CUT 2017-11-15T16:37:41+00:00

CUT

The cut of a diamond is not the same as the shape, as many might believe. However, the cut of a diamond is most representative of the beauty and value of a particular diamond. When analyzing the quality of a diamond, the cut of the stone is the most technically difficult to pin down. But, it’s never hard to see the differences in light performance from one diamond to another.

In order to determine the cut of a diamond, jewelers use the GIA Diamond Cut Scale to measure:

Brightness – The internal and external white light reflected from a diamond.

Fire – The dispersion of light into all the colors of the rainbow.

Scintillation – The amount of sparkle a diamond produces, and the pattern of light and dark areas and flashes of light when a diamond is moved.

The cut grade also considers the design and craftsmanship of a diamond before providing a final cut grade, including its weight relative to its diameter, its girdle thickness (affecting durability), the symmetry of its facet arrangement, and the quality of polish on those facets.

The GIA Diamond Cut Scale for standard round brilliant diamonds contains 5 grades ranging from Excellent to Poor. As Boston’s premier fine jewelry store, our diamonds are hand selected for maximum brilliance and quality. We pride ourselves on the fact that each of our diamonds is spectacular, competitively priced and all naturally occurring.

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Excellent

  • The diamond, which has an even pattern of bright and dark areas, scores in the top category for all grade-setting determinants.

  • Although its proportions are different from the diamond in the first example, this diamond also has an even pattern of bright and dark areas and scores in the top category for all grade-setting determinants.

  • This diamond also scores in the top category for all grade-setting determinants.

Very Good

  • This diamond’s grade is determined by brightness, scintillation, and polish. Although no individual proportions would necessarily cause its brightness or scintillation to perform poorly, the combination of this particular set of proportions leads to increased darkness in the pavilion mains.

  • This diamond’s grade is determined by its fire, scintillation, and weight ratio. 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.

  • This diamond’s grade is determined by its brightness, scintillation, and finish. There is a slight darkening within the table and along the upper-girdle facets.

Good

  • This diamond’s grade is limited by its scintillation. In this case, the somewhat shallow pavilion angle produces dark pavilion mains.

  • This diamond’s grade is determined by its fire, scintillation, and weight ratio. A somewhat steep crown angle, combined with a slightly steep pavilion and this total depth, leads to a diamond that displays a slightly dark ring within the table edge, as well as somewhat dark upper-girdle facets.

  • This diamond’s grade is limited by its scintillation. The shallow crown angle and low crown height lead to a face-up appearance with a lack of contrast in its pattern and localized darkness (especially in the table area).

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.

  • This diamond’s grade is determined by its fire, scintillation, and weight ratio. A slightly steep crown angle, combined with a steep pavilion angle and large total depth, causes this diamond to display general darkness in the table area and a very dark upper-girdle area.

  • This diamond’s grade is limited by its brightness and scintillation. The large table and a somewhat shallow crown height, with this pavilion angle, cause a general darkness in this diamond, along with a slight fisheye that becomes more evident when the diamond is tilted.

Poor

  • This diamond’s grade is limited by its weight ratio. Although most of the proportions for this diamond are fairly standard, the extremely thick girdle greatly increases the total depth. Therefore, this diamond’s diameter is much smaller than its carat weight would indicate.

  • This diamond’s grade is limited by its fire and scintillation. This slightly steep crown angle, very steep pavilion angle, and large total depth all cause this diamond to have a very dark table area, along with a very dark upper-girdle areas.

  • 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.

Courtesy of GIA
Excellent
Very Good
Good
Fair
Poor