Understanding contrast in diamond performance

Your perception of a diamond is different than its actual shape. As light hits a facet, it splits into dark and light components. Diamonds can be evaluated based on their light performance, and certain diamond cut shapes produce better results than others. For this reason, contrast is important in diamond cutting.

Performance cuts

Round brilliant cut diamonds are prized for the way they optimize the light entering their structure. These shapes, more than other cuts, split and reflect light to create illusions that enhance their perceived brightness. These diamonds are among the most popular because they create a dramatic shimmer while balancing cut, color, clarity and size. For years, cutters have studied the round cut diamond to create the highest performing shape they could design. Hearts and arrows diamonds use symmetry to create contrast between light and dark, and enhance the perceived brilliance of the gem.

Contrast

One of the most important concepts to understand when grasping light performance is contrast. This refers to the difference between light and dark patches of color or light. For example, pure white sharply contrasts black. Gray and black have a much smoother contrast, as they are closer in shade. The difference between the two shades enhances the appearance of both. Black looks blacker next to white, and vice versa. Ergo, for the bright sparkles in a diamond to appear brighter, they should be paired with spots of darkness.

When it comes to round cut diamonds, the dark areas need to be strategically placed to have the strongest effect. The more evenly distributed the dark spots are, the brighter the white areas will appear. To achieve this, a diamond cutter must be sure his work is symmetrical. This means each facet is cut identically. Symmetrical brilliant cut diamonds will create a visible light defined by areas of lightness and darkness. For example, if you look at the top, or table, of one of Brian Gavin's hearts and arrows diamonds, you will see both of those shapes reflected back at you. Imperfect cuts will not have a consistent pattern.

Grading

Diamond grading of performance-based cuts looks at light performance as well as proportions and finish. The performance side focuses on brightness, contrast, dispersion and leakage. The American Gem Society uses 3D software to assess these features, though the system is based on visible light performance. This means that grading criteria is based on what consumers will see when observing the diamond.