September 23, 2020

We often think of a diamond's cut as a shape but what a diamond-cut does mean how well a diamond's facets interact with light. A diamond’s cut refers to how well-proportioned the dimensions of a diamond are, and how these surfaces, facets, are positioned to create sparkle and brilliance. Precise artistry and workmanship are required to fashion a stone so its proportions, symmetry, and polish deliver the magnificent return of light only possible in a diamond.


The Five different cut Grades

Excellent: This diamond is scored 3% of the top category for all-grade-setting determinants. It reflects most of the light that enters the diamond.

Very Good: This diamond is scored 15% of the top category for all-grade-setting determinants. It has a “splintery” pattern, most likely caused by a higher crown height with a somewhat steeper crown angle, accompanied by a. long lower-girdle facets.

Good: This cut represents roughly the top 25% of a diamond cut quality. This diamond’s grade is limited by its scintillation. In this case, the somewhat shallow pavilion angle produces dark pavilion mains.

Fair:  This diamond's grade is limited by its scintillation. The combination of a shallow crown angle and a somewhat shallow pavilion angle leads to a face-up appearance with a lack of contrast and general darkness.

Poor: This diamond's grade is also limited by its weight ratio. The somewhat steep crown angle, slightly steep pavilion angle and very thick girdle greatly increase the total depth. Therefore, this diamond's diameter is much smaller than its carat weight would indicate.

Grading Scale

How do you know what is a well-Cut Diamond?

Brilliance relates to the reflection of white light

Fire is the dispersion of light into the colors of the rainbow

Scintillation is the play of contrast between dark and light areas – it’s the sparkle

The Anatomy Of A Diamond:

Table: The largest facet of a gemstone

Crown: The top portion of a diamond extending from the girdle to the table

Girdle: The intersection of the crown and pavilion which defines the circumference of a diamond

Diameter: The measurement from one girdle edge of a diamond straight across to the opposing side

Pavilion: The bottom portion of a diamond, extending from the girdle to the culet

Cutlet: The facet at the tip of a gemstone. The preferred culet is not visible with the unaided eye (graded “none” or “small’)

Depth: The height of gemstone from the culet to the table


Diamond-Cut And Diamond Shape Are Not The Same Thing

Although these terms are sometimes used interchangeably, diamond cut and diamond shape mean different things.

A diamond-cut assesses the light performance of a diamond and is based on a combination of factors: proportions, symmetry, and polish (the overall surface condition of a diamond's facets).

The diamond shape is related to the outline of a diamond.

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