Selecting a diamond ... Diamond cut

Edward Bush

Diamonds are prisms that interact with light. The brilliance of a diamond is determined by the way it is cut. The depth and width of a diamond has a tremendous effect on how light will reflect and refract within the diamond. If a diamond is too wide in relation to its depth, light will be lost causing less brilliance. If a diamond is too deep in relation to its width, the diamond may look dark or shaded. The diagrams below explain the various parts of a diamond.

At Barmakian Jewelers we welcome the opportunity to show you the difference in how diamonds are cut, and how proportions can effect the brilliance of a diamond. We take the time to educate you about the exquisite diamonds we offer.


A diamond's brilliance is affected by:

a) The depth of the diamond compared to its diameter
b) The diameter of the table compared to the diameter of the diamond


All the facets of a diamond are not equally hard, it is therefore possible to polish and shape a diamond.
The polish rating refers to the minute lines left on the diamond after the polishing process; these lines are straight in appearance. After cutting, each diamond facet is polished to improve the appearance and light return and so it is important to note all facets when considering this grade. If one of these facets has a burn mark from the polishing process then this will significantly affect the rating even though this may be unnoticeable when the diamond is set. A polish grade of good or higher will normally mean that no polish lines are visible to the unaided eye. However, below this rating polish lines may be visible, significantly reducing the overall brilliance of the diamond.


Symmetry refers to the alignment of a diamond’s facets and its overall fire and brilliance. The light bounces around inside a diamond reflecting off the facets, if the facets are not properly aligned then the light will not be returned through the top of the diamond into the eye*. The symmetry of a diamond has an important influence on the overall appearance of the diamond, for example if a round diamond has poor symmetry then the overall appearance will not be round as the different sides of the diamond will not look the same.

* The term Hearts and Arrows is used to describe the visual effect achieved in a round diamond with perfect symmetry and angles, once this type of diamond is set the hearts and arrows pattern will not be visible.

Diamond Pricing

Whilst the Color, Clarity and Carat of a diamond are a good indication of the overall appearance of the diamond you will receive, they will often not be the final determining factors in the brilliance of the diamond and therefore the price of the diamond. Being that 98% of a diamond’s brilliance is controlled by the quality of its Cut those interested in the most brilliant diamond should be aware of the diamond Cut. The industry has made this synonymous with the shape of the diamond but these are very different. When we refer to a diamond Cut we are in reality referring to the compilation of three main factors, these are the proportions, polish and symmetry of the facets of the diamond. It is important to understand these terms when comparing what may appear to be equal diamonds in terms of their Color, Clarity and Carat weight with significant price differences.

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