GIA or the Gemological Institute of America is probably the most recognizable nam in the United States.
Other reputable labs around the world are just as reliable. Virtually any lab will have a way of cross-referencing grades.
Q: Should I demand a certificate with any significant diamond purchase?
A: Absolutely - Although you may want to forego a certificate for inexpensive stones when dealing with reputable sellers since certification does add cost.
Q: Whose certificate should you insist upon?
A: The one that will make you comfortable.
Q: So, as long as I get a certification with a diamond, I'm safe?
A: NO! One common fraud involves having diamonds cut to an existing certificate. Here is how that works:
Fraudster buys a gem, say a 2 carat round brilliant VVS1-H, and gets the gem graded at a respected lab. Then he sells the diamond in the wholesale market where dealers are comfortable buying diamonds without certs.
Next, Fraudster buys a 2.1 carat VS2-K, very similar in size and shape to the VVS1 he sold.
Fraudster takes the VS2 to a cutter and has it re-cut to the exact proportions and size that are on the certificate.
Then Fraudster sells the VS2 to an unsuspecting person who is trusting the certificate. There is a big difference in price between a VVS1-H and a VS2-K
Q: So how do I avoid the fraud?
A: Deal with reputable merchants and don't be afraid to have a diamond re-checked with the lab that issued the certificate.
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Note: Other reasons for certification.
- Many reputable labs will not issue a cert on a "clarity enhanced" diamond.
- Whitening treatements are detected and disclosed
- Professional and Trusted Gem Grading Laboratories.
- European Gemological Laboratory
- Gemological Institute of America
- American Gem Society