The Anatomy of a GIA Diamond Grading Report

The GIA Diamond Grading Report is a report on the authenticity and quality of a diamond that has been used and trusted by fine jewelers for more than 50 years. The diamond’s premier credential issued by the GIA includes the assessment of the 4C’s of a diamond – it’s cut, clarity, color, and carat weight as well as a plotted diagram of the character of its clarity and the graphic representation of the proportions of the diamond. A GIA Cut grade is also included in the report for standard round brilliant cut diamonds within the D-Z color range.

Diamond grading reports are issued by the GIA laboratory for natural, loose diamonds within the D-Z color range weight 0.15 carats or more. The GIA does not issue Diamond Grading Reports for simulants, synthetics, mounted diamonds or stones that have been through unstable treatments like filled fractures or coating. Some reports are issued for laser-drilled diamonds or those that went through HPHT processing, but the report prominently discloses these stable treatments that were done on a diamond.

A Diamond Grading Report issued by GIA is a comprehensive report detailing the characteristics of the diamond and the date the diamond was examined by the GIA. Every report has an identification number registered in the GIA’s global database. The unique GIA report number may be inscribed using a micro-laser into the diamond upon the request of the customer.

Each GIA Report can be identified by its unique identification number and contains the following:

  • Description of the shape of the diamond or its outline, and the cutting style or pattern of the facet arrangement. Learn more about shapes and cuts.
  • The diamond’s dimensions written as “minimum diameter – maximum diameter x depth” if the diamond is round, and “length x width x depth” if the diamond is fancy-shaped.
  • The carat weight of the diamond, listed to the nearest hundredth of a carat.
  • The assessment of the diamond’s color from colorless to light yellow to brown based on the GIA Color Scale
  • The assessment of the clarity of the diamond, the relative absence of inclusions and blemishes. The clarity grade is expressed as Flawless to Included based on the GIA Clarity Scale.
  • The assessment of the quality of the cut such as face-up appearance, craftsmanship, and design.
  • The assessment of the polish (quality of the surface condition), and the placement, shape, and size of the facets, including symmetry or evenness of the outline.
  • The assessment of the smoothness and overall condition of the surface of the diamond expressed as excellent to poor.
  • The assessment of the symmetry or exactness of the outline of the diamond, and the shape, alignment, and placement of its facets expressed as excellent to poor. Learn more on symmetry
  • The assessment of the strength and color of the diamond or its fluorescence when seen using long-wave ultraviolet light.
  • The comments section where some additional features or identifying characteristics not included in the report are described.
  • List of logos, symbols, numbers, or text inscribed on the diamond.
  • A plotting diagram with the approximate shape and cutting style of the diamond.
  • The Color and Clarity Scales used by GIA
  • The Cut grades of GIA
  • The proportion diagram of the diamond, showing the graphic profile of the actual proportions of the diamond
  • The key to the symbols shown and the characteristics used in the plotting diagram.
  • Security features to safeguard the integrity of the report and facilitate the authentication of the document.

This article was contributed by Frank Fisher.

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learn everything you need to know before you buy a diamond in this detailed book!

learn everything you need to know before you buy a diamond in this detailed book!