Category Archives: gem value

Natural Heliodore, Golden Beryl from Connecticut

10986: 2.11 Carat pear shaped brilliant cut with exceptional vivid color and crystal.

by Richard W. Wise, G.G.

10987 A 1.74 Carat ovall brilliant heliodore from the Roebling/Merryall MIne, Litchchfield, Ct. The gem exhibets an exceptional vivid medium toned golden hue.

10987 A 1.74 Carat oval brilliant heliodore from the Roebling/Merryall Mine, Litchfield, Ct. The gem exhibits an exceptional vivid medium toned golden hue.

Golden Beryl; An American Gem

In the 19th Century, the state of Connecticut was known as a major source of golden Beryl.

In the past few years a fair amount of golden beryl a.k.a. heliodor has entered the gem market. Material currently in the market is coming from Pakistan, Brazil and Ukraine and although there is no reliable gemological test that will prove irradiation, much of this material is thought to be enhanced by gamma radiation, a method that leaves behind no footprints. Of late there have been misguided attempts to cash in on the gem's more famous sibling by re-labeling the gem as "yellow emerald."

The continental United States is not known for its gem wealth though historically both California and especially the New England states have produced some exceptional gems. In the 19th Century, Maine was known as a repository of gem quality tourmaline, some beryl and amethyst. Most of the gems found in New England are of pegmatic origin the result of long super-hot magmatic fingers working their way up through cracks into the country rock causing localized melting into a chemical stew and its constituents, where beryllium oxide was present, might reform into beryl crystals. Many of the most important strikes were found in Maine including the famous Mt. Mica Mine which resumed operations in 1990 after a long hiatus. Pegmatites are found in all the New England states excluding Rhode Island and are particularly numerous in Maine and New Hampshire. Gem mining was in most cases simply a byproduct. The mines were mainly exploiting mica, Beryllium and feldspar.

Beryl is a family name whose best known offspring are emerald and aquamarine. If a beryl is pink it is known as morganite if red it is called bixbite or simply red beryl. In the 19th Century, golden beryl was quite rare and Connecticut was considered a major source. The term heliodore, from the Greek meaning "gift of the sun" was originally a trade name made up to describe yellow beryl from Southwest Africa.

"A Gift from the Sun," Gem Mining in Connecticut:

Few realize that the George Roebling or Merryall Mine located in Litchfield County, Connecticut was, historically, one of the most productive and commercially important gem mines in the United States. This mine opened in 1880 as a feldspar and mica mine and worked intermittently until 1955 when it was closed. According to the late John Sinkankas, Merryall is known to have produced particularly fine beryl in shades of blue, yellow and green including a 40.44 blue-green heart shaped gem that now resides in the Smithsonian. The mine produced some sizable aquamarine, but most of the heliodore production was limited to very small faceted gemstones.

We recently acquired a few particularly fine rough examples of natural unenhanced heliodore, portions of a single large crystal, sourced at the Roebling/Merryall Mine site from a pile of unsorted mine run material in the early 1980s. The crystal was inside a large boulder. This material has been precision cut into a few lovely heliodore gems. These gems are flawless to the eye, exhibit a particularly fine crystal structure, a high degree of transparency and a vivid pure yellow hue and perfectly cut by our lapidary.

10987 Rough material from which the 1.74 carat oval, 10987, was cut.

10987 Rough material from which the 1.74 carat oval featured at the beginning of this post, 10987, was cut.

As Sinkankas points out, very little of the material sourced from this location is of gem quality never mind eye-flawless material. Mine run material containing 1% Beryllium is considered a rich deposit. Gems from this site have not been on the market in many years. For the gem collector, this is an or for the jewelry lover looking for a lovely vivid yellow gemstone, this is an opportunity to buy American and acquire a particularly fine gem from a truly rare source.

Gemstone Cut Grading; Distinctions Without a Difference II

Of Tilt-Windows, Off-center culets and other minor issues:

The image of the gem quality 1.44 carat alexandrite might lead the uncritical observer to conclude that the gem is windowed. What the gem is actually exhibiting is some extinction beneath the table. In a perfect world, both are minor faults, but we are talking about the rarest gem on earth. In the world of true rarity, beauty not mathematical perfection of symmetry is the ultimate criterion.

The first time I ever heard the term tilt-window was on the Pricescope forum. As you know, a window is a part of the gem when viewed face-up that exhibits transmitted light. Windows are almost always found right beneath the table. A quick test is to place the stone over a piece of newsprint. If you can read the print, you are looking through a window. Windows are the result of a shallow pavilion, a too shallow depth to width ratio. Windows are considered faults because they are a portion of the gem that does not sparkle.

Gem cuts are designed and engineered to be judged face-up with light perpendicular to the table. Tilt the gem away from the perpendicular and every gem other than a briolette will exhibit a window. Ironically the more precise the cut, the more likely the gem is to window when tilted as little as five degrees from the perpendicular. Some gems, particularly those with a bit of fat around the pavilion, may exhibit some brilliance when tilted as much as ten to fifteen degrees from the perpendicular. What cannot be eliminated must be embraced. A tilt window, forgetaboutit!

Grading; From Minus To Plus:

Gems with bulbous pavilions are often criticized for being overweight, meaning that the stone’s face is smaller than it would be if the stone was perfectly cut. The irony here is that such stones may actually exhibit a greater arc of brilliance which contributes to the beauty of the gem. Once the eye is four to five feet from the gem, the overall brilliance becomes the real issue, not the stone’s mathematical diameter. Broader bellies also extend to the length of the light path and may enrich the color (hue, saturation and tone) of the gem.

In another Pricescope thread, one ubiquitous poster put a link to an alexandrite (pictured above) on my website and criticized me for the failure to disclose an off-center culet. How did this forum member determine that the stone had such a terrible fault? The page included a side view image of the stone face-down. If there was an attempt to hide the fault, it was hidden in plain sight. http://www.rwwise.com/products/id,255 Unfortunately her interpretation of the image was quite wrong. The stone does not have an off-center culet. What the forum member saw was a very minor symmetry fault, one side of the pavilion has a slight indent coupled with a tilted crown which when placed on a flat surface caused the culet to appear off-center. And if the gem did have a slightly off-center culet, so what! We are talking about one of the earth’s rarest treasures, a gem quality alexandrite!

Each Gem Is an Individual with a distinct personality and should be judged on its merits:

Gem aficionados usually begin their love affair with the colorless diamond. They learn the famous 4 C’s and attempt to apply those criteria, namely color, clarity cut and carat weight uncritically to colored gemstones. As I have said elsewhere all Cs are not created equal. In the connoisseurship of colorless diamond, cut is the 1st and most important criterion. Diamonds have no color, they are all about brilliance and sparkle, so naturally cut, which delivers sparkle is the most important single criterion. I knew a neophyte jeweler once who was not satisfied with eye-flawless sapphires, he demanded that all of his sapphires be flawless under 10x magnification. The problem, without inclusions it is almost impossible to determine if a stone has been enhanced and determination of geographic origin is absolutely impossible.

Colored gemstones as their name suggest are all about color and cut is, at best, a secondary consideration. An off-center culet in a diamond would be a major symmetry fault and materially effect price. In a colored gem, an off-center culet in and of itself is a minor fault which has no effect on price. Why do such things exist? A culet might appear off-center for a couple of reasons. The lapidary may have removed a potentially eye visible inclusion or have placed the culet slightly askew to smooth out color zones so that the zone does not appear in the gem when viewed face-up.

It should be remembered that colorless diamonds are not truly rare. The introduction of cut and clarity scales that have nothing to do with beauty are more about creating the appearance of rarity than the thing itself. The connoisseurship of gemstones requires discernment and careful contemplation. Gems cannot be accurately graded by image. The aficionado should beware attempts to reduce it to a formula or a check list.

Gem Cut Grading; Distinctions Without A Difference

A Non-Issue:

This is a good example of a non-issue. Non-symmetrical cuts, rectangle, oval, pear viewed under a single beam light source will always show brilliance across half the face of the gem when the stone is tilted away from the perpendicular. Why, because the gemstone is not symmetrical and therefore treats light in a non-symmetrical fashion. In the cuts just mentioned, some facets particularly the pavilion facets which are responsible for delivering brilliance, cannot be uniform. Some are larger, some are longer therefore light hitting these facets will refract in an irregular fashion. Symmetrical cuts, rounds and square cushions, by contrast have uniform facet patterns and do not suffer this phenomenon.

For this reason, asymmetrical gems are graded under a single light source, viewed at at a 45 degree angle away from the light source angled toward the eye. At this viewing angle, half the gem, the bottom half is potentially brilliant. The percentage of that half is then compared with the other half when the gem is rotated 180 degrees and viewed a second time. Add the relative percentage of each half and voila you have the total percentage of brilliance. In colored gemstones, 80% brilliance is considered excellent which means that at any given time, 20% of the gem will exhibit extinction.

One trick for viewing the brilliance of the entire stone at once is the use of sky light. Turn your back to the sun and view the gem at the same 35 degree angle toward the eye. In this position the light filtering around the body of the viewer should light up the 100% of the gem. Any lack of brilliance in this position is a fault and should be subtracted from the theoretical 100% to arrive at the percentage of brilliance. In most cases, gem photographers correct for this phenomenon by photographing gems with non-symmetrical outlines by using multiple light sources.

A Little Extinction Contributes To A Gem’s Beauty

Extinction is another much misunderstood phenomenon. I am often asked, particularly by members of this forum, if a particular gem shows extinction. First lets define our terms, what is extinction. This phenomenon is caused by off-axis refraction. When light enters a gemstone, it enters the crown and reflects internally off the pavilion (back) facets and eventually back through the crown to the eye. Inevitably some light refracts at an angle that is not toward but rather away from the eye, the greater the angle the more extinct it becomes, in a tonal continuum from gray to black.

All faceted gemstones without exception exhibit extinction, no extinction, no scintillation. the great German philosopher Hegel said determinatio est negatio. which when reduced to simplest terms means g all positive requires a negative. Sweet has no meaning without salty, good does not exist without evil, etcetera. So too with gems. Scintillation, sparkle is the result of light being broken up into pieces, tiny scintillas of light that are refracted back to the eye in little pieces. Between those pieces is darkness, extinction. Want a gem to light up like a flashlight with no sparkle, eliminate extinction. Some degree of extinction is therefore required as contrast.

Extinction As A Fault:

Extinction can have other causes as well, dark is the absence of light. Gems lacking transparency will often show what one of my clients once called a “heart of darkness” at the center of the gem beneath the table. This is particularly prevalent in sapphire and the cutter will often cut a window to let in light through the culet, the apex of the cone shaped pavilion of the gem. So while some extinction is desirable, in fact necessary to the beauty of the gem, large areas of extinction are a definite and definable fault.

Evaluating Gem-e-Wizard; Gem Grading/Pricing Software

Ease of Use:

The software is easy to use. First you are presented with a fairly clean screen with buttons and drop boxes. There are three tabs; Fancy Search, Price List and Price Calculator. The default screen, Fancy Search allows you to select a gem variety, size, shape, weight, clarity, treatment.

Gem-e-price Home screen showing range of colors in yellow diamond.

Unfortunately it didn’t take long for the first bug to appear. Once you select “color” (primary hue) and “modifier” (secondary hue) and move on to shape, you quickly realize that though you can select your shape from a graphic series, only two shapes will actually appear in the gallery, select round or square cushion, choose any other shape and square cushion is shown.

The images, which in the colored diamonds section covers the basic grades, fancy through fancy dark, are not pictures of actual gemstones or photographic images at all, they are graphic representations. When I first saw these during the introduction of gem-e-price for colored gems, I referred to them as grading by cartoon. However, one function of the software helps overcome this lack of veracity to some degree. Once the color has been selected, say yellow, the “Fancy Ruler” button to the right will take you to a screen with a spectrum representing all colors, from there a “Select Color” button in the center of the screen takes you to a new screen with all permutations of the given color (hue): brownish yellow, brown yellow, orangy yellow and so forth. You get a good relative overview of what the graphic range is supposed to represent and is useful for honing in on the appropriate nuance of color.

Gem-e-price screen showing range of primary and secondary hues in pink diamonds.

It also provides you with a more or less universally accepted color descriptive shorthand, e.g. VpB (vivid purplish blue). I should add that you are able to upload, at the home screen, an actual image of the diamond that you wish to compare and that image follows you from screen to screen.

Nomenclature Issues:

Is the pricing accurate? As Shakespeare said, “aye, there’s the rub.” The answer is yes, no and sometimes. I compared the Gem-e-price with a couple of my own diamonds, then called colored diamond expert Stephen Hofer author of Collecting and Classifying Coloured Diamonds and compared various price lists, pink, gray and blue diamonds generated by the Gem-e-price software. The prices made no sense at all until in a conversation with Gem-e-price developer, Menahem Svedermich, he revealed that the price is pegged fairly low. This will require a bit of explanation.

The point I make in my book, Secrets Of the Gem Trade, is that all fancy vivid diamonds are not created equal. GIA’s colorless diamond grading system has 24 grades, the GIA colored diamond grading terminology has only between 5-7 depending upon the hue. These are fancy light, fancy, fancy intense, fancy vivid, fancy deep and fancy dark. In the vivid category, for example there can be high, medium and low vivids depending upon the saturation/tone of the hue. Gem-e-price assumes a 1-5 saturation grid at each level and pegs its price to level 2. Why not the median? Good question! Well, one week later, Gem-e-price has been updated, it now sports three price levels for each color grade, Regular, Fine and Extra-fine categories and these have helped to better define price levels.

Pricing Accuracy:

With Hofer’s help I took a look at a one carat Fany Intense Pink diamond( FIP). A two thousand dollar spread, in pink diamonds, hardly worth mentioning, the price was spot on. I then went to a 0.70 FVY-O from my own inventory. This is a problem stone, The GIA grading report calls it Y-O, to me its a orangy yellow (oY). So, I tried it both ways. The Yellow-Orange price was way out of the box, the Orangy-Yellow was pretty close to my actual cost. Next I tried a 1.75 Fancy Intense Blue IF which Hofer described as a top stone. The Gem-e-price was between under Hofer’s price by between 100-200,000 per carat—sounds like a lot but we are talking blue diamonds here so it is fair to say that Gem-e-price is in the ballpark. I did some further work, switching over to colored gemstones I priced out emerald, ruby and sapphire. The emerald and sapphire prices came out in the zone, the ruby price, we are talking super-unheated-gem in one carat sizes came out very high. I asked Antoinette Matlins author of the second best book on colored gemstones—opps there goes my Bonanno award—she checked my price and reported results that were similar to mine.

Overall Evaluation:

Overall I like it. Is it perfect, no! It is designed for professionals, in the hands of someone without a wealth of experience it could be a potential disaster, but then what isn’t? Gem-e-price is a useful tool, its got a few bugs, but it is getting better, Svedermich and his team made adjustments as I worked and will, I am sure, continue to improve the product. I like the price grids! A subscription with monthly updates is $300.00 per year and, in my opinion, well worth the price.

Kashmir Sapphire, Another Auction Record

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Dateline: Hong Kong

Current world record holder, 26.41 Carat Kashmir Sapphire Courtesy: Christie's

A New World’s Record:

November 29th, Christie’s Auction House, Hong Kong, sold a 26.41 carat Kashmir sapphire for 3,838,508 or $145,342.00 per carat. This sale establishes a new world’s record price of Kashmir sapphires sold at auction, besting the former world’s record also established at Christie’s (New York) for the 22.66 carat Hill Sapphire which sold in April 2007 for $3,064,000 or $135.216.00 per carat.

Kashmir sapphires were originally found on a small hillock 13,000 feet up in the mountains of the now disputed Indian state of Kashmir in 1881-1882. The harsh conditions at this altitude meant that the mines could only be worked about one month per year. By 1887 the output of the mines had diminished substantially. The original lessee abandoned the diggings in 1905. Four other groups had a go at it with little success and the sites were more or less abandoned in 1928. A bit of material is still occasionally found, alluvial material at the bottom of the ridge, but the major production of Kashmir sapphire lasted a mere six years.

Kashmir stones are highly esteemed for their color, a vivid purplish blue, a hue often described as “cornflower blue.” Others, most notably Richard W. Hughes, author of the seminal book Ruby and Sapphire, describe the finest color as a Pepto Bismol bottle blue. The problem with this characterization is that Pepto Bismol bottles are now pink—but there are those of us who are old enough to recall when the bottles were a bright medium blue. I recall seeing only one stone of this description and it hailed from Sri Lanka.

Kashmir’s famous characteristic, however, is the silky, milky or fuzzy texture that somewhat diminishes the diaphanity (crystal) of the stone. Myriads of tiny inclusions that resemble dust caught in a ray of sunlight or a sub-microscopic milky way, will, when present, diffract and refract the light, causing the stone to take on a velvety glow. Similar inclusions are sometimes found in gems from Madagascar and Sri Lanka, but absent geographical certainty, these “Kashmir type” sapphires do not command nearly the price of those with old mine provenance. The current record holder was accompanied by four laboratory reports certifying Kashmir origin. This, of course, begs the question: If gems are all about beauty and sapphires from other locations have all the characteristics of the finest Kashmir, why does anyone care where the stone is from? The short answer is branding. The market recognizes a value in stones from the original mine. It is also fair to say that although stones can be found with the characteristic glow, very, very few approach the pinnacle of Kashmir color. I have only seen two stones that can be described as #1 Kashmir color and both were from the old mine.

What a difference a light makes, record breaking sapphire before re-cut, note the large culet visible through the table. Photo courtesy Stone Group Labs.

What a difference a light makes; the current record holder before a re-cut shaved a single carat. Note the large culet visible through the table and the characteristically velvety texture or crystal. Photo courtesy Stone Group Labs.

Rapidly Escalating Prices:

Kashmir prices have been increasing steadily since the late 1980s. According to connoisseur and author Benjamin Zucker, a twenty carat fine quality Kashmir sapphire was worth $25,000 per carat in 1976, though I recall an exceptional stone that sold at auction in the early 1980s for $12,500 per carat. By the turn of the last century prices for extra-fine examples at auction passed $100,000 per carat. Pricing must be taken with a grain of salt. Given varying qualities, the vicissitudes of auction houses, and the lack of any real standardized grading system, it is difficult to compare stone to stone.

Prices for premium gemstones, fancy color diamonds, type IIa colorless diamonds, ruby, sapphire, emerald and lately spinel, have all increased markedly since the 2008 bust. This can be traced to a lack of confidence in paper currencies, generally, and the dollar and Euro in particular.

Connoisseurship–Opinions Vary:

Bear Williams of Stone Group Labs, the first gem laboratory to evaluate the new record holder, was impressed. “My hair kinda stood up on end, it had some sort of magic,” he said describing his first look at the sapphire. When Williams saw it, the stone weighed over 27 carats before it was re-cut slightly and re-polished. From all indications the stone is quite superior to the Hill Sapphire, which American Gem Labs President Christopher Smith described as a “nice stone.” in 2007. Smith rated the former record holder, the Hill Sapphire, at an 8-8.5 on a 1-10 scale. Williams puts this new one well into the 9s, “maybe a 9.8” he says. Chris Smith at American Gem Labs, who did a full quality evaluation, gives the stone an overall Total Quality Integration Rating (TQIR) of Exceptional and a color grade of 2.5 (1-10 scale). Note that AGL’s TQIR factors in rarity, together with quality factors. A five carat Kashmir or the same quality would be graded Excellent.

Grading Tanzanite; In Praise of Purple

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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.

Foreign Investment Scams, Slouching Toward Disaster II

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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:

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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!

Golconda orType IIa Diamonds; Big Prices at Auction

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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.

Boldly Going Where No Lab Rat Has Gone Before

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Boldly going where No Lab-rat has gone before.

by Richard W. Wise, G.G.

Gemological Laboratories are under increasing pressure to add quality grading to their traditional role of determining origin and treatment of gemstones. One laboratory, AGL had been doing this for several years. However, recently under the aegis of the Lab Harmonizing Committee several of the leading labs have decided to aggressively go where no lab has gone before into the world of marketing. Gem Labs have entered the nomenclature business and into a firestorm of controversy .

The question of nomenclature is often more about tradition than science. You can study internal inclusions and make a determination about treatments and point out what specific anomalies led to your conclusions but how do you decide what to name a gem? The recent flap over Mozambique cuprian tourmaline that I covered in an earlier post is an excellent example. http://gemwiseblogspotcom.blogspot.com/2006_06_01_archive.html

Traditionally we name a gemstone based on species and variety but what happens in the case of a gem that is of the species corundum but derives its name strictly from a mix of colors? What gem am I thinking of? I’ll give you a hint; padparadscha sapphire.

In my book Secrets Of The Gem Trade, The Connoisseur’s Guide To Precious Gemstones, www.secretsofthegemtrade.com, following the late great GIA gemologist Richard Liddicoat, I define padparadscha as a light to medium tone of pinkish orange to orangey pink. Up until recently, labs have avoided the issue by simply calling the colors; “pinkish orange” and so forth.

A consortium of gem labs under the title: The Laboratory Manual Harmonization Committee (LMHC) met in Milan and has drawn up a standardized definition of padparadscha. The LMHC consists of seven of the world’s major laboratories (AGTA Gem Testing Center, CISGEM (Milan), GAAJ (Japan), GIA (USA), Gemological Institute of Thailand, Gübelin Gem Lab (Switzerland) and SSEF Swiss Gemmological Institute (Switzerland). Some of these labs, excluding for the moment GIA-GTL, have begun to call and consumers have begun to demand a lab certificate that uses the term padparadscha to describe the stone. The question is, where is this definition coming from and is this the beginning of a brave new world wherein laboratory gemologists begin to dictate to dealers and connoisseurs?

“Well”, I can hear you say, “somebody’s got to cut through all the confusion.” and I agree. But, be careful what you wish for. Leaving aside the question of how this definition was arrived at, like it or not, once established the criteria determined by the labs will become the accepted definition. Are we ready for this and what in the training of a gemologist prepares them for this role? I received my Graduate Gemologist diploma some years back and I can tell that what a neophyte Graduate Gemologist doesn’t know about quality in gemstones would fill many volumes. A newly minted G.G. is little more than an apprentice scientist. Oh sure, he learns the GIA diamond grading system but…

According to Richard Hughes well known author and gemologist with the AGTA gem laboratory which makes him one of the most prominent lab-rats, laboratories have no business making such calls. He was particularly upset by the fact that the LMHC did not include a representative from Sri Lanka at the meetings where the decision was made (I mean where does the term come from?). Hughes also had problems with the adoption of a printed color chart developed by Franck Notari (GIA Geneva). Hughes makes the point that the definition of padparadscha is fuzzy at best and he feels that the insistence on hard a fast definitions is not appropriate. As proof of this assertion, Hughes did an analysis and discovered that the magnificent 20.84 carat padparadscha (pictured above left) that sold last year at Christies falls outside the parameters as defined by the chart adopted by the LMHC.

Stay tuned…