I can’t stress enough the importance of having a grading report in any diamond jewelry purchase you make. More commonly known as a “diamond certificate”, the grading report contains essential details about the qualities and characteristics of a particular stone.
For consumers who want assurance that you are getting exactly what is described in a piece of diamond jewelry, you should only buy diamonds with reports issued by an independent gemological laboratory like GIA or AGS.
Besides the evaluation and assessment of a diamond, such reports are also important if you want to sell unwanted jewelry or if you are planning to buy an insurance policy to protect your investment.
The surprising behavior I noticed in the majority of shoppers is that they don’t pay enough attention to what is stated on the “certification”. In fact, most people simply take a casual look at the report and never give any deeper thoughts about the information inside it.
Before we delve deeper into analyzing details, I’m going to show you how to read a diamond grading report correctly first. Remember, knowledge is power. The more knowledge you have about diamonds, the better equipped you will be for making rational choices.
While the diamond certificate might reveal some details on a stone’s cut, it doesn’t tell you the whole story. Don’t commit the same mistakes the majority of consumers make when choosing a diamond. Click here to uncover the secrets that jewelers won’t tell you and learn how to go beyond the 4Cs…
I am going to use a GIA diamond grading report to do a breakdown of various elements found in the “certificate”. The reason behind using GIA as the benchmark is that they are the foremost authority in gem grading and are highly recognized in the industry.
Here’s a quick historical trivia – Did you know GIA invented the system of grading diamonds with the 4Cs? Due to the elegance and simplicity of relaying a diamond’s gemological information, the grading system was well-received by both consumers and members of the trade. In fact, the majority of other gemological organizations adopt a similar version of GIA’s grading system today.
That is to say, if you are able to read a GIA report, you won’t have much difficulties with grading reports from other organizations like AGS or HRD. The main differences between these lab grading reports lie in the different nomenclature and classification terms used.
The first detail to look for is the name of the issuing laboratory. The more well-known labs are GIA, AGS, EGL, IGI, and HRD but there are also plenty of other “specialty services” who issue reports too.
The more important question here is who uses these specialty services and why? You might have encountered the notoriously “cheap” diamond deals that come with obscure grading reports from “independent” appraisers or in-house gemologists.
The truth is, there are no deals here. These “cheap” diamonds are usually what they are; low quality diamonds that aren’t worth the fees of sending it to a proper lab for grading. Instead, unethical jewelers bank on the lax grading standards of “independent” appraisals and biased in-house reports to make low quality diamonds sound better on paper.
The bottom line is that you should only consider buying diamonds graded by GIA or AGS. The other labs have lenient standards and often over-grade diamonds for the benefit of the jeweler. For more information, you can refer to our article on the differences between gemological labs.
The next detail you would notice is the report number, which is a unique series of digits for record keeping purposes. Most labs retain this number in their database in case you misplace your report and need a replacement. More importantly, this number also allows you to have a direct verification of the document via the gemological lab’s website.
Laser inscription seen under 10X on the girdle of an Asscher cut
Continuing downwards, you can find information about the diamond’s characteristics, listed in this order: shape and cutting style and measurements. The first feature describes the shape of the stone and its cutting style, such as round brilliant or pear modified brilliant. After that, you can see information about the diamond’s physical dimensions measured to the nearest hundredth of a millimeter.
Moving on to the next section is the carat weight, which describes the weight of the stone measured to the hundredth of a carat. The color grade is based on an assessment of the lack of color in the diamond. Color grades start from D to Z and the fancy color grading system is applied if a diamond displays a color intensity beyond the Z color rating.
The clarity grade is determined by a gemologist who examines the stone under 10X magnification for inclusions and imperfections.
If the diamond is a standard 57 facets round brilliant, all reports dated after 2006 will include a cut grade. The cut grade is assigned based on a scale of excellent to poor in a GIA report. For the layman, this is one of the most essential qualities to look out for since it directly affects the brilliance and sparkle of the diamond.
With that said, each of these Cs are important factors for consideration when you are buying a diamond. I had covered each topic extensively in different sections of our website. For more details, make sure you use the header menu of the website and navigate to the corresponding categories.
The finish of the diamond is influenced by 2 factors; polish and symmetry. The ratings assigned here will affect the shape appeal and cut grading as they contribute towards the diamond’s appearance.
Polish is an indication of how smooth the diamond’s surface is. A well-polished diamond can produce crisp looking reflections and undistorted light transmissions. Symmetry is the comparison of how the stone’s facets are aligned in relation with one another. For detailed information on polish and symmetry, click here.
The next feature you can find in this section is the description of the diamond’s fluorescence properties. The fluorescence a diamond is described based on the intensity and the color it glows with when exposed to ultraviolet (UV) light.
Is fluorescence a friend or a foe? This is perhaps one of the most misunderstood diamond property and there is a lot of misinformation about fluorescence. We addressed those questions here and I strongly encourage you to read this article if you intend to buy a diamond with fluorescence.
Under the “Other Comments” section, all other miscellaneous information about the diamond will be listed here. For example, laser inscriptions (if any), additional details to help with identification and clarity characteristics that are too complicated to be plotted in the reference diagram can be found here.
While most comments made in this segment are benign, there are a couple that raise a red flag and requires closer examination. This article takes an in-depth look at all the possible notes made under the “Other Comments” segment and shows you what to look out for.
Every diamond is unique in terms of its clarity characteristics. Like our fingerprints, the clarity plot diagram is a graphical representation of the diamond’s “birthmarks”. When looking at the symbols and identifying the types of flaws, you should pay extra attention to what you see.
Blemishes (external) are marked in green color while inclusions (internal) are marked in red. If you are interested to see how the different clarity characteristics look like in real life, head over to this page here to view photographs and diagrams.
Next, you find the critical proportions of the stone indicated in a profile view. This proportions diagram is useful for people who wish to analyze the diamond based on numbers like table %, depth %, crown angles, pavilion angles and girdle thickness. Note: The proportions diagram given for fancy shapes usually omit values for crown and pavilion angles.
On the proportions diagram, the presence of a culet and the girdle thickness are also indicated. For modern brilliant cuts, the absence of a culet (None) is preferred because a large culet can actually cause the appearance of the diamond to detract from its usual appeal. For girdle thickness, a range between thin – slightly thick is preferred so that the diamond faces up bigger.
In the final part of the report, you should look out for security features as they can help prove the authenticity of the document. Typically, these security marks come in the form of a hologram, a universal product code or an embossed stamp. For a peace of mind, most labs provide an online verification service where you can perform an instant verification. For your convenience, we have compiled a list of URLs where you can do the checks here.