4Cs 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.

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".

The GIA cut scale runs Excellent, Very Good, Good, Fair and Poor. “Excellent” cut diamonds have incredible sparkle, size, and beauty. “Very good” stones have strong sparkle at a lower price point. “Good” diamonds still look good. In our opinion, “Fair” and “Poor” diamonds should be avoided for engagement rings entirely.

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, and you can compare them all in our diamond shapes guide. 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.

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.

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.

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

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. Where a fancy shape carries no cut grade, read the proportions instead: table percentage, depth, and how evenly the facets mirror each other.

Much of the market will tell you to drop to a “Very Good” cut grade to save money, and for a mined diamond that is reasonable advice. Ronora does not offer that trade. Every stone we sell is Excellent cut, because lab grown pricing means you no longer have to give up cut quality to afford the carat weight you want. Ask us for the IGI report on any diamond of one carat or more and you will see the grade for yourself before you buy.