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Diamond Cuts: The Essential Guide

Diamond Cuts

How will you know to choose between all the different diamond cuts available in a jewelry store?

The cut is one of the most critical characteristics influencing the brilliance of a diamond. The diamond cut refers to the diamond’s radiant qualities (or sparkle) and not the shape. The best cut stones give the best light performance and sparkle–and are truly stunning. However, with low quality cuts, light tends to leak out the bottom or the sides of the diamond. This means there is less light being reflected,  giving the diamond a dull and lifeless appearance. A good rule of thumb is that a higher cut grade diamond will sparkle the most and can look larger than other stones of identical carat weight.

Diamond Cuts and Grading

With cut being so influential in a diamond’s light performance, gemologists have developed the following grading system to help categorize diamond cuts:

  • Ideal Cut: If you are thinking that the words “ideal cut” mean that the diamond is flawlessly cut in the most favorable way, you are correct. This cut allows almost all light entering the diamond to reflect back to the eye. A truly exceptional and superior cut.
  • Very Good Cut: Most of the light that enters the diamond is reflected in a very good cut, allowing for a significant amount of fire and brilliance. An excellent and slightly more affordable alternative to the rare Ideal Cut.
  • Good Cut: A great deal of light enters these diamonds. These diamonds are wonderful choice for customers wishing to keep in their budget, but do not want to forgo brilliance or quality.
  • Fair Cut: Out of all the light that enters a fair cut, only a portion of the light actually enters it. These types of diamonds sacrifice cut in order to increase carat size. However, they are still considered a decent diamond but will not be very brilliant.
  • Poor Cut: These types of diamonds lose the majority of light around the sides and bottom and are generally not desirable.

How Are Diamond Cuts Chosen?

You may think that choosing a specific way in which to cut a diamond is solely up to the cutting team’s imagination. However, most of the time it’s a fine process that involves a lot of precision guessing. An experienced cutter will know to cut the diamond in such a way that he/she preserves the most out of the original stone while not sacrificing too much of its brilliance or fire. So when we say fine guessing, we really mean that diamond cuts need a great deal of luck mixed in with that skill to create the perfect gem.

The most common traits that determine a diamond’s shape are the following:

  • The original, uncut shape. Most gem cutters’ first aim is to preserve the original shape of the diamond. Then come brilliance and fire.
  • The internal flaws of the gem. Few diamonds are flawless before cutting. Depending where these defects are placed, the diamond may be cut in different ways.
  • The original carat weight. Heavier gems are more expensive, therefore, another important factor is preserving the carats of the original uncut gem.
  • The wish of the customer. An old saying says that the customer is the master. Therefore, if a customer needs an older table cut to fit an antique crown, the cutter must do as instructed or he won’t get paid. Simple as that.

Besides these basic rules, there are a few exceptions and gem-cutting laws that come into play. A diamond can either be cut to make a round brilliant or a fancy cut gem. A fancy cut is not a style of cutting per-se as it is a category of gem-cutting. Within it, professional jewelers generally have freedom of form, within a few basic patterns.

Even though round brilliants are preferred for aesthetic purposes, jewelers often decide against this since most uncut diamonds are already quite small and such a cut greatly diminishes their carat value.

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Two emerald cut diamonds and two round brilliant cut diamonds.

What Is a Round Brilliant Cut Diamond?

You’ve heard us mention it here and a lot of times before this as well, so it’s about time we did some explaining. A brilliant cut diamond is usually either a very good cut or an ideal cut in terms of grade. It’s also the most common form of diamond. It’s quite possible that the standard image of a diamond in someone’s mind is this one.

The shape we see now developed around the year 1900 as a continuation of the classic diamond shapes that led to the Old European Cut. It’s considered a perfect state in which to cut a diamond since it provides a perfect shape for optimal light reflection. Still, the proportions of a Round Brilliant generally vary. The main traits of a brilliant are:

  • The diameter. This is the precise width of the diamond, measured from the two extremes of the girdle.
  • The table. This is the diameter of the flat surface on top of any diamond.
  • The crown height. This is the small portion in between the girdle and the table.
  • The girdle. This portion is usually divided into two measurements when speaking about a round brilliant. These are the thick and thin parts of the girdle.
  • The pavilion depth. This one goes from the bottom side of the girdle to the very tip of the diamond. The pavilion is always the largest part of the brilliant cut diamond.
  • The crown angle. Angle measurements need to be precisely taken when aiming for a well-graded The crown angle of a brilliant is measured between the point at which the crown meets the table and the girdle.
  • The pavilion angle. Like the crown angle but symmetrical. This one’s measured from the basis of the girdle and it goes to the wall of the pavilion. In a flawless round brilliant diamond, the pavilion angle is precisely 7.12 ° bigger than the crown angle.

Here’s a table of the basic 7 benchmark values for the round brilliant diamond cuts:

Benchmark Crown
American Standard 16.2% 43.1% 53.0% 34.5° 40.75° 99.5%
Practical Fine Cut 14.4% 43.2% 56.0% 33.2° 40.8° 99.95%
Scandinavian Standard 14.6% 43.1% 57.5% 34.5° 40.75° 99.5%
Eulitz Brilliant 14.45% 43.15% 56.5% 1.5% 33.36° 40.48° 100%
Ideal Brilliant 19.2% 40.0% 56.1% 41.1° 38.7° 98.4%
Parker Brilliant 10.5% 43.4% 55.9% 25.5° 40.9° Low
AGA 14.0–16.3% 42.8–43.2% 53–59% 34.0–34.7° 100%

What Are the Fancy Diamond Cuts?

Fancy diamond cuts are basically any type of cut that isn’t a round brilliant cut. The fancy cut can be achieved on purpose, on when an attempt to cut a brilliant shape fails. Given that the round brilliant cut is the most popular of all the diamond cuts, it’s only logical that most fancy cuts are modified brilliant cuts. Apart from these, the other types fancy diamond cuts are mixed cuts, rose cuts, and step cuts.

Each basic type of fancy cut has its distinctive features:

  • The modified brilliants are the most common type of fancy cuts. Because they resemble the round brilliant so much, these diamonds are most often sold easily, but even this greatly depends on their weight and grade. Examples of modified brilliants: the marquise, the heart, the trillion, the oval, the pear, and the drop.
  • The step cuts are generally square diamond cuts and rectangular diamond cuts. To achieve this type of cut, the diamonds are generally cut at the corners until they resemble one of the two geometrical forms. The most popular step cut is the emerald diamond cut, closely followed by the baguette, the triangle, the kite, the lozenge, and the trapeze.
  • The mixed diamond cuts are, as you may have guessed, a mix between the round brilliant shape and the step cut A newer cut and part of the more different diamond cuts, this one typically has its crown shaped like in a brilliant cut, but the pavilion is flattened like in a step cut. This unusual combination has made it quite a success among connoisseurs of the diamond world. One very popular form of mixed cut is the princess cut diamond.

Did you know…

the Princess cut diamond is so popular it now has its own grading system? It closely resembles the round brilliant while also preserving the most out of the original stone compared to all other diamond cuts!

  • The mogul and rose diamond cuts are older cuts that have been used for centuries (unlike the mixed diamonds which have only been around for about 50 years). The rose cut lacks a pavilion and its crown is shaped inward by triangles, similarly to how a rose looks when fully opened. The mogul cut is similar to this one, with a great number of triangles across its surface. It’s called this way after the Great Mogul diamond.
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A heart cut diamond next to a smaller, brilliant cut diamond.

Diamond Cuts: Which Grade and Cut Should You Buy?

The cut grade really depends on your budget and how many stones are in the setting. If you start to find that the quality of diamonds for the price is lowering significantly, you may want to consider substituting some diamond simulants as side stones and upgrade to a diamond when finances permit. Either way, there will always be jewelers who are willing to work within your budget and in this business, a little research goes a long way.

It’s important to remember that diamond cuts grades and cuts vary according to each other. A higher grade brilliant cut may not be as expensive as a fancy cut if it’s smaller since the carat is still a very good indicator of price.

Image sources: depositphotos.com.


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