The amount of facets that are cut in the diamond, and their proportion to one another, will depend entirely on the shape that is planned for the stone. Different styles of polishing the diamond are preferred for different shapes. Today, there so many variations, that it would be impossible to define each and every style of cut.
From left to right, a Round-Edge Fancy, a Step Cut, a Modified Cut, and a Mixed Cut
Read more about different cuts used in the most common diamond shapes.
The objective of a fancy colored diamond is quite different than a colorless stone. The goal is to increase the color intensity and improve the color saturation. Therefore, Fancy Colored Diamonds often contain asymmetric, elongated facets. This helps to control the light that reflects through the stone. Since the color is actually the most important attribute of a fancy colored diamond, cutting it in a way that causes this affect can only help increase the value of the stone.
In order to obtain the correct objective, one needs to study the stone meticulously before sending it to the polishing wheel
Read more about the defining the intensity of a diamond.
The depth of the stone compared to its overall size is generally cut between 55% - 65% (the calculation of the depth compared to the width). A diamond that is 'fat,' meaning above 65%, often weighs more than its size appears. That means compared to other stones with a lower depth percentage it might appear a little smaller. The benefit of a 'fat' stone is the color intensity is often quite high as there is more room for the light to reflect within. A diamond that is 'flat,' meaning below 55%, often looks larger than other stones with the same carat weight. The only problem is if the stone is too 'flat,' it can create a window in the middle of the Table.
The image above displays specifically what affect diamond depth has on the appearance of the diamonds shown. From left to right: a 0.45ct stone with a 28% depth, a 1.24ct stone with a 46% depth, 0.56ct stone with a 58% depth, and a 1.14ct stone with a 70% depth.
Still, how the diamond appears, even with a window depends entirely on the presentation of the stone. There are some famous stones that have a widow in the table and still look absolutely breathtaking.
Read more about the Make of fancy color diamonds.