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Diamonds 101: The Round Cut

It’s safe to say, round brilliant cuts are synonymous with diamonds in general. However, they were not the first diamond cut and have only been around for a little over 100 years. So what makes them so special and sought after?

A Brief History

The Round Brilliant cut was first introduced in 1919 by a Belgian Mathematician named Marcel Tolkowsky. With his background in mathematics, he calculated the precise angles and proportions needed to create the most brilliant diamond cut possible.

While round diamonds were already in existence, they had never been this brilliant, or light-catching. With this new cut, round brilliant diamonds also became known as Ideal Cuts. Previous round cut diamonds were Rose Cuts, Single Cuts, and the Old European Cut.

Rose Cut Diamonds Vs. Brilliant Cut Diamonds


Old European Vs. Round Brilliant Cut

What to Look For

If you’ve decided you want a round diamond engagement ring, regardless of your setting choice, there are a few key factors to consider when shopping for your center stone.


Round Brilliant diamonds are great at masking color. With that in mind, we recommend opting for a stone within the D-J range to effectively hide any potential color.


Round Brilliant diamonds are the only shape that (should) have perfect symmetry! They are also the only diamond cut that can be graded as “Triple X” or Triple Excellent—diamonds that have Excellent cut, Excellent polish, and Excellent symmetry. Additionally, round diamonds are the only shape that receives a cut grade! Keep reading about the differences between round brilliants and Old European cuts.


The faceting of Round Brilliant diamonds helps hide imperfections better than other diamond shapes. In fact, round brilliant diamonds hide color so well, you could opt for a stone with a minimum of SI2 clarity!


One thing most people don’t know about round diamonds is that due to their perfect symmetry, they appear larger than other shapes of the same carat weight. Unfortunately, this is the main reason why round diamonds are also more expensive than other shapes of the same size and quality.

Round Cut Ratios

Length-to-width ratio is very important for all cuts because they vary from shape to shape given the ideal proportions most people want for their desired shape. For rounds, however, there isn’t a range of ideal ratios as round diamonds should be perfectly symmetrical. In this case, the ideal ratio for all round cut diamonds should be 1:1 or 1:1.05 at the very most

Round Brilliants vs. Other Shapes

The third most popular shape of 2021 was the round cut. Because it is the most recognizable diamond shape, it will probably always have a spot in the top 3 most popular diamond shapes. While round brilliant diamonds are both unique and classic, they share many similarities to other diamond shapes like the cushion cut and Old European rounds.

Round Brilliant vs. Cushion Cut

Cushion and round cut diamonds are sister shapes with an emphasis on brilliance and sparkle. Both square cushion cuts and round brilliant cuts have a 1:1 ratio giving each shape lots of flexibility when it comes to setting styles.  Additionally, the triangular facets of cushion and round “brilliant” cut diamonds effectively hide color allowing for budget flexibility. As for sparkle, round brilliants will have more fire than a cushion cut—and all other shapes for that matter. However, the ability to choose different styles of cushion cuts is very appealing in addition to all of them lending themselves well to a wide range of ring designs.

Round Brilliant vs. Old European

Old European and Brilliant cuts are both round in shape, but as the cliche goes, it’s what’s on the inside that counts. These specific round cuts are deeper cuts with a smaller table, higher crown, and a larger, open culet. In fact, one of the most distinguishing features of the Old European cut is that you can see the culet as a circle in the middle of the diamond. While we recommend getting a stone in the D-J color range, some people prefer a lower color grade to enforce the vintage look, making the stone appear more warmer/yellower.

3.82ct Old European Lab Diamond Solitaire Engagement Ring

Popular Lauren B Round Brilliant Cut Rings + Jewelry

Like any other shape, there are settings that we’ve found are most popular among our clients. If you aren’t sure how you want to set your round cut diamond, check out some of our most popular designs!

Engagement Rings

4.52ct Round Diamond Three-Stone Engagement Ring

3.00ct Round Diamond Yellow Gold Solitaire Six-Prong Ring

4.60ct Round Diamond Six-Prong Engagement Ring 

Wedding Bands

5.8ct Round Lab-Grown Diamond Close Basket Eternity Band 

1.25ct Round Diamond Closed Basket Eternity Band 

1.00ct Round Diamond Compass-Set Band 


2.64ct TW Lab-Grown Diamond GIA Graded 6-Prong Studs

1ct TW Illusion Set Diamond Tennis Bracelet 

1.5ct Lab-Grown Round Diamond Solitaire Pendant GIA 

Celebrity Round Cut Engagement Rings

Most famous engagement rings have some kind of wow factor—giant center stones, custom detailing, and they are usually fancy shapes (anything other than round). Nevertheless, there are a few famous round cut engagement rings out there.

In 2018, producer Brad Falchuk proposed to Gwyneth Paltrow with a nontraditional round, blue sapphire ring. This stunning stray from the norm perfectly represents the power couples’ relationship.

Let's Talk About Gwyneth's Engagement Ring | The Adventurine

Gwyneth Paltrow engagement ring.

3.36ct Sapphire Round Cathedral Platinum Ring

In 2016, Houston Astros pitcher Justin Verlander, proposed to his model girlfriend, Kate Upton with an 8 carat round natural diamond engagement ring. With six prongs and a platinum pave band, we can’t help but stare at this gorgeous ring!

Kate Upton, MET Gala 2016, Engagement Ring

4.30ct Round Diamond Six-Prong Engagement Ring 

Other celebrities with unique round engagement rings include Miranda Kerr, Emily Blunt, Natalie Portman, Rosie Huntington-Whitely, and Nikki Reed.

Even members of the royal family have opted for traditional, round diamond engagement rings. Princess Beatrice of York was proposed to with a round three-stone ring with baguette side stones on a pave band.

The Adventurine Posts Princess Beatrice’s Engagement Ring Is Stunning

Round Moissanite Three-Stone Pave Engagement Ring 

Additionally, Queen Elizabeth’s engagement ring center stone was one of the crown jewels; Prince Philip was given a tiara from his mother in which he used the diamonds to design his future fiance’s engagement ring. He then used the excess diamonds to make her a bracelet as a wedding gift.

Queen Elizabeth’s engagement ring was an Old European cut round diamond flanked by smaller diamonds on the side.

True Story of Prince Philip Finding Queen Elizabeth's ...

Is Round the Shape for You?

Whether you’ve decided which shape you want or not, our design consultants are ready, willing, and able to help guide you through the ring design process. Whether that’s starting with a ring setting or just picking the right metal color, we’ve got you covered!

Browse through our in-stock engagement rings for more inspiration or book an appointment below to get started right away!