Understanding Diamond Lab Reports

Educating yourself on purchasing a diamond might seem like a daunting task at first.  At first glance it may seem like so much to learn before making such an important purchase. We are very thorough in showing our customers the importance of diamond subjectivity and what to look for when selecting the perfect diamond for your engagement ring.

Diamond grading consists of the 4 C’s; Cut, Color, Clarity and Carat weight.  Each of these grades will affect the overall value of a diamond. Shane Co. employs trained graders, certified from GIA (Gemological Institute of America), to complete an internal grade on each diamond that we have for sale. The majority of our diamonds will also come with a 3rd party diamond lab report listing their grade assessment.

Diamond ‘Certs’

Diamond lab reports are often referred to as ‘certificates’.  In the diamond industry, you may hear them referred to as ‘certs’.  When a Shane Co. diamond has a GIA certificate it almost always mimics our diamond graders analysis. Certain grading laboratories are more lenient in their grading. For example; a diamond that we have listed as an I1 in clarity and G in color, may have been graded by the EGLI as an SI1 in clarity and an F in color. When spending time looking at diamonds in our showroom we show you these differences so that you can become more educated in choosing your diamond.

There is no science to ‘converting’ a 3rd party lab report to what the GIA would say about a diamond.  We have had some diamonds in our stores that we have graded as a ‘G’ in color that have additionally been graded by a 3rd party lab as a ‘D’ in color. To show how subjective diamond grading can be, we’ve sent the same diamond to the same lab on two separate occasions (within a one month time span) and received different results on color and clarity!

What to Look For

If you are going to inspect a diamond lab report to aide in your diamond selection, there are a few important things to look for.  Let’s use a GIA lab report as our focus:

Color, Clarity and Carat weight are going to be the first things that you focus on.  These are very clearly stated on a diamond cert. For more information on these criteria visit www.gia.edu.

Measurements are going to show you the specific width, depth, and facet lengths, attributing to the overall symmetry and cut quality of the diamond.  With a round diamond you are going to want a very small amount of variance between the length/width.  This is going to let you know that the diamond appears very round when looking straight at it.  With any other diamond shape this will allow you to calculate the Length:Width ratio.  ‘Fancy-shaped’ diamonds are likely to have some variance between their length and width (e.g. Not all cushion-cuts are perfectly square and some are quite rectangular). This is something that you are going to want to pay attention to for overall appearance. What looks most beautiful to you?

Cut Grade, Polish and symmetry are each individual aspects that are going to affect the diamond’s overall brilliance, sparkle and fire. Diamonds start as a piece of rough and are then carefully cut by gifted diamond cutters whose focus is on maximizing carat weight as well as these categories.  Some diamonds are going to allow for higher grades in these categories once they have been cut.  Keep in mind a diamond with a high clarity and color isn’t going to be worth much if it has been cut poorly.

A “Full” certificate will often show you a “plot” (diagram) of the diamond as well as additional comments. A “Dossier” will list the clarity characteristics without a plot.  To check the diamond against the certificate, a Dossier will have the certificate number inscribed on the diamond girdle, whereas the Full certificate will have a plot (diagram) of the inclusion to match the diamond. It is common that a Full certificate will include the certificate number inscribed on the diamond as well.

Diamond clarity is assessed using 10x magnification. When creating a report, GIA will typically show you the grade setting inclusions in the diamond. Most of the plots will show you what type of inclusions the diamond has as well as their locations. It is common that the plot will fail to list every inclusion inside of the diamond, as the certificate plot is there to show you the grade setting inclusions. Taking a look at the additional comments section on a report will inform you of other clarity characteristics not plotted that were visible under 10X magnification. For instance: ‘feathers, clouds, pinpoints and/or twinning wisps are not shown.’

Buying a diamond based on what a lab report says is something that should be done with caution.  Looking at a variety of diamonds in person is going to help educate you and ultimately help you to choose a diamond based on what should be important; Does it sparkle? Is it the right size? Is it in your price range? If you want to see these differences in person visit us at Shane Co. We will always have a selection of diamonds in your price range to choose from. If you happen to find a diamond that you really like and would like to have a diamond lab report completed, it can be sent to the lab of your choice to be assessed.

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