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Diamond Certifications 101

Diamond Certificates

Some diamonds from KAY are accompanied by an independent certification as to their quality and value. The report from that evaluation is called a diamond certificate - also known as a diamond grading report, diamond dossier, diamond quality document or diamond light performance certificate.

Your independent diamond certification is produced by trained professionals and will include the following information:

  • The 4Cs of diamond quality: the color, clarity, cut and carat weight of a specific diamond as viewed under magnification.
  • A diamond's characteristics: proportions, finish and treatments.

Depending upon the diamond, you may also receive a light performance certificate:

  • Light performance measures the bright white light (brilliance), bright color light (fire) and scintillation (sparkle) of a diamond.

Because no two diamonds are exactly alike, a diamond certificate can even serve as your diamond's fingerprint or identification in case of loss or theft.

Learn more about some of the most well-known diamond grading laboratories

Gemological Science International (GSI)

GSI is an independent gemological laboratory based in the heart of New York City's Diamond District with additional offices in diamond centers around the world.

GSI offers gemstone identification, grading and appraisal services exclusively to the fine jewelry industry.

The lab's business model is built on integrity, innovation, professional service and shared research education.

American Gem Society (AGS)

AGS Laboratories developed the AGS Performance-Based Cut Grading System.

The key to the system is tracing light as it travels through the diamond. That's what determines whether a diamond looks bright and lively or dull and mediocre.

The lab offers several levels of grading reports. The most popular is the Diamond Quality Document. It shows cut (if available), color, clarity and carat weight accompanied by a profile showing that individual diamond's measurements, along with a custom plot for the actual facet arrangement and inscription details.

Gem Institute of America (GIA)

GIA pioneered diamond grading in the 1940s, creating a consistent way to describe a diamond in common language.

Today, GIA grading certificates are considered the hallmark of integrity in the diamond world.

The private laboratory issues two types of reports:

  • The GIA Diamond Grading Report provides scientifically determined information on shape, clarity, color, cut, carat weight, proportions, finish and treatments. It also includes a diagram of the diamond showing any inclusions that affect clarity.
  • The GIA Diamond Dossier is a more concise version of the full report and is available for loose diamonds between .15 and 1.99 carats.

International Gemological Institute (IGI)

IGI is an independent grading and appraisal organization with centers in New York City and Los Angeles, as well as in Antwerp, Bangkok, Mumbai, Tokyo, Dubai and Toronto.

Several gemologists carefully analyze each diamond and produce an accurate description of its characteristics, such as color, clarity, carat weight and the quality of its cut. The information is stored in IGI's computer database so you may request an update of your report if the need arises. IGI also offers colored gemstone certificates, educational courses and laser inscription services.

GemEx Systems
GemEx is an independent laboratory that focuses on light performance, or the movement of light through the diamond.

Trained professionals use the GemEx BrillianceScope Analyzer to measure a diamond's white light (brilliance), color light (fire) and scintillation (sparkle).

These measurements are then compared to those of other diamonds of the same shape. The highest and lowest amount of white light, color light and scintillation possible for each shape was set by measuring thousands of diamonds.

The GemEx Light Performance Report illustrates the measurements for your diamond in a three-bar graph.

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