The Guide to Round Brilliant
Cut Diamonds

Possibly the most iconic diamond cut, and certainly the most popular, the round brilliant cut diamond skyrocketed to stardom in the mid 1900s and never looked back. Round brilliant cut diamonds account for about 75% of all diamonds sold, and about 60% of all engagement ring stones. All this popularity comes with a lot of benefits, but there are some things you definitely need to know if you’re considering the round brilliant cut diamond. We’ve put together a complete breakdown of this stunning diamond cut and the best ways to make it into a special engagement ring.

History of Round Brilliant Cut Diamonds

Rounded shapes for diamonds have been used as cuts for many years, with popular examples today being the rose cut and old mine cut. But fully circular shapes weren’t possible until the invention of the bruting machine in the late 1800s. This machine allowed for diamonds to be cut in a completely circular shape rather than a shape that resembles a modern day cushion cut. With this invention, the first known round diamond cut was established, the old European cut.

The round brilliant cut that we know today developed many years after the European cut and looks significantly different. In 1919, Marcel Tolkowsky published his thesis that would come to be the catalyst for the birth of the round brilliant cut. An engineer by trade and member of a family of diamond cutters, Tolkowsky’s thesis “Diamond Design: A Study of the Reflection and Refraction of Light in Diamond” posited a mathematical formula for cutting diamonds to perfect proportions and maximum light return.

Over the decades that followed, technology advanced and cutters adjusted the proportions and angles to better refine the maximum light return. With its 58 precisely placed facets – 33 on the crown of the diamond and 25 on the pavilion – the cone shape of the cut funnels light through the top, maximizing reflection of light and creating a brilliantly sparkly diamond. Around the early 1940s, this version of the round brilliant cut was finally reached and the rest, as they say, is history.

round brilliant cut diamond ring

When to Go Round: Pros & Cons

The round brilliant cut diamond is by far the favorite, especially for engagement rings, for a host of excellent reasons. But diamond cut is always a matter of preference, so we’ve put together the pros and cons of the round brilliant cut diamond to consider:



  • - It’s a timeless shape that looks great on any type of hand and will never go out of style.
  • - The most brilliant cut of all diamond cuts that offers the most light return and endless sparkle.
  • - Round brilliant cut diamonds are widely available in all sorts of carat weights, sizes, and varying combinations of gradings, so options are never ending.
  • - One of the most versatile diamond cuts, a round brilliant is perfectly suited for any ring setting style or metal type.



  • - Round brilliant cuts are usually the priciest of all diamond cuts.
  • - The only variety is in carat weight and gradings qualities – every stone will be round, unlike fancy-shaped cuts like oval, marquise or emerald that can look longer or shorter, fuller or thinner.
  • - Will often look smaller than another diamond cut of similar carat size.
  • - High quality stones are going to come at a premium and maybe even some competition.

Exploring Different Diamond Shapes

Evaluating a Round Brilliant Cut Diamond: the 4Cs  


One of the most brilliant design features and important factors when it comes to grading a round brilliant cut diamond is the cut. After all, a diamond’s brilliance is what makes it so special and appealing, and the quality of its light performance is heavily impacted by the quality of the cut. This grading tells you how well-proportioned and aesthetically pleasing the diamond is, and therefore how well the diamond will reflect light and provide brilliance.

The GIA grades round brilliant cut diamonds on a scale from Excellent to Poor. But it’s important to keep in mind that while the GIA cut grade is important, it is not the sole aspect to consider when it comes to cut. Roughly 55% of GIA certified round cut diamonds available are Excellent cuts. This tells you there is a wide range within that grade, going from stunning to mediocre based on other attributes.

To ensure a great quality cut, you’ll want one that is not too shallow or too deep. When the cut is too shallow, light strikes the pavilion at a low angle leaving a large amount to escape through the sides causing the diamond to lack brilliance and fire. When cut too deep, light strikes the pavilion at a sharp angle causing light to exit through the bottom and making the diamond appear dull. For maximum brilliance and fire, light strikes each pavilion and reflects back to the eye through the crown and table.


Round brilliant cut diamonds offer a wonderful situation when it comes to color. The multiple facets and high level of brilliance from reflecting light contribute to the ability of round brilliant cut diamonds to conceal color. On a scale from D to Z with D being colorless or white and Z being easily seen brown or yellow tint, a GIA lab report will indicate the level of tint or color noticeable within a diamond.

While round brilliant cuts are so fantastic at concealing color, you should still be diligent about determining the level of color in any diamond you’re considering. When viewing a diamond on its own, the eye has a very difficult time discerning color in a diamond. And when viewing two adjacent color grades side by side, there is unlikely to be a noticeable difference in color.

For all of these reasons, as well as the fact that metal choice will affect visual color as well, an I-J color grade can appear perfectly white when set in platinum or white gold, and a K color grade will have a beautiful warmth when set in yellow or rose gold. When it comes to color in a round brilliant cut, there’s a lot of room to play to see what works well with the rest of each diamond’s attributes.

1.5 Carat Round Brilliant Engagement Ring


The most important aspect of clarity is determining if the diamond is eye clean outside of the clarity grade on the certificate. For a diamond to be eye clean, you won’t be able to see any inclusions, blemishes, or dark spots when looking at a diamond without magnification. In many cases when comparing diamonds side by side, a VVS2 diamond and a VS1 diamond will appear identical to the naked eye. But although they look the same and are free of any inclusions, the cost of the VVS2 will be much higher, all other grades being the same.

Diamond clarity is graded on a scale from Flawless to Inclusions with 11 possible clarity grades. It’s important to remember that all diamonds have inclusions and blemishes, even those that are graded as flawless. So making sure that the diamond is eye clean as well as watching for the locations of imperfections will produce a great diamond. If imperfections are located near the perimeter, they’re much easier to hide and can even be placed under a prong in a setting.


The carat is the standard unit of measurement for the weight of a diamond. When you’re purchasing a diamond, you’ll be paying a set price per carat. And whenever you reach a full carat number – so your 1, 2, 3, 4, and so on carat weight – the price will take a significant jump. There’s often a lot of appeal to the whole carat number, so they are priced accordingly.

A great benefit of round brilliant cut diamonds is that they are widely available and there is practically no limit to the carat weight either. There will be a lot to choose from in the 1-3 carat range, and then after that, there will start to be fewer options as the carat weight increases. But if you’re searching for a round brilliant cut diamond, there will be an abundance of carat weight options to choose from.

Choosing an Ideal Round Brilliant Cut Diamond

With a round brilliant cut diamond, so much of the beauty of the stone is going to rely on the cut quality. It’s too broad to just look for a diamond with an Excellent cut grading because there’s a lot of space in there for proportion, symmetry, fluorescence, etc. to play a major role in the beauty of the stone. So while the cut grade is important, it’s more important to see how the stone interacts with light and whether that looks good to you. While you don’t want to compromise much on the cut grade, there are still beautiful diamonds outside of the Excellent grade.

Color is based on personal preference and you should always consider how you want to set your diamond before making your color determination. And keep in mind that D-F color grade diamonds are highly sought after and people are willing to pay more for them purely to get that colorless grading. However, the actual noticeable visual differences between these grades and an F, G, or H are typically undetectable, and certainly not when the diamond is viewed alone.

When looking at clarity, you’re going to be afforded a lot of wiggle room for the grading you want to get an eye clean diamond. Since the faceting style of the round brilliant cut is so good at masking inclusions and imperfections, going lower on the clarity grade can still produce really lovely eye clean stones. Just remember to take note of where they’re located in the stone and steer clear of anything located near the center of the stone as it will be visible through the table.

An excellent way to get the most of your budget and a stunning diamond is to think about staying away from whole carat stones. Go for something ‘just shy’ of the whole carat, like a 0.98 carat or 1.93 carat diamond. You will never be able to tell that the diamond isn’t the full carat size, and you’ll avoid the big price jump that occurs at the whole carat number.

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Round Brilliant Cut Diamond Prices

Round brilliant cut diamonds are the most expensive diamond shape for a couple of reasons. For one, during the cutting process, only about 40% of the original stone remains at the end. This is termed as a lower yield of diamond, so more rough stone is needed when cutting a round cut. By comparison, a princess cut diamond retains about 80% of the stones original rough. Secondly, the popularity of the round brilliant cut means that the demand is constant and high. As a result, it’s estimated that a round diamond can cost up to 15-35% more than a fancy-shaped diamond.

While the price of a diamond is mainly determined by factors of cut, color, clarity, and carat size, there are other attributes that can have an effect, like fluorescence or cut precision – it’s the consideration of the overall rarity and beauty of that stone. With that being said, it’s important to keep in mind that there will be a large range for price for round brilliant cut diamonds, especially because there are so many available. For instance, a quality 1 carat round diamond can vary between $3,000 to $10,000 depending on color/clarity ratings for a natural mined diamond.

Designing a Ring with a Round Brilliant Cut Diamond

The versatility and iconic look of the round brilliant cut diamond is practically legendary. There is no setting that will cause this diamond to look bad. However, there are some settings that naturally stand out as perpetual winners when it comes to showcasing a round brilliant cut diamond.

The forever favorite is the solitaire engagement ring. The simplicity of the solitaire setting lets the beautiful round diamond take center stage and this timeless look will never go out of style. You can go for a bezel setting, as with our Katie, a prong setting with a unique and romantic basket, as with our Aliss, or debut a lovely nature-inspired one-of-a-kind ring, as with our Pembroke.

Another standout look is the pavé setting. The added elegance of the pavé setting combined with the round brilliant cut diamond is like wrapping the stone in sparkle. For a classic pavé look, take our Jessie with a solitaire setting on a pavé band and peekaboo pavé under the stone. Or grab an organic, nature-inspired look with Celeste, featuring an exquisite stone sitting on a sculptural, wavy band, precisely set with pavé diamond.

Continuing with added sparkle, the halo is always a popular setting for round brilliant cut diamonds. And with the beauty of the center stone, you can really go big with the halo. For our Annabelle, we surrounded the center stone with a large round diamond halo and set that all on a pavé band. And for Inolah, we paired a triple halo setting with a three-stone ring for a truly spectacular engagement ring. Our Samanthina features a more subtle "hidden halo" look.

And finally, you can never go wrong with a round brilliant cut diamond in a vintage-inspired setting. The intricate design details of a vintage setting perfectly enhance a round cut stone. Just consider the old world details and charm of our Kimberly, Margrette, and Rachael. Each features meticulous craftsmanship to create vintage looks showcasing milgrain, filigree, and sweeping romantic and elegant metal design.

If you’re looking for a timeless diamond cut with out-of-this-world brilliance, look no further than the round brilliant cut diamond. Although it’s a popular cut, follow our tips to get a stunning diamond without the big price tag and allow yourself to get creative for the setting to design something truly unique to last a lifetime!

Round Brilliant Ring Set

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