Trade Alert
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Fracture filled diamond before and after ( above )at
Jewellery Auctions
Recently in a story to be soon released in the mainstream media about the state of the Australian jewellery industry's failure to police it's own code of ethics, a fracture filled diamond was sold by an Australian high profile jewellery auction house backed up by a valuation issued by a member of the National Council of Jewellery Valuers.
The valuation did NOT disclose the diamond was fracture filled.
Failing to disclose is deceptive and fraudulent.
Such inferior diamonds are worth considerably less ,if nothing at all, because most fracture filled diamonds are reject diamonds that can not be sold as commercial gem quality to dealers.
These otherwise unattractive cracked diamonds need to be treated and enhanced to make these lowest quality diamonds marketable.
In addition the misleading and deceptive certification of the coated pink diamond inaccurately documented by the Bolton Gem's created Australian Diamond Grading Laboratory, the Queensland wholesaler of their branded " Eternity " diamonds, has not gone unnoticed and we have recently been approached by several journalists who are in the midst of preparing their own independent stories.
COME IN SUCKER !!! The jewellery auctioneers love ya !
Most of the jewellery auctioneers are low life scum bags who have no appreciation for fine jewellery with credentials that make used car dealers look reputable.
In fact used car dealers are more reputable ! The motor traders association have a self regulating code of ethics they abide by. The GAA, JAA and NCJV do not.
The GAA, JAA and NVJC are powerless gutless two faced sperm burps who smile a lot and are extremely polite. Egg farts have more power and smell better too. They make me sick and I do not hide my contempt for them.
This is not the first time NJCV valuations have appeared as inaccurate confirming that the jewellery consumer has very little protection.
Channel 7's Today Tonight Show last year did a story on three NCJV jewellery valuers who gave three different valuations on the same diamond only to be exposed later as being utterly incompetent because the diamond was a synthetic diamond.
Accusations of entrapment followed but so what ? Schmucks like this need to be exposed and they only have themselves to blame.
The two " industry experts " that were approached by the JAA were unable to identify a coated diamond yet are still certifying diamonds. This was despite the fact they did not even conduct the required testing methods due to lack of up to date testing equipment yet the Diamond Certification Laboratory of Australia who identified the ADGL certified coated diamond orignally were castigated and blamed for warning everyone of the danger.
Mike Muller of the Australian Diamond Grading Laboratory, a more grand sounding business organisation than it really is, with his twenty five years of experience even admitted he had not seen enough coated diamonds to be experienced in their identification and falsely stated that there was not enough information out there or stones avaialble for gemologists to examine. This was not true.
GIA and other respected gemmological labs reports on these coated diamonds had already been documented years earlier. A simple Google search is proof enough.
ADGL's Mike Muller who is a member of the JAA and who certified the coated diamond, offered numerous excuses but only looked more foolish by attempting to cover up his own unprofessional ineptitude while claiming to have twenty five years of experience and grading to GIA standards.
A sworn affadavit by Mike Muller sent to me is futher proof of how ADGL has failed to safeguard jewellery retailers and not the public consumer. More about this in another story suffice to say the questionable independence of ADGL's diamond certificates are laughable and just downright stupid if not just incredibly embarrassing.
The silly thing was that you could easily see the coating on the diamond using a 10x loupe.
Of course it was all a plot and a conspiracy being orchestrated by those of us who were unable to compete as was claimed by some of the very same people who themselves are still trading unfairly.
We have written to both the Gemmological Association of Australia and the National Council of Jewellery Valuers regarding the following and no response to these issues have been currently addressed :
1) Professional Honesty & Integrity
2) Misleading and deceptive behaviour
3) Diminishing public confidence
4) Conflict of interest issues
5) Inability to correctly identify and accurately grade diamonds.
6) Disciplinary action and expulsion.
The public consumer of diamonds is not protected.
Both the GAA and the NCJV are a trade organisation that continues to ignore it's own code of ethics.
Most of the jewellery auction houses retain the services of these incompetent valuers and hide behind their official-looking valuation reports. Toilet paper is more functional.
Both auctioneers and valuers who often collude are NOT to be trusted.
The valuations are usually exaggerated and over inflated giving the impression to the potential consumer they are ready to land a bargain.
Real bargains do not have to be sold at auctions. They are usually snatched up prior by dealers.
The public are being taken for suckers !
Jewellery purchased from auction houses are generally perceived as being bargains when most times you can purchase a brand new item of jewellery for the same price at a wholesale level from a small manufacturing jeweller rather than some high profile brand name retailer.
NCJV : Another Bullshit Trade Organisation & Top 5 Myths About Jewellery Valuations
Top 5 Myths About Jewellery Valuations
MYTH 1 : An insurance valuation can only be done by a registered valuer
WRONG! An insurance valuation is an assessment how much it would cost to replace a particular piece of jewellery in the current marketplace. The significant determinants of value of diamond jewellery are the 4 C's of the diamond together with retail market pricing information. If all this information is available, a replacement value can be computed. If the diamond is accompanied by an internationally recognised grading certificate, the 4 C's are known and accurate. All that remains is to price that diamond in the current marketplace. All that is important to your insurance company is that the valuation is detailed and accurate. This will ensure you of like-for-like replacement.
MYTH 2 : I got a great deal, I was shown a valuation of double the ticket price
WRONG! You should be extremely suspicious of a jeweller who shows you a high valuation as proof that you are getting a great deal. In many circumstances, the jeweller using the valuation to sell you the item is in fact the valuer. If you were buying a house, would you let the seller perform the building inspection for you? A valuation should only be offered AFTER you have completed your purchase. After all, the true insurance replacement value of the piece of jewellery is what you paid for it.
MYTH 3 : A valuation is accurate even if your diamond is not certified
WRONG! A valuation can only be accurate if the characteristics of the diamond have been accurately determined. Although many valuers have vast experience in the industry, the accurate determination of the characteristics of a diamond is a scientific process requiring extremely expensive diagnostic equipment. Only internationally recognised laboratories possess this required equipment. All a valuer can do for an uncertified diamond is make an educated guess of these characteristics. Unfortunately, even slight differences in the valuers grading to an accurate laboratory grading could translate to thousands of dollars in value.
MYTH 4 : A valuer does not have to be independent
WRONG! Some jewellers use valuations as selling tools. If the jeweller and the valuer are not independent, the valuation may be inflated to enable the jeweller to sell the diamond. The easiest way of inflating a valuation is to overstate the grade of the diamond. This can only occur if the diamond is uncertified. The valuer should have no vested interest in the specific value attributed to your jewellery.
MYTH 5 : The higher my valuation, the higher my insurance payout
WRONG! You will pay higher insurance premiums, but, in the event of a loss, your insurance company reserves the right to replace the jewellery with a similar piece. The insurance company can and will source the replacement at a cost much lower than you actually paid, regardless of the valuation. The only situation in which you will be paid out is if you have under-valued the item and the insurance company cannot replace it for your insured value.
Why diamond buyers have contempt for jewellers
Another Dodgy Grading Laboratory
Telephone Enquiry
ADGL : " Dodgy Grading Laboratory, may I help you? "
Caller: " Yes, I'd like some information about your laboratory. "
ADGL : " OK, what would you like to know ? "
Caller: " I don't know. That's why I called."
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Diamond Enhancement
From Wikipedia, the free encyclopedia
Diamond enhancements are specific treatments, performed on natural diamonds (usually those already cut and polished into gems), which are designed to improve the gemological characteristics — and therefore the value — of the stone in one or more ways. These include clarity treatments such as laser drilling to remove inclusions, application of sealants to fill cracks, color treatments to improve a white diamond's color grade, and treatments to give fancy color to a white or off-color diamond.
The CIBJO and government agencies such as the United States Federal Trade Commission explicitly require the disclosure of most diamond treatments at the time of sale. Some treatments, particularly those applied to clarity, remain highly controversial within the industry — this arises from the traditional notion that diamond holds a unique or "sacred" place among the gemstones, and should not be treated too radically, if for no other reason than a fear of damaging consumer confidence.
Treated diamonds usually trade at a significant discount to untreated diamonds. This is due to several factors, including relative scarcity — a much larger number of stones can be treated to reach gem quality than are found naturally occurring in a gem quality state — and the potential impermanence of various treatments. Therefore, it is unusual to see a diamond with good overall gemological characteristics undergo treatment. Diamonds which are chosen for treatment are usually those that would be otherwise difficult to sell as gem diamonds, where inclusions or fractures noticeably detract from the beauty of the diamond to even casual observers. In these cases, the loss in value due to treating the diamond is more than offset by the value added by the mitigating of obvious flaws.
Contents
Clarity enhancements
1.1 Laser drilling
1.2 Fracture filling
2 Color enhancements
2.1 Irradiation
2.2 Coatings
2.3 High-pressure high-temperature treatment
3 See also
4 Footnotes
5 References
Clarity enhancements
See also: diamond clarity
The clarity, or purity, of a diamond — the relative or apparent severity of flaws within the stone — has, like the other "four Cs", a strong bearing on the evaluation of a diamond's worth. The most common flaws, or inclusions, seen in diamonds are fractures (commonly called feathers, due to their feathery whitish appearance), and solid foreign crystals within the diamond; such as garnet, diopside, or even other diamonds. The size, color, and position of inclusions can reduce the value of a diamond, especially when other gemological characteristics are good. Those who prepare diamonds for sale sometimes choose to reduce the visual impact of inclusions through one or more of a variety of treatments.
Laser drilling ( pictured above )
The combustibility of diamond has allowed the development of laser drilling techniques which, on a microscopic scale, are able to selectively target and either remove or significantly reduce the visibility of crystal or iron oxide-stained fracture inclusions. Diamonds have been laser-drilled since at least the mid-1980s. Laser drilling is often followed by glass infilling.
The drilling process involves the use of an infrared laser (wavelength about 1060 nm) to bore very fine holes (less than 0.2 millimeters or 0.005 inches in diameter) into a diamond to create a route of access to an inclusion. Because diamond is transparent to the wavelength of the laser beam, a coating of amorphous carbon or other energy-absorbent substance is applied to the surface of the diamond to initiate the drilling process. The laser then burns a narrow tube to the inclusion. Once the included crystal has been reached by the drill, the diamond is immersed in sulfuric acid to dissolve the crystal or iron oxide staining. This process is not effective for inclusions which are diamonds themselves, as diamond is not soluble in sulfuric acid.
Several inclusions can be thus removed from the same diamond, and under microscopic inspection the fine bore holes are readily detectable. They are whitish and more or less straight, but may change direction slightly, and are often described as having a "wrinkled" appearance. In reflected light, the surface-reaching holes can be seen as dark circles breaching the diamond's facets. The diamond material removed during the drilling process is destroyed, and is often replaced with glass infilling, using the fracture filling techniques described below.
Fracture filling
Around the same time as the laser drilling technique was developed, research began on the fracture filling of diamonds to better conceal their flaws. The glass filling of diamond often follows the laser drilling and acid-etching of inclusions, though if the fractures are surface-reaching, no drilling may be required. This process, which involves the use of specially-formulated glasses with a refractive index approximating that of diamond, was pioneered by Zvi Yehuda of Ramat Gan, Israel. Yehuda is now a brand name applied to diamonds treated in this manner, and the process has apparently changed little since its inception. Koss & Schechter, another Israel-based firm, attempted to modify Yehuda's process in the 1990s by using halogen-based glasses, but this was unsuccessful. The details behind the Yehuda process have been kept secret, but the filler used is reported to be lead oxychloride glass, which has a fairly low melting point. The New York-based Dialase also treats diamonds via a Yehuda-based process, which is believed to use lead-bismuth oxychloride glass.
The glass present in fracture-filled diamonds can usually be detected by a trained gemologist under the microscope: the most obvious signs — apart from the surface-reaching bore holes and fractures associated with drilled diamonds — are air bubbles and flow lines within the glass, which are features never seen in untreated diamond. More dramatic is the so-called "flash effect", which refers to the bright flashes of color seen when a fracture-filled diamond is rotated; the color of these flashes ranges from an electric blue or purple to an orange or yellow, depending on lighting conditions (light field and dark field, respectively). The flashes are best seen with the field of view nearly parallel to the filled fracture's plane. In strongly colored diamonds the flash effect may be missed if examination is less than thorough, as the stone's body color will conceal one or more of the flash colors. For example, in brown-tinted "champagne" diamonds, the orange-yellow flashes are concealed, leaving only the blue-purple flashes to be seen. One last but important feature of fracture-filled diamonds is the color of the glass itself: it is often a yellowish to brownish, and along with being highly visible in transmitted light, it can significantly impact the overall color of the diamond. Indeed, it is not unusual for a diamond to fall an entire color grade after fracture-filling. For this reason fracture-filling is normally only applied to stones whose size is large enough to justify the treatment: however, stones as small as 0.02 carats (4 mg) have been fracture-filled.
The fracture-filling of diamond is a controversial treatment within the industry — and increasingly among the public as well — due to its radical and impermanent nature. The filling glass melts at such a low temperature (1673 Kelvin) that it easily "sweats" out of a diamond under the heat of a jeweler's torch; thus routine jewelry repair can lead to a complete degradation of clarity or in some cases shattering, especially if the jeweler is not aware of the treatment. Similarly, a fracture-filled diamond placed in an ultrasonic cleaner may not survive intact. Yehuda diamonds are however given a warranty, which allows owners of their diamonds to return them for retreatment following any degradation of the glass filling.
It is notable that most major gemological laboratories, including that of the influential Gemological Institute of America, refuse to issue certificates for fracture-filled diamonds. Labs that do certify these diamonds may render any treatment benefit moot by disregarding apparent clarity and instead assigning the diamond a grade reflecting its original, pre-treatment clarity.
Colour enhancements
See also: diamond color
Generally there are three major methods to artificially alter the color of a diamond: irradiation with high-energy subatomic particles; the application of thin films or coatings; and the combined application of high pressure and high temperature (HPHT). However, there is recent evidence that fracture filling is not only used to improve clarity, but that it can be used for the sole purpose to change the color into a more desirable color as well. [1]
The first two methods can only modify color, usually to turn an off-color Cape series stone (see Material properties of diamond: Composition and color) into a more desirable fancy-colored stone. Because some irradiation methods produce only a thin "skin" of color, they are applied to diamonds that are already cut and polished. Conversely, HPHT treatment is used to modify and remove color from either rough or cut diamonds—but only certain diamonds are treatable in this manner. Irradiation and HPHT treatments are usually permanent insofar as they will not be reversed under normal conditions of jewelry use, whereas thin films are impermanent.
Irradiation
Pure diamonds, before and after irradiation and annealing. Clockwise from left bottom: 1) Initial (2×2 mm) 2-4) Irradiated by different doses of 2-MeV electrons 5-6) Irradiated by different doses and annealed at 800 °C.
Sir William Crookes, a gem connoisseur as well as a chemist and physicist, was the first to discover radiation's effects on diamond color when in 1904 he conducted a series of experiments using radium salts. Diamonds enveloped in radium salt slowly turned a dark green; this color was found to be localized in blotchy patches, and it did not penetrate past the surface of the stone. The emission of alpha particles by the radium was responsible. Unfortunately radium treatment also left the diamond strongly radioactive, to the point of being unwearable [2]. A diamond octahedron so treated was donated by Crookes to the British Museum in 1914, where it remains today: it has lost neither its color nor radioactivity.
Nowadays diamond is safely irradiated in four ways: proton and deuteron bombardment via cyclotrons; gamma ray bombardment via exposure to cobalt-60; neutron bombardment via the piles of nuclear reactors; and electron bombardment via Van de Graaff generators. These high-energy particles physically alter the diamond's crystal lattice, knocking carbon atoms out of place and producing color centers. Irradiated diamonds are all some shade of green, black, or blue after treatment, but most are annealed to further modify their color into bright shades of yellow, orange, brown, or pink. The annealing process increases the mobility of individual carbon atoms, allowing some of the lattice defects created during irradiation to be corrected. The final color is dependent on the diamond's composition and the temperature and length of annealing.
Cyclotroned diamonds have a green to blue-green color confined to the surface layer: they are later annealed to 800 °C to produce a yellow or orange color. They remain radioactive for only a few hours after treatment, and due to the directional nature of the treatment and the cut of the stones, the color is imparted in discrete zones. If the stone was cyclotroned through the pavilion (back), a characteristic "umbrella" of darker color will be seen through the crown (top) of the stone. If the stone was cyclotroned through the crown, a dark ring is seen around the girdle (rim). Stones treated from the side will have one half colored deeper than the other. Cyclotron treatment is now uncommon.
Gamma ray treatment is also uncommon, because although it is the safest and cheapest irradiation method, successful treatment can take several months. The color produced is a blue to blue-green which penetrates the whole stone. Such diamonds are not annealed. The blue color can sometimes approach that of natural Type IIb diamonds, but the two are distinguished by the latter's semiconductive properties. As with most irradiated diamonds, most gamma ray-treated diamonds were originally tinted yellow; the blue is usually modified by this tint, resulting in a perceptible greenish cast.
The two most common irradiation methods are neutron and electron bombardment. The former treatment produces a green to black color that penetrates the whole stone, while the latter treatment produces a blue, blue-green, or green color that only penetrates about 1 millimeter deep. Annealing of these stones (from 500–900 °C for neutron-bombarded stones and from 500–1200 °C for electron-bombarded stones) produces orange, yellow, brown, or pink. Blue to blue-green stones that are not annealed are separated from natural stones in the same manner as gamma ray-treated stones.
Prior to annealing, nearly all irradiated diamonds possess a characteristic absorption spectrum consisting of a fine line in the far red, at 741 nm — this is known as the GR1 line and is usually considered a strong indication of treatment. Subsequent annealing usually destroys this line, but creates several new ones; the most persistent of these is at 595 nm.
It should be noted that some irradiated diamonds are completely natural. One famous example is the Dresden Green Diamond. In these natural stones the color is imparted by "radiation burns" in the form of small patches, usually only skin deep, as is the case in radium-treated diamonds. Naturally irradiated diamonds also possess the GR1 line. The largest known irradiated diamond is the Deepdene.
Coatings
The application of colored tinfoil to the pavilion (back) surfaces of gemstones was common practice during the Georgian and Victorian era; this was the first treatment — aside from cutting and polishing — applied to diamond. Foiled diamonds are mounted in closed-back jewelry settings, which may make their detection problematic. Under magnification, areas where the foil has flaked or lifted away are often seen; moisture that has entered between the stone and foil will also cause degradation and uneven color. Because of its antique status, the presence of foiled diamonds in older jewelry will not detract from its value.
In modern times, more sophisticated surface coatings have been developed: these include violet-blue dyes and vacuum-sputtered films resembling the magnesium fluoride coating on camera lenses. These coatings effectively whiten the apparent color of a yellow-tinted diamond, because the two colors are complementary and act to cancel each other out. Usually only applied to the pavilion or girdle region of a diamond, these coatings are among the hardest treatments to detect — while the dyes may be removed in hot water or alcohol with ease, the vacuum-sputtered films require a dip in sulfuric acid to remove. The films can be detected under high magnification by the presence of raised areas where air bubbles are trapped, and by worn areas where the coating has been scratched off. These treatments are considered fraudulent unless disclosed.
Another coating treatment applies a thin film of synthetic diamond to the surface of a diamond simulant. This gives the simulated diamond certain characteristics of real diamond, including higher resistance to wear and scratching, higher thermal conductivity, and lower electrical conductivity. While resistance to wear is a legitimate goal of this technique, some employ it in order to make diamond simulants more difficult to detect through conventional means, which may be fraudulent if they are attempting to represent a simulated diamond as real.
[edit] High-pressure high-temperature treatment
A small number of otherwise gem-quality stones that possess a brown body color can have their color significantly lightened or altogether removed by HPHT treatment, or, depending on the type of diamond, improve existing color to a more desirable saturation. The process was introduced by General Electric in 1999. Diamonds treated to become colorless are all Type IIa and owe their marring color to structural defects that arose during crystal growth, known as plastic deformations, rather than to interstitial nitrogen impurities as is the case in most diamonds with brown color. HPHT treatment is believed to repair these deformations, and thus whiten the stone. (This is probably an incorrect conclusion, the whitening due to destruction of stable vacancy clusters according to one of the researchers). Type Ia diamonds, which have nitrogen impurities present in clusters that do not normally affect body color, can also have their color altered by HPHT. Some synthetic diamonds have also been given HPHT treatment to alter their optical properties and thus make them harder to differentiate from natural diamonds. Pressures of up to 70,000 atmospheres and temperatures of up to 2,000 °C (3,632°F) are used in HPHT procedure.
Also in 1999, Novatek, a Provo, UT manufacturer of industrial diamonds known for its advancements in diamond synthesis, accidentally discovered that the color of diamonds could be changed by the HPHT process. The company formed NovaDiamond, Inc. to market the process. By applying heat and pressure to natural stones, NovaDiamond could turn brown Type I diamonds light yellow, greenish yellow, or yellowish green; improve yellowish Type IIa diamonds by several color grades, even to white; intensify the color of yellow Type I diamonds; and make some bluish gray Type I and Type IIb colorless (although in some cases natural bluish gray diamonds are more valuable left alone, as blue is a highly desired hue). In 2001, however, NovaDiamond quit the HPHT gem business because of what the company's leader, David Hall, characterized as the underhanded practices of dealers. Apparently, dealers were passing off NovaDiamond enhanced gems as naturally colored, and the company refused to be party to this deception.
Definitive identification of HPHT stones is left to well-equipped gemological laboratories, where Fourier transform spectroscopy (FTIR) and Raman spectroscopy are used to analyze the visible and infrared absorption of suspect diamonds to detect characteristic absorption lines, such as those indicative of exposure to high temperatures. Indicative features seen under the microscope include: internal graining (Type IIa); partially healed feathers; a hazy appearance; black cracks surrounding inclusions; and a beaded or frosted girdle. Diamonds treated to remove their color by General Electric are given laser inscriptions on their girdles: these inscriptions read "GE POL", with "POL" standing for Pegasus Overseas Ltd, a partnered firm. It is possible to polish this inscription away, so its absence cannot be a trusted sign of natural color. Although it is permanent, HPHT treatment should be disclosed to the buyer at the time of sale.
See also
Crystallographic defects in diamond
Material properties of diamond
Brown diamonds
Synthetic diamond
Diamond simulants
Diamond color
Diamond clarity
Diamond cut
Footnotes
^ A recent 2004 GIA report on fracture filled diamond turning its color into pink. (Gems and Gemology 2004)
^ Crookes commentary on his experiments in 1904. (1909). Diamonds: chapter dealing with diamond treatments, phosphorescense and irradiation of loose diamonds
[edit] References
O'Donoghue, Michael, and Joyner, Louise (2003). Identification of gemstones, pp. 28–35. Butterworth-Heinemann, Great Britain. ISBN 0-7506-5512-7
Read, Peter G. (1999). Gemmology (2nd ed.), pp. 167–170. Butterworth-Heinemann, Great Britain. ISBN 0-7506-4411-7
Webster, Robert, and Read, Peter G. (Ed.) (2000). Gems: Their sources, descriptions and identification (5th ed.), pp. 683–684, 692–696. Butterworth-Heinemann, Great Britain. ISBN 0-7506-1674-1
Collins A. T., Connor A., Ly C.-H., Shareef A. and Spear P. M. (2005). High-temperature annealing of optical centers in type-I diamond. J. Appl. Phys. 97 083517 (2005) doi:10.1063/1.1866501
Retrieved from "http://en.wikipedia.org/wiki/Diamond_enhancement"
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