1. you will probably pay way more than you would for a better looking stone you could track down (with some effort).
2. you can buy fracture filled (with glass so you cant see the flaws) diamonds that look great - do you want to? they are about 40% less.
3. what about when the chinese and eastern bloc countries start producing these diamonds and the price plumets?

here are some bits about the subject from my website - they changed the name from pegusus (didnt fly) to belataire:-

'Genetically Modified' Diamonds
July 2000
The giant General Electric Company make synthetic diamond abrasive grits and are leading diamond researchers. Last year they began marketing Pegasus diamonds, artificially treated to improve their colour. They said the process could not be detected, so need not be declared, but fortunately De Beers and Swiss researchers devised a number of gemmological tests to isolate Pegasus from natural diamonds.

GE Bleached Pegasus Diamonds
Disclosure is an issue of great concern. General Electric Company has produced synthetic diamonds for industrial abrasives since 1955. In 1999 GE's research and development people discovered a way to improve the colour of some rare large diamonds (type II) using an advanced high pressure / high temperature treatment. The whitened gems more than doubled in value and are marketed as Pegasus diamonds.

The gem industry was confronted with an ethical dilemma. Legitimate gem dealers are required to disclose any treatments on invoices, but GE maintained the process duplicated nature and could never be detected thus disclosure was unnecessary. The issue would have remained un-resolved but for gemmologists discovering a number of tests to identify Pegasus diamonds.

All should have a laser inscription on their girdle identifying them as Bellataire or GE-POL.

Many are characterized by "graining" comments on the GIA reports that come with these diamonds. This is some degree of cloudiness which may or may not seem visible to most observers. Some have no graining, many do, and some have enough that you can detect it with naked eye examination.

If you do not pay a premium for such a stone, I'd say it they are excellent diamonds. They are not really worth more money regardless of great sales pitches that can be employed. Bought in a competitive environement they can be an excellent stone.

I see no durability problem or deterioration problem. The color improvment is a permanent situation. Eventually someone other than GE-Kaplan will have this process perfected. At that point some of these treatments may be less costly. We cannot predict much about future diamond values anyway, so why worry, be happy!

Would I fear buying one? No, if it fullfilled my budget and quality parameters better than any competing stones, then I would not have any hesitation. I would not seek one out intentionally, but I would not avoid considering one for possible purchase.
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David Atlas
Accredited Gem Appraisers

Your technical understanding of what may have taken place is way beyond the normal consumer's concept of these hi-tech treatments. It might make you more cautious about treatments, but most people will know only the little that they are told which is so very positive. Salesmanship in action.