4Cs - Cut

Education Center

Education Center

Everything You Need to Know About Diamond Cut

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While all 4 C’s contribute to a diamond’s beauty and sparkle, cut is the most important. A poorly cut diamond looks like a dull, lifeless rock no matter how clear and colorless it is.

The thing is, cut quality varies; even between same-grade diamonds. Fancy shapes - i.e. anything but a round brilliant - have no rules at all for grading cuts. All of this can make finding a well-cut diamond hard. 

To clear things up, let’s take a look at what makes a well-cut diamond and what to look for when engagement ring shopping. 

What is diamond cut, exactly?

Cut plays a huge role when it comes to the quality, beauty, and price of a diamond. It affects everything: proportions, sparkle, and even size. Poorly cut diamonds are bottom-heavy, meaning they look smaller than their carat weight face-up. 

But what is cut, exactly? 

Well, mined and grown diamonds start out lumpy and unpolished. Jewelers cut them into different shapes and then polish them. Depending on how well a diamond is cut, it gets a grade from “poor” to “excellent”. 

“Excellent” cut diamonds have incredible sparkle, size, and beauty. “Great” diamonds have excellent sparkle and beauty at a lower price point. “Good” diamonds still look good. In our opinion, “Fair” and “Poor” diamonds are to be avoided for engagement rings. 

Are cut and shape the same?

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Although the terms “cut” and “shape” are sometimes used interchangeably, shape and cut are different. A diamond’s shape refers to its silhouette. Pear, round, and oval are examples of shape. 

A diamond’s “cut” describes its symmetry, proportions, and anatomy. Most shapes have a perfect cut; a standard to aspire to. The closer a diamond to this ideal, the higher its grade and the better its appearance. 

What affects a diamond’s cut grade?


The relationship between a stone’s width, depth, facet size, etc needs to hit certain ratios. A diamond with poor proportions won’t reflect light and can look cheap. A diamond that does hit these ratios, on the other hand, will look and sparkle like a million dollars. 

The two main aspects of diamond proportion are… 

Table percentage. The top facet of a diamond is known as the table. The ratio between the table and a stone’s widest point is called the table percentage. A table percentage that’s too high or too low can create dull, odd-looking diamonds.

Depth. Diamonds that are cut too deep look less bright and vibrant.  If a diamond is too shallow, it won’t reflect much light and will appear dark. The key is to strike the perfect balance for the diamond shape of your choice.


Diamonds with high cut quality have excellent symmetry. In diamond speak, this means that the facets on each side of the diamond are symmetrical. This allows a diamond to take in and reflect as much light as possible, giving it that signature diamond brilliance and sparkle.

Diamonds with poor symmetry lack in the sparkle department. Their asymmetrical cuts reflect less light, letting less light out through the stone’s uneven facets. A diamond that’s cut symmetrically has infinitely more brilliance and fire.


Diamonds are polished during the final stage of the cutting process. Polishing a diamond helps remove blemishes and imperfections, maximizing sparkle and smoothness. Underpolished diamonds can look cloudy; poorly polished ones can look scratched-up and milky.

Making the cut

Diamond cut is graded on a scale ranging from Excellent to Poor. Here’s a breakdown of each cut grade and what they mean:




An excellent or ideal diamond cut has superior brilliance, fire, and scintillation.

Very good

Diamonds of this grading are still exceptionally bright and to the naked eye are similar to excellent cuts.


Diamonds will be a bit darker with less scintillation but are still bright.


Very little brilliance or scintillation. 


Poor proportions and near to no sparkle.

Seems like a pretty straightforward system, right? Well, there is a catch - this grading system is tailored to round-cut diamonds. Although jewelers use these grades with fancy shapes like Asschers and cushions, there’s no set grading standard. In other words, fancy shape grades are subjective. 

Note that Keyzar only stocks diamonds with cut grade “Good” and above. When shopping with other jewelers, be careful; anything below “Good” will look dull and a little lifeless. 

How do I choose a diamond based on cut?

<span>The better the cut, the more brilliance, fire, and sparkle you’ll be able to enjoy.</span> image
The better the cut, the more brilliance, fire, and sparkle you’ll be able to enjoy.

If you’re looking at Round Brilliant stones, you can go based on the grade on the certificate. There are strict standards for this shape; you know exactly what you’re getting. 

With fancy shapes, look at the grade on the certificate as well as the diamond itself. If you want to do the latter online, use Keyzar’s 3D preview tool to see what you’re about to buy. 

Above all, be realistic about your budget. Diamonds with an “Excellent” cut grade are best… But stones with a Very Good cut grade still offer tremendous brilliance and beauty while giving you massive savings. 


Cut can make or break the beauty of your diamond. The better the cut, the more brilliance, fire, and sparkle you’ll be able to enjoy. If you choose a high cut grade for round brilliants, and become familiar with industry accepted guidelines for other shapes, you’ll end up with a gorgeous diamond with high quality, long-lasting good looks.

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Choose your engagement ring from our Collections

The Pave Nelly WG R

The Pave Nelly

Round White Gold 14K Low Profile Pave Maia, Round White Gold 18K Low Profile Pave Maia

Low Profile Pave Maia

The Alex WG R

The Alex

Round White Gold 14K The Low Profile Kamellie, Round White Gold 18K The Low Profile Kamellie

The Ellie