Diamond Pricing and the Four C’s – Part 3 (Cut)

This is part three (of four) of our Diamond Pricing and the Four C’s article. Read Part two here (Clarity).


Cut refers to how well proportioned the diamond is. The cut is arguably the most important characteristic of a diamond, since it has the greatest influence on the overall beauty of the diamond. The better a diamond is cut, the more brilliance, fire and scintillation it will have.

Brilliance is a measure of all the “white” light that is reflected by the diamond. Fire refers to the sparkles of colored light. And Scintillation describes the bursts of light you see when the diamond moves. For more info, check out our article on diamond sparkle.

The term “cut” can be confusing as it often also used to describe the diamond’s shape: round cut, emerald cut, princess cut, etc. However, the “cut” refers to the proportions of the diamond, not its shape.

diamond cutdiamond cut

The cut of a diamond determines the gem’s light performance. When a diamond is cut well, it reflects the light back out of the top of the diamond (the “table”). If the cut is too deep, then light escapes out of the side; too shallow, and light leaks out of the bottom making the diamond appear lifeless or dark.

For standard round brilliant diamonds, the GIA (Gemological Institute of America) rates diamonds on a cut scale ranging from Excellent to Poor.

Excellent The highest grade of diamond Cut. Reflects almost all the light that enters it. Maximum sparkle.
Very Good Very Good: A great amount of sparkle and fire is evident in these gems. Reflects most of the light that enters it.
Good An above average appearance. May offer a good value for the money. Reflects a majority of the light.
Fair Diamonds which allow much of the light that comes in to escape. Brilliance and sparkle are reduced.
Poor The brilliance and sparkle of the gem is greatly reduced. Most of the light entering the diamond is lost.


Note: GIA only provides cut grade for Round diamonds. Fancy cut diamonds, such as the Princess cut, do not have an official GIA grade. However, jewelers often establish their own cut grades for fancy cut diamonds, which unfortunately are not standardized. Some jewelers may have more “generous” cut gradings than others. As always, buyer beware.

Looking at the chart of Diamond Prices vs Cut Grade, the numbers are the percentage relative to the price of a Very Good Cut diamond. (Note, an Excellent Cut diamond costs about 15% more than a Very Good. A Good is about 10% less than a Very Good)

Diamond Cut Buying Tips

Most online jewelers do not offer Fair cut or Poor cut diamonds.

Try to obtain the best Cut diamond you can afford as the diamond’s sparkle and brilliance is determined by the cut. Excellent/Ideal is preferred.

Below: Nice video showing the difference between a GIA Excellent cut vs a GIA Very Good cut. (The Very Good cut isn’t as good as the excellent cut, but it holds its own pretty well.)

…Continued in Part Four of Diamond Pricing and the Four C’s (Carats).