The GIA Diamond Grading Report

Abstract: A basic understanding on how to interpret a GIA Diamond Grading Report will go a long way for an appreciation on the diamond that you are buying. And it is important that when you purchase a diamond, it should be accompanied by a GIA Grading Report.

The Gemological Institute of America (GIA) is the world’s premier authority on diamond certification. Diamonds certified by GIA is accepted by all diamond dealers of the world.

When buying a solitaire diamond, hence, it is preferable to be accompanied by a GIA Diamond Grading Report as this authenticates that the diamond is natural, as well as describing the specifications on the grades of the diamond.   

There are two types of paper-based GIA Diamond Report. A third type of diamond grading service as offered by GIA, called the eReport, has not really taken off the ground, as buyers still preferred the old fashion paper laminated certificate to accompany a diamond.

The first type is called the GIA Grading Report. It is printed on A-4 size paper, which is double folded and there is a plastic envelop to contain the report. This report is normally for solitaire diamonds above 0.75ct. There is a plotting diagram showing the location of inclusions, if any.

The second type is called the GIA Dossier Report. It is printed on half A-4 size paper, single fold accompanied by a plastic folder. This report is normally for diamonds below 0.75ct. The difference here is that there is no plotting diagram showing the location of inclusions.

To deter forgers, all GIA certificates issued after the year 2014 have two types of security features, namely, the QR Code and the special proprietary paper blend. There is also an online database directly link to the GIA website where one can check for the authenticity of the diamond certificate being issued by GIA as genuine.

Content of a GIA Diamond Report

Date: This is the date when the report is done. The date should be as current as possible. A report dated several years back is still valid, there is no question about it. However, mishandling of the diamond over the years might result in some minor wear and tear, especially around the girdle, where it is most vulnerable. Though diamond is hard, but a diamond can still cut another diamond when they are placed together. Hence, this might lead to a down-grade on any of the 4 Cs of the diamond grade.

GIA Report Number: This is the laser inscription registry number on the diamond. The prefix GIA followed by a 10-digit number is laser inscribed on the girdle. Below the certificate there is a description of the same.

It can be viewed under a 10X loupe, though it takes some skill to read. But with a microscope of 60X, the laser inscription can be clearly seen. When you purchase a loose diamond and request it to be set, the jeweler must ensure that the laser inscription is not hidden by one of the prongs.

Normally for diamond solitaire, when it is to be set for an engagement ring, it should be prong set, either with 4-prong or 6-prong. In 1886, Tiffany pioneered a specific solitaire 6-prong setting to maximize the light return on the diamond. This plain band setting has come to be known as the Tiffany Setting.

Diamonds with laser inscription are seldom bezel set as this will cover the girdle completely.  

Shape & Cutting Style: This is the shape of the diamond. In this case, this is the Brilliant Cut.

Measurements: This is measured in the metric system in millimeters. For Round Brilliant Cut, the first two measurements are the diameter of the diamond taken at various points, and the largest and the smallest number are chosen. The closer they are the better as it denotes the exact roundedness of the diamond.

In one of the certificates as shown, the difference is 0.04mm out of the larger diameter of 6.43mm, which is 0.62% variance of the overall diameter and is quite negligible. However, one should not be too overly concerned on this unless the two measurements are very far apart, in which case the Cut Grade will tell you the cut is Fair.

The last measurement is the depth of the diamond.

Carat Weight / Color Grade / Clarity Grade: These 3 are the 4Cs specification of the diamond. Refer here for more information.

Cut Grade: This is not the shape of the diamond. This is one of the 4C of a diamond specifications. Cut is what we call ‘make’ of the diamond. It defines how well and how proportionate is the cutting to bring out the fire and brilliance of a diamond. The grades are Excellent, Very Good, Good and Fair.

Polish / Symmetry: These shows the polish and the symmetry of the cut diamond. The grades are Excellent, Very Good, Good and Fair.

Fluorescence: A diamond’s fluorescence is determined as None, Faint, Medium or Strong, which is based on its reaction to ultraviolet short-wave and long-wave.

Key to Symbols: This is the graphical representation of the inclusions found within the diamond.

Hence, when you are buying a solitaire diamond, ensure that it is accompanied by a GIA Diamond Grading Report.

Photo credit: gia.edu

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