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Cut [Performance]

Cut Shape vs. Cut Performance: What’s the difference?

In various grading reports, you’ll often see cut referred to as Cut Grade and shape referred to as Shape and Style, or Shape and Cutting Style, for example. The shape is merely the outline that defines the facet structure of the diamond. Cut Performance includes the polish, symmetry, and proportions of a diamond as well.

3 diamonds

At Black by Brian Gavin, we understand Cut Performance (or Cut Quality) to be the most important factor of diamond grading. That’s why we group Cut Performance with the 4Cs as a “+1.”

What is Cut Performance?

From a technical standpoint, Cut Performance is determined by individual factors that contribute to overall diamond performance. In the case of the American Gem Society (AGS), for example, those factors are Polish, Symmetry, Proportions, and Light Performance.

What Does It Mean to The Wearer?

Cut Performance is the biggest factor in determining the overall wow factor of your diamond. It dictates the volume of light return, the sparkle factor, and the visual vibrance of your diamond as a whole.

Factors That Go Into Cut Performance Grading

Gemological laboratories like AGS and GIA determine the overall cut grade of a diamond based on the cumulative results of individual grades for Polish, Symmetry, and Proportions. AGS goes a step further and analyzes Light Performance as a factor in determining Cut Performance. Because of this extra analysis, every Black by Brian Gavin diamond is submitted to the AGS for grading.

  • Factor 1: Polish

    The polish grade of a diamond is based upon the perfection of polish or the finish of the surface of the diamond, which is evaluated by a trained gemologist using 10x magnification. The highest rating for polish from AGS is Ideal. The next level down is Very Good, then it drops down to Good, then Fair, then Poor.

    All diamonds in the Black by Brian Gavin Black collection are Ideal for polish.

  • Factor 2: Symmetry

    Symmetry grading is conducted by a trained gemologist who uses a 10x magnification to determine the consistency of facet shape, size, and alignment. This type of symmetry is known as meet point symmetry because one of the factors taken into consideration is how well the facet junctions meet up with each other.

    Here again, the highest rating for polish from AGS is Ideal. The next level down is Very Good, then it drops down to Good, then Fair, then Poor.

    All diamonds in the Black by Brian Gavin Black collection are Ideal for symmetry.

  • Factor 3: Proportions

    The concept behind proportions grading is easily demonstrated by thinking of the upper and lower sections of a diamond as mirrors that are designed to direct light through the diamond in a specific direction. The angle that the crown or pavilion section is cut to will have a direct effect on the direction that the light will move through the diamond. When the two primary reflective surfaces of the diamond are properly aligned, the volume of light reflected back out the top of the diamond is maximized.

    The proportions grading scale created by the AGS is based on a scale which runs from AGS Ideal-0 which is the highest grade, down to AGS-10 Poor which is the lowest. Diamonds cut to AGS Ideal-0 proportions exhibit a significantly higher volume of light return and appear brighter than diamonds which are cut to lesser proportions, such as AGS-2 Very Good, or AGS-3 Good, and so on.

    All diamonds in the Black by Brian Gavin Black collection are AGS Ideal-0 diamonds.

One Grade To Rule Them All

The overall cut grade of a diamond automatically defaults to the lowest grade of the factors considered during Cut Performance evaluation. If the individual grade for each factor is AGS Ideal, then the overall cut grade of the diamond will be AGS Ideal-0. However if the polish grade of the diamond is Very Good, and the symmetry grade is Excellent, and the proportions of the diamond are AGS Ideal-0, then the diamond will have an overall cut grade of AGS-2 Very Good if the diamond is graded by the AGS Laboratory.

Judging The Optical Symmetry of a Diamond

While the Polish, Symmetry, and Proportions grades of a diamond are critical components of light return and visual performance, the most important factor is the perfection of facet shape and alignment. This goes beyond the basic fundamentals of symmetry grading that gemological laboratories like AGS take into account.

At the present time, the gemological laboratories do not grade diamonds for optical symmetry; however it is relatively easy to grade diamonds for optical symmetry using various reflector scopes which are designed to show whether a diamond exhibits a crisp and complete pattern of Hearts & Arrows. The advantage of diamonds with pristine optical symmetry is that they tend to exhibit a higher degree of light return, and produce larger flashes of light and more sparkle than diamonds cut to a lesser degree of perfection.

The Black by Brian Gavin approach to Cut Performance

Cut Performance brings together all of the most defining characteristics of a diamond, and this is where Black by Brian Gavin shines. Every Black by Brian Gavin is selected from the upper echelon of our finest diamonds. That means individual grading of Polish, Symmetry, Proportions, and in the case of AGS grading of light performance, all have to meet those same standards of excellence, and it can be seen in the overall Cut Performance grade. It’s proof of every process being done impeccably well at each step, and it’s a defining factor in what makes every Black by Brian Gavin an incredible sight to behold.

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