Diamond Certificates – Things to Watch Out For
Diamond certificates (aka grading reports) are documents certifying a diamond is genuine and describing the diamond features – weight, color grade, etc.  Well-respected laboratories (listed below) evaluate loose diamonds and attach the evaluations to the stones so buyers have a clear and legitimate understanding of what they’re buying.  If you’re diamond shopping and come across a diamond with no certificate put your wallet back in your pocket and see what you can do about getting an evaluation.  The extra cost and inconvenience is worth the trouble - we could be talking a difference of thousands of dollars.  Here are a few other things to watch for…

Counterfeit Certificates

Some suppliers and dealers take advantage of our limited knowledge of the diamond industry and pass on counterfeit or altered certificates.  To prevent this from happening to you, take the diamond and its certificate to a credentialed appraiser to verify that the report is authentic and accurate.  If you don’t know a trusted appraiser, call the certificate’s lab and give them the certificate number – they will be able to verify the information. 

Be weary of appraisers recommended by jewelers trying to sell you uncertificated diamonds.  The jeweler may be conspiring with an appraiser to fool the buyer and split any profit gained by selling their misrepresented diamonds.  

Bogus Labs
Producing a certificate from a nonexistent lab is an increasingly common problem.  You may want to contact the Better Business Bureau to confirm the lab is legitimate and learn if it has any complaints against it.  If the lab seems legitimate, call to verify the information on the certificate.  Of course, a second option is to send the diamond to another gemologist or recognized lab and request a certificate yourself.

Stone Switching
In some cases, the certificate is real but it belongs to a different stone.  Fortunately, labs  now have clever techniques to ensure against switching.  Gemprint, one popular technique, produces an electronic “fingerprint” of a diamond’s reflection pattern using laser technology and registers its image in a database.  GIA and other labs can also inscribe its report number on the girdle of the diamond, forever linking it to its appropriate grading report. 

One last thing

If you are going to ask the jeweler to lend you a diamond and certificate to check everything out, make sure you ask the jeweler to write down all of the stone’s dimensions (diameter, depth and weight, etc) and the last day you can return the stone.  This is to help ensure that you are not accused of switching the stone after leaving the premises, or encountering issues with their return policy.

SOME RECOGNIZED LABS

American Gemological Laboratory

American Gem Society Laboratory

CISGEM – External Service for Precious Stones

European Gemological Laboratory

Gemmological Association and Gem Testing Laboratory of Great Britain

Gemological Association of All Japan

Germ Certification and Assurance Lab

Gemological Institute of America

Gem Trade Laboratory

Gemworld International Laboratories

Germain Gemmological Laboratory

Gubelin Gemmological Lab

Hoge Raad voor Diamant

Professional Gem Sciences

Swiss Gemological Institute