I can’t stress enough the importance of having a grading report in any diamond jewelry purchase you make. Sometimes called a diamond certificate, a grading report contains essential details of the qualities and characteristics of a particular stone.
For the general consumer who want to know exactly what you are getting in a piece of diamond jewelry, you should only buy diamonds that have 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 your unwanted jewelry or if you are planning to buy an insurance policy to protect your investment.
The surprising behavior I found that in the majority of shoppers is that they don’t really pay attention to what is stated on the certification. In fact, most simply take a casual look at the report and never give a deeper thought about the information they are reading.
Before we even delve deeper on analyzing details, I’m going to show you the basics of how to read a grading report correctly. 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 that the majority of consumers make when choosing a diamond. Click here to uncover the secrets of that jewelers won’t tell you and learn to go beyond the 4Cs…
I am going to use a GIA report to do a breakdown of the different elements in the certification. 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.
Did you know that GIA was also the first to come up with the system of grading diamonds with the 4Cs? Due to the simplicity of relaying crucial information with their grading system, all other labs started to implement a modified version of GIA’s system within their operations.
That is to say, if you are able to read a GIA report, you won’t have difficulties with the others. The main differences in reports issued by other labs are that they might use different nomenclature or classification terms for essentially the same information.
The first detail to look for is the name of the issuing laboratory. The better known issuing labs are GIA, AGS, EGL, IGI, and the HRD. However, there are dozens of specialty services who can also issue reports.
For example, you might frequently see “cheap” diamonds with obscure grading reports from like independent appraisers or in-house gemologists. They are usually what they are; cheap and low quality diamonds that aren’t worth the fees of sending to the labs. Jewelers bank on biased in-house reports to make them sound better on paper.
You should only consider diamonds graded by GIA or AGS. The rest of the labs have lenient grading standards and are often under-grading the diamonds so that jewelers can sell them for more money. For more details, refer to our article on the differences between the different gemological labs.
The next detail is the report number, which is a unique number for the purpose of keeping records. Most labs retain this number in case you misplace your report and they also allow a direct verification of the document via their website. Also, certain reports include a laser inscription number which appears below the laser inscription registry.
Laser inscription seen under 10X on an asscher cut
Continuing downwards, you can read the details of the diamond qualities, listed in this order: shape and cut, measurements. The first feature describes the shape of the stone and the cutting style, such as emerald or pear. After that, you can see the 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 rating is based on an assessment for the lack of color in the diamond. Color grades start from D to Z and fancy colors are assigned if a diamond lies outside the Z color rating.
The clarity grade is determined by a skilled gemologist who examines the stone under 10X.
If the diamond is a standard 57 facets round brilliant, all reports dated after 2006 will include a cut grade. Cut grade is assigned based on a scale of excellent to poor a GIA report. This is an essential quality to look out for because it determines how much the diamond will sparkle and shine.
While the majority of the gemological labs don’t assign a cut grade for fancy shapes like the heart, marquise or pear, they might use a different formatting to present cut data and information.
With that said, each of these Cs is important consideration for decision making and we 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 called polish and symmetry. The ratings given here will affect the diamond’s appeal and cut grading as they play a role in determining the diamond’s brilliance and luster.
Polish specifies the smoothness of the stone’s surface and the best rating for polish shows that the cutter took exceptional care in crafting the gem. Symmetry is the comparison of how the stone’s facets are aligned in relation with one another. For more information on polish and symmetry, click here.
The next feature you can find in this section is the fluorescence description. Fluorescence is the observation of the type of color and intensity a diamond displays when exposed to ultraviolet (UV) light.
Is fluorescence a friend or a foe? This is perhaps one of the most misunderstood properties in the grading report and consumers are frequently fed with inaccurate information about fluorescence. We addressed those questions here and I strongly encourage you to check the article out if you intend to buy a diamond with fluorescence.
Under the “Other Comments” section, any other information that the stone has. For example, laser inscriptions, additional information to help identify the stone or other clarity characteristics that are too complicated to be placed on the inclusion plot are listed here. While most the comments made here are benign, some may raise a red flag for attention. This article takes an in-depth look at the notes made under “Other Comments”.
Every diamond is unique in terms of its clarity characteristics. Like our fingerprints, the clarity plot diagram is a graphical representation of the “birthmarks” found in the diamond. Be careful when reading the important symbols identifying the type of flaws.
Diamond inclusions and flaws can come in vary types and shapes. Blemishes are marked in green color while inclusions are marked in red. If you are interested to see how how some of the more commonly found clarity characteristics look like, head over to this page here that shows clarity characteristics with 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 (finish). Do note that the proportions given for fancy shapes usually omit the values for crown and pavilion angles.
On the proportions diagram, the presence of a culet is also indicated. Generally speaking, we don’t want to see culet sizes that are bigger than small as it can cause the appearance of the diamond to detract.
Girdle: This part of your diamond grading report describes the dividing line between the crown (top part of the stone) and the pavilion (bottom part of the stone). A faceted girdle can sometimes improve the value of your diamond.
Finally, you should also look out for security features on the report. These features can help prove the authenticity of the document and may include a hologram or a universal product code. Most labs provide an online verification service where you can plug in the report number to do an instant verification. We have compiled a useful list here for your convenience.