The Gemological Institute of America (GIA) created the first, and now globally accepted standard for describing diamonds: Color, Clarity, Cut, and Carat Weight.
Today, the Four Cs of Diamond Quality is the universal method for assessing the quality of any diamond, anywhere in the world.
The creation of the Four Cs meant two very important things: diamond quality could be communicated in a universal language, and diamond customers could now know exactly what they were about to purchase.
In this article we take a comprehensive look at Color Grading. If you prefer a more condensed version please check out our: “The Four Cs: An Overview” article.
Even the slightest change in diamond color can affect the quality and value of a diamond. Although most diamonds are thought of as colorless (that is, not fancy-colored), most colorless diamonds actually contain hints of brown and yellow.
These differences in color are often very subtle – so subtle that an untrained eye can’t tell the difference between a nearly colorless diamond and a colorless one. Yet these minute color variations can have a significant impact on the purchase price of the stone.
All non-fancy diamonds sent to a laboratory for grading are graded according to GIA’s internationally recognized D-to-Z color-grading scale, with D representing the top end of the scale, as a completely colorless diamond, and Z the bottom end of the scale, representing the obvious presence of a light yellow or brown hue.
Each letter in the scale denotes a combination of tone (lightness or darkness) and saturation (intensity), creating a value called “depth of color.”
When GIA color graders grade a D-to-Z diamond’s color*, the diamond is viewed table down, under highly controlled lighting conditions. It is compared to a set of carefully assembled master comparison diamonds known as ‘Master Stones”
Although each letter in the GIA D-to-Z color scale designates a specific color range, letters are also grouped into broader categories:
D through F: Colorless. These diamonds are the most chemically pure of the D to Z range.
G through J: Near colorless. Coloration often unseen except by trained graders. Very valuable.
K through M: Faint. Coloration still difficult to see by the untrained eye.
N through R: Very light. Coloration can be seen in larger stones by untrained eye.
S through Z: Light. Colorations can be seen in many sized stones. Distinctly yellow or brown but not so colored to be considered a “fancy” diamond.
Overall, the important thing to remember is that the lower the letter, the higher the grade, and the more valuable your diamond.
When people really start looking into diamond grading, a common question is, “Why does the GIA color grade start with a D?”
Historically, metaphoric terms were used in the very old days. “River” and “water” were used for the most colorless diamonds, or they might be categorized by a geographic location from places where similarly colored diamonds were seen. For instance, there was “Cape” for pale yellow diamonds from the Cape of Good Hope.
The choice was made to differentiate the GIA grading system from other less clearly defined ones that used designations such as “A” or “AA”.
Additionally, American Gem Society (AGS) had its own numerical scale, which was only for AGS member use. So when GIA chose to develop a diamond grading system, it had to use new terms. Hence, the “D.”
All else being equal, diamond price increases with a higher color-grade, because these diamonds are more rare. But remember that two diamonds of an equal color can have very different values (and prices) depending on three other factors within the 4Cs: clarity, carat-weight, and cut.
We hope you found this article helpful in getting an overall sense of how Color affects the quality and subsequently the cost of a diamond. However, should you have any additional questions about this or any other jewellery related topics, you can always: “Ask Our Jeweller”
If you’re hungry for even more information on diamond color grading be sure to check out our video-post! (it was produced by The Gemological Institute of America)
You may also enjoy this “interactive application on The Four Cs.“
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