Most confusion arises when discussing the term "Ideal Diamond Cut". What is cut? Is it the shape of a diamond (say, round, princess)? Is it how well proportioned the different parts of the stone are? Well, most experts agree it is actually a combination of numerous factors (including the ones aforementioned). Nevertheless, and to make things simpler, we will concentrate on three of the most widely used criteria used to measure a diamond's cut. 

Shapes

Shape refers to the inherent shape of the diamond. Among the most common shapes available on the market are the round cut, the marquise, the pear shape, the oval, the princess cut, the emerald cut, the heart shape and the radiant cut.

Proportions

It is in the hands of the master diamond cutter to bring out the scintillating fire of a diamond. Well cut diamonds reflect the maximum amount of light, through the diamond from one mirror-like surface to another, dispersed through the top of the stone. Diamonds cut too shallow or too deep lose light that spills through the side or bottom. Consequently, a poorly proportioned stone is less brilliant and spectacular and accordingly less valuable. Click here to learn more about.

Ideal proportions for a round diamond, for instance, are 59% - 61% Depth (the proportion of the total height of the diamond compared to the girdle diameter) and 53% - 57% Table (the proportion of the table size compared to the girdle diameter). By definition, this is called the "ideal cut" and round diamonds showing these proportions are very expensive and highly sought after.