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The 4C's Cut

A diamonds cut refers to its proportions and finish, influencing the value of a diamond. The way it is cut is the only factor that we have a say in, as it is not determined by nature. A skilled professional will work on a diamond stone to give it its cut, transforming it from its natural form, and cutting it into a finished shape that is more familiar.

The cut should not be confused with shape, which refers to the shape of the finished diamond, such as princess or baguette. For more information on shapes, please visit our [Link to Diamond Shape Guide].

The cut of the diamond can affect the way the light catches the stone, effecting the way it sparkles. The way a diamond is cut affects three important diamond-attributes:

  • Brilliance – the total light reflected from a diamond
  • Fire – the dispersion of light into the colours of the spectrum
  • Scintillation – the flashes of light, or sparkle, when a diamond is moved.

A perfectly cut diamond will allow rays of light from all sides to bend towards the centre of the stone, and be reflected back through the top of the stone in a burst of rainbow coloured light. Diamonds with a poorer cut will allow light to 'leak' or 'escape' through the base or sides of the stone.

A diamond that is cut too deep will allow most of the light to be lost through the sides of the stone as light is reflected to opposite facets at the wrong angle. This can give the diamond the appearance of having a black middle. If the diamond is cut too shallow, then the light may be lost through the bottom of the stone, and so produce a dulled reflection.

The quality and grade given to the cut of the diamond can be measured by the following attributes:

  • Proportion – This refers to the relationship between the table size, crown angel and pavilion depth. This affects how the stone interacts with light (making it sparkle), and there are many proportion combinations available.
  • Symmetry – This refers to the precision of the shape and the placement of the facets, and again affects the stone's relationship with light.
  • Polish – This refers to the overall condition of a gem's facet surface, and is the finishing touch put on a newly cut and crafted diamond.