem from the same mining area. Both, however, have been grading "Pigeon's blood" by GRS, Swiss Lab, Bangkok. As you might imagine this lab sees an awful lot of rubies. Both stones are from the Mogok Valley, this is the place, going back to the Bronze Age, where the original stones were mined back when the term pigeon's blood was coined. A lot of the gems currently in the market are from a new mining areas Mong Hsu that is about half way between Mogok and the Thai border. Mong Hsu stones can certainly be pigeon's blood color but since we are talking about a historical term I thought it best to use illustrations from the old mine.

With the discovery of new sources of ruby in Africa a controversy has arisen over use of the term pidgeon's blood to describe the color of gems most specifically from Mozambique. The Chinese have outright banned the use of the term for ruby other than those of Burmese origin.

At the 2012 Hong Kong show I purchesed two exceptional unheated gems from Mozambique that were described in a GRS report as "vivid red" with a color identical to Burmese stones with GRS Pidgeon's Blood certificates. If, as I have suggested here and in my book, pigeon's blood is a definable hue then it seems to me that any ruby that meets those criteria can and should be labeled the same.

Want to Learn more?

Follow me on gem buying adventures to the old Burma ruby mine at Mogok. Learn how to judge the quality of rubies, sapphires, emeralds, garnets and 31 other gems. 120 carefu
lly selected photographs showing examples of the highest quality gems to educate the eye, including the Rockefeller Sapphire and many more of the world's most famous gems. Consider my book: Secrets Of The Gem Trade, The Connoisseur's Guide To Precious Gemstones.

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"Secrets Of The Gem Trade: The Connoisseurs Guide To Precious Gemstones by Richard W. Wise is an impressive new reference for dedicated dealers and collectors of gems, gemstones, and … pearls. Introducing and descriptively exploring each and every gem covered in the easy-to-use reference, Secrets Of The Gem Trade contains an illustrated summary of each stone inclusive of its history and general information, hue and tone, saturation, which may be noticed as the finest, an understanding of the particular gems rarity, and the caution for synthetics and how to depict them, however depending upon the stone there may be description of clarity, color fading, multi-color effect, etc. Secrets Of The Gem Trade is very highly recommended to anyone interested in gemology as a superbly organized, authoritative, comprehensive, and easy-to-follow reference."

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April 2006

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Labels: gem prices, gemstones, new gem strike, spinel prices, Tanzania gems, Tanzanian Spinel