The 4th C: GIA’s Cut Grading

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Often when people discuss diamonds they talk about the 4 C’s, which are Carat, Color, Clarity and Cut. However, the 4th C is not often a priority for many buyers in the market. Sadly, without an adequate cut, a diamond of the best carat, color, and clarity can still look dull.

The GIA Cut Scale ranges from Excellent to Poor. The cut of a diamond gives that allure that people love. It is what draws people to the diamond. The cut of every diamond has three characteristics: brilliance, fire, and scintillation. The total amount of white light a diamond reflects is the brilliance. The colors of the spectrum the light disperses is called fire. Finally, the flashes of light, or sparkle you see when a diamond is moved is called scintillation.

To first understand how diamonds are cut, it is important to know how they are categorized. A round brilliant diamond traditionally has 58 facets and is used most commonly in all types of jewelry. All other shapes are considered fancy shapes.

When determining the value of a diamond’s cut, three factors are taken into account. These include a diamond’s proportions, symmetry, and polish. When looking at a round brilliant cut diamond from the side, it is divided into three sections: the crown, girdle, and pavilion. Sometimes a fourth section is included which is a tiny flat facet on the bottom called a culet. The flat facet on the top of the diamond is called the table. A diamonds proportions are based on the relationship between the table size, crown angle, and pavilion depth, all of which affect how light interacts with the diamond. If a diamond is cut too deep or shallow, light escapes through the side or bottom and does not reflect back through the crown. For more information on the GIA’s 4 C’s, visit
Overall, there are two types of diamond cuts: brilliant and step. On its side, a brilliant cut diamond extends from the center in a triangular shape. Round and princess cut diamonds are excellent examples of this. A step cut looks somewhat like a staircase when viewed through the crown.
Between each category of grading, there is a slight difference; however between an excellent and a poor cut diamond, there is a significant difference. When comparing diamond cuts, it is also to important to note the difference in price. If a diamond has an excellent cut, excellent polish, and excellent symmetry (also known as a Triple X in the jewelry industry), it will cost more than a diamond with excellent cut, very good polish, and very good symmetry and much more than a good cut, polish, and symmetry. Here at Inta Gems, we typically recommend purchasing a very good cut or above.

Many customers ask, “What is more important?” Out of the three factors that determine cut, we consider cut to be the most important. If you have a diamond that has an excellent cut with good polish and symmetry, that is a nice diamond. If you are on a tight budget and need to sacrifice color and clarity, we recommend that you attempt for a higher cut quality. Although the diamond may have a lower color and clarity, it will still have excellent brilliance, fire, and scintillation. In other words, it will still have a lot of sparkle, which is usually most important to many women, aside from carat size. For more information on our diamond inventory, visit