Author Archives: Harry Bernard

Gem Grading: The Death of the Lightbulb and Other Brilliant Ideas

Color temperatures a various types of lighting. 5500-6500 is the Kelvin temperature of daylight. GIA uses a 6200 Kelvin light source for diamond grading.

New Technologies May Require Changes is How We Look At Gems:

In 2007 amid little fanfare, Congress passed a law that required that the efficiency of that iconic household standby, the incandescent light bulb, be improved or perhaps accept its doom. The bulb has been around a long time and the technology has remained virtually unchanged since it was invented by Thomas Edison in 1881. Turns out the old bulb is a real energy waster, only 10% of the energy used is given off as light, the rest is dissipated as heat. Though some called it the death of the incandescent light bulb, Congress merely dictated an increase in efficiency, 20% by 2014, 60% by 2020.

Though the efficiency standards do not state what is allowed, such a dramatic increase in efficiency is bound to require new technologies which are likely to mean changes in the light spectrum produced by whatever technology replaces the old standard. No one has given much thought to the consequences this will have in the gem trade. The new standards are scheduled to take effect this January.

In the evaluation of quality, gemstones have been traditionally viewed under two light sources, noon daylight or more lately daylight equivalent fluorescent lighting and plain old incandescent (in the 19th Century it was candlelight). A stone that looked good by day but muddied up under the lightbulb is taken to be inferior to one that holds its color in both lighting environments. In 2003 I published a book, Secrets Of The Gem Trade, that divides gems into daystones and nightstones. The terms refer to gem varieties that look best under a given source. This seemingly bright idea may mean dramatic reductions in oil imports, but wait! What about the gem business, what’s a connoisseur to do?

The Tea Party To the Rescue:

Well our worries may be over, just last week the House passed legislation to deny funding to the law. Apparently the bill’s original Republican sponsor, Texas Representative Michael C. Burgess had an epiphany. He has seen the, ah, light. “The government has no right to tell me or any other citizen what type of bulb to use at home,” no matter how much energy it might save says Mr. Burgess. We have the right to waste all the energy we like in the privacy of our own bedrooms, says so in the scriptures.

But seriously folks! Sooner or later, new, more efficient types of lighting are bound to replace the old standby. Will there be a new standby? Probably not. We are pretty much at the point where the type of lighting used will be dictated by the setting that it is used in. Call it dial a light! At that point will gem grading light be standardized. To some degree it already has. Most laboratories use some artificial version of daylight. The Gemological Institute of America (GIA-GTL) uses a 6200 fluorescent bulb, American Gemological Labs uses a 5500 Kelvin bulb. What is the next step? Stay tuned to GemWise.

Book Review: The Colour of Paradise, The Emerald In The Age of Gunpowder Empires

Kris Lane

The Colour of Paradise, The Emerald In The Age of Gunpowder Empires

280 pages including appendices

ISBN: 978-0-300-16131-1

The history of the gem trade is a difficult research topic because gemstones are very small objects of great value that have been highly sought after for millenia by rich and powerful people looking for wealth that was portable and easily concealed. The trade itself has been controlled for centuries by minority groups, often oppressed minorities, Jews, Armenians and Indians for whom secrecy was a proven form of self preservation. Kris Lane is a historian, a Professor of History at the College of William and Mary. In The Colour of Paradise, Professor Lane focuses very well honed research skills on the history of the emerald, one of the rarest, most mysterious and highly valued of all gemstones.

The book contains no particularly major revelations. Most historians of the trade are aware that India’s so-called “old mine” emeralds were, in fact, Colombian emeralds imported by the Spanish into India in the Sixteenth and Seventeenth Centuries. Lane’s contribution is to meticulously document both the early history of Spain’s brutal exploitation of Colombia’s indigenous people and its gem wealth. He gives us a well documented overview of early trade routes and uncovers some very interesting and original information concerning 16th Century production; methods and emerald values.

Lane begins with the 16th Century and follows emerald production in Colombia right up to the present, with a good account of politics and production into the 1990s.

All and all this well organized and well written account brings real clarity to a relatively murky area of history. The book also contains detailed appendices estimating early emerald at Muzo, relative values of emerald and diamond in Europe in the 17th Century and an extensive bibliography. The author has uncovered several original accounts that have until now been unrecognized. Highly recommended.

Online Gem Evaluation; Slouching Toward Disaster, Part III

12 Replies

by Richard W. Wise, G.G.

You Just Can’t Hide Those Lying Eyes:

Image A: Before photoshop, this is the image the camera saw. Photo Courtesy Precision Gem

In my first post on this subject, I made the point that making a purchasing decision or merely comparing prices by comparing images is fraught with difficulty. Photoshop and other similar programs are a good part of the reason why. The two images to the left illustrate the point. Image A is a custom cut Mali garnet. Based on the image, the stone appears to be a slightly greenish (10% yellow light toned garnet of medium saturation, not bright but not overly dull with a slight gray mask.

In Image B of the same stone, the original image has been altered by a simple tweak of the Saturation Enhancement Tool in Photoshop. The green secondary hue now appears more prominent, perhaps 15-20%. The big change, however is in the level of saturation. The color must now be described as vivid effectively doubling the value of the stone. The only hint that this is the same image is that the background in image A is slightly cooler (grayer) than the background in image B. However, if the photographer simply took two shots under the same lighting he could easily disguise that fact. Backgrounds can also be removed or replaced with a uniform black. Assuming that these two images appeared at similar prices on separate websites, an online bargain hunter would wrongly conclude that the owner of the stone labeled image B was offering his goods at a much more favorable price.

Approaching the Pinnacle of Perfection, Small bumps in Quality Equal Big Bumps in Price.

In low quality commercial grade gemstones, small differences is quality will not make a great difference in price. However, as quality nears theoretical perfection the importance of smaller differences is magnified. In the stratosphere of gemstone quality, small differences can make for very large price differentials. Lets take an example that everyone knows, the D flawless diamond. I chose this example because diamonds are very precisely graded using an internationally accepted grading system. According to The Guide a well respected industry publication, the current wholesale price of a 1.00 carat D-IF is 31% higher than the very next color grade, E-IF, compared by clarity grade, (D-Fl vs D-VVS1) the spread is slightly less, about 29%. A similar comparison between diamonds with a color grade of L and O shows only a few hundred dollars separating the two grades. These differences will not show up in an online image.

In colored gemstones these same percentages apply and the grading equation becomes much more complex. Colorless diamonds are graded based on slight tonal variations of yellow. Color, any color, breaks down into two additional factors, hue and saturation which must be added to tone in the quality equation. In nature there are few pure hues. The hue of a gemstone is composed of primary, secondary and sometimes tertiary components, a top color ruby for example, may be 75% red, 15% purple and 10% orange. A blue sapphire with 10% (or less) green secondary hue which will likely not be visible in an online image will sell at a dramatically lower price than a stone with a pure or slightly purplish blue hue. Similarly, an emerald that is 75% green with a 10-15% secondary blue hue can sell for double the price of a slightly yellowish stone. These slight differences in hue do not show up even in professional images. This makes online comparison between two images very deceptive and of little or no value.

Image B: The same gemstone after a tweak of the Saturation Enhancement tool in Photoshop

The Value of Images:

Online images are of some value. As a professional, I never use images to determine which stones I will buy though sometimes they can identify a stone that I will not buy. It is usually possible to tell something about the clarity and cut of a given gem by viewing the image. Both come with caveats.

Online Images are Many Times the Size of The Stone; so are the inclusions:

The Mali garnet at left weighs approximately one carat. That means the stone is somewhere in the range of 6 mm in diameter. The image shown is 38mm, 6.33 times larger. Many gems that are eye-flawless will appear visibly included (flawed). In colored gemstones, the eye standard replaces the loupe standard, what the eye sees is what is important, magnification doesn’t effect price. In most varieties of colored gemstones, the difference between eye-clean and visibly included is dramatic. It is similar to the difference between a diamond graded flawless and another graded SI2.

In some cases the image will actually distort what the eye sees. Award winning gem photographer, Robert Weldon, makes the point that due to the limits of depth of field, the camera’s lens will compress inclusions into a single plane increasing the prominence of the inclusions in the image. This compression can lead to particular difficulties when trying to accurately render images of expensive type II and III gemstones such as emerald where the difference in value between an eye-clean gem and one with eye visible inclusions will be dramatic. Online images are normally in j.peg format. This format is created, Weldon points out, by subtracting information in the original high resolution image.

Images can be useful in evaluating cut but bear in mind that the visual performance in a gem depends upon lighting. A well lighted gemstone may appear to perform better than one that is less well lit. The lighting environment is not visible, multiple light sources of the type normally used in photography can mask real deficiencies in cut.

Color and Lighting:

In the good old days, there were two types of light; the sun and light from a natural flame, a fire or a candle. This, as I point out elsewhere, is the source of the legendary “ruby red” alexandrite. When that gem was discovered in the mid nineteenth century, incandescent light was supplied by a candle and candlelight is distinctly reddish—after the invention of the light bulb, the ruby red alexandrite became distinctly purple because that light source is yellowish. With today’s technology, it is possible to virtually cherry pick a lighting environment that is strong in a given color. You can light sapphires with blue light, rubies with red. Again the light source is not visible—so how would you know until your gem arrives in the mail.

Grading Tanzanite; In Praise of Purple

10 Replies

Gem quality tanzanite showing both its primary blue (left) and secondary purple (right) hues. Wise, Richard W., Secrets Of The Gem Trade, p.219

by Richard W. Wise, G.G.

“Roses are red violets are blue but tanzanite ain’t violet.”

In 2007 The Tanzanite Foundation came out with a “standardized” grading system for tanzanite. Shortly later, The American Gem Trade Association’s laboratory adapted this grading system for use on its grading reports. All tanzanite would henceforth be graded on a color scale from violetish blue (vB) to bluish violet ( bV). Great idea, only one problem, they got the colors wrong, they missed purple.

Tanzanite’s primary hue is often blue but never a pure blue. Tanzanite exhibits a secondary hue which is always present. The secondary hue ranges from violet to purple, which though often confused in common speech are distinctly and definably different hues. Violet is a primary spectral hue that lies halfway between purple and blue and Purple is a secondary or modified spectral hue meaning that it results from a mixture of two primary spectral hues (red and blue). That explains why it doesn’t show up when you view the rainbow. Purple is positioned halfway between blue and red. The confusion of violet and purple is not new it goes a long way back but lets begin with Newton. Sir Isac is rightly given credit for initial work in color theory— published in 1706, his was the first color wheel.

The original color wheel courtesy of Sir Isac Newton. In 1708 a Frenchman, Claude Boutet (Traité de la peinture en mignature) added purple.

If you squint (image right) you will see that Newton identified indigo and violet as the two hues existing between blue and red. He either forgot purple or was perhaps pre-purple. Prior to the movement to standardize nomenclature in the 18th Century, colour names, like spelling, were not standardized. Tavernier, for example described the great blue diamond that he sold to Louis XIV as “violet.”

What isn’t generally understood as that Newton’s color wheel was all about opaque colors. Colored light adds a whole new dimension to the color equation.

Using oil paints, mix equal amounts of the two opaque colors red and blue together and the color you get is magenta. Purple can be mixed but painters are reluctant to use the term, preferring blue-violet instead, further adding to the confusion.

“Roses are red, violets are purple sugar is sweet and so is maple surple”

Roger Miller

Change from opaque media to to colored light you dramatically change the result. Mix equal amounts of red and blue light together and you get, guess what, purple.

After tanzanite has been heated, and virtually all tanzanite is heat treated, it is dichroic. That means that light entering the gem crystal divides into two rays each containing a portion of the visible spectrum. The dichroic colors of tanzanite are red and blue—the red is often reddish purple. If the gem is properly oriented before cutting, the face up color will mix the two yielding a range of hues from violetish blue (vB), to purplish blue (pB), to purple-blue (PB) to bluish purple (bP).

Where is the Lab Harmonizing Committee When You Really Need Them?

Studies show that it is particularly difficult for the human eye to distinguish purple, particularly at light tonal levels. This is known as the Bezold-Brücke effect. When purple is present in light-toned gems, the eye wants to see blue. In fact at light tones and low levels of saturation it is difficult to separate purple from violet or even pink. This occurs a lot in light toned topaz. Dealers will often categorize light purple as pink topaz. At darker tonal levels the eye is not bothered by the Bezold-Brücke effect. Yes tanzanite can often be violetish, even blue-violet, but finer stones are purplish-blue so how can purple be left out of the definition?

Traditionally tanzanite has been graded by what I call the “look-alike” standard. When the stone was first discovered, Harry Platt, the Vice President of Tiffanys compared it to sapphire. Platt declared that the finest color of tanzanite was a pure sapphire blue, which means that the finest tanzanite, like sapphire is a medium dark tone (75-80%) slightly violet to purplish blue. A medium dark toned true blue barely exists in nature and only in tanzanite when viewed in noon daylight or daylight fluorescent lighting. Put a “pure” blue tanzanite under the light bulb and a distinct violet to purple secondary hue will always be visible. In the finest stones, a medium dark toned purple adds a velvety richness to the blue, so beautiful that even the folks all the way over at the Tanzanite Foundation, at AGTA and even at GIA should be able to see it.

Quality Grading Opals, The Toughest Challenge of them all

5 Replies

by Richard W. Wise, G.G.

Three black opals showing two tones of body color. The Australian valuing system recognizes nine degrees of body tone. The gems at right would be graded N1, the oval to the left N3. Photo: Cody Opal

Over the past decade it has been my privilege to get up close and personal with some of the world’s most fabulous opals. My love affair with this idiosyncratic gem began in 1991 with a visit to the opal fields of Queensland. At that time I was researching an article that would eventually be featured in Gems & Gemology, the journal of the Gemological Institute of America, under the title: Queensland Boulder Opal.

Queensland, like most of the Australian outback, has come to embody the frontier spirit, the ethos of America’s old west. Strong solitary loners, men of few words with names like Texas Jack and Silk Shirt Joe, labored under almost unbelievably harsh conditions, nourished by the stubborn belief that sooner or later they would hit pay dirt. It took just a few days days with the guidance of the late Vince Evert to realize that even in the waning days of the 20th Century, much of that spirit lived on.

With Evert as our guide, the adventure began when our Piper Apache approached a bumpy dirt airstrip that had been carved out of the arid plains on the outskirts of Winton (marked w/red dot), a frontier town 350 miles into the Queensland outback. The Evert family are among the town’s most substantial citizens. Proprietors of a gift shop and the town’s only outdoor theater, they are also one of the area’s largest mining operations–entrepreneurs and opal cutters. It was Vince, dressed in khaki with a plain brimmed Akubra hat—Australia’s five gallon version of the ten gallon hat—who stood waiting as our single engine plane taxied to a dusty stop.

It was a sunny day in early March, the temperature hovered around 120°F. The outback is basically desert, and water is drawn from bore holes, wells that reach as much as 3,000 feet down below the cracked brown earth; the water comes up hot and stinking of sulfur.

Describing Opal:

Opal nomenclature can be a bit tricky. In the old days unwieldy and confusing terms such as white, crystal, semi-black, semi-black crystal and black were used. The new Australian system of classification now recognizes nine levels of body color or body tone (N1-N9).

Figure 1: Opal body tones, there are nine basic grades and opal gets noticeable lighter in body color as you go down the scale. Photo: Cody Opal

Body color is the background color, the color of that part of the opal which shows no chromatic fire (play of color). Opal classifications are based strictly on visual appearance. Black opal, generally speaking, is found at Lightning Ridge, but all opals produced at The Ridge are not described as black. This differs from the system of pearl classification where, for example, any pearl produced by the Pinctada Margaritifera (black lip) oyster, regardless of body tone, is termed a black pearl.

Grading Opal:

“You can learn diamond grading in an afternoon, learning to grade opal might take twenty-five years.”

Richard T. Liddicoat

In my book, Secrets Of The Gem Trade, The Connoisseur’s Guide…, I devote considerable space to a comprehensive discussion of the grading of opal, thus I will not attempt to cover all bases in this post. The descriptive system cited above was not in use at the time the book was published (2003).

Saturation levels in opal. Viewed from left to right the stones show higher levels of saturation (brightness). Be careful of the last one on the right as it depicts a pattern of large flashes which will appear brighter than the smaller more discrete pinfire play of color in the images to the left.

Figure 2: Saturation levels in opal. Viewed from left to right the stones show higher levels of saturation (brightness). Be careful of the last one on the right as it depicts a pattern of large flashes which will appear brighter than the smaller more discrete pinfire play-of-color in the images to the left. Photo: Cody Opal

Opal is like a light bulb–the brighter, the better. It is not the given hue, but the brightness or saturation of hue that is the primary criterion of value. Color, as we know, divides into three components: hue, saturation and tone. Hue is color as the term is ordinarily used, e.g. greenish blue, pinkish purple. Saturation refers to the quantity, or brightness of a given hue. Figure 2 depicts levels of saturation, although some opal experts prefer the term brilliance. Moving from left to right, the colors become more intense. As opal types, the first two stones in figure 2 would be classified N1, the third N2 and the fourth probably N3. N1-N4 are examples of what is normally called black opal. N6-N7 are called crystal opal and N8-N9 are light opal.

A black opal exhibiting the rare "peacock's tail" pattern. The opal was cut in a shape that resembled a butterfly's wing. At the risk of mixing metaphors, we designed and created an opal butterfly with a peacock pattern in 18k yellow, rose and white gold. The design rendering is shown as background. Courtesy: R. W. Wise, Goldsmiths. Photo: Jeff Scovil

Patterns:

Pattern is important. Larger blocks of color are more highly desired than smaller. Figure 2: Moving from left to right the color becomes increasingly more saturated. Note also that the stone at the far right is more beautiful because the color is not only more saturated (brighter), but also because the pattern of larger chunks of color is both more visible and more pleasing to the eye. The grading of patterns is unique to opal. Some, like peacock’s tail, are easily identified because they closely resemble their pattern-name. There is a hierarchy of rarity associated with pattern that any true opalholic must learn by rote.

Generally speaking, those evocative patterns which are readily identifiable with names like Grass, Chinese Writing and Mackerel Sky are the most desired. At the very top of the list sits Harlequin, rarest of the rare. This pattern is named for the ambiguous clown-like figures dressed in suits with large diamond shaped patches which inhabit the paintings of Picasso’s Blue period (see below left). I have seen only three harlequins in twenty years and only two with a true red component.

Millenium, a 25 carat Harlequin opal sourced by Cody Opal and sold several years ago by R. W. Wise, Goldsmiths The gem has the the double virtues of large angular blocks of color and a dominent red which is the rarest hue in opal.

Millennium, a 25 carat Harlequin opal sold several years ago by R. W. Wise, Goldsmiths. Millennium is known as a red multicolor because the gem has the the double virtues of large angular blocks of color and a dominant red, which is the rarest hue in opal. Photo: Rudy Weber

Pricing Opal:

Opal prices can vary from a few dollars to hundreds of thousands. Additional criteria including color and transparency are also key to the valuing equation. Beauty is, as always, the defining criterion.

In 2008, opal experts Andrew and Damien Cody published a beautiful booklet, The Opal Story, A Guidebook (ISBN: 978-0-9805987). Aside from some of the most magnificent photographs of some of the finest opals ever to see the light of day, the Codys identify seven value factors in the grading of opal: type, brilliance, body tone, transparency, pattern, dominant diffracted colors, thickness of color bar and shape. These criteria are consistent with the new Australian system of valuing. I would advise anyone seeking to sharpen their understanding of opal grading to purchase a copy of this booklet. The Opal Story Book and DVD is available for $29.95 AUD plus shipping and handling of $6 AUD. Orders can be emailed to opal@codyopal.com . The order should include mailing address and phone number together with credit card details.

Book Review: Terra Spinel by Vladyslav Yavorskyy

5 Replies

by Richard W. Wise G.G.

Tucson Gem Shows; A Brief Roundup:

Early Saturday morning, Rebekah and I woke from a deep sleep and reluctantly dragged ourselves to the Tucson International Airport. Our two weeks at the annual gem-orgy was over, goodbye blue skies, hello ice and snow. The Berkshires may look “dreamlike on account of that frosting” (James Taylor) but we are, quite frankly, over it! The icicles on our roof are four feet long!

Tucson was quite productive this year. The recession appears to be on the wane. Attendance was up and most vendors were quite pleased, with sales as much as 50% above last year’s—though in some cases, that’s not saying much! Prices in most gem varieties were strong with vendors unwilling to discount. Big auction prices realized by exceptional rubies and sapphires appear to be putting some upward pressure on smaller, finer goods.

Book Review: Terra Spinel:

Yavorskyy, Vladyslav and Hughes, Richard W., Terra Spinel, 2010 Privately Published and Printed in Hong Kong. Full Color, 200 pages; 240 x 260 mm ISBN: 978-0-615-40901-6

Though this is hardly news, in the past three years, spinel prices have doubled, particularly for finer qualities of red, pink and Cobalt blue varieties. Spinel has a long and illustrious history in the gem world, but it languished and traded in an indifferent market through most of the past century. Perhaps this is due to the fact that colorless spinel was used as a diamond substitute in the 19th Century and the bad odor of “simulant” clung to the stone for much of the 20th. This also explains why there has never been a comprehensive book written on spinel. For those looking for such a volume, Terra Spinel is not it.

A magnificent red spinel before and after

Terra Spinel, a large format coffee table sized portfolio (9.75 x 10.25″), designed, edited and written with the help of Richard W. Hughes, author of the seminal Ruby & Sapphire, is a picture book, but what pictures! Both Hughes and Yavorskyy are great photographers. My wife and I look forward each year to receiving Yavorskyy’s annual photo-calendar (not available this year due to the cost of producing the book). Vlad’s photographs burrow down and capture the gritty, often humorous and at times profound everyday realities of the remote regions he visits in search of gemstones. Like the dustjacket pictured above, the book is printed on a medium-dark gray background which makes the images really pop.

Old man, a villager from remote Afghanistan, by Yavorskyy

Beginning with the magnificent 110 carat polished red spinel rough pictured on the cover, the book chronicles some of the fine gemstones Yavorskyy has sourced over the years. Each page, even those with full page images of mines, villages and temples, and these are the majority, includes an example of a beautiful gemstone often juxtaposing rough and polished images of the same gem. Most of these images are labeled with the weight, at least, of the cut version, but many are not. Unfortunately this is also true of the final section entitled Spinel by the Book, which is essentially a seven page thumbnail sketch of the entire collection. Given its importance, a list of sizes would have been very useful.

Hughes does begin with a brief but informative history of both the gem and its ancient names– spinel, balas ruby and lal. Brief biographies and large images of three of the world’s most famous spinels; Timur’s, The Black Prince’s and Catherine the Great’s rubies, are also provided. Having recently visited the Imperial Collections in Moscow and St. Petersburg (October), I can attest to the fact that the color renderings of these important gems are the best available. There are full color maps of both the major historical and current mining areas. The book also contains a helpful two page bibliography.

Terra Spinel is a beautifully designed and sumptuously produced hardcover. The book is swathed in black cloth and wrapped in a thick chrome-coat dustjacket. The title and authors’ names and blind stamped in embossed silver on both front cover and spine. A color panorama begins on the inside front cover (endpaper) and extends to the endsheet; ditto inside the back cover. These are all expensive extras which more than justify its $95.00 price. Unfortunately shipping from Bangkok will cost another $65.00 bringing the total to $160.00. The book may be ordered directly from the website. For those traveling, the book will be available at the Hong Kong International Jewellery Show: 4–8 March 2011. Grand Hall, Booth G09; Baselworld: 24–31 March 2011. Booth C30, Hall 3.1.

Foreign Investment Scams, Slouching Toward Disaster II

8 Replies

by Richard W. Wise, G.G.

Of Dentists and Doughboys:

What is it about gemstones that gives buyers the idea that somewhere, somehow they can get something for nothing? Why are dentists particularly vulnerable? Over the course of my career I have spoken to not less than five members of that gullible fraternity who “invested” in gems. One salesman told my dentist that Japanese investors were eager to pay twice the price for low grade aquarium gravel contained in that little sealed packet. “Why didn’t you suggest that the salesman board a jet to Tokyo and reap those high profits”? I asked Dr. Pain. He shrugged, smiled sheepishly and looked down at his shoes.

Did you hear the one about the smart New York lawyer who, after I told him about a buying trip to Thailand and Burma, blithely asked, “Yeah, but do they know what they’ve got?” Well, yes Virgina, these folks have have been mining and marketing gems since the Bronze Age, I think it’s fair to say that they have finally figured it out.

A Potentially Explosive Investment:

I suppose the neophyte gem investor is really no different from the clueless homeowner who believed those friendly folks at Country-Wide when they told him he could support his lifestyle by the continued plundering of the equity in his home and is now so far underwater he can’t even draw breath through a snorkel—a fool and his money…I remember another occasion, a young couple, yoga students who had spent time in an ashram in India. They met an Indian fellow who’s father owned a ruby mine. Despite my warnings they returned to India and sunk $10,000 into dyed and oiled ruby bead made from low-grade East African rough that originally sold for $150.00 per kilo.

Emerald Mine, Panjshir Valley, Afghanistan: Photo courtesy Vincent Pardieu

More recently I was approached by two army officers currently serving in Afghanistan to appraise gemstones that they had bought for investment. One of the men, a lieutenant who seemed particularly eager to buy, told me he was a specialist in the very dangerous profession of mine clearance. I advised him to stop buying and volunteered to take a look at his purchases. After vetting his collection which included lead-glass filled ruby and low end tanzanite, I suggested that purchasing gems for investment on the open market in Afghanistan could very likely have a more explosive impact on his finances than his current day job.

Our service members should be aware that there appears to be an entire industry in Afghanistan, similar to the one that existed in Pattaya, Thailand during the Vietnam War, dedicated to fleecing members of the American military. According to Gary Bowersox, a gem dealer who travels frequently to Afghanistan and co-author of Gemstones of Afghanistan: “The Afghanistan market is flooded with treated and synthetic gems where uneducated Afghan gem dealers are selling volumes of gems to foreign soldiers who are also uneducated in gemology.”

Professional appraiser, Charlene Bradbury, G.G. has appraised 50-100 stones brought back by approximately ten servicemen from Afghanistan over the past two years. she notes that 90% were either synthetic with a fairly large proportion of lead glass filled rubies. Most others were low grade, lead glass filled rubies.

Getting The Lead Out: (above)Lead glass filled ruby after heating that removed some of the glass. Below: Same ruby under magnification. Photo: Shane F. McClure

Our Responsibility:

I know that I promised more on the topic of Online Gem Evaluation and I will, but I really feel that my experience with the two army officers is a cautionary tale that needed to be told. Our boys in the military are doing a dirty and very dangerous job for us in Afghanistan and I believe that we, as members of the gem fraternity, have a responsibility to protect them in whatever small way we can.

Countdown To Tucson:

The annual free-for-all smorgasbord known collectively as the Tucson Gem Shows will begin at the end of this month. I have been attending the shows for over twenty-five years and have watched awestruck by the spectacular growth of this annual event. My wife and I spend two weeks and work every day and still find it impossible to take in all of the shows. As always, I enjoy the hunt. It can be frustrating but there is nothing more satisfying than the thrill of sourcing a particularly fine gem at an out of the way booth, tucked into some back alley show.

Online Gem Evaluation or Slouching Toward Disaster:

6 Replies

by Richard W. Wise, G.G.,

author: Secrets Of The Gem Trade.

With the commercialization of the internet we have entered a new era for collectors of all stripes. Whether you are interested in antiquarian books or colored gemstones there is a great deal of information available and the opportunity to compare prices for the best deal.

If you are buying a commodity and I define commodities as items of uniform quality that are produced in multiples, comparisons are straight forward. Deciding between two new copies of the latest Jacky Collins romance novel is simply a question of price though you have to watch the shipping charge.

When it comes to collectibles, such as old coins where condition is a primary determinant of price, the buying decision becomes a bit more difficult. Two identical 1870 U. S. ten dollar gold pieces will vary dramatically depending upon condition.

Purchasing gemstones is much more complicated. First, no two gems are alike. Even colorless round brilliant cut diamonds that are traded with “certificates” that grade each of the four C’s vary in the relative percentages of brilliance, dispersion and scintillation. Even the so-called “ideal cuts” will vary markedly because the definition of what constitutes ideal varies from lab to lab.

Colored gemstones present an even broader set of variables and presents an almost insurmountable barrier to effective online comparison. In gemstones, color is the most important determinant of value and sub-divides into three factors, or values; hue, saturation and tone. Accurate grading of a gemstone depends upon two factors; the lighting that the gem is viewed in and the viewer. Change either and you no longer have consistent or accurate grading.

Online Color Comparison; The Impossible Dream:

The rise of internet forums has lead to the dubious practice of online grading by pixel. A neophyte gem buyer will post an image of a prospective purchase with a plea to the forum members to basically appraise the gem and by comparing quality with the purchase price, determine if said newby is getting a good deal. Unfortunately a number of forum members, many of whom ought to know better, jump in and tender their opinions. Though many online grading gurus would disagree, this sort of color comparison is nearly impossible.

There are a host of variables each of which will fundamentally alter the color that you think, you see. The image itself was taken by a specific camera in a specific lighting environment. Each make and model of camera has specific pluses and minus when it comes to accurately rendering color. Some are good with greens, some with blues others with reds. The color temperature of the specific lighting will make a big difference is the color you see. Natural light is reddish at dawn, turns yellow in the late morning, is neutral white at noon then turns bluish in the afternoon and finally reddish again at sunset. Artificial light can be controlled to emit almost any hue all of which affect the apparent color of gemstones.

Apparent color can also be altered by easily altered by editing software. Photoshop, the world’s most popular color editing software employs sophisticated tools that can easily alter the hue/saturation/tone of an image. With five minutes of training, the most unsophisticated Photoshop user can be taught to turn a ruby into an amethyst or even turn it green as an emerald. Though I have seen some forum gurus claim to be able to detect images that have been altered, such claims are pure nonsense.

Now we get to the monitors. Each monitor is different. 24 bit monitors differ markedly from 16 bits and from manufacturer to manufacturer and even day to day. Jennifer Robbins author of Learning Web Design tells her readers: “Let go of precise color control. Yes, once again, the best practice is to acknowledge that the colors you pick won’t look the same to everyone, and live with it. Precise color is not a priority in this medium where the colors you see can change based on the platform, monitor bit-depth, or even the angle of the laptop screen.”

No Computer Monitor on Earth…

$On one popular forum this spessartite garnet, offered by a Thai vendor, was said to show brown. Anyone with experience photographing this gem variety knows that the camera will often show brown where there is none. A result of off axis refraction.$

On one popular forum this spessartite garnet, offered by a Thai vendor, was said be brown or brownish. Though all my monitor shows is deep orange, those with experience photographing this gem variety know that the camera will often show brown where none exists. This is a result of lighting and off axis refraction.

The problem in accepting Ms. Robbin’s advise is that precise color is a priority nay a necessity in color grading gemstones. The Colorscan grading system pioneered by C. R. Beasley, founder of American Gemological Laboratories (AGL), the only U. S. lab that quality grades colored stones uses 36 different hue/tone combinations together with two degrees of gray masks yielding 108 different colors each associated with a specific quality level and therefore price, in blue sapphire. No color monitor on earth, even if properly calibrated can render all these combinations. The current director, Gemologist Christopher Smith, uses sample gemstones for stone to stone comparisons, he says he has literally hundreds of sample stones.

Viewed face-up, a gemstone is a mosaic of color, it is a complex scene. A static image captures but one aspect of a gem under a specific lighting environment. Many factors will effect the image you see. Lighting, viewing angle, lens and angles of refraction. The images shown here illustrate some of the problems.

I’ve chosen to discuss brown in orange gemstones because brown is dark toned orange. This means that the color you see is particularly vulnerable to misinterpretation. The gemstone acts a a prism, bending and bouncing light about like a demented pinball. If the light ray refracts at an angle from the perpendicular, off axis, the hue will appear darker, if totally away from the eye, black.

This professionally taken image of a 3.29 carat Nigerian spessartite from my inventory is almost identical in color (hue/saturation/tone) with the 7.46 carat stone at left yet it appears on my monitor as distinctly more orange and 15% darker in tone. Photo: Jeff Scovil

This 7.46 carat spessartite shows visible brown. It is from my own inventory so I can state with certainty that the stone itself has absolutely no brown.

In the image, this 7.46 carat spessartite shows a distinct visible brown. It is from my own inventory so I can state with certainty that the stone is a rich, vivid pure orange with absolutely no brown secondary hue or mask. On my monitor, the stone the image appears distinctly yellowish with brownish scintillation. Compare to the image of the 3.29 carat stone at right. Photo: Jeff Scovil

The Nuances of Grading:

Few jewelers and fewer collectors ever have the opportunity to see the complete range of quality possible in any given gem variety, be it sapphire, ruby, emerald or spessartite. Without that overview a grader lacks context. As the quality of a given gem approaches perfection, the beauty and rarity and therefore the price of a gemstone will increase dramatically. In the next post I will discuss the subtle nuances of grading that define those gems that are truly transcendent. Stay Tuned or sign up. You can receive GemWise by email or RSS feed, don’t miss another gonzo post, look along the right side and sign up ! I don’t guarantee that you will always agree but I promise it will never be boring. Comments welcome!

Wikileaks, Zimbabwe & Blood Diamonds, Part II

9 Replies

by Richard W. Wise, G.G.

Wikileaks, if it has done nothing else, has directed a searingly bright light on the hypocritical world of international relations in general and the Kimberly Process in particular. For those who don’t know about it, The Kimberly Process comes down to a series of criteria, developed by the diamond industry, whereby a chain of ownership is established to enable sellers to certify that the diamond you are buying for your wife, to celebrate the birthday of the Prince of Peace, was not obtained from a starving West African miner at machete point. The process was initiated because of a storm of press reports generated by Global Witness, another bunch of whistle-blowing trouble makers who objected to people having their arms and legs hacked in the pursuit of diamonds to fund bloody civil conflicts in West Africa.

In August 2010 the Zimbabwe government auctioned 71 million in Marange diamonds certified by The Kimberly Process. The Process as it relates to current events in Zimbabwe has become something of a joke. In June 2009, Ian Smillie, a conflict diamond expert, architect and Director of The Kimberly Process resigned, stating: “when regulators fail to regulate, the systems they were designed to protect collapse.” In an interview with Bob Bates of Jewelers Circular Keystone, Smillie has this to say about Zimbabwe:

“With Zimbabwe, the government of South Africa is really protective of the Mugabe regime. But it isn’t just them. The Russians say this is not a human rights organization. But what is it exactly supposed to be? It’s there to protect people against conflict diamonds. Some governments are placing their small regional political interests over the interest of the diamond industries. Others in the region just hope that people won’t care. Interview with Ian Smillie former Director of The Kimberly Process: Source: Jewelers Circular Keystone, 2009

Jennifer Connelly and Leonardo Di Caprio in a scene from the movie Blood Diamonds. I have been to a lot of gem mines but I have never run into Jennifer.

Jennifer Connelly and Leonardo Di Caprio in a scene from the movie Blood Diamonds. I have been to a lot of gem mines but I have yet to run into Jennifer.

According to cables originating from the American Embassy in Zimbabwe, undocumented diamonds mined in Marange area are sold directly to foreign buyers:

“Although Zimbabwe is a participant in the
Kimberley process, the diamonds from Chiadzwa are
undocumented and therefore are not in compliance with
Kimberley, which requires loose uncut diamonds to be
certified.” Source: Wikileaks

This assertion is backed up by an article written by in 2008 by Chenjerai Hove a celebrated Zimbabwean writer who was driven out of Zimbabwe in 2001 for criticizing President Robert Mugabe. “Marange and Chiadzwa are now international destinations. Israelis, Lebanese, Belgians, Afrikaners, Japanese, Americans, Germans, national political heavyweights and businessmen, all sorts of diamond gladiators who sniff the air for wealth, have been seen visiting the once-neglected Chiadzwa, Marange.” Read the full article.

The leaked cables go on to state:

“The highest quality diamonds are not sent to Dubai,but are shipped to Belgium, Israel, or South Africa for
cutting” Source: Wikileaks

It is important to that these quotations are taken from cables classified by Ambassador McGee, a representative of the United States government to assure that the information they contained would not be made public. Who was at risk here, which sources and who’s assets? According to the leaked cables these assets include:

“Cranswick said that RBZ Governor Gideon Gono,
Grace Mugabe, wife of President Robert Mugabe, VicePresident
Joyce Mujuru, Mines and Mining Development Minister Amos
Midzi, General Constantine Chiwenga and wife Jocelyn, CIO
Director Happyton Bonyongwe, Manicaland Governor Chris Mushowe, and several white Zimbabweans, including Greg Scott, and Hendrik O,Neill, are all involved in the Marange diamond trade.”

Source: Wikileaks

Why were these cables classified? Was it Ambassador McGee’s objective to protect the people named above or was it simply to avoid embarrassing a senior attache’s wife who might choose to wear her shiny new three carat diamond ring to an embassy cocktail party?

Grace Mugabe, wife of the President of Zimbabwe has filed a 10M dollar libel suit. What's that on your finger, Grace?

Yesterday it was reported that the wife of the president of Zimbabwe, Grace Mugabe had filed a defamation suit against the South African newspaper The Standard for reproducing reports from Wikileaks.

Are Zimbabwe Blood Diamonds Identifiable?:

Unlike colored gemstone that are, for the most part, formed in the earth’s crust and contain inclusions specific to the geographic areas where they were formed, diamonds are formed in the mantle. For the most part, it is not possible to separate diamonds by origin. However, I have read several reports that seem to indicate that these diamonds are easily identifiable, at least in the rough. The following is quoted from www.diamonds.net:

“The source suspects that Marange diamonds were being filtered out to most of the major diamond centers, including Israel, South Africa and Belgium for larger stones, and India and Dubai for the smaller goods. He described Marange diamonds as being unique in appearance and therefore very recognizable “even to the layman.” They vary in value from $5-per-carat industrial stones to $1,000-per-carat gem-quality diamonds, he explained.”

This source gives not details as to how Marange diamonds might be identified by a layman, but according to one of our readers, Deepak, a diamond dealer from India, Marange diamonds do show a distinctive green tint (see Part I, Deepak 12/19 comments). Diamonds are color graded by placing them table down in a white tray under special lighting. Under these conditions, according the Deepak, Marange stones will betray a slight greenish cast, we are not talking green diamonds here, just a very slight tint, but distinctive enough to be seen by an experienced grader.

The possibility that immediately comes to mind is that the green tint is the result of natural radiation. Fancy green diamonds derive their coloring from natural radiation. Is this the source of the green tint in the stones from Zimbabwe? If so, these stones should be easily detectable. It would seem that a U. S. Customs agent, armed with a Geiger counter, or a more advanced instrument, might significantly reduce the flow of blood diamonds into the U. S., the world’s largest diamond market.

Wikileaks, Saint or Savior?

The U. S. Government is doing its best to demonize Wikileaks. President Obama has taken a posture that has him, seemingly, talking out of both sides of his mouth all at once. “While I’m concerned about the disclosure of sensitive information from the battlefield that could potentially jeopardize individuals or operations, the fact is, these documents don’t reveal any issues that haven’t already informed our public debate on Afghanistan…” Mr. Obama said.” Well, which is it? Wikileaks revelations are damaging our national security or they are irrelevant? Clearly people are dying in Zimbabwe, about five per week according to documents leaked.

Government sources are fond of using the term collateral damage. It means innocent people died, but usually not our innocent people. When, for example, a drone strike is called in on a suspected Al Qaeda or Taliban gathering in Afghanistan, the civilians who are killed as part of our efforts to suppress these two movements is called unfortunate and ultimately dismissed as collateral damage. In the case of Zimbabwe and its brutal exploitation of both its resources and its people, the outing of those responsible is necessary. If it is not done, many more will suffer and by some accounts they have, at the rate of several per week. The question we must ask is why the secrecy? Why were official U. S. Government cables detailing these atrocities suppressed by classifying them? What vital American interests are we protecting? De Beers, the diamond industry, big business?

I believe that it is opacity that is the true cause of collateral damage in this case and most others. President Obama came into office with a promise of transparency. It appears that this is another promise that will not be kept. When Wikileaks reveals the names of American agents in the field, they are at risk. When our government suppresses information about blood diamonds in Zimbabwe, people die. When we accept a public relations ploy such as The Kimberly Process in place of a real certification, a few people get rich and more people die. I think the real issue here is not Wikileaks, it is transparency. If we had transparency, Wikileaks would not only be irrelevant, it would not exist and there would be no issue and a lot fewer deaths.

Wikileaks, Zimbabwe & Blood Diamonds, Part I

29 Replies

by Richard W. Wise. G.G.

Diamond fields outside of Chidzwa Village, Marenge, Zimbabwe, 2008

Wiki-leaks has been very much in the news and despite dire predictions from the Obama administration that material being leaked would put the lives of American officials and their assets abroad in danger, much of what has so far been discussed reads more like a series of tabloid news reports.

Among the 251,287 cables just released of which about half are labeled Secret or Confidential and half are unclassified, we learn to everyone’s surprise, that American officials are not particularly impressed with Afghan president, Mohamed Kharzi. The cables also contain disparaging remarks about Russian Prime Minister Vladimir Putin running a “virtual Mafia state” and about Italian President Berlusconi‘s relationship with an 18 year old Moroccan dancer.

Of particular interest to those of us in the Gemstone/jewelry community are Wiki-leaks of a series of cables written from the Office of the former Ambassador to Zimbabwe, James McGee in 2007-08 that relate to the situation in the Marenge diamond fields near Chidzwa Village in Zimbabwe.

Andrew Cranswick, CEO of African Consolidated Resources (ACR) is named as the source of much of the information. ACR a publicly traded British firm was the leaseholder until 2006 when ACR was ousted and the lease was taken over by the Zimbabwe government’s own Mineral Marketing Corporation (MMCZ). So it is safe to say that Cranswick has an axe to grind. “It was highly irresponsible for Wikileaks to publish names,” he told The Daily Telegraph. “This is extremely dangerous and puts peoples’ lives at risk.” Cranswick is reported to be going through bankruptcy proceedings in Australia.

Marenge Diamond Fields Said To Be Exceptionally Rich:

Cranswick describes the fields as exceptionally rich:

“Cranswick told us he was confidentially shown a report prepared for the De Beers Corporation by noted geologist John Ward. The report estimated that Chidzwa had a CPHT (carats per hundred tons) of over 1,000. By comparison, the Rio Tinto/Rio Zimbabwe-owned Murowa diamond mine near Zvishavane in Midlands province has a CPHT of 120.”

To put these number in perspective, Australia’s famous Argyle Mine was rated at 30.5 CHPT in 2005. De Beer’s South African claims average 85 CPHT. The highest CPHT previously noted was found in a small pipe adjacent to Slave Lake in Siberia that yielded 139 CPHT but the pipe was played out within two years.

Jawaneng Mine, Botswana

The three pipes at the Jwaneng Mine in Botswana, described by De Beers as “the richest mine in the world” have a CPHT of 141.

To properly evaluate Marenge’s potential it is also important to know the average value of the production per ton. For example although the Onea mine is rated at only 0.5 CHPT, the average per carat value is $880 versus $11.50 per carat from Argyle. According to Cranswick in the Wikileak-ed cables, a Russian group purchased $500,000 dollars worth of diamonds at $29.00 per carat. Cranswick describes the production as 60% industrial and 40% gem or facet-able material, other reports put the ratio closer to 70/30

More to come. Bypassing The Kimberly Process: Next on GemWise

Golconda orType IIa Diamonds; Big Prices at Auction

12 Replies

By Richard W. Wise, G.G.

(portions originally published in 2008)

Another Auction Record? Well Not Quite:

On Tuesday, Christies sold a 27.03 carat DVVS1 cushion cut type IIa diamond for 3.55 million or $131,502 per carat. In a fit of salesman-like overstatement, Rahul Kadakia, referring to a 30 carat D-Flawless type IIa that sold last year for $130,000 per carat, stated that “This represents a 45% increase in the value of top diamonds in just twelve month’s time.” While it is true that a flawless diamond will command a significant premium over a mere VVS, Kadakia is ignoring recent history. At a Sotheby’s Magnificent Jewels auction held in New York on April 17th, a 24.42 carat D color Internally Flawless diamond sold for 3.6 million or better than $148,443 per carat. One day earlier at Christies another rectangular step cut diamond weighing 27.91 carats (pictured above left) sold for 4.04 Million or $145,933 per carat.

Collectors Paying Big Premiums for type IIa diamonds:

Sales talk and hyperbole aside, Type IIa diamonds are regularly knocking down auction records. Gems of this type are often called “Golconda” diamonds after the famous Indian mines that supplied a majority of the world’s diamonds until they were mined out in the early 18^th Century. Collectors, particularly Europeans are willing to pay high premiums for these rare gems and for good reason.

Most of the world’s big name diamonds, those mined before 1725, the Koh-I-Noor, The Sancy and for that matter, The Hope diamond came from the fabled diamond mines of India, all are type II diamonds.

Type IIa is a rare type of diamond that contains no measurable amounts of Nitrogen. Nitrogen is the impurity that imparts the yellow color in diamonds. As a result “white” diamonds of this type tend to be colorless (D-F) colors and have few inclusions. (see GemWise:http://www.thefrenchblue.com/rww_blog/?p=29

Type IIa diamonds have unique characteristics. Stones of this type are famous for their exceptional lack of color, a color that goes beyond D and is sometimes referred to as super-D.

“…the old Golconda stones were by comparison ‘whiter than white.’ Place a Golconda diamond from an old piece of jewelry alongside a modern recently cut D-color diamond, and the purity of the Golconda stone with become evident.”

Benjamin Zucker; Gems & Jewels; A Connoisseur’s Guide

Type IIa diamonds have also been found in Brazil and at South Africa’s Premier Mine. It is estimated that only about 1% of the world’s diamonds are type IIa. The auction houses tend to lump together all type IIa stones, but be warned; not all type IIa diamonds are created equal. It is not enough that a stone fits the scientific definition. A true Golconda or perhaps I should say Golconda-type gem is not only “whiter than white”, diamonds of this type have other characteristics that contribute to their unique beauty, characteristics that sets them apart from the common herd.

Gems of The Finest Water:

Prior to the invention of modern terminology, exceptionally fine diamonds were referred to as “gems of the finest water”. The “term” water goes back to at least the Seventeenth Century. Water combines two concepts; color and transparency. For the purposes of rhyming I have renamed this later quality crystal and include it along with color, clarity and cut as one of the “Four Cs of Connoisseurship”. For a gem to be truly considered fine it must have both exceptional color and crystal so “super-d” too refers to more than just the total absence of color:

“This designation (super-d), one that sounds about as romantic as a name-brand motor oil refers to antique diamonds from India’s legendary Golconda mines—stones that are reputed to exhibit an extraordinary transparency.”

Richard W. Wise; Secrets of The Gem Trade, The Connoisseur’s Guide To Precious Gemstones

The True Blue White Diamonds

Type IIa diamonds have yet another characteristic, one that is not well understood or even well known among gem professionals; under certain conditions the stones will emit a blue glow in daylight.

The mechanism that produces this phenomenon is not well understood but it is not ultra violet fluorescence. About one third of all diamonds fluoresce blue under ultra-violet light. A few of these, diamonds with very high fluorescence, will actually appear milky or foggy, i.e. lose transparency in daylight. Golconda-type IIa diamonds, rarely possess fluorescence in any meaningful degree:

In a paper presented in 1975 at the 15^th International Gemmological Conference, gemologist and author Herbert Tillander made the following observations:

“This type (type II) includes all natural blue diamonds, the only current source of which is the Premier Mine and some really blue-white stones without fluorescence.”

“Type II diamonds in general do not fluoresce although they give a bluish afterglow.”

Herbert Tillander, The Hope Diamond and its Lineage, p. 7

The problem is that the blue glow is quixotic and unreliable; Like the famous green flash at sunset that is sought, usually after a couple of Margaritas, by Caribbean vacationers, this phenomenon refuses to dance to the gemologist’s tune.

“Here, in the afterglow of day, we keep our rendezvous beneath the blue And, in the same and sweet old way I fall in love again as I did then.”Twilight Time,

The Three Suns

French 17th Century gem dealer, Jean Baptiste Tavernier

My love affair with this curious phenomenon began at about 2:30 one sunny late June afternoon in the Berkshires. A client and I were comparing two 10 carat type IIa diamonds. Both had GIA certificates, both graded D-Flawless with no fluorescence; one, a modern radiant and the second an Old European, said to be an old Golconda stone that looked like the Regent’s younger sibling. We placed the two together in the afternoon sun, suddenly a phenomenon like a blue haze appeared to dance above the old cushion, while the modern cut stone just sat quietly.

“…the never failing test for correctly ascertaining the water is afforded by taking the stone under a leafy tree and in the green shadow one can easily detect if it is blue.”

Jean-Baptiste Tavernier, 1689

The old Golconda diamonds exhibited these three characteristics, ultra-colorlessness, a high degree of transparency and, if Tavernier is to be believed, a delicate blue glow. Tavernier as quoted above bought all his diamonds in India. Given his statement it would seem to follow that in the original meaning of the term, a blue white diamond was not, as most experts believe, a blue fluorescent stone but rather a non-fluorescent Golconda diamond.

“The Regent possesses that unique limpidity characteristic of so many of the finest Indian diamonds together with a beautiful light blue tinge.”

Ian Balfour, Famous Diamonds

Balfour gives the following description of the 135.92 carat Queen of Holland diamond (pictured left)

“Yet there are experts who, after examining it think that the ‘Queen of Holland’ is a typical Golconda stone. It has been classified as an ‘intense blue’: although it is a white diamond it does possesses a definite blue tint, rather like the colour of cigarette smoke. The Gemological Institute of America has graded the ‘Queen of Holland’ as ‘internally flawless’ and ‘D’ colour…”

Ian Balfour, Famous Diamonds

Very little of any information about Golconda diamonds exists in the current or historical literature. This explains why so few experts are aware of Golconda-type IIa diamonds and their characteristic beauty marks. Specialists that I consulted, at both Christies and Sotheby’s, were totally unaware of the phenomenon of the blue glow. Perhaps this is because, in at least some cases, this ethereal phenomenon is, as I have said, quixotic. It only appears under certain as yet indefinable conditions. It can be seen in sunlight and most gem experts, particularly those in New York, don’t get out much and when they do in the polluted haze that hangs over The City, perhaps the phenomenon is not visible at all.

Mystery Solved?

I had a conversation with Tom Moses who is GIA’s point man on grading fancy color diamonds. Finally a living person other than myself who has seen this affect. Moses is indeed familiar with the blue phenomenon which he describes as the Tyndell Effect similar to the affect that makes the sky blue. This same cause was suggested by Fancy Color diamond specialist Stephen Hofer in a conversation I had with him two years ago.

According to Moses, Type IIa diamonds usually do not fluoresce or if they do, the fluorescence is so weak that it is not reported on GIA’s grading reports. The blue glow is not at all characteristic of a specific location; Moses has seen it is Type IIa diamonds from South Africa, Brazil and Russia. Only a small percentage of type IIa diamonds exhibit this blue glow.

New Technologies May Require Changes is How We Look At Gems:

The Tea Party To the Rescue:

Book Review: The Colour of Paradise, The Emerald In The Age of Gunpowder Empires

You Just Can’t Hide Those Lying Eyes:

Approaching the Pinnacle of Perfection, Small bumps in Quality Equal Big Bumps in Price.

Image B: The same gemstone after a tweak of the Saturation Enhancement tool in Photoshop The Value of Images:

Online Images are Many Times the Size of The Stone; so are the inclusions:

Color and Lighting:

Where is the Lab Harmonizing Committee When You Really Need Them?

Describing Opal:

Grading Opal:

Patterns:

Pricing Opal:

Tucson Gem Shows; A Brief Roundup:

Book Review: Terra Spinel:

Of Dentists and Doughboys:

A Potentially Explosive Investment:

Our Responsibility:

Countdown To Tucson:

Online Color Comparison; The Impossible Dream:

No Computer Monitor on Earth…

The Nuances of Grading:

Are Zimbabwe Blood Diamonds Identifiable?:

Wikileaks, Saint or Savior?

Marenge Diamond Fields Said To Be Exceptionally Rich:

More to come. Bypassing The Kimberly Process: Next on GemWise

Another Auction Record? Well Not Quite:

Collectors Paying Big Premiums for type IIa diamonds:

Gems of The Finest Water:

The True Blue White Diamonds

Mystery Solved?

Image B: The same gemstone after a tweak of the Saturation Enhancement tool in Photoshop

The Value of Images: