Diamond Cut Grades

What to Know Before You Buy

Diamond Cut Grades


How to Choose the Right Cut

One of the secrets to picking out a diamond that sparkles is finding the right cut. If you’re shopping for a diamond, you’ve probably already heard of the 4Cs and maybe even that cut is often considered the most important one. Diamond cut is the magical effect of how much light is ushered through the diamond and reflected back through the top. It happens to be the most technically complex to analyze and grade, but it’s important to learn about it so you can choose your perfect diamond. 

While shopping for a diamond can be overwhelming, this guide explains everything you need to know about diamond cuts.

What Does Diamond Cut Mean?

The diamonds on the engagement rings you try on in-store don’t have the same elegance when they’re first pulled from the earth. Instead, the rough diamonds appear as dull, somewhat opaque, and even tinted crystals. A diamond’s beauty is revealed only after it’s cut and polished, taking on complex geometrical shapes comprised of many faces — or facets — that maximize the brilliance, scintillation, and fire.

Diamond cut refers to the number, size, and orientation of these facets, determining how light sweeps through the gemstone and how large it appears. A tricky balancing act exists, as diamond cutters must achieve an ideal cut without removing too much material, i.e. carat weight. One more thing — not every diamond is cut to the same degree of quality. 

Similar to how your reflection bounces around the room in a house of mirrors, a diamond’s facets control how the light moves through it. The way those facets are laid out and how accurately they are proportioned can drastically affect the quality of light behavior and ultimately the diamond’s sparkle and shine (the thing we care most about). 

If a diamond is cut too shallow or too deep, the light will spill out of the sides and bottom of the gemstone, causing it to lose some of its potential scintillation and fire. When a diamond has an ideal cut, it will reflect the maximum amount of light, creating that signature sparkle and capturing your attention like a bright sunrise.


A raw diamond being cut on a cutting wheel

Are Diamond Cut and Shape the Same Thing?

It’s easy to confuse terms like princess cut and radiant cut with diamond cut, but they have different meanings. They’re often used interchangeably, but a diamond’s shape is not the same as its cut. Shape is one of the most special aspects of picking out a diamond and refers to the overall form that a diamond is cut into — such as round, princess, cushion, oval, emerald, and more — while cut refers to the accuracy and subsequent beauty of its facets. However, a shape’s size and orientation still play a role in a diamond’s facets and how much brilliance and fire you will see.

Diamond Cut Styles

Diamonds can be cut in a few styles or techniques, which determine the ideal number, size, and layout of a diamond’s facets. Depending on how much sparkle you are hoping for, you are going to want to choose a cut wisely.

Brilliant Diamond Cut

This classic cut resembles a cone-like shape and offers the maximum amount of eye-catching light. Brilliant diamond cuts are mostly used on round diamonds to strengthen the light performance of the stone rather than accentuate various fancy shapes. If you’re looking for a center stone for a solitaire diamond engagement ring you’re likely looking for a round brilliant cut diamond due to its show-stopping brilliance. Oval and princess cut diamonds can also feature brilliant cuts.

Step Diamond Cut

The step cut is essentially what it sounds like — a series of parallel rectangular facets, each angled off the last in a stepped fashion. Square and rectangular diamond shapes, like your princess, emerald, and asscher diamonds, use step cuts. Due to a reduction of facets to reflect light with (think of a three-panel mirror), there is less potential for fire and brilliance compared to a brilliant-cut gem.

Mixed or Hybrid Cut

Some fancy-shape diamonds incorporate both types of diamond cut techniques to achieve their form. Radiant and princess cut diamonds, for example, make use of sweeping parallel facets as well as triangular ones to round off corners and add detail to their interesting geometry. This helps increase their sparkle and create a breathtaking diamond shape overall.


Factors That Affect Diamond Cut Quality

Whichever cut style and shape is chosen, the quality of the cut will depend on two main factors: polish and symmetry.

The better the polish and symmetry are, the more superior a diamond’s fire, brightness, and scintillation will be. There are a few ways to determine the quality of a diamond’s cut.


Symmetry refers to how well-aligned the diamond’s facets are in shape and size. If any facets are off-center, suboptimally angled, or even missing outright, the stone will lose some of its light performance and receive a lower cut grade. It’s a similar concept to a submarine’s periscope. Both mirrors must be placed at the same angle so light can travel through the tube. If the mirrors aren’t placed correctly, the light won’t bounce off the mirrors.


Polish is the final element of the diamond cutting process. To ensure that a diamond’s light performance is the best it can possibly be, the diamond cutter will polish every facet to a perfectly smooth surface. Anything less, and light will scatter off of the slight natural bumps or cutting marks left on the stone. Polish is essential for a diamond that will sparkle like crystals on a beautiful wedding gown.

Diamond Cut Grades

To impartially categorize diamonds based on their cut, diamonds are professionally analyzed by gemologists from a variety of gemological institutes. One world-famous diamond grading organization is the Gemological Institute of America (GIA). While many of our diamonds are GIA-certified, we also use multiple grading labs and internal GIA-certified graders to assess the 4Cs of diamonds.  

To assign a clarity grade to a diamond, the gemologist carefully studies the proportions of the stone’s facets to evaluate its face-up appearance and ultimately how successfully it emits brightness, fire, and scintillation. Graded diamonds come with a grading report that delivers more information about the stone’s cut (as well as the other three Cs) as an indisputable verification of its quality.

Some specific factors included in a diamond’s cut analysis include:

  • Weight relative to the diameter
  • Girdle thickness
  • Facet symmetry
  • Polish quality

After all is said and done, the diamond receives its cut grade — one of five possible grades, ranging from Poor to Ideal or Excellent. Because each diamond is one of a kind, each grade signifies a range of cut qualities that many diamonds fit into. It’s important to keep in mind that even stones within a specific diamond cut grade can appear different. At Shane Co., we only carry the diamonds with the most sparkle in each grade.

At Shane Co., you’ll find the following diamond cut grades:

  • Shane Classic: A grade that is specific to our diamonds, Shane Classic diamonds are cut to exacting parameters to maximize sparkle and provide the most light return, creating supreme brilliance and fire.
  • Excellent/Ideal: Ideal or Excellent cut diamonds are rarer and more brilliant than Very Good diamonds. They reflect almost all of the light back out of the top of the diamond for magnificent sparkle.
  • Very Good: It boasts a very similar sparkle as an Excellent or Ideal cut at a more affordable price.
  • Good: Diamonds of this cut grade marry carat weight and brilliance quite evenly. The result is slightly uneven brilliance and fewer dark areas than Fair cut diamonds.
  • Fair: A Fair cut diamond maximizes weight, resulting in uneven or mottled brilliance with some dark areas. It is still a quality diamond but does not match the brilliance of a Good cut gem.
  • Poor: This category of diamonds has the least brilliance of any with more noticeable dark areas than the other cuts.
A collection of diamond tennis bracelets

Diamond Cut vs. Budget

The early days of cutting facets into diamonds and polishing them were a massive undertaking. Skilled tradespeople in the sixteenth century painstakingly carried out the entire process by hand. This meant that the best cut diamonds were as rare as the most skilled cutters and exceedingly expensive.

Today, rough diamonds are machine-cut by lasers, and the quality of the cut is more dependent on how much emphasis the cutter puts on cut over carat weight than it is a raw skill. This led to many more diamonds on the market with excellent symmetry and polish and reduced the price difference between cut grades in the process, which makes sparkly diamonds more in reach during the ring shopping process. Still, diamond cutters must balance preserving the size and shape of the rough diamond with achieving a good cut, meaning some diamonds are still cut better than others. 

The right diamond cut grade for you will ultimately depend on your budget, how you prioritize the 4Cs, and other factors. If you want the best of all worlds, consider shopping for a Shane Classic diamond, which is among the top one percent of diamonds for clarity, color, carat, and cut.

Now that you have a better understanding of diamond cuts, you’re one step closer to picking the perfect diamond. If you desire a unique ring and are ready to pop the biggest question of your life, create your dream engagement ring

If you still have unanswered questions about the buying process, we’re here to make diamond shopping as enjoyable as possible. Check out our educational resources to become a diamond expert in your own right.