The importance of Cut

The way a gem or a diamond is cut can have consequences on its clarity, colour and therefore on its value.

The cut is the man’s contibution to the beauty of a diamond.


The proportions of cut of each facet of a stone partly influence the brilliance: if the proportions are respected, the refraction will be perfect.


Normally, the proportions of a diamond contribute to the correct reflection of the light through the gem influencing its brilliance (or refraction) and its fire (or dispersion). The ray of light entering the table of a diamond or gem with poor proportions, follows an improvised and casual path exiting on the side of the pavilion. In this way we have a dark and brightless diamond, because it has been cut without taking care of the depth percentage. The proportions are expressed in percentage and degrees. Starting from 100%, that is the diameter of the diamond, we determine:

  • Crown height
  • The diameter of the table
  • The pavilion depth
  • Girdle thickness;

The ideal proportions give the best brilliance and shine to the stone. The way the stone is cut gives brilliance to diamond. The facets have to be perfectly proportioned, a brilliant cut diamond must have 57 facets or 58 if the culet is cut too.

The Round Brilliant Cut, the classic brilliant cone-shaped cut, has 58 facets (including the size-culet) and it is the most precious cut, used especially in colorless diamonds.

The Cut Scale

  • Excellent;
  • Very Good;
  • Good;
  • Fair;
  • Poor.


The finishing is the most important element which gives the diamond its final look and it is also the result of what reaches our sight thanks to two basic elements: polishing and symmetry.

  • Polishing = word indicating the conditions of the whole surface of the diamonds. Thanks to its natural hardness (the highest in the world), the diamond gets the best in this field compared to the other gems. The valuation of the polishing must consider possible abrasions, irregularities, rough girdle, scratches and polishing lines on the surface.
  • Symmetry = symmetry is the precisness and balance of the diamonds cut. In this case the valuation has to consider elements like not perfectly pointed facets, a not perfectly octagonal table, twisted facets, a not centered culet or table and a not centered table and girdle. If there was only one of these elements, the aspect of the diamond would be completely unbalanced.


The word carat comes from the carob seeds used to weigh stones in the past. The diamond weight determines its size and its diameter.



The colour is a very important characteristic for a diamond and it is also the main element that influences our appreciation of a gem, especially when mounted on a jewel.



Clarity is the main element to dermine the value of a diamond for investement or of a precious stone.



Fluorescence is the visible light which is released from some diamonds when exposed to the ultraviolet light, invisible to the naked eye.

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