Diamond Cut 101


lab created Diamond Cut comparison

What is the Cut of a Diamond?

Similar to natural mined diamonds, the cut of a lab-grown diamond refers to how well a diamond is cut and how well-proportioned its dimensions are. A diamond’s cut is not to its shape (round, pear, etc.), but rather the balance of proportion, symmetry and polish of its dimensions.

A diamond’s cut is therefore the dimensions of diamond that determine how its facets interact with light to create sparkle and luster. 

Importance of a Lab-Grown Diamond’s Cut

A diamond’s cut determines the amount of light the diamond reflects. One of the 4C’s, cut is arguably the most important diamond characteristic and key consideration while buying a diamond because a well-cut diamond will not only appear larger than a poorly cut diamond of the same carat weight, but also have enhanced color and clarity.

Even though a diamond may be large in carat weight, high in color grade and of top clarity, if it reflects only a little light it will appear dull and lifeless. Therefore, a diamond’s cut is essential in making the diamond radiate with fire and brilliance.

A diamond’s cut directly influences a diamond’s beauty, i.e., the better a diamond is cut, the more amount of light it reflects and refracts, and the more beautifully it sparkles. Through precise and skilled craftsmanship, modern diamond cutters have established a set of specific proportions that optimize a diamond’s internal brilliance to display it in the best light.

Anatomy and Proportion of a Diamond

Diamond Cut anatomy of parts chart

The proportion of a diamond means the ratio of its different dimensions in comparison with each other. The anatomy of a diamond comprises of:

Table: The flat top surface and the largest facet of the diamond

Crown: The top portion of a diamond that ranges from the girdle to the table

Girdle: The rimmed area between the crown and pavilion that defines the circumference of a diamond

Pavilion: The bottom portion of a diamond that extends from the girdle to the culet

Culet: The point facet at the tip of the diamond; often preferred to be invisible to the naked eye

Diameter: The distance from one girdle edge of a diamond to the opposite end

Depth: The height of the diamond, measured from the culet to the table, that can be categorized as shallow, deep or ideal.


Different ratios such as a diamond’s diameter compared to its depth or a diamond’s table size determine the amount of light reflected from a diamond. A well-cut diamond is proportioned to ensure most of the light that enters the stone exits back through the top of the stone. A poorly-cut diamond, with even a slight misalignment, leads to light exiting through the bottom of the stone, known as light leakage, and makes the center look dark and overall diamond look dull.

Characteristics of A Well-Cut Diamond

Three key characteristics of a well-cut diamond that reflects light from its top are:


Brilliance: the reflection of white light on the surface

Fire: the dispersion of light into a spectrum of rainbow colors through refraction

Scintillation: the play of contrast between dark and light areas and the sparkle on the surface in all directions

Grading Diamond Cut

The Gemological Institute of America (GIA) certifies diamond cut on a 5-grade scale:  Excellent, Very Good, Good, Fair, Poor. The grade classification is based on the craftsmanship of the diamond, including its table and depth percentages, its weight relative to its diameter, its girdle thickness, the symmetry of its facets, and the quality of polish on those facets. For maximum brilliance, every facet should be symmetrically aligned, and each facet should be polished after the cutting process.

Excellent or Ideal is a rare cut where the diamond reflects almost all the light that enters it from the top. Only the top 3% of diamond cut quality receive this classification.

Very Good and Good reflect almost nearly as much light as an excellent cut but are available at a lower price. Good cut grade reflects slightly lesser light than Very Good cut grade.

Fair and Poor are lower cut grades that reflect much lesser light than other cut grades. These include diamonds that are often too shallow or too deep, allowing light to escape from the side or bottom of the stone.

Diamond Cut Versus Diamond Shape

Often confused for each other, diamond cut, and diamond shape are not the same thing.

While diamond cut determines how the diamond interacts with light to sparkle, diamond shape refers to the physical outline or form of a diamond. Diamond shapes include round, oval, cushion, princess, pear, emerald, marquise, asscher, radiant, and heart shaped diamonds.

While round brilliant diamonds are the most popular shape, it is worth considering other fancy-shaped diamonds before choosing your stone. Learn more about lab-grown diamonds here