Wondering what a diamond cut is and how it affects the price of a diamond?

Perfect, you’re in the right place!

In our opinion, the cut of the diamond is the most important “C” in the 4C’s of diamonds.

 Read this guide to get the skinny on what you need to know to make the best buying decision.

What Is A “Diamond Cut”?

Brilliance may be one of the diamond’s natural calibres but the cut will determine just how much a diamond’s beauty sparkles. Precisely cut diamonds shine marvellously as the angles let light pass through the crown (or the top) and back. You may have heard of a few cuts like princess, emerald, cushion, etc.

However, don’t be fooled by the word “cut”- this complex process is more than just giving the diamond its’ shape, and has significant implications for the value and price of a diamond. In this guide, we’ll take you through the various cuts in a diamond, including quality and grade. As you read on, you’ll also get a glimpse of how important a diamond’s cut is to maximize the gem’s optical properties.

What’s The Difference Between Cut and Shape?

A diamond’s cut is the dimensions of the diamond that dictates how shiny it becomes. In simpler terms, the more precise the cut, the better brilliance, fire, and scintillation (see above for definitions) your diamond will show. On the other hand, a diamond’s shape refers to the general appearance of the stone. A diamond’s shape is determined by the outline of its two-dimensional edges.

How Does A Diamond’s Cut Affect Price?

A diamond’s beauty and price are hugely dependent on the precision and quality of the diamond’s cut.

Producing facets that are in equal proportions is the key to having a sparkling diamond. For instance, in a brilliant round cut diamond, the 33 facets on the crown must be in equal proportions otherwise there will be leakage of light.

A poorly cut diamond will look dull even in higher carat weights or table sizes. Without brilliance and fire, a diamond’s value is lower than average. Since all the 4Cs have significant effects on the price of a diamond, focusing on the best cut has an important impact on the beauty of your diamond. If you really want a high-quality cut diamond, you may have to compromise the GIA Color or Clarity just to find the best-cut diamond.

What Are The Different Types Of Diamonds Cuts?

When picking the right diamond, it is important that you get to know which cuts give out the best. Here are some of the common cuts made from diamond roughs.

Cushion Cut

 A cushion cut has rounded edges and large facets, which maximize the brilliance of a diamond. Sometimes it can be hard to distinguish from other cuts depending on how pronounced the curves along the edge are.

Round Cut

 This is probably the most common cut, especially in engagement rings. If you are looking for very specific components, most diamonds will fall under this category. Round cut diamonds have been produced over the years in a bid to bring out the most sparkle. Most top tier cut grades are only done in round cut diamonds.

Princess Cut

 A princess-cut has quite sharp corners, resembling a generally square shape. Princess cut diamonds will have a fiery brilliance when viewed from all angles.

Emerald Cut

An emerald cut diamond has rectangular facets and looks like a large open table. Since no two diamonds are the same, the length-width ratio may be different from diamond to diamond. The beauty of an emerald cut stone is that you’ll be able to easily identify diamond inclusions and defects, especially with SI2 stones or worse.

Marquise Cut

A marquise-cut diamond is generally made to look long and as large as possible, resembling a shield-like appearance. A marquise-cut diamond will make one’s fingers look longer and slender.

Pear-Cut

A pear-cut diamond resembles a teardrop and like the marquise-cut, it will make your fingers appear longer and slender. When browsing through pear-cut diamonds, be mindful of the bow-tie effect, a common defect with such cuts. This also happens with the oval cut.

What Are The Different Diamond Cut Grades?


When viewing a diamond’s cut grade, you should refer to GIA’s grading. Even though the institute is an independent entity, it is by far the most recognized and accepted among experts and industry specialists.

Here is how GIA’s grading looks like in terms of a diamond’s cut.

Excellent Cut

Excellent cut diamonds have proportions that give the highest levels of brilliance and fire. Because the facets are so perfect, almost all light that passes through them is entirely reflected. In AGS certificates, such cuts are graded Ideal Cut.

It should be noted that only round cut diamonds are officially recognized as Excellent or Ideal. Fancy shaped diamonds like princess cut and cushion cut may say they are excellent cut, but there’s no exact standard for these shapes. The proportions are within the best guidelines for the most light performance for that shape. 

Very Good

For all non-round diamonds, Very Good is the best cut grade. However, you should match up the individual proportions according to the shape of the diamond you’re looking at. 

Very Good Cut diamonds have exceeding brilliance and fire. A great deal of light that passes through the diamond’s facets is reflected through the table. However, Very Good diamonds may have the same sparkle as those of Excellent grade, at least to the naked eye.

Good Cut

Good Cut diamonds show tolerable levels of brilliance and sparkle. They’ll reflect enough light through the table to the viewer’s eyes. These diamonds may have lower price points since brilliance levels are not up to standards.

Fair Cut

Diamonds in this grade don’t reflect much of the light that passes through. As a result, the fire and brilliance are massively cut down. Diamonds with Fair Cut grading may not be suitable for centerpieces but will fit perfectly as side stones in jewelry.

Poor Cut

Poor Cut diamonds may not exhibit any brilliance, fire, or scintillation of any sort. Since the facets are disproportionate, light entering through the diamond passes at the bottom of the diamond.

How To Determine Cut Quality

The cut of a diamond is typically influenced by three major factors which are symmetry, proportion, and polish. Ultimately, each of these factors affects a diamond’s fire, brilliance, and scintillation. Let’s find out how these factors stack up on the quality of a cut:


Proportions
The proportion of a stone’s cut entails the relationship between the angle, shape, and size of each stone’s face, mainly related to the internal properties of the stone. A well-proportioned diamond maximizes the amount of light passing through.

Polish
The polish grade of a stone dictates how smooth the facets look after cutting and polishing. This allows the stone to exhibit maximum brilliance. However, a polish may not affect the brilliance that much but a very good polish rating is good enough.

Symmetry
A symmetrical stone will have perfectly balanced facets with proper alignments. In case the facets are not symmetrical, the stone’s sparkle will be greatly compromised.

Our Recommendation When It Comes To Diamond Cut


Firstly, it should be clear that a diamond’s cut is by far the most important of the 4Cs in helping you find the best selection of diamonds. When you go to any diamond retailer, be mindful with diamonds described as Excellent Ideal Cut, Super Ideal Cut or anything of that sort.

Why?

You’ll notice that the difference in cuts at the top tier grading is like the old apple to apple comparison. Before you get enticed, make sure to check out the AGS or GIA grading report. For GIA Certified diamonds, consider Excellent Cuts, and in AGS Certified diamonds, Ideal Cuts are the best. Relying on the retailer’s grading system alone may have loopholes.

Apart from relying on AGS and GIA, you can also do some background research examining the stone’s varying proportions including all measurements and angles. It may seem a lot of work, but you want to avoid getting ripped off thousands of dollars because of a single “Cut” mistake. If you’re shopping online, we recommend you head over to James Allen as you will be able to view any diamond with up to 20x magnification.

Ultimately, the cut will carry most of the baggage while looking for the best diamonds. A cut can hide inclusions, increase brilliance, mask secondary hues, and make your diamond sparkle!

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