Round diamonds are the only diamond shape that the GIA grades for cut. A diamond’s “cut” refers to how well the stone’s angles align, and how perfectly the stone was polished. Cut is the single most important factor when purchasing a Round. This is because how well your diamond is cut determines how sparkly and bright your stone is! The GIA assigns Rounds with the following cut grades: Excellent, Very Good, Good, Fair, and Poor. We personally only recommend purchasing Round cut diamonds with an Excellent cut rating, which is the highest cut grade the GIA assigns. We suggest this because minor mistakes in a diamond’s angles can have a major impact on its sparkle. You can find the below proportions on your GIA Diamond Certificate.

Note on “Ideal” cuts: Though some diamond search engines may be populated with the term “ideal cut,” GIA does not recognize this term. So, your GIA certificate will never define cut as “ideal.” We have populated our own “ideal cut” criteria in the table below to help you pick out the best of the best round cut diamonds.

Pro Tips for MAX SPARKLE:

Table: The “table” of your stone is the large flat facet on the top of your stone. Larger tables show more white sparkle (or “brilliance”), and smaller tables show more colored sparkle (or “fire”).

Pavilion angle v. Crown angle: The “pavilion angle” (the angle of the bottom part of your diamond) and the “crown angle” (the angle of the top) work together to return light as sparkle. The Tolkowsky ideal is a 34.5 degree crown and a 40.8 degree pavilion, but you don’t need these exactly. A good rule of thumb is for every 1.0 degrees steeper your crown, subtract 0.2 degrees from your pavilion (for example: 35.5 crown, 40.6 pavilion). Likewise, for every 1.0 degrees shallower your crown is, add 0.2 degrees to your pavilion (for example: 33.5 crown, 41.0 pavilion). Have questions? Email our gemologist here: [email protected]!

A Round diamond’s color is how white or slightly warm the gem looks. The color scale begins at D and ends at Z. Round diamonds with color grades D, E, and F are “colorless.” Grades G-Z show increasing amounts of warmth. However, many customers may actually prefer the ever so slightly warmer colors of a G-H diamond over the cool colorlessness of a D-F diamond. In fact, most of the price premium associated with Round diamonds at the higher end of the color scale is driven by supply and demand; the customers who want D-F color grades are willing to pay a premium to get them. In a world without diamond color grading, the price premium for higher grades would be much lower. This is because the actual difference in similar color grades is quite difficult to perceive.

One thing to keep in mind is that larger diamonds tend to show color more readily than smaller diamonds. So, the color chart below will help you evaluate color, depending upon size.

A diamond’s “clarity” is how crystal-clear the gem is, or how many internal marks (“inclusions”) it has. GIA provides excellent help with their clarity grades. Still, it is important to understand that each customer will have a unique standard for clarity. Some may be perfectly comfortable with an inclusion as long as they cannot easily see it. Others may insist on a more technically flawless appearance.

Most couples look for a stone that is “eye clean.” In other words, a diamond in which the inclusions are not visible to the naked eye. Eye clean clarity is the best value. However, the clarity grade you need to get an eye clean stone depends on its size. So, the clarity chart below can help you choose an eye clean clarity in your Round cut diamond.

Note! Your jeweler should always double check for eye clean appearance. We check every conflict free diamond ring we sell and inform our couples if it is not eye clean.