GIA Report check - a User's Guide (Part 1)

In a previous article - GIA Certification of Colored Diamonds – background was provided of the Gemological Institute of America and the GIA Colored Diamond Grading Report. This report should be an integral part of buying a color diamond as it affords buyers the security and peace of mind that they are buying a stone that has been objectively appraised by one the most reputable authorities in the diamond industry.

This series of articles is intended to further educate buyers on how to fully utilize and analyze the plethora of important information provided in the GIA Color Diamond Grading Report. A logical, in-depth description of the fields in the report is provided to further enable buyers of color diamonds to make an informed purchasing decision.

Below is a copy of a GIA Colored Diamond Grading Report. This document will now be described in a format that will enable a user to best utilize the information contained therein.

Colored Diamond Grading Report

A GIA scan of a "Colored Diamond Report" (A.K.A full report)


The report can be divided into the following sections:

  • General Information
  • Grading Results
  • Additional Grading Information
  • Reference Diagrams
  • Scale References
  • Bar Code, Disclaimer, and Security Features


General Information

General information about the GIA is displayed across the top of the report, including the GIA letterhead, address and contact details of the GIA Laboratory where the report was prepared, list of other GIA Laboratories, and GIA website address.

Beneath this information is the name of the report, i.e. Colored Diamond Grading Report, followed by the following data:


Colored Diamond Grading Report-1

• Date – this refers to the date when the report was printed not when the stone was graded. In the sample above, the date is May 06, 2010.

• Shape and Cutting Style – this describes the outline of the diamond, i.e. its shape and the pattern in which the facets have been arranged, i.e. cutting style. In the sample above, the shape is Cushion and the cutting style is Modified Brilliant.

The shape of a diamond describes the outline of its girdle, and includes: Round, Oval, Radiant, Asscher, Marquise, Princess, Emerald, Pear, Heart, and Cushion. This list is not extensive as with today’s advances in laser cutting equipment specific cuts are made by companies which are licensed under their own brand names, for example the Hearts On Fire Diamond and the Asscher Cut.


The cutting style of a diamond describes the type of faceting and includes: Brilliant Cut where the facets are shaped like triangles and kites; Step Cut where the sloping, four-sided facets are cut below the table and run parallel to the diamond's girdle; Emerald Cuts are step cuts with their corners clipped off; and Mixed Cuts which  include faceting elements from both the brilliant and step cut techniques, either side by side or in different areas of the gemstone – this is a very popular technique for color diamonds.


Read More on Common Diamond shapes

• Measurements – dimensions, in millimeters, of the diamond rounded to the nearest hundredth. For a round cut stone, the measurement is “minimum diameter – maximum diameter x depth (culet to table).” For fancy-shaped diamonds, the measurement is “length x width x depth (culet to table).” In the sample above, the measurement is 6.74X 5.82 x 3.70mm.

• GIA Report Number – the vertically displayed number on the left-hand side of the document is the unique diamond identification number. The laboratory keeps an internal copy of all data on this report and it is cataloged according to this number. In the sample above, the GIA Report number is 1126068331.

• Laser Inscription Registry – not displayed on our example, an option available to the buyer of a diamond is to have the GIA Report number inscribed on the diamond by micro laser. This is irrefutable proof that the diamond described in the report is the same diamond purchased.


Continue reading, Go to part 2 of  "The GIA Colored Diamond Grading Report - a User's Guide"



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