The following article is reproduced without alteration from the lab notes of Gems and Gemology, the quarterly scholarly journal of GIA, as excerpted from GIA Insider. Volume 9, Issue 21.

Phenakite as a Rough Diamond Imitation

The GIA Laboratory regularly receives near-colorless transparent crystals, pieces of rough or fragments for identification, often because they were sold as – or are hoped to be – diamond. Such was the case with a 67.94 ct. near-colorless transparent crystal (figure 1) that was recently submitted to the New York Laboratory.

The specimen was similar enough to a water-worn dodecahedron-like diamond crystal to prompt submission to the Lab. It showed abundant dissolution features, parallel growth striations (figure 2), trigon-like features, and an orangy red included crystal. Initial physical indications, however, such as a lack of either adamantine luster or dispersion (both of which could have been obscured by the irregular surface) and a modest “heft,” suggested that it was not diamond. In addition, during spectroscopic testing the sample was placed on a block cooled by liquid nitrogen. When it was removed, the crystal did not feel cool to the touch as a diamond should have, indicating low thermal conductivity.

Further testing revealed that the specimen was doubly refractive and uniaxial, with a spot refractive index of approximately 1.65 and a hydrostatic specific gravity of 2.96. These properties ruled out glass, cubic zirconia and diamond. The crystal had a weak, pinkish-violet reaction to short-wave ultraviolet radiation, revealed no absorption lines in the spectroscope, and had no transmission luminescence. Step-like striations were evident, but the trigon-like features were raised, not depressed as trigons usually appear on a diamond.


Raman spectroscopy confirmed that the specimen was phenakite, Be2SiO4, which has a trigonal rhombohedral structure with one cleavage direction, and is often confused with quartz. Nevertheless, the rough exhibits features that could be mistaken for those of natural diamond. Interestingly, its etymology comes from the Greek word phenakos, meaning “to deceive.”


This entry was prepared by Donna Beaton, Joshua Sheby and Riccardo Befi of the GIA Laboratory in New York. For the latest findings from the GIA Laboratory, read the Lab Notes section in every issue of Gemology.

Fig. 1 (left) rough crystal thought to be diamond submitted to the lab , Fig 2 (right) showing parallel step-like growth striations similar to those seen on diamond.


On Monday the managing director of the De Beers Group, Gareth Penny, appealed to diamond traders worldwide to support De Beers in its backing of African attempts to retain rough diamonds for polishing within the continent. Citing the creation of jobs and stability for African democracies, Penny said “We don’t embrace this out of some misguided enthusiasm or altruism, we embrace it because it makes good business sense and because it’s the right thing to do.” Penny went on to invoke the global view on conflict diamonds, stating people no longer buy them and that mining companies wont invest money to extract from conflict areas, but that the industry needed a stable group of companies for maximizing supply since “producing and selling diamonds in or from a country of chaos or worse, conflict, is simply not an option.” (Clearly global view has changed De Beers policy on this matter, since it was not very long ago that the cartel had no problem at all selling diamonds from war torn African nations.)

The truth of the matter is that the diamond cutting industry in African nations is almost non existent by comparison to Belgium, Israel and the United States. Antwerp became exceedingly wealthy from Belgium’s rule of the Congo and the CEO of Antwerp World Diamond Centre, Freddy Hanard, has stated it does not view the African industry as a threat. De Beers called upon Antwerp, Tel Aviv and New York to fund this pet project, and to train African polishers. Penny from De Beers has said the company is currently spending more than $100 Million per year in the search for new mines, including areas in the Democratic Republic of Congo and Angola.

Courtesy of Canadian Arctic Diamond

Diamond Polisher (Photo: Canadian Arctic Diamond)

Sotherby’s auctioned off an emerald cut 6.04 carat fancy vivid blue diamond ring which commanded the highest price per carat paid at auction for any stone in history.  The auction was held in Hong Kong, and the diamond originated from South Africa, as is the case with almost all blue diamonds.  The stone boasts a clarity of internally flawless (IF), and it is showcased in a simple platinum ring with an emerald cut white diamond flanking each side of the center stone. The winning bid was made by Moussaieff Jewelers of London, a very esteemed and respected firm; known for such acquisitions as the Moussaieff Red, and many other extraordinarily costly stones. The stone was sold by a private Asian collector. The diamond sold for $7.98 million USD, or $1.32 million per carat. The prior record at auction was $926,000 per carat for the Hancock Red, a natural red diamond sold in 1987.

This represents a very important statement about the current market demand of natural fancy colored diamonds, and the rapidly increasing popularity they have gained in recent years among serious collectors.

A Reuters video of the stone can be found here. This is the best video I have found to show the stone’s true color. Note the dim lighting in the picture below, the stone is actually a true bright vivid blue.

6.04 ct, IF, fancy vivid blue diamond – sets new auction record.

In Late August, news began circulating worldwide that what could prove to be the world’s largest diamond had been discovered in South Africa. The small scale mining company claimed to have found a stone that weighed around 7,000 carats (around the size of a coconut), and was of a green color. An early publication by the BBC of the account can be found here. After reading this article you will see why I chose not to sensationalize this “finding”, as it seemed fraudulent from the very beginning.

Immediately, skepticism from everyone in the industry became widespread. De Beers publicly stated that the north-west province of South Africa was not known for producing diamonds, but that if tests proved conclusively the item in question was a diamond, that it would be the discovery of the century. This was a statement made by De Beers, in a rather nice way, to let everyone know that De Beers was stating those making the claim were full of it.

The Mail & Guardian article about the truth of the “stone” in question can be found here. I honestly do not wish to take a whole lot of time to cover this issue in depth. I knew in the beginning this was a bogus find, and the audacity of those who perpetrated this fraud is appalling.

“The world’s largest diamond” as it appeared on BBC.co.uk, next to a cell phone.

Burma: The Jade Trade

Burma (Myanmar)… When it comes to localities known for the production of truly fine gemstones, few rival this region. It is after all, well renowned for its breathtaking and exquisite rubies, sapphires and peridot, among many others. While Burma is a beautiful country, rich in culture and natural resources, it has never been rich in economic or political stability. It has been ruled by a military dictatorship since 1962. The United States over recent years has levied and renewed embargoes against Burma, banning any product or material (including gemstones) originating from there. It is however still legal to possess gems obtained from Burma prior to the embargo, and of course it can be easily circumvented if you buy the stones from them indirectly (buy from a Thai dealer… or something like that).

But let’s focus now on an aspect of the gem trade that has thousands of years of history… the jade trade. Burma is the key player in a material known as jadeite. Jade is not actually a single mineral form, but a name given to gem varieties of both nephrite and jadeite. Jadeite is the more highly prized because of its rich translucent emerald green color. Many people are simply not aware of how valuable truly fine jadeite actually is, as they may only be familiar with the carved nephrite variety common in Chinese carvings; or worse yet “B-jade” grade varieties which are dyed to achieve their color. The other reason most are unaware of fine jadeite is that they simply have never encountered it, and probably will not ever encounter it.

In Burma, jadeite is found in both rivers and in mountain regions, as well as in situ deposits. In all but in situ deposits, jadeite occurs as boulders covered with a “thick skin”. “River jade” has an advantage in that the boulders are weathered and often the outside of the boulders are worn, exposing glimpses into the center of the stone and the color it contains. Jadeite recovered from mountain areas lacks the weathering necessary to erode the thick skin of jadeite boulders, so most often, no glimpses into the material are possible without cutting into the stone. In Burma, the jadeite is gathered (quite a painstaking process), and is then brought to trading centers in major districts for auctioning and open sale. Mandalay represents the largest market for jadeite, among other things… “Burma’s largest jade market is in south Mandalay, a city that is said to operate on the three “lines” – white (heroin), red (ruby), and green (jade)” (Cummings and Wheeler, 1996). Most jadeite is sold and resold several times before it is ever touched by a saw, and most of the material being sold is unknown in quality. Once cut open a boulder could contain a fortune in quality jadeite, or it could be worthless. Many dealers play this high risk game of spinning the jade wheel. Fortunes have been made and lost in a single small boulder.

Fine jadeite has a consistent deep emerald green color. Most fine material is highly translucent with some approaching transparency. In November 1999 a bangle bracelet made of Burmese jadeite (50mm inner diameter) sold for over $2.5 Million. The highest price ever paid for jadeite was for a strand of twenty seven (27) 15mm beads. The strand known as the “Doubly Fortunate” commanded $9.3 Million in 1997.

Cummings J., Wheeler T. (1996) Lonely Planet Travel Survival Kit: Myanmar (Burma), 6th. ed. Lonely Planet, Hawthorn, Australia, 393 pp.

Gems & Gemology, Vol. 36, No. 1, pp. 2–26.

Lot of rough Burmese jadeite, note the reserve auction price in Euros.

For those who do not know, almost all (>99%) of blue topaz available obtains its color via neutron or electron radiation.  The sources of irradiation are either the inside of a nuclear reactor core, or a linear accelerator.  This has been a long standing practice, and as most people know (even the lay person), blue topaz has been readily available in the United States for a long long time.  What most people don’t know are the legal aspects of it.  David Federman of Colored Stone put it well by stating according to the Nuclear Regulatory Commission, “…all topaz blued in a nuclear reactor is illegal for sale unless tested and cleared by a NRC-licensed distributor.  Since there are no licensed distributors in America, all “London Blue” topaz imported into this country in the past decade is technically classifiable as contraband”.  Earlier this past spring, the NRC finally figured out their own policy on this and sent out heart felt letters to major jewelry retailers, demanding the names of their blue topaz suppliers and warning them that purchasing the material was against the law.  The retailers of course quickly pulled all material from their shelves.

The Nuclear Regulatory Commission then sought the help of the Gemological Institute of America (GIA) and the American Gem Trade Association (AGTA), to obtain all of the testing data for blue topaz.  Armed with this information, their next step which has been carried out up through September has been to go to New York and test random sample batches of stones from dealers.  The results from this testing were that all batches, but one, tested at levels consistent with background radiation; while the other batch tested at twice the level of background radiation.

Duncan White, chief of the NRC’s State Agreements and Industrial Safety Branch, said that “Thus far, the NRC has found no health or safety problems, and consequently is considering an approach that would substantially soften the impact of its renewed attention to irradiated gem.  Right now, we are considering ‘grandfathering’ existing inventories of all blue topaz within the U.S. – allowing companies to sell their goods and applying new requirements to material still overseas”.  Duncan White offered no definitive answer on when this would become effective, but stated the NRC is continuing to test blue topaz material from other sources until it can be concluded there is no threat to the public.

Currently, many in the industry state that they are reluctant to consider selling blue topaz any time soon for fear of lawsuits.  Others have experimented by substituting diffusion-coated blue topaz for the irradiated material.  Diffusion-coated blue topaz derives its color from an electro-coated layer on a colorless stone.

Personally, I think all of this material is garbage, along with any variety of cheaply treated stones including mystic topaz, london blue topaz, swiss blue topaz, etc.  If I never saw another piece at a show I could not be happier, and I only publish this article in the interest of current events.

“London Blue” Topaz 

The 23rd annual Rio Tinto Argyle Pink Diamond Tender is around the corner. Bidding officially ends in 25 days, in what is possibly the world’s most exclusive diamond auction. You cannot simply sign up to become a bidder, you have to be chosen by Argyle, and even then the list is limited to 100 bidders. As always, the exact location of the tender isn’t revealed to the bidders until the last minute for security reasons. All bids are confidential, and winners will be notified in person by representatives of Argyle in October. Of course names of the future owners and the amounts realized at auction will remain confidential. This year there are 65 diamonds that made the cut to become part of the tender. Argyle states that this year’s tender “…promises to be a vintage year for collectors. Many of the 65 Argyle Signature Stones on offer are deeper and more vivid in colour than previous years”. On the menu this year are “…a number of spectacular purplish reds, as well as deep pinks, and a rare gray-violet”. Argyle produces around 30 million carats of rough diamonds per year, and only around 8,000 carats of these end up being polished pink diamonds. Of these, just 65 carats were deemed suitable for this years tender.

As we all know, red and purple diamonds are the rarest of all diamond colors (purplish reds are unimaginably rare), with red diamond prices historically reaching $1,000,000/ct. Purplish red diamonds are even rarer than simple reds. According to JD Boles, Director General of the British Gemmological Institute, the stone now known as the Supreme Purple Star (a purplish red), stated the stone sale price of around $4,000,000/ct. They are after all the world’s rarest natural objects.

Oh boy… Where to begin… The recent GIA newsletter was not encouraging. Perhaps we should start by taking a look at how overzealous De Beers DTC sightholders tried to impress daddy earlier this year by buying up rough at insane prices to make themselves look better. Or perhaps we should look at how Argyle is in serious trouble after commencing an enormously expensive operation to convert the mine from open-pit mining to an underground operation. Even better, we might want to start by taking a look at the US economy lately, especially in regards to lowered consumer confidence in combination with a collapsed sub-prime market. Finally, diamond mining profits have dropped this year, as the decline of the USD (miners are paid in USD) against other world currencies, in conjunction with higher energy costs, more taxes and foreign policy. And if all of that doesn’t work, blame Canada.

Regardless of how we start to look at this situation, one thing is for certain, India is very concerned right now; and rightfully so considering they are the world’s largest diamond manufacturing center. Estimates are that India has $1 Billion USD in inventory sitting around right now that they cannot move (with additional inventories stored in New York, Hong Kong, and Antwerp). The overall market for diamonds in India and other parts of Asia are very good right now, but when the world’s number one consumer of diamonds (that would be the US) has an anemic demand for finished stones, this threatens to cripple everyone below that wrung on the ladder. According to GIA, a Surat manufacturer said rough that yields a carat or smaller finished stone is priced 15-20% too high for the current market; and that a major correction would have to take place before firms became profitable again.

On that note, it now costs more to purchase and manufacture lower quality rough diamonds than US retailers are willing to pay for the finished gem… Think back to Econ 101, that’s not a good situation for the manufacturer. Poor India, it gets better for them though right? Hardly. The Argyle mine in Australia, the world’s largest diamond mine by volume produced, is under imminent economic threat; so much so it is speculated that it’s parent company Rio Tinto has put the property up for sale (Rio Tinto has not commented). Considering that cutting centers in Ahmadabad, employ hundreds of thousands of cutters solely to manage the output from Argyle, India is concerned that the mine’s closure would leave hundreds of thousands jobless (it’s not like they can go down the street and work for another cutting center). Diamond cutters are a dime a dozen in India.

The De Beers DTC sightholders did not do the market a favor either when bidding each other up in price for diamond rough in tenders earlier this year. Apparently, they were trying to show an increase in the production volume their firms handled for the next sightholding term… not thinking about how they were going to liquidate the material once they obtained it. Pure genius at work there.

Finally, the US housing market scene and general overall economic decline has had an effect on diamond demand. According to the Consumer Board in August, “The number of consumers claiming present-day conditions are ‘good’ decreased from 28.3% to 26.4% in July, while those saying conditions are ‘bad’ increased from 14.5% to 16.3%.” In addtion: “Those especting business conditions to worsen within the next six months rose to 10.6% from 8.2%”. Surely, the collapse of the sub-prime housing market had no impact on consumer confidence right? People generally try and make the mortgage payment before purchasing diamond jewelry. Oh wait, they don’t do either? How strange.

Aerial view of the Argyle diamond mine.

It’s no secret that copper bearing tourmalines from Mozambique have caused an immense feeding frenzy in the gem market since it’s recent discovery and introduction. The material is a copper (and sometimes gold) bearing elbaite tourmaline, that has been found in ravashing vivid neon colors, nearly on par with the famed material of Paraiba, Brazil (thus the common trade name of Paraiba Tourmaline). The material from Paraiba, Brazil was first introduced in 1989, but the amount of rough stones being produced dwindled rapidly, and now the source is almost depleted. Fine Brazilian Paraiba commands extremely high prices of $10,000 – $20,000 / carat in fine neon blue stones.

The introduction of a new source of copper bearing elbaite was a glorious event for the market, as this represented a renewed possibility of being able to obtain such a wide range of neon colored cuprian tourmalines at a more affordable price range than those from Brazil. While the best material from Mozambique is not quite as vivid as the Brazilian material (it comes extremely close in some cases), the color range available is wider. For instance many collectors are seeking purple Mozambique material (very highly sought after). But whatever color of cuprian elbaite you prefer, you’ll be relieved when you look at it’s pricing. In typical consumer gem grade material, you can aquire the material for as little as $100/ct in whatever color floats your fancy. Of course truly fine quality material is more expensive, but still tends to top out around or less than half of the cost of it’s relative from Brazil. It is for this reason that this material (while some believe it to be over hyped), offers one of the strongest buys on the market today. Let’s face it, the material from Mozambique won’t last long, as the deposits are small (some estimates are around 50kg of total rough production).


Classic color of cuprian elbaite (left), purple cuprian elbaite (right) – both from Mozambique.

Before I go into a long tirade about this, let’s first examine the last major Thailand scam…

The last time the gem world was rocked by dishonest Thai dealers using atrocious practices targeted corundum, specifically sapphires which were subjected to beryllium diffusion. Beryllium diffused sapphires were released like the Great Flood upon the market into the hands of unsuspecting dealers. The problem was so great that it threatened to cripple the market for sapphires. Beryllium treatment is a process that replaces the trivalent aluminum in the crystal lattice with divalent beryllium. The color change process is very complicated, and due to this, other trace elements often give away a signature that can be detected. Without going into extreme detail (which would take pages to discuss), a brief example of Be treatment could be when: [Mg2+ + Be2+] > [Ti4+ + Si4+] a trapped hole of color is formed by Be2+ and Mg2+ to produce yellow color. If though instead you reverse this process so that [Ti4+ + Si4+] > [Mg2+ + Be2+], more donating electron ions exist to deform the trapped color hole and yellow color is not produced. Blue color can be produced in sapphires using the transfer of Fe2+/Ti4+. This practice lasted for years, even though gemologists could detect the process, many dealers passed the stones along unknowingly representing them as legitimate heat treated only or worse yet, natural untreated gems. For the most part this problem has settled down, but still rampantly plagues online auction venues such as eBay.

Now, in regards to Thailand and topaz… The industry has been aware of inexpensive colorless or light tan topaz being treated with Cobalt-60 radiation or X-Ray radiation that turns the stones into a lovely deep reddish/orange to deep pinkish-brown color. The purpose of this would be of course, none other than to defraud a buyer by making the material appear to be very costly precious or imperial topaz. The problem is, that with only 1 day’s worth of exposure to natural sunlight, the process is completely destabilized, and the material’s color washes out to it’s original color (or lack thereof rather).

The difference in price between common colorless/tan topaz and true imperial topaz is a difference between as little as $1-5/ct for common material and upwards of $1,000/ct for stones 10cts+ in size of super rich color imperial topaz. This practice has had an immense impact on the trade and is the equivalent of taking a direct hit by a 20 megaton hydrogen bomb. It is a seriously destabilizing move against the industry by fraudulent individuals.

This case has become rather personal for me, in that someone I am close to has been affected by this scam. The individual purchased a 30 ct+ topaz from a dealer that operates off of eBay. The material was represented as untreated and was sold for about $1000 for the stone. This unfortunately should have been the individual’s first clue, when the material was priced around $30-35/ct, that this could not possibly be the famed material from Oro Preto, Brazil that commands prices of $500-1000/ct in sizable stones. But regardless, this person was misled – as the material was represented by the dealer as untreated. Upon seeing this material, I immediately knew that something was dead wrong. The saturation was too deep, there were a couple bands of internal color zoning that are atypical of zoning formations of precious topaz, and it flat out just didn’t look right. Upon suspecting the worst, I gave my opinion on the material, and suggested that we subject it to natural sunlight. I took pictures prior to subjecting the stone to natural light. Unfortunately, I didn’t have any AA batteries available for my digital camera, so I used a film camera (hope the shots came out ok). When I develop the pictures I will upload them here.

The process was timed to expose the material for 8 hrs to direct sunlight. What happened within the first hour of exposure alone was horrifying… the material lost half of it’s color saturation. Within subsequent hours, the material lost more and more color saturation. What started out as a very deep gorgeous reddish brown topaz was reduced to barely a light tan stone within 5 hours. eBay is still a huge source, if not the number one source of this treated material. I can’t stress enough how important it is to know your source and know what you are buying and what treatments are out there.