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Diamond Grading Reports

What You'll See in a Diamond Grading Report

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Rare Oval Diamond

Rare Oval Diamond

Photo by Peter Macdiarmid/Getty Images

What Is a Diamond Grading Report?

Think of a diamond grading report as a road map that reveals most aspects about a diamond, including details about its clarity, cut, color and carat weight -- a collection of topics known as the Four Cs. The Gemological Institute of America developed the Four Cs system of grading diamonds, and provides jewelers and diamond buyers with detailed reports.

Does the GIA Grade All Diamonds

The GIA will prepare a report for loose, natural diamonds that fall in the D-Z color range, which includes all white, or colorless, diamonds.

Grading reports are not available for diamonds that are mounted into a setting, or diamonds that have been treated in ways that are regarded as unstable, including fracture filling and coating. The GIA will issue a report for diamonds that have been laser drilled to improve their appearance, but the treatments are disclosed on the report.

What Will I See on the Diamond Grading Report?

  • Each report is labeled with a date and a unique number, making it easy to retrieve the information at a later date.

  • Laser inscription can be used to mark the report number on the diamond with its report number. Ask the GIA if other inscriptions are desired (they will be included on the report).

  • The diamond's shape and cutting style are recorded on each grading report. The diamond's measurements are listed, and a drawing represents the gem's actual proportions.

  • Carat weight is included, and recorded to the nearest 1/100th of a carat, also known as one point.

  • To determine color grade, a diamond is compared to a control diamond, and the notation may range from colorless to yellowish to brown. Diamonds are graded within a standard color environment, and by more than one grader.

  • Diamonds are graded for clarity by viewing them with a jeweler's loupe of 10X magnification. Internal inclusions, known as flaws, are recorded, and so are external blemishes. If none are found, that characteristic is noted. At least two graders view each diamond, and sometimes additional graders are asked to offer an opinion.

  • Color and clarity graphics are used to provide a visual reference that shows where a diamond 'ranks' in those categories.

  • A plotting diagram is used to mark any clarity characteristics that are noticed.

  • A GIA Cut grade is provided for round brilliant diamonds in the D-Z group.

  • The report includes a diamond's finish and polish -- its size, shape, symmetry of facets and polish.

  • Diamond fluorescence is noted -- the characteristic that makes some diamonds appear to change colors in different lighting conditions.

  • A comments section is used to make important remarks that are not a part of the standard form.

  • Symbol keys are illustrated to help readers understand the markings on a report.

  • Reports contain security features, including a hologram and micro-print lines.

How Much Does a Diamond Report Cost?

Prices change over time, but the GIA offers pricing details on its website.

Does the GIA Grade Fancy Colored Diamonds?

Yes, but hue, tone and saturation are the characteristics considered most when grading colored diamonds.

  • Hue refers to a diamond's color
  • Tone indicates how light or dark the color may be
  • Saturation indicates a color's depth

The color grader chooses one of 27 hues for a diamond, and then describes tone and saturation by using terms such as fancy Light, fancy intense and fancy vivid.

Two different grading reports are available for fancy color diamonds.

  • The GIA Colored Diamond Grading Report contains the same Four Cs details as for a colorless diamond.

  • The GIA Colored Diamond Identification and Origin Report lists the stone's color intensity and reveal if the color is natural or has been intensified with a treatment.

What Is the GIA?

The Gemological Institute of America is a nonprofit organization that was founded in 1931 by Robert M. Shipley, who envisioned an resource that would be involved with gem research and education. Today, the GIA has locations in 14 countries, and has trained more than 300,000 students. The organization is one of the most respected gemological organizations.

Why Should I Purchase a Diamond Grading Report?

A grading report helps you understand the true characteristics of a diamond, and the notations on the report may even help you identify the gem if it is ever lost or stolen. Weigh the advantages of a report with its cost -- and the value of the diamond -- to decide if a report is needed.

Is a Diamond Grading Report the Same as an Appraisal

No, a grading report does not attempt to put a value on a diamond -- it is a description of the gemstone's characteristics. However, an appraiser will use the report to help determine value.

Is the GIA the Only Organization that Offers a Diamond Grading Report?

Other organizations offer diamond reports, but reports differ and are known by a variety of names:

The American Gem Society (AGS) provides a Diamond Quality Document and a Diamond Quality Certificate.

The International Gemological Institute (IGI) offers reports for diamonds and other gemstones.

European Gemological Laboratories (EGL USA and EGL International) both offer certificates that outline a diamond's characteristics.

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