J53605104 – AGI | International Gemological Laboratory

What are the 4Cs of Diamonds?

The 4Cs refer to a global standard for the four primary characteristics of a diamond: Carat, Color, Clarity and Cut. These characteristics interact to produce the beauty and sparkle that make diamonds so attractive.

Carat

Carat weight is the standard unit of measure for diamonds. It originally derives from an ancient unit of measure called the carob seed. These seeds were roughly uniform in size and weight so they were used as early units of measure. The modern carat is equivalent to 200mg.

Color

Diamond color grading is focused on measuring the absence of color. The degree of colorlessness is ranked from D to Z, with D representing completely colorless and color increasing down to a rating of Z. These grades are very finely tuned and even trained gemologists have difficultly distinguishing between adjacent color grades, like F and G, under natural conditions. For standardization, color grading is done under controlled lighting and viewing conditions.

Clarity

Diamonds are formed under intense heat and pressure in a process that takes over a billion years in nature. Over the course of formation, any number of imperfections can be introduced. For gem quality diamonds these are referred to as inclusions if they are internal and blemishes if they are external.

AGI’s diamond clarity scale has 11 grades ranging from Flawless (FL) to Included (I). The classification system focuses on how difficult it is for a skilled grader to see inclusions and blemishes under 10x magnification.

Cut

A diamond’s cut grade measures how all the dimensions of the stone interact to produce a visual effect. The cut of the stone is what gives a diamond its sparkle, fire, and brilliance. A poorly cut stone will look dead – either dark or see-through like glass. Getting a well-cut diamond has a huge impact on appearance, which is why it is typically referred to as the most important of the 4Cs.

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