What Are Round Cut Diamonds? Everything to Know

Round diamond guide

Below are the approximate diamond characteristics for round diamonds and their cut grading scales. A round diamond will typically be between 1.00 and 1.03 ratio. Above 1.05 length to width ratio, the diamond will not be quite round. For more information about round diamonds and their sizes, view our comprehensive round diamond size chart in millimeter and carat measurements.

You can get an idea of the different sizes for the round diamond in the chart below. We're included carat weight measurements as well as millimeter size measurements:

Don't sacrifice when it comes to cut

The beauty of the round cut diamond lies in the mathematical precision of the cuts, maximizing light and brilliance through the 58 facets. This is one of the factors that makes the round cut the most expensive diamond cut. We recommend choosing a round stone with the highest cut grades, that is ideal or very good. For symmetry and polish, look for grades ideal, excellent and very good. Then it is left up to your own budget and personal preference as to which style or setting you prefer or that your bride will love. There are a number of ways you can make a lower color grade diamond look amazing in a round cut diamond engagement ring, but if you sacrifice on cut, the ring will sparkle less.

Depth % for Round Diamonds

Excellent: 67%-57%

Very Good: 68%-53%

Good: 72%-49%

Table % of Round Diamonds

Excellent: 65%-53%

Very Good: 69%-51%

Good: 74%-47%

Length to width Ratio for Round Diamonds

1.00

Round color and clarity guide

Depending on the size of your round cut diamond, there are varying color and clarity grades that will have implications on diamond sparkle. We’ve made a chart to quality these ranges, which you can find below. You'll find that it's broken down by carat size. The 4Cs can affect different sized diamonds differently, so we wanted you to know how to get the most gorgeous 2 carat round diamond ring and where you could compromise on a 1 carat round diamond ring. But if any of this is confusing or it's unclear how these ranges will impact your round diamond cut ring, we have expert gemologists on staff who can help you out. (And if you're looking to go bigger than our chart with, say, a 3 carat round diamond ring, they can help you with that, too.)

Color Grades For Round Diamonds

> 0.50 ct

• Ideal: D-H
• Great: I-K
• Good: L

0.50-1.00ct

• Ideal: D-G
• Great: H-J
• Good: K-L

1.00ct-2.00ct

• Ideal: D-F
• Great: G-I
• Good: J-L

< 2.00ct

• Ideal: D-F
• Great: G-H
• Good: I-L

Clarity Grades For Round Diamonds

> 0.50 ct

• Ideal: FL- VVS1
• Great: I-K
• Good: L

0.50-1.00ct

• Ideal: D-G
• Great: H-J
• Good: K-L

1.00ct-2.00ct

• Ideal: D-F
• Great: G-I
• Good: J-L

< 2.00ct

• Ideal: D-F
• Great: G-H
• Good: I-L

Round brilliant diamond cut history & origins

Technological advances have improved the process of cutting diamonds, and today we can enjoy the 58 facet round diamond cut. Its circular shape showcases 58 different eye catching facets of the diamond. It maximizes and catches the light from all angles, which is why it is popularly referred to as round brilliant diamond. The round cut is the most popular shape, is easily identified, and lends itself to every occasion night or day and every wearer, young or old, contemporary or traditional.

The search for the cut to showcase the facets of the diamond gemstone’s radiance and brilliance has led the way to many new cuts throughout the years. For many years the technology or the machinery simply did not exist for the round cut diamond. The invention of the bruting machine towards the end of the 1800s made the round brilliant diamond cut possible. Before the circular cut was invented, diamonds sported a cushion cut popular in Europe. In 1919 the circular cut went through another transformation with Marcel Tolkowsky’s Diamond Design Thesis.

Round diamond engagement ring settings

Diamonds in this shape are classic, and their effortlessly elegant silhouette means they match a wide variety of settings. And that means that choosing a round diamond ring setting ultimately comes down to personal preference and style. A round diamond solitaire ring can be just as stunning as something more complex, like a round diamond with baguettes (like our Three Stone Baguette Diamond Engagement Ring). Your creativity and style is truly the limit when it comes to round engagement rings. So here are some ideas for getting started with finding your ideal round diamond setting, and how to make yours stand out.

A halo is not just a halo

A round diamond with halo setting has also become a classic, like it's more basic cousin the solitaire. That's probably because accent diamonds set in a halo are an elegant and cost-effective way to add size to your center stone. In fact, they can make it appear up to a half-carat larger. But not every diamond halo is the same. A round diamond in a square halo, like you'll find on our East West Halo Diamond Engagement Ring, is enticingly complex. Your eye dances over the different lines: some straight, some arched. This setting takes it one step further by rotating the halo, a contemporary and trendy spin on classic settings.

There's even a perfect solution for brides to be who were stuck in the round diamond vs cushion cut debate. A round diamond with a cushion halo can look like a cushion cut from afar, and a gorgeous round diamond up close. It lends visual appear to the entire ring and may help shoppers torn between the two ultra-popular diamond shapes. But even if you're set on your round engagement ring with a halo that mimics the shape of the diamond, you still have unique options. Double halos add a dramatic effect to your ring. And some settings, like our Star Halo Diamond Engagement Ring, play with accent diamond sizes to create a round diamond halo ring that's inspired by nature. (We think this one looks a little like a flower and a bit like a snowflake at the same time.)

Metal can change everything

Two round diamond rings with the same setting and the same size stone can look completely different in two different metals. So if you're worried about your round diamond ring with a halo looking like everyone else's, be sure to familiarize yourself with your metal options. Many people don't know that even within the same metal choice, like yellow gold, you'll get completely different hues in 14k and 18k. A round diamond rose gold engagement ring, for example, will look pinker if you opt for 14k, but more of a champagne hue if you go instead with 18k.

Lab Round Diamonds vs Natural Round Diamonds

Lab created round diamonds and natural diamonds are essentially the same. They have the same look, sparkle and characteristics and are graded on the same parameters of carat, color, clarity and cut. Because the same labs like GIA and IGI are grading both lab and natural diamonds, rest assured you can compare one to the other easily. Because the supply chain and the the manufacturing process for lab diamonds is shorter, lab diamonds are typically about 30$ less expensive than natural diamonds of the same quality.

FAQs

What are round diamonds called?

Round diamonds are called round, brilliant cut rounds or circular diamonds. Depending on the style of the cut there can be additional variations like old mine cut can be added to the name.

Are round diamonds more expensive?

Round diamonds can be more expensive than other fancy shapes due to the fact that more rough diamond needs to be cut away to achieve the brilliant faceted look. However, for lab grown diamonds, round shapes can often be less expensive than natural diamonds of the same carat weight and quality. If looking for savings, lab round diamonds are the way to go.

Does a round diamond sparkle the most?

Due to it's 58 brilliant facets, round diamonds do sparkle the most. This style of cutting enables all the fire, scintillation and all the colors to be unleashed when the diamond refracts light. This brilliant cutting style is also used in other shapes like cushion and oval among others.

Is round the best diamond shape?

Round diamonds are the most popular and most commonly used for lab grown or natural diamond engagement rings. They are a classic that does not fade in popularity. However, the taste of the wearer is ultimately what determines the popularity of the diamond shape.