Cut Grades

Diamonds can have cut grades of Ideal, Very Good, Good, Fair, and Poor. The cut, or proportions and angles, of a diamond determines how it reflects light. A diamond's reflective properties are referred to as "fire" or "brilliance." Too shallow a cut will let light escape through the sides of the diamond before it has a chance to reflect, making it appear watery or dull, while too deep a cut will allow light to be lost through the bottom of the diamond, making it appear dark, especially in the center.

The overall cut grade represents a number of cut factors, including the diamond.s proportions of table and depth percentage, and polish and symmetry. The cut grade can have a major impact on the value of the diamond, with Ideal cut round diamonds having the highest relative value for cut. However, keep in mind that the price of a diamond reflects all value factors, including color, clarity, and carat weight.

Ideal

A diamond cut to extremely exacting proportions of depth, diameter, and angles, allowing for maximum brilliance (white light returning to the eye), dispersion (the play of colors you see in a diamond.s reflections ), and scintillation (sparkling flashes that are seen when the stone, light source, or the viewer moves ). Diamonds with an Ideal cut grade are much rarer and more expensive than diamonds with a Very Good or Good cut grade.

Note: Ideal only applies to the round brilliant diamond shape. With non-round diamonds (called 'fancy shapes') there is a wider range of acceptable and attractive length-to-width ratios, depths, and silhouettes.

Very Good

A diamond cut to exacting proportions, allowing it to reflect almost as much light as an Ideal cut would. Diamonds with a Very Good cut grade are brilliant diamonds with lower prices than Ideal cut.

Good

A diamond that might be slightly deeper or shallower, or have a slightly larger or smaller table facet, compared to an Ideal cut. Cutters may choose a Good cut in order to strike a balance between cut and carat weight retention. Diamonds with a Good cut grade reflect most of the light entering them and are an excellent value.

Fair

A diamond that may have significantly larger or smaller table or depth percentages, or may have more significant symmetry or polish variances, but still reflects light well and costs less than a Good cut.

Poor

A diamond that does not reflect light efficiently because of its angles and proportions, as much of it exits the stone through the bottom or sides versus the top. Diamonds with this cut grade should be much less expensive than a Fair cut grade. Amazon.com does not sell diamonds with a cut grade of Poor.