Cut
Most commonly confused with the shape or size of the diamond, the cut is all about proportions. When referring to the cut, a well-cut diamond is proportional, therefore it reflects more light and brilliance to create the maximum amount of sparkle. The cut of a diamond is possibly the most important factor when buying diamonds as even a diamond with perfect clarity and color grade can appear dull if it has been cut poorly.
Grades are assigned using the diamond cut grades established by the Gemological Institute of America. Diamonds which are assigned ideal, excellent or very good cut grades are considered well cut.
Top Tips
To help you choose the perfect diamond Cut, we have collated a few top tips
Those opting for a larger diamond should note that cut has more of an effect on sparkle in higher carat weight than those with lower.
As Round diamonds are generally more brilliant and tend to produce more sparkle, you can choose a cut grade of good or better. For those wishing to opt for a fancy shaped diamond, it is good to note these styles are less forgiving, therefore choose a cut grade of very good or better for the best results.
How Light Passes Through The Diamond
Please view the diagram below, which illustrates how light passes through different types of cuts.

Types of diamond cut:
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Ideal or Excellent Cut
A very rare and excellent quality diamond. Diamonds with ideal or excellent cut reflect almost all the light that enters.
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Very Good Cut
The light reflected is nearly the same when compared to ideal or excellent cut diamonds, but attracts a lower price.
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Good Cut
Good cut reflects most of the light that enters. Such diamonds are available at a lower cost and thereby make it a more affordable option compared to ideal or very good cut diamonds.
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Fair Cut
A fair cut diamond typically reflects a small portion of light. This cut is still considered to be a better quality of diamond. These diamonds have been cut to maximize the carat weight over most other considerations and are therefore better value for money.
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Poor Cut
This diamond cut is generally a diamond that has been cut too deep or too shallow. When this occurs the diamond will lose significant amounts of light. A major benefit of this type of diamond is the price. A diamond that is a poor cut will be significantly lower in price than any other diamond cut grade.
Using Independent Certification
If you're looking to specify a particular type of cut, you can ask for an IGI/GIA option which will allow you to narrow it down to exactly which cut quality you require.