Skip to Content

Round Brilliant Cut Diamonds: Everything You Need To Know

Round Brilliant Cut Diamonds: Everything You Need To Know

The complexity behind round brilliant cut diamonds made them a fan favorite all across the world. When it comes to choosing an engagement ring, the round brilliant cut diamond is the one that’s most bought, averaging nearly 75% of all diamonds sold!

What makes these round brilliant cut diamonds so desirable, though? Are there any interesting historical facts behind this cut? How much can you expect to pay for a round brilliant cut stone – and what factors influence their value the most?

In the article below, you’ll discover some vital information regarding round brilliant cut diamonds – the brilliance behind their cut, their lengthy history, and how people struggled in the early days when needing to manufacture them.

Stick around and learn everything there is about round brilliant cut diamonds!

History Of Round Brilliant Cut Diamonds

Even in the early days, people were anxious to discover better ways to approach diamonds from the cutting perspective. As we all know, the overall beauty, sparkling, and levels of light reflected by the diamond are heavily related to the craftsmanship of cutting diamonds.

Diamond experts from the 18th century started their monumental discoveries and made the first blueprints of what they believed would one day become a magnificent stone: The round brilliant cut diamond.

Unfortunately, the tools they had at their disposal back then couldn’t do this magnificent cut any justice. Round brilliant-cut diamonds dating from the 18th century can’t come close to today’s diamonds manufactured with state-of-the-art machinery. 

The full potential of the round brilliant cut’s shine and sparkle had to wait for someone to make a breakthrough and develop a more straightforward diamond cutting method. As it turns out, it needed to wait nearly two centuries. 

But the waiting game came to a full stop in the late 20th century, when the first saw used to cut diamonds was created, revolutionizing the entire approach to cutting round brilliant stones.

From then onward, the method of shaping round brilliant cut diamonds saw unbelievable levels of progress. Now that they were hindered by the less-than-favorable working conditions and the lack of suitable tools, diamond cutters could finally reveal the round brilliant cut in its full glory.

Marcel Tolkowski – and his famous book, published in 1919, Diamond Design – defined the ideal proportions of a round brilliant cut stone and changed the history of this cut forever.

Discarding the use of old, often imprecise tools and making room for highly precise lasers made it possible to showcase the true perfection of the round brilliant cut. We’ll get to that later, though. 

It’s safe to conclude that round brilliant cut diamonds have a long history behind them, paved with numerous breakthroughs and excellent ideas that all resulted in making one of the most beautiful, world-renowned diamond cuts.

But let’s take a break from this history lesson – and learn more about the actual cut.

What Is A Round Brilliant Cut Diamond?

Round cut diamonds – or round brilliant diamonds, as they’re most often referred to – have long held the title of the single most popular diamond shape. In fact, they account for roughly two-thirds of all precious stones sold worldwide.  

And when you take one look at them, it’s easy to see why. They’re the sparkliest of them all! In addition to that, round brilliant-cut diamonds represent a powerful symbol of the brilliance and ingenuity behind their shape. 

But that’s the thing – that also makes them one of the trickiest diamond cuts to achieve: The round brilliant cut is characterized by 58 facets – including the culet – and is generally known as the cut that maximizes white light reflection, known as brilliance.

Out of those 58 facets, 33 are located on the crown – eight start facets, eight kite facets, and 16 upper girdle facets. The remaining 25 facets are found on the pavilion, with 16 lower girdle ones and eight main pavilion facets. Yes, that amounts to 57, but that’s because there’s one more – the optional culet.

Cutting a diamond in a round brilliant shape can prove troublesome, as making a single mistake could result in devastating consequences.

Another “issue” is that in order to make round brilliant cut diamonds, professionals must cut way more of the original stone than they would with other diamond shapes. And that means that a lot of it goes to waste. 

From their rough shape to the round brilliant cut, these diamonds need to shed a lot of weight. And unfortunately, the more a diamond is cut, the less of it remains in the final piece. The round brilliant cut remains one of the most challenging ones to “get right.”

Ideal Proportions For Round Brilliant Cut Diamonds 

A gem’s proportions – the angles of its crown and pavilion and the size and placement of facets – are significant factors. Cut a stone too shallow – or too deep – and all the light will leak right out of the diamond rather than make it sparkle. 

Keep in mind that all those facets act like tiny mirrors that bounce light around. So, if any of them are distorted or out of line, that light will go somewhere else.

Now, as you might know, the diamond proportion is calculated based on its table size, crown height, and pavilion depth, all measured in relation to the stone’s diameter. For round brilliant diamonds, the numbers look like this: 

  • Table percentage of 55 to 59%
  • Depth percentage of 60.1 to 62.6%
  • Thin to slightly thick girdle 
  • No culet 
  • Length-to-width ratio of 1-1.01 

The Length-To-Width Ratio Should Be Just Right 

The length-to-width ratio typically indicates how long or short (square or rectangular) a diamond appears. Now, you’re looking to buy a round brilliant diamond, meaning the length-to-width ratio should be near perfect. And by “perfect,” we mean – as close to the 1.00 ratio as possible. 

Of course, a few points off (1.02, for example) won’t make that big of a difference, but you must never – ever – settle for a round brilliant stone that deviates outside of the specified range. If you do, you’ll likely end up with a not-so-round and less-than-brilliant diamond. 

That defeats the purpose of getting a round brilliant cut diamond, doesn’t it?

4 C’s Of The Round Brilliant Cut Diamonds

To determine the quality and, in turn, the value of any diamond, it’s necessary to evaluate its 4 C’s. What are the 4 C’s of diamonds, you ask? Well, let’s dissect them one by one and clear that up!

The Cut Of The Round Brilliant Cut Diamond

Most people will agree that the cut of the diamond is the most important aspect when placing a price tag on it – and we can agree with that. Don’t get us wrong; the cut quality is crucial. An adequately cut diamond will exhibit phenomenal results in terms of light performance. 

The importance of cut quality becomes even more evident in round brilliant-cut diamonds. They are, as we previously explained, perfectly optimized for brilliance, meaning that there is virtually no room for mistakes. 

Every aspect of the round brilliant cut is calculated and designed to provide the highest level of white light reflection. If any part of the diamond’s cut is “off,” the brilliance will be affected – and significantly so.

The Color Of The Round Brilliant Cut Diamond

When it comes to nearly all diamonds, most people will lean towards a “white” – or colorless – gemstone. But to understand why, we should first discuss the color grading scale as a whole. 

The color scale starts with a D and ends at Z, with each grade indicating an increase in the stone’s warmth. This bit should go without saying, but the diamond color should generally depend on the wearer’s taste and preferences. 

For instance, someone who enjoys warmer tones will naturally be drawn to the diamond color grades ranging from G to H, while someone more into cool tones will likely go for D to F color grades. 

That’s the thing with round cut diamonds: The differences between these color ranges are generally subtle enough and hardly noticeable – especially to the naked eye. And that means that you can usually compromise on color and get a better bang for your buck in other areas!

With that said, round brilliant diamonds that have a D, E, or F grade are considered “colorless” and, as such, come with a premium price tag. But again, the actual difference is hard to pick up, which is why we recommend something more reasonably priced: 

Get yourself a round diamond with a G color rating, and you’ll avoid the hefty pricing while still getting a white-looking stone. It’s generally hard to grasp the difference between the different color ranges – especially during everyday wear. So, it doesn’t make much sense to pay more for something you will hardly even notice.

The Clarity Of The Round Brilliant Cut Diamonds

Clarity, in essence, represents the presence of inclusions within a diamond. All natural gems will contain some imperfections; the question is – how visible are they? There’s no one-size-fits-all solution for round brilliant cut diamonds here. However, the consensus is:  

A clarity grade of VS2 or SI1 is suitable for diamonds weighing less than one carat. As the carat weight goes up – beyond the one-carat point – the preferred clarity grade does, too. So, for a big stone, you’ll want to go up to VS1 or VS2. 

For any diamond bigger than two carats, aim for VVS2 to FL – if your budget allows it, of course.

The Carats Of The Round Brilliant Cut Diamonds

Diamonds should always be measured in carats, with one carat being equivalent to 0.2 grams – or 200 milligrams. With that, we can discuss the truth behind the carats of the round brilliant cut diamonds.

It’s delicate to ask what the “ideal” number of carats for round brilliant cut diamonds is – mainly because this cut requires a lengthy process where a lot of the gem’s initial weight is lost. Plus, your budget plays a role in this, too. So, it’s hard to give you a definite answer. 

Price: How Much For A Round Brilliant Cut Diamond?

As we previously mentioned, the worth and value of all diamonds – round brilliant cut diamonds included – is determined by examining the 4 C’s. Diamonds with a higher carat weight will cost more. The level of transparency will influence the price tag of diamonds greatly – and so will their color grade and cut quality.

So, the answer would be: It depends. Now, you should be aware that round cut diamonds are generally the most expensive, and there are several reasons for that: 

  • A significant portion of the rough stone is lost in the cutting process 
  • The high demand and general popularity of the cut drive the prices higher 
  • The classic appeal and unmatched brilliance warrant a higher price 

For general reference, though, prices of a one-carat round cut diamond can range from $4,000 to $10,000 depending on a stone’s clarity, color grades, and cut quality. Another factor that may influence its cost would be the setting, which brings us to our next point. 

The Best Setting For A Round Brilliant Cut Diamond

As with most things regarding diamonds, individual preferences are key and serve as a crucial factor in determining what someone likes when it comes to settings. Some people prefer seeing round brilliant cut diamonds set in a ring; others like to see them in necklaces.

When it comes to the kind of jewelry you’ll most often see round brilliant-cut gems set in, rings are the most popular choice. More specifically, engagement rings represent nearly 75% of all diamonds sold across the globe. 

The beauty and sparkle of round brilliant cut diamonds offer flexibility when picking the perfect setting. However, there are general guidelines diamond shoppers should follow: Round brilliant-cut diamonds tend to look their best in four-prong settings – although, of course, you should opt for a six-prong setting if you’ve got a larger stone.

Related Read: 4 Prong Vs. 6 Prong: Which Diamond Ring Setting Is Better?

On the flip side, you should typically avoid bezel settings that wrap around the entire gem. Why? This type of setting will block some of the light – and can slightly reduce the brilliance of your stone.

That said, while you shouldn’t use a bezel setting for gems with a higher cut and color grade, it is perfectly acceptable for diamonds with good to fair grades. 

In Conclusion

As we approach the final segment of this story, let’s take a quick revision of the key elements of round brilliant cut diamonds:

  • Marcel Tolkowski defined the ideal proportions of this cut in his famous book “Diamond Design” published in 1919. 
  • It’s the most popular cut in the world, accounting for two-thirds of all diamonds sold. 
  • The round brilliant cut is characterized by a total of 58 facets, which is why it shows an incredible level of shine and sparkle. 
  • The average price tag for one-carat round brilliant cut diamonds ranges from $4,000 to $10,000. 
  • The best settings for round brilliant cut diamonds are four- and six-prong settings. 

Yes, it’s expensive – but it’s also incredibly stunning. And if you’re in the process of shopping for a diamond, the round brilliant cut is definitely something to consider.

See Also: Round Vs. Oval Diamond: Comparison Guide