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Diamonds - the 4 Cs

  Carat Weight
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Diamond Certificates

Diamond Treatments

Gems from the Lab


Diamond Certificates

The Gemological Institute of America (GIA) has established gemstone grading systems that have been adopted internationally.

For a fee, the GIA laboratory will examine and grade any diamond over .23 carat and will disclose its findings in a paper known as a Diamond Report or Diamond Certificate. For identifying diamonds, or for settling disputes over qualities of particular gems, a GIA diamond certificate is regarded as an impartial arbiter.

The GIA only grades diamonds, it does not appraise (that is, it does not assign value).

NOTE: In 2000 the GIA changed the format of their diamond report. Below is the new certificate.

GIA Certificate (front)
GIA Certificate (back)

GIA Certificate (front)

GIA Certificate (back)

The American Gem Society Lab is relatively new, but well respected. A sample of the AGS Diamond report (designed to describe the characteristics of a diamond, not appraise) is shown below.

AGS Diamond Quality Document (front)
AGS Diamond Quality Document (back)

AGS Diamond Report (front)

AGS Diamond Report (back)

Click on any graphic for a larger image

PDF versions:

GIA Certificate (front)
GIA Certificate (back)

AGS Diamond Report (front)
AGS Diamond Report (back)

Shopping Considerations and Caveats

Beware of bogus certificates

Read about bogus certificates in our February 2003 newsletter. Read about whether valuations can be trusted in our March 2003 newsletter. The April 2003 newsletter tells you how to spot a bogus certificate.

Buyer's Tip

Be certain that it is a genuine diamond certificate. See our article about counterfeit diamond certificates in the May 2003 newsletter.