Diamond Grade Scale

Learn how a Diamond Grade is Determined

Of the four C’s of diamond grading, color is one of the most important. While color systems have been complicated in the past, today, the Gemological Institute of America’s D-through-Z color scale makes it simple to understand the quality and diamond grade of the stone you’re considering and to compare it to others.

Diamonds are natural crystals of carbon, created in the heat and pressure deep under the Earth’s surface. Perfect diamonds should be clear. However, a perfect diamond is extremely rare. Usually, the processes that form diamonds sometimes trap trace amounts of other elements or cause imperfections in their crystal structure. This can give an otherwise “white” diamond a slight yellowish hue.

The GIA developed a grading scale where it compares a diamond to set of stones, called master stones, of known colors. As the letters go up from D to Z, the master stones become more and more yellow. Gemologists assign a diamond grade by comparing a stone to the masters.

The less yellow that a diamond is, the lower its color letter, and the higher its value. Diamonds rated D through F are referred to as colorless, while those rated G through J are considered “near colorless.” A K through M diamond grade corresponds to a faint yellow diamond, N-R indicates very light yellow and S through Z grades indicate that the diamond is light yellow. Colored diamonds, which have strong hues are not included in this color-based diamond grade system.

When you come into our store and look at an E diamond grade stone next to an F stone, you probably will not be able to see the difference. If you see an H or I rated stone, it might even look colorless to you. Generally, our customers perceive diamonds rated J or better as being colorless. However, to the trained eye of a jeweler, there is a significant difference between a D and a J-rated stone.

Our staff can help you choose how to use the stone’s color and the rest of the 4 C’s to find the right blend of diamond grade characteristics for you. Whether you want the beauty of a perfectly clear colorless stone or you would like to trade off a little bit of color for a larger or better cut gem, we can show you a full range of options to find the perfect stone for you. As a first step, receive a copy of our Clarkson Jewelers Magazine to learn more about the store and our fine jewelry.