Documentation: Certificates and Appraisals

The Carob Bean is the source of the carat weight measurement.

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Certificates, Reports, and Appraisals

In this modern day, many gemstones come with papers of description - written documentation outlining characteristics of a stone. Papers may take the form of certificates or reports which describe specific aspects of the stone itself. Documentation in the form of appraisals assign a dollar value to an identified stone or piece of jewelry.

Certificates or reports are most credible when issued from independent scientific laboratories specializing in examining gemstones and describing them. Not all labs are equal. The important thing, though, is that an independent source has examined your stone and defined what it is. Some jewelry stores, retail chains, and manufacturers issue their own certificates or reports. These, of course, are not independent opinions and may not be objective.

Certificates and reports identify the type of stone and many other measurable or identifying features. Look for information such as:


  • Carat - weight in carats (learn about the origins of "Carat")

  • Color and tonal quality - basic color, intensity of color and secondary hues (labels for different terms vary depending on the system used)

  • Cut - shape and faceting style of the stone (round brilliant, oval, pear, etc... )

  • Clarity - clearness/cleanness of the stone; identifying marks (inclusions) in the stone

  • Size - measurements in millimeters

  • Polish - quality of the surface integrity and luster


Lab documents will also describe whether a stone is "natural" or "treated". These terms have specific definitions in the trade. In fact, certain types of stone may actually have specific processes applied and still be called "natural".

Stones might be heated, oiled, dyed, irradiated, grown, clarity enhanced, or any of a myriad of other processes that at some point did, or to some degree still do, affect the gemstone. Generally, but not always, these processes are used to increase the value of a stone. Laboratory documents will code processes used.

Sometimes a report will give a "country of origin" designation, which can have a large bearing on the cost/value of a stone.

Appraisals provide a description, but also a value, of the stone or jewelry. The appraiser may well use a certification (cert) or report from another source to help in the valuation. There are several types of appraisals; you should discuss with your appraiser what type of appraisal you require. Most often consumers request appraisals in order to obtain insurance coverage.

Labs - Primary independent laboratories used in the US market:

  • GIA - Gemological Institute of America - diamonds and fancy color diamonds

  • EGL - European Gemological Laboratories - white diamonds only

  • AGL - American Gemological Laboratories - colored stones only

  • AGTA - American Gem Trade Association's Gemological Testing Center - colored stones only

  • AGS - American Gem Society - white diamonds only


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