The GIA was founded in 1931 and is headquartered in Carlsbad, California.
The non-profit organization's field of activity includes the scientific research of gemstones and the communication of this acquired knowledge. The GIA is therefore working in detail to develop generally valid and verifiable guidelines for assessing the quality of colored gemstones and diamonds in particular. This approach has met with a great response, as the classification of diamonds introduced by the GIA in the middle of the 20th century using the so-called Four C's (carat, clarity, cut, color) has now become established as the standard.
The GIA Diamond Grading Report
A GIA certificate for diamonds contains detailed information about its characteristics. It states the cut shape of the diamond and its dimensions in millimeters.
It also contains a weight indication in carats; the color of the diamond is defined using the color grading scale from D to Z introduced by the GIA.
The system developed by the GIA is also used for clarity, which ranges from flawless (IF) to very large inclusions (I3).
There are five rating levels for the cut: excellent, very good, good, fair and poor.
In addition to the Four Cs, the GIA evaluates polish and symmetry – polish is the evenness of the diamond's surface and symmetry is the accuracy of the outline as well as the shape, placement and orientation of the facets.
In the certificate, the GIA informs about any fluorescence of the diamond and provides graphics that illustrate its cut shape and proportions.
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