Start with Our Diamond Quiz
What Are Diamond Cuts?
Diamond cut, one of the 4 C's that determines diamond quality, refers to how effectively a diamond's facets interact with light. Many people confuse diamond cut with diamond shape (the external outline of a diamond, like round, oval, or pear), but cut is responsible for a diamond’s ability to transmit light and sparkle.
Precise artistry and craftsmanship are required to cut a diamond so that its proportions, symmetry, and polish deliver maximum light return and stunning shine. Simply put: the better the cut, the more a diamond will sparkle.
Why Is the Cut of a Diamond Important?
Cut is important when selecting a diamond because it directly determines a diamond's sparkle. An excellently cut diamond creates that classic, unmistakable brilliance you expect. On the other hand, a poorly cut diamond lacks light performance and appears dull.
How Are Diamonds Cut and Graded?
Diamonds are cut using specialized tools to facet and polish the stone, creating brilliance and symmetry. Because cut has such a direct impact on a diamond’s appearance, grading systems were developed to consistently evaluate cut quality.
These grading systems assess three key factors: appearance (brilliance, fire, scintillation), design (proportions), and craftsmanship (polish and symmetry). While the criteria are similar, most independent institutes use their own terminology to grade the overall cut of a diamond.
At Brilliant Earth, we also use specific scale language to help our customers understand the subtle differences in cut that affect price and quality. We base our scale on the cut specifications provided by the certifying gemological laboratory and grade diamonds from Super Ideal to Ideal, Very Good, Good, Fair, and Poor. This means that, for example, a GIA-certified diamond with an Excellent cut grade will be listed as a Super Ideal or Ideal diamond on the Brilliant Earth site.
- Gemological Institute of America (GIA) Cut Grading System: Excellent, Very Good, Good, Fair, Poor
- International Gemological Institute (IGI) Cut Grading System: Ideal, Excellent, Very Good, Good, Fair
- Brilliant Earth Cut Grading System: Super Ideal, Ideal, Very Good, Good, Fair, Poor
Anatomy of a Diamond’s Cut
To understand how cut is evaluated, it helps to first look at the physical parts of a diamond that make up its structure. Each part plays a role in how light enters, reflects, and exits the stone. When these characteristics are well balanced, the result is a diamond with exceptional brilliance and sparkle.
Table
Crown
Girdle
Pavilion
Culet
Depth
Table
The flat surface at the top of the diamond.
Diamond Cut Quality Factors
A diamond’s cut grade is determined by three quality factors: appearance (brilliance, fire, scintillation), design (proportions), and craftsmanship (polish and symmetry). Together, these qualities influence how a diamond interacts with light and are assessed by gemological institutes to assign an overall cut grade.
Appearance
Brilliance: Brilliance, sometimes referred to as brightness, is the internal and external white light that reflects from a diamond. Each time light enters a diamond, its internal facets send it off in different directions, depending on the angle and tilt of the facets. Masterfully cut diamonds demonstrate superb brilliance because they bounce light off multiple facet surfaces.
Fire: Fire is the scattering of white light into the colors of the rainbow. Diamonds are excellent at scattering light and displaying it as a spectrum of colors that glint sparks of red, orange, yellow, green, or blue. Diamonds must be precisely cut for light to disperse in this manner. Imprecise, poorer cuts do not refract or scatter light as efficiently; instead, they allow the white light to escape before it can disperse a rainbow of sparkles.
Scintillation: Scintillation refers to the sparkle a diamond emits as you move it in the light: the facets split the white light into a spectrum of colors, creating sparks of light that appear to dance along the surface of the diamond. This is contrasted sharply against the darker, colored flashes that refract through the inner facets. The symmetry and balance between lighter and darker areas create the overall sparkle.
Design
Proportions: A diamond's proportion is measured by its crown and pavilion angles and the overall measurements of its facets. As facets are like tiny mirrors, their proportion can be a crucial contributor to the overall face-up appearance of a diamond. Proportion can also help professionals understand how well a diamond will produce sparkle.
Craftsmanship
Polish: Polish is the quality of a diamond's external surface condition as a result of the polishing process. Various features, such as pits or nicks, are considered in evaluating polish. It is graded on a scale ranging from Ideal or Excellent to Poor and is generally listed on a diamond certificate.
Symmetry: Symmetry is the exactness of a diamond's external shape and the even arrangement of its facets. Therefore, it can be divided into two categories: proportion-related (external) and facet-related (internal). It is also graded on a scale ranging from Ideal or Excellent to Poor and is generally listed on a diamond certificate.
Diamond Cut Grades
At Brilliant Earth, we use a detailed grading scale to help you understand differences in cut quality when choosing your diamond.
Super Ideal Cut Grade
A Super Ideal cut diamond's proportion, polish, and symmetry have all received a top grade (known by the GIA/IGI as Triple Excellent). These are the highest-quality stones and feature incredible, eye-catching sparkle.
Ideal Cut Grade
An Ideal cut diamond's proportions must be within the ideal range, and polish and symmetry can each be one less than the highest grade. To the untrained eye, an Ideal diamond is just as beautiful as a Super Ideal diamond of the same color and clarity.
Very Good Cut Grade
A Very Good cut diamond's proportions are just outside of the ideal range, and polish and symmetry can range from the highest grades to more moderate levels. These diamonds can present an incredible sparkle at a more accessible price point.
Good Cut Grade
A Good cut diamond's proportions will be only slightly imperfect, allowing for plenty of light to reflect light. However, good-cut diamonds will not be as bright as higher-cut grades, as flawed ratios will leave more dark spaces in the stone, causing it to look duller. Depending on the balance of the other 4 C's, good-cut diamonds will generally feature a more accessible price point.
Fair Cut Grade
A Fair cut diamond has little light refraction compared to diamonds with higher cut grades. This is caused by gray areas surrounding the crown or areas of darkness or dullness within the table, girdle, or both. While Fair cut diamonds will be more accessible from a price point perspective, their lack of sparkle deters many customers from selecting them.
Poor Cut Grade
Poor cut diamonds are generally not recommended as light spills from their pavilion, culet, or both. They will show a marked reduction in fire and scintillation from those with higher cut grades, as the dark areas are prominent and distracting. Please note that Brilliant Earth does not carry Poor-cut diamonds.
Different Types of Diamond Cuts
Now that we've discussed the different characteristics of cut grading, it's time to discuss how the facets of a diamond are cut. Note: it's important to remember that diamond cut and shape are not the same thing — but diamond shape informs how a diamond is cut.
Round Brilliant Cuts
By far the most popular and common shape of all, round brilliant cut diamonds are cut with 57 (without culet) to 58 (with culet) facets to return incredible brilliance, fire, and scintillation.
Fancy Cuts
Anything that isn't a round shape requires a fancy cut.
Modified Brilliant Cuts
A modified brilliant-cut diamond is a diamond altered from its traditional round shape. Pear, marquise, cushion, oval, and heart are all examples of modified brilliant cuts.
Step Cuts
Step-cut diamonds have rectangular facets. Compared to Brilliant cuts, step cuts can have less brilliance and fire due to the shape of their faceting. Emerald, asscher, and baguette diamonds are examples of step cuts.
Rose Cuts
Unlike step cuts or brilliant cuts, the lower halves of rose cuts are relatively flat. While this means they can be low profile, they don't feature the same brilliant sparkle. Any diamond shape can be rose cut, though round is the most common rose cut.
Vintage Cuts
Before modern technology, diamond cutting was a slow process — so the less material a cutter removed from the original rough diamond, the better. Because of this, old mine-cut and euro-cut diamonds typically have larger facets that result in less sparkle than a diamond of today’s standard.
How Does Diamond Cut Impact Price?
Grades in all of the 4 C's can impact price. Cut is no different — generally, the higher the cut grade, the higher the price. Finding the right diamond is a balancing act between your budget and the 4 C's. For example, if sparkle is the most important to you, you may need to prioritize cut and sacrifice on carat, color, or clarity to stay within budget.
Diamond Cuts FAQ
What does diamond cut mean?
Diamond cut means how well a diamond's facets interact with light. Precise artistry and craftsmanship are required to cut a diamond so that its proportions, symmetry, and polish deliver maximum light return and stunning shine. The better a diamond is cut, the more sparkly it will be.
What's the difference between diamond cut and diamond shape?
Diamond cut and diamond shape are not the same thing. Diamond shape refers to the external outline of a diamond (round, oval, or marquise, for example). Diamond cut refers to the precision and artistry used to craft a diamond's internal faceting and, therefore, brilliant sparkle. While both shape and cut are critical factors to consider when picking the perfect diamond, we suggest first deciding on the shape and then finding a diamond that balances the 4 C's of cut, color, carat, and clarity with your budget.
Is cut the most important of the 4 C's?
All of the 4 C's are important. Which will be the most important depends on your preferences. If a super sparkly diamond is imperative for you, cut will be the most important.
What is the most expensive diamond cut?
The most expensive diamond cut is generally the Excellent/Super Ideal cut, as it is the highest-quality cut grade. The ultimate price of the diamond will depend on the balance of all 4 C's.
What is the cheapest diamond cut?
The most affordable diamond cut is generally the Poor cut, as it is the lowest-quality cut grade. The ultimate price of the diamond will depend on the balance of all 4 C's. We don't recommend nor offer Poor-cut diamonds. We suggest at least a Very Good cut diamond to balance sparkle and budget.
Which diamond cut sparkles the most?
An Excellent/Super Ideal cut diamond will sparkle the most. A round brilliant diamond with an excellent cut grade will generally provide the most sparkle out of all shape/cut combinations.
What is the best diamond cut?
The best diamond cut is Excellent/Super Ideal. Determining the best diamond cut for you will depend on your budget and a balance of the other 4 C's.
What is the most popular diamond cut?
The most popular diamond cut ranges between Good - Excellent/Super Ideal.
What does a diamond look like before it's cut?
Before they are cut, diamonds feature rough forms that can vary in shape. While still quite beautiful, this cut does little to maximize the effects of light moving through the stone.
What are the different cuts of diamonds?
The different types of diamond cuts are round brilliant and fancy. Round brilliant cuts are the most popular and common shape of all. Anything that isn't a round shape requires a fancy cut. So fancy cuts can include modified brilliant cuts (pear, marquise, cushion, oval, heart), step cuts (emerald, Asscher), rose cuts, and vintage cuts (old mine, European).
