Polish refers to the overall smoothness and condition of the diamond’s surface. This is typically a result of the polishing process undertaken by the cutter.
When a diamond is cut and polished, microscopic surface defects may be created by the polishing wheel as it drags tiny dislodged crystals across the diamond's surface. Depending on the severity, these defects may disrupt light patterns as the light rays enter and exit the diamond.
Thus, a diamond’s polish features are located on the surface of a diamond. Flaws inside the diamond on the other hand are graded within the “clarity” category of the 4Cs as inclusions.
A diamond with an “Excellent/Ideal” Polish grade has a very smooth surface that lets the light in and out in the most efficient manner.
However, we would not recomend spending extra money on achieving an excellent or very good polish grade on a diamond. This money is better spent on a higher cut or symmetry grade.
The GIA polish grade categories are; Excellent, very good, good, fair, poor, very poor.