A Diamond's Cut

Sometimes Cut is confused with the Shape of a diamond. The term “cut” refers to the way that light is reflected throughout an individual diamond.

Learn About a Diamond's Cut Here

The quality of the cut of the diamond is the most important factor in determining how well a diamond will sparkle and how well it reflects and refracts light.

  1. If the cut is too shallow, light escapes through the pavilion before it can be refracted.
  2. If the cut of the diamond is too deep, some light escapes through the opposite side of the pavilion.
  3. When a diamond is cut to good proportions, light is refracted from one facet to another and then dispersed through the top of the stone.

The balance of craftsmanship unlocks a diamond's brilliance. If the cut is too shallow, light escapes through the Pavilion before it can be refracted and if the cut of the diamond is too deep, some light escapes through the opposite side of the Pavilion.

When a diamond is cut to excellent proportions, light is refracted from one Facet to another and then dispersed through the top of the stone.

Depth and Table Percentages

The two prime factors in assessing quality of cut are Depth and Table.

Depth and Table percentages are what affect the proportions of the diamond. The graphic below will assist in determining the ideal percentages for each Shape. Without knowing these percentages, the other "C’s" of diamond education don't matter. If you only remember one thing, it should be percentages.

Cut Preferred Too Long Too Short
Emerald 1.50-1.75:1 >2.00:1 1.10-1.25:1
Heart 1.00:1 >1.25:1 <1.00:1
Triangle 1.00:1 >1.25:1 <1.00:1
Marquise 1.75-2.25:1 >2.50:1 <1.50:1
Oval 1.33-1.66:1 >1.75:1 1.10-1.25:1
Pear 1.50-1.75:1 >2.00:1 <1.50:1
Princess 1:1 >1.50:1 <0.75:1

ADX TIP: If you want your diamond to really sparkle, double check and remember the Depth and Table percentages for each Shape.

Polish
Polish refers to the overall finish of the diamond and is graded from excellent to poor. Diamond polish is examined under 10X-power magnification and it identifies surface blemishes that do not affect clarity grade such as polish lines, burn marks, rough girdle, scratches, pits, abrasions and lizard skin.

ADX TIP: Polish is the only grading category that can be improved without reducing carat weight.

Symmetry
The symmetry of a diamond is based on how well the Facets of your diamond match up and it is graded from excellent to poor. A symmetrical diamond has an even display of brilliance, fire and scintillation. The majority of diamonds have symmetry issues so bear in mind that the Depth and Table percentages are more important.

Ratio
Ratio is important when looking at fancy diamond Shapes. The ratio comes down to personal preference as it affects the look and dimensions of the Shape. Below is an illustrative example of different ratios for the different Shapes.

ADX TIP: When shopping for Shapes, have your ideal ratio in mind which will enable you to compare intelligently.

Learn about Certification

Education

Alberta Diamond Exchange
© 2017 Alberta Diamond Exchange