WHAT KIND DIAMONDS DOES
"GE POL" USE TO IMPROVE COLOR
By Joe C. C. Yuan-- G.G., D.G.A.
Pegasus Overseas Limited which is a new subsidiary of the Lazare Kaplan International, Inc. Their office is located in Antwerp, Belgium. POL announced an exclusive agreement which will market natural diamonds that have undergone a new General Electric process. They declared these diamonds has been processed to improve its color, brightness, and brilliance. This improvement is permanent and irreversible.
Actually, the process is made on rough to change only the color of the diamond. After the process, the stones are cut in good proportion. Later, they are inscribed "GE POL" on the girdle with laser (Fig. 2-1). All the stones are sent to GIA to be graded. GIA certificates with the following comments:
"GE POL" is present on the girdle. Pegasus Overseas Limited (POL) states that this diamond has been processed to improve its appearance by General Electric Company (GE).
They sell these processed diamonds through POCL in Antwerp, Belgium. Early June, the author received 2 pieces of "GE POL" processed diamonds with GIA certificates. One weights 0.56 ct, brilliant round, G IF. The other weights 0.69 ct, oval, E VS1. These two stones were sent to IGI for many tests, which include general examination, DiamondSure™ and DiamondView™. As well as visible light spectroscopic test. The stones were also sent to AGTA laboratory for FTIR and Raman Spectroscopic tests. The author comes to the following results and conclusions:
Color: Ovalís E color should definitely qualify as D color. BRís G color contains brownish hue.
The author believe GIA fundamentally do not give these processed diamonds D grade in color, even it is indeed a D in color. The author was told that most "GE POL" diamonds have brownish hue, as this round diamond with G color proves.
DiamondSure™: The test shows both diamonds are without 415 nm absorption. Further tests need to be conducted.
DiamondView™: Both diamonds shows parallel grain lines in some ares (Fig. 2-2 & 2-3). Inside the stone, they exhibit characteristics of typical grain lines of natural brown color diamonds.
Visible Light Spectroscopic Meter: The round stone visible spectroscopic diagram (Fig. 2-4) shows slight peak at 700nm which is resulted from the G color grade. The oval stone has an almost even spectroscopic diagram (Fig. 2-5) because the E color grade.
FTIR: Both diamonds show type IIa without nitrogen absorbent peak between 1000-1400 cm-1 (Fig. 2-6 & 2-7), the peak at 2190 cm-1is cause by the presence of CO2 while the air in the chamber while the diamonds were undergoing analysis. Under normal condition, the air in the chamber should have be replaced by nitrogen.
Another natural fancy brown diamond was tested (Fig. 2-8). The diagram shows exactly the same as these two processed diamonds.
Raman: (Fig. 2-9 & 2-10) After skip the ultra high peak of diamond carbon at1332 cm-1, before 1250 cm-1, no significant data were found. Between 1450 to 4000 cm-1, both diamonds show only double peak of pure carbon of diamond which is represented as the three peaks located between 2200 to 2700 cm-1. The BR diamond only shows simple carbon, but a peak at 3761 cm-1 is observed in the oval diamond.
The conclusion from all the above tests, the rough diamonds "GE POL" used are type IIa brownish color diamonds.