The truth about fancy colored diamonds.
For drama and rarity, fancy colored diamonds are more highly prized that their colorless cousins. Before you purchase fancy colored diamonds, you really ought to know what they are, where they come from, and how they get that way.
Rare & Dear: The Natural
Intensely colored diamonds used to be the preserve of only the very rich. Most people didn't even know they existed. Diamonds in vivid blues, greens, yellows, pinks, even purples, are extremely rare in nature and priced accordingly. Typical customers for such stones were informed consumers, collectors of diamonds, who knew what they wanted and where to seek it.
The world-famous Hope Diamond - 45.52 carats
These days, colored diamonds are carried by more retailers and in a much wider price range. This is due to two developments: new treatments to change the color of diamond, and the manufacture of synthetic diamond.
From Plain to Fancy: Color Treatments
To produce a vividly colored diamond, technicians usually begin with a slightly tinted diamond, a diamond that is yellowish or brownish and would not be appealing as a colorless diamond. They subject the diamond to one or more treatments to alter its color.
Irradiation — Irradiation produces green and blue colors, and additional treatments can create yellows, oranges and reds. The colors are attractive, but there is some question about their permanency. Irradiated diamonds are guaranteed to survive "normal, everyday wear and tear," but the color may change when the stone is exposed to high heat, such as produced by a jeweler's torch when he is setting the stone. Irradiated blue stones typically become yellowish green when subjected to such heat, and this change is irreversible.
The irradiation treatment can be detected by a jeweler using gem lab equipment.
HPHT — High pressure high temperature HPHT is a
more recent option for coloring diamonds. This process is used both to de-colorize
off-color diamonds (change a diamond from H to F, for example) and to add
rich colors. HPHT costs more than irradiation, but it produces colors that
are stable even under intense heat.
A variety of tests have shown the HPHT color treatment to be permanent.
Disclosure vs. Marketing
Many jewelry industry professionals are wary because the HPHT treatment is not as easy to recognize as irradiation. It's possible that HTHP-treated diamonds could pass as natural fancies in the marketplace, with consumers and even retailers being fooled and overcharged.
From the standpoint of consumers, jewelry retailers and insurers, disclosure of the treatment is crucial. Some manufacturers, though, are reluctant to have the process seen as a treatment (requiring disclosure).
Bellataire, for example, markets each treated gem as "a gift of nature, restored by man to its intrinsic beauty." The story on its brochure is that these diamonds began perfect and clear but during their "turbulent journey through the earth's crust" were "subjected to volcanic forces that disguised their essential beauty." Bellataire thus claims a role comparable to that of an art restorer, returning these gems to their original state.
The company's nod to disclosure is that all its HPHT-treated diamonds are laser-inscribed on the girdle with the names GE-POL and Bellataire. (The Gemological Institute of America will not grade/certify an HPHT-treated diamond unless the girdle is laser-inscribed.) However, when a stone is in a setting, an inscription on the stone's girdle is not visible. In any case, laser-inscriptions can be easily removed.
Color-enhanced fancy colored diamonds may be a good buy, but the treatment should be disclosed. Customers less familiar with shopping for gems may go to an untrained or untrustworthy retailer or may be attracted to a "bargain" that they have no way of evaluating. The insurer must be sure the appraisal for a fancy colored diamond specifically describes the stone, including treatments, so its value can be verified.
Making Fancies in the Lab: Synthesizing Diamond
First, let's be clear: synthetic diamond is real diamond. It is not an imitation or simulant, like cubic zirconium, made of a completely different material. Synthetic diamonds are genuine diamonds, with the same physical, chemical and optical properties as mined stones.
Yet skilled gemologists can recognize in these diamonds traces of their origin. For example, certain types of inclusions or characteristic color patterning (visible when the stone is studied with proper gemological equipment) indicate the process used to produce the stone.
What other word says "synthetic"?
Gem manufacturers like to avoid using the word synthetic. Though it simply means "put together," consumers often take it to mean that the diamond is not genuine. Diamond producers are introducing alternate terms they hope consumers will find appealing.
Cultured diamonds, comparable to cultured pearls, has been gaining usage.
Some manufacturers describe their gems as lab-grown. Gemesis calls its diamonds Gemesis-created.
Is disclosure necessary?
This is controversial in the jewelry industry. The issue there, as in the insurance industry, is economic.
In nature, fancy colored diamonds are extremely rare and their market price reflects this. In the lab, they can be produced in large quantities and with great predictability. Costs are lower for manufacture than for mining, and we can expect costs to go down as sales increase and technology improves.
Suppliers of natural diamonds feel that sales of natural fancies will suffer, and the public will be confused, if the market is flooded with synthetic stones that are not so identified.
Some diamond manufacturers, on the other hand, say that, since their products are real diamond in every sense, the distinction between mined and lab-grown is unimportant. They point out that subjecting carbon to high pressure and high temperature mimics how diamond is produced in the earth. The process is merely sped up — what took nature millions of years, takes only a day or two in the lab.
HPHT is used to grow synthetic diamond on a "seed" of natural diamond. This is similar to the way cultured pearls are produced, and it further blurs the distinction between natural and synthetic.
Because that distinction involves a great difference in valuation, to the insurer (and consumer) disclosure is vital. Synthesized diamonds are worth less than natural diamonds of similar appearance, and the high price of natural fancy diamonds makes this price difference immense.
Gemesis, the first company to market gem-quality synthetic stones, has its name inscribed on all its diamonds over 0.25 carats. This is a good-faith gesture by the manufacturer, but others down the buying chain (distributor, retailer, appraiser, buyer) may remove the inscription and pass off a synthetic gem as natural. Insurer as well as customer will suffer if there is a break in the chain of disclosure.
The JISO Solution
Because of the extreme value difference between synthetic fancy colored diamonds and natural ones, and because of the value and permanency issues involved with color treatments, it benefits both jewelry buyers and insurers to have:
A JISO 78/79 Jewelry Appraisal, which
- describes the jewelry in detail;
- states whether the stone is natural or synthetic;
- lists any treatments;
- is prepared by a Graduate Gemologist who is a Certified Insurance Appraiser™.
A Diamond Report from a respected independent laboratory, such as the Gemological Institute of America (GIA), the American Gem Society (AGS), or the Antwerp Diamond High Council (HRD).