The cut quality is a complex parameter which can be defined as a combination of proportions, symmetry, and polish:

Cut grading = proportions grading + symmetry grading + polish grading

The diamond price strongly depends on cut quality, since diamonds with different cut quality differ greatly in appearance. However, it is not easy to determine how some particular proportions, symmetry irregularities, or polish defects affect the price. For this reason, price lists usually do not contain any tables indicating price additions or deductions corresponding to variations in cut quality. A stone may have proportions which are attractive to one person but unappealing to another. Hence, the cut quality is a speculative parameter, which enables market dealers to buy at a lower price and sell at a higher price.

arrowt.gif (841 bytes) Grading of round brilliant cuts
arrowt.gif (841 bytes) Grading of fancy cuts