4Cs - Cut

Education Center

Education Center

Everything You Need to Know About Diamond Cut

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 blemish-free and colorless it is. It’s important to understand, the cut-grade scale is mostly relevant only to round brilliant diamonds. Fancy cuts such as the Asscher or oval cut are not always given a cut grade.

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.

But what is cut, exactly? Mined and grown diamonds start out lumpy and unpolished. Jewelers cut them into different shapes, then polish them. Depending on how well a diamond is cut, its cut is graded from "poor" to "excellent".

Oval cut Diamonds

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

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’s cut is 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 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. Diamonds that are cut too shallow won’t reflect much light and will appear dark. The key is to find the perfect balance between the two with respect to the diamond shape of your choice.

Round cut Diamond


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 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 is cut symmetrically has infinitely more brilliance and fire.


During the final stage of the cutting process, a diamond undergoes polishing. Polishing a diamond helps remove blemishes and imperfections, maximizing sparkle and smoothness. Under-polished diamonds can look cloudy, scratched or milky.

Making the cut

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




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

Very good

Diamonds of this grade are still exceptionally bright.To the naked eye, they're incredibly similar to excellent-grade cuts


A bit darker with less scintillation, but are still bright.


Very little brilliance or scintillation.


Poor proportions and near to no sparkle.

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?

Cushion, Radiant, Round and Oval Diamonds

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, so you can be sure you know exactly what you’re getting. With any shape other than the brilliant round, check to see if there is a cut grade on the diamond certificate. Even if the diamond has a cut grade, be sure to check the symmetry and sparkle of the diamond using our 3D tool.

Above all, be realistic about your budget. Diamonds with an “Excellent” cut grade are best, but won't be kind to your bank account. Stones with a ‘Very Good’ cut grade 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 enjoy. Choosing a high cut-grade (if it pertains to the diamond silhouette of your choice) when searching for a center stone will translate into a gorgeous diamond with high quality, long-lasting good looks.

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