Tuesday, December 8, 2009

Spotting Color Enhanced Diamonds...Even Your Browns Should be Tested!

It seems that while every cautious jeweler is double checking to make sure that the pink, yellow and even more rare colored diamonds are natural and untreated, many overlook the champagne and cognac colored stones, assuming that they are untreated.

Sometimes it's a shock to find out that even a lesser valued, brown colored diamond might not be natural. But it's not a surprise considering how popular champagne and cognac diamonds have recently become for men's rings and fashion designs!

If you're going to buy brown diamonds, we highly recommend that you insist on diamond grading for the larger stones to avoid the disappointment of being had by unscrupulous diamond dealers.

On the other hand, it is often the best bet to ensure the highest quality of color at more affordable prices by simply choosing to go with color enhanced natural diamonds--even your brilliant browns! By working with trusted and open jewelry designers like Etienne Perret you can decide what's best for you and quite often that's color enhanced.

Take a look at this beautiful brown-orange diamond that GIA testing revealed to be treated by irradiation and annealment, much to the disappointment of an unsuspecting buyer. The article mentions that Sally Chan and Paul Johnson GIA Laboratory, New York used the DiamondVision as one tool in determining the treatment of this stone. Below I have reprinted their GIA article:

                     DiamondView Indicates Treatment 
                            in Brown-Orange Diamond

The GIA Laboratory in New York recently examined a 1.49 ct pear-shaped brilliant that was color graded Fancy Deep brown-orange. Although the stone’s bodycolor appeared evenly distributed when viewed face-up, microscopic examination revealed that it was concentrated in the crown and penetrated only a shallow distance into the stone, with a sharp boundary that followed the girdle facets.

Such facet-associated color zoning would be expected for an artificially irradiated diamond. Infrared absorption spectroscopy revealed that the diamond was type IaB, which is consistent with the presence of banded brown graining. When exposed to long- and short-wave UV radiation, the stone fluoresced an intense chalky green that followed the graining. UV-visible absorption spectroscopy showed a strong absorption at 595 nm, which - along with the color zoning - indicated that this diamond had been artificially irradiated to induce the brown-orange color.

Of particular interest was the stone’s appearance in the DiamondView. The pavilion fluoresced a strong blue, while the crown facets fluoresced a strong green-yellow. These contrasting areas were separated by a clear, sharp boundary between the pavilion and the crown/girdle facets.

The combined gemological and spectroscopic features recorded for this diamond proved it had been irradiated and annealed, with the table and crown facets facing the high-energy beam. Although the DiamondView is commonly used to separate natural from synthetic diamonds, this example demonstrates its power to quickly alert the gemologist to the possibility that the stone is treated.

                                    Article By:  

- Sally Chan and Paul Johnson
GIA Laboratory, New York

So, if you want to know exactly where your colored diamonds came from and whether or not their color was enhanced, chose a reputable fine jewelry designer like Etienne Perret. View Etienne's colored diamond designs at Etienne's photo album

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