Diamond Cut vs. Color: Which is More Important?

The symmetry of a diamond refers to its facets' alignment and proper positioning. A good artisan will expertly place each facet in appropriate proportions that complement the surrounding ones. The facets should be positioned with expert precision because misaligned facet junctions make a diamond appear uneven. Furthermore, the symmetric proportions of a well-cut diamond deter excessive carat weight from hiding in the profile, making a stone seem right for its weight.

The alignment of the facets also determines a stone's interaction with light. Some light that strikes a stone immediately reflects as surface glare. While a portion of the light that enters the diamond escapes through the bottom, having no visual effect on an observer. A too shallow or too deep cut allows light to leak out through the crown or the diamond's internal walls, making many facets appear dark or dull, and the overall appearance is less brilliant and sparkly. Properly positioned facets maximize the amount of light that bounces back (reflects) from the tabletop or bends (refracts) and off the internal walls into an observer's eye.

The observable effects of the internal and external interactions with white light constitute a stone's brilliance. Scintillation will result from an equal balance of dark and light areas, forming a crisp, clear pattern with no distracting dark outlines as the light exits a stone. Fire results from the light being dispersed into a rainbow of spectral colors. If the light source, diamond, or the observer moves, spots of light that flash (sparkle) will be noticeable.

Like symmetry, diamond polish is a vital component of the cut quality. Polish refers to the precise condition of diamond facets. Very few diamonds have no imperfections due to polish because, unlike inclusions that occur naturally, polish marks result from craftsmanship errors. To minimize flaws, every facet of the diamond should be carefully polished at the end of the cutting process. A stone is well-polished if it has exceptional smoothness and excellent regularity, such that it is free of nicks, burn marks, polishing/wheel marks, abrasions, and lizard skin. However, diamond surfaces are anisotropic, meaning that there are softer and harder zones. As a result, 14 areas (dead spots) in equally spaced three-dimensional zones would cause the facets to be non-polishable. Usually, the dead spots are found on the octahedral and cube faces. To ensure that the brilliance and fire of a stone are not affected, cutters try to ensure that none of the facets coincide with these dead spots. The craftsman can go as far as moving facets, which compromises the symmetry, to ensure that all cut facets can be polished.

The proportions of a diamond directly affect its interaction with light, which ultimately determines a stone's overall appearance. Hence, the depth, table, and width must be in the correct proportion.

Depth

The depth of a diamond is the distance in millimeters from the tabletop to the culet, which is the entire stone's height. The result is the depth percentage by dividing the depth by the diamond's diameter. Generally, the higher the depth percentage, the lower the optical illusions of a more prominent face-up appearance in diamonds of the same carat weight.

When light strikes a diamond, depth plays an intricate role in determining how the interaction with light plays out through reflection or refraction, which affects brilliance and sparkle. Therefore, a stone whose pavilion facets are in correct proportions allows light to be refracted within the diamond and reflected at angles in line with an observer's eye—increasing the beauty of the diamond by making it appear more sparkly and masking imperfections. Conversely, incorrect depth percentages lead to unattractive fish-eye effects and undesired dark nail heads. The ideal depth percentage varies with shape, similar to other diamond proportions.

Table

The table is the largest flat surface at the top of a stone, while the table percentage is the ratio of the table's width to that of the stone. A diamond's overall brilliance and sparkle are directly affected by whether the table percentage is in the correct proportion to its depth. For a stone with a meager table percentage, when light strikes the table, it is trapped inside and emitted through the parts that are unlikely to reach the eye, such as the culet. A larger table percentage also negatively impacts interactions with light, as reflection will not occur on facets and crown angles. Instead, the light will escape from the crown, and the stone's brilliance and fire will be significantly reduced.

Width

A diamond's girdle is the measurement from one end of the diameter's widest point (girdle) to the other end of the girdle. The width is important because it is factored in the calculation of table percentage and depth percentage, which impacts the appearance of a stone.

Bear in mind that no magic combination of percentages gives the perfect diamond. Instead, the calculations are used as a guideline for filtering undesirable choices.

The cut grade of a diamond considers the combined effect of the alignment and positioning of facets, table, and depth proportions, as well as the degree of polish and symmetry. The intricacies of proportion may not be apparent to the eye, but the overall beauty and sparkle are telltale signs. Besides appearance, the cut grade also reflects whether the cut is shallow, deep, or just right. Almost all light will bounce back to the observer's eye in a perfect cut, giving the diamond a stunning brilliance and lively fire.

Diamond color is essential but not as significant as cut quality. In the diamond industry, there is a marked preference for colorless diamonds. Only some people know that an excellent cut will mask the yellowish tint in a near-colorless diamond, while the most colorless diamond cannot hide the dullness of a poor cut grade. Moreover, the differences in color grades are so minor that the discrepancy is nonexistent to the untrained eye. But because colorless diamonds are so rare, the color grade significantly impacts the price tag, with diamonds at the top of the color scale sold at astronomical prices.

To assign color grades, grading labs follow strict guidelines that dictate the kind of neutral background and type of lighting used and how a diamond is held and viewed throughout the assessment. The diamond is placed down, and its color is compared to a set of color-comparison stones known as master stones, whose color grade on the D-Z scale is known. Viewing the diamond from the culet reduces the multifaceted appearance of a faceted colorless to near-colorless diamond when viewed from the tabletop.

Color is also subject to personal preference, while cut grade always stays in style because it has the most significant impact on the overall beauty of a diamond. Who would not want that stop-in-your-tracks stunning brilliance and lively fire of a well-cut diamond?