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Round Cut Diamonds: Mystery & Brilliance Unveiled

by Willyou.net * Jun 28, 2022

Key Takeaways

  • The Round Brilliant’s popularity is unrivalled by any other shape out there, and it has been this way for many, many decades. It is, for that reason, significantly more expensive than other less popular shapes.
  • Not only does it offer a beautiful and versatile shape for an engagement ring, but it’s even proportions and distinctive facet pattern mean that it is the ultimate cut for producing fire and brilliant – and that, if sparkle is your priority, the Round Brilliant will represent the most obvious contender.
  • The Round Brilliant does not go in and out of style – it’s a classic of the diamond world.
  • Cut is vital. But, while they’re backed by strong marketing, Hearts and Arrows diamonds are rarely worth the added investment.
round cut diamond
Round cut diamond

Of all the diamond shapes available today, the Round Brilliant is surely the one that needs the least introduction – though there’s plenty more to this shape than what meets the eye.

The Round Brilliant enjoys a level of prominence no other diamond cut has. Whether on its own, or set within a solitaire engagement ring, it’s a symbol as recognizable as the heart is for love, commitment, and a moment so many of us dream about: the moment she says yes.

Traditional, versatile, and just that little bit more brilliant than any other diamond shape out there, the Round Brilliant is one that will tempt all of us during our search for the perfect engagement ring – but is it right for you?

The Cut

While you’re do doubt familiar with the silhouette of the Round Brilliant, there’s a lot more to know before you decide it’s definitely the one for you…

What Does Round Brilliant Cut Mean?

‘Round Brilliant’ is the proper term for the modern Round cut, which was specifically designed to generate the highest level of brilliance (sparkle) possible.

A brilliant cut is one that utilizes a particular facet pattern (the many faces on the surface of a cut diamond) to maximize the diamond’s sparkle.

The cut was created in the 1700s, but reworked in the early twentieth century by a diamond cutter known as Marcel Tolkowsky, with the express intention of creating a diamond shape capable of creating a better light performance than any other.

As a result, the Round cut is also known as the brilliant cut, with any of the other diamond shape that utilizes a brilliant facet pattern referred to as a ‘modified’ brilliant. These modified brilliant shapes include the Oval, the Pear, the Cushion, and the Marquise cuts, which, while capable of creating a lot of sparkle themselves, are not able to rival the level of brilliance and fire created by an exquisitely proportioned Round cut.

A brilliant cut represents the opposite of the step cuts, found in Emerald and Asscher cut diamonds.

The cut is, of course, a round diamond with no sharp edges, featuring 58 separate facets (including the culet). Of all diamonds, the Round cut shows the most sparkle if you look at it from above.

What is the Difference Between Round and Brilliant Cut Diamonds?

There is no difference. The modern Round shape is a brilliant cut.

Since the Brilliant Round cut represents the best iteration of the Round shape, designs that came before this one are no longer utilized. As a result, jewelers will often simply refer to it as the Round cut, rather than the Round Brilliant.

Of course, as we mentioned above, there are other shapes that utilize a Brilliant facet pattern, but these will be referred to as modified brilliants.

What Does a Brilliant Cut Diamond Look Like?

A Brilliant cut will feature many small, pyramid shaped diamonds placed base-to-base across the face of the diamond.

Thirty-three of the Round diamond’s facets are found on the crown, which is the angled portion found around the edge of the diamond’s table – the largest facet, through which most light is received and reflected.

The rest of the facets are found below the girdle, in the pavilion, which narrows to a sharp point or a small culet, depending on the diamond. As with any diamond, the proportions will vary from stone to stone, but there is an ideal range any shopper should aim for if they want to get the most beauty and sparkle out of their diamond (more on that in the tables below).

Round Cut Diamond History

It was in the 18th century that the Round Brilliant cut was introduced. In the beginning, it had 17 facets on the crown (upper half), although this was eventually increased to 33, which enhanced its fire and brilliance.

By 1900, modern diamond cutting techniques were advanced with incredible speed, and the development of diamond saws and good jewelry lathes made it possible for the Round brilliant cut to be perfected. As we mentioned, this cut was analyzed in 1919 by Marcel Tolkowsky, whose calculations took brilliance (how much white light was reflected) and fire into consideration, creating a delicate balance between the two. Future brilliant-cut modifications, guidelines, and standards would be based on these calculations, to this very day.

By the 1940s, with the release of De Beers’ pivotal advertising campaign for diamond engagement rings, the Round cut was transformed into the instantly recognizable symbol of love and commitment that we know so well today.

Since then, many other diamond cuts have enjoyed time in the limelight – but always alongside the Round cut, which enjoys a permanent place in our hearts as the most versatile and sparkly diamond cut available to it. It’s no wonder that it’s such a popular choice for brides. 

Is Round the Most Expensive Cut?

Yes, Round diamonds can be hundreds or thousands of dollars more expensive than other diamond cuts, even if the diamonds in question feature the same grades for cut, color and clarity, and the same carat weight.

Why? For several reasons. First off, the Round Brilliant cut is the most popular cut available today. As we mentioned above, there really has been no point in the last hundred or so years when the Round cut was not revered as a classic and beautiful choice for jewelry, and that has led to it holding a higher value on the market.

Another reason behind its higher cost has to do with the difficulties involved in cutting it. Obviously, diamonds are mined from the earth in highly irregular shapes and, while some diamond shapes enable the diamond cutter to preserve, creating a high quality round cut requires the diamond cutter to sacrifice a lot of the original stone. Of course, they can use this wastage to create another diamond – or many other, smaller diamonds – but the greatest value always lies in creating the largest diamonds possible, which means that a Round cut is rarely the most economical choice.

round twisted infinity engagement ring

Their sparkle and versatility – not to mention the fact that they’re practically synonymous with the traditional engagement ring – allows them to enjoy high popularity around the world.

We’ve already touched on how superior the Round diamond’s sparkle is, and how no other cut – even one of the modified brilliant cuts – can rival a well-cut Round diamond in terms of fire, brilliance, and scintillation. For some people, this is enough to make the process of choosing a diamond shape a done deal, and to convince them that Round Brilliant is the way to go.

For others, their ability to look beautiful in any setting is enough.

Take this simple, understated Round Solitaire Engagement Ring, for instance. Here, the diamond does all the talking – and every little detail that makes the Round Brilliant cut so exquisite is made obvious by the subtle setting.

At the other end of the scale, this shimmering Round Halo Engagement Ring in Platinum boosts the cut’s high sparkle even further, and creates something that almost appears to create its own source of light, and create an other-worldly, bright glitter on the finger. 

In these two examples alone, you can see quite how easy it is to transform this beautiful cut into something that suits your future bride’s tastes, and demonstrates the cut’s innate beauty.

Are Round Diamonds Out of Style?

No, Round diamonds continue to enjoy the highest level of popularity among engagement ring shoppers.

This brings us to yet another selling point for the Round cut: it ability to endure through countless trends and styles, and remain the classic choice for any bride to be.

Some styles, like the Pear and Heart shapes, tend to come in and out of popularity over the years. While these rings always look beautiful, the cuts are pretty used to enjoying a little while in the sun before being pushed down in favor of other styles for a few months or years.

The Round is often referred to as the ‘Little Black Dress’ of the diamond world, as it sits above the changing tides of fashions and trends and offers a beautiful staple for a timeless ring design.

Is a Round Engagement Ring Boring?

Not at all. The Round Brilliance is a classic shape, and not one that comes in and out of style every few years.

There is every chance that plenty of readers have made it this far, only to find that the little voice in the back of their heads – the one saying, ‘Go for the Round Brilliant’ – is no quieter.This shouldn’t come as a surprise, given the face that Round cut diamonds account for more than half of the engagement rings purchased in the US each year. While every diamond shape is beautiful, for so many of us it is impossible to improve upon the classics.So, no, a Round diamond – even a Round cut Solitaire, the most traditional design of all – is far from boring, you’re not boring for still coming back to it no matter how much you learn about the other shapes.

Choosing a Round Cut Diamond

So, you’ve made up your mind to pursue the beautiful Round cut for your engagement ring. In one sense, the hard part is over but, in another, it’s only just beginning. To get you started, here’s what you need to know in order to make sure you pick a knock-out diamond for your bride-to-be.

A Round cut diamond should be set with 4 prongs or 6 prongs to protect the diamond polish and light. Round cuts work with many different styles, including solitaire and three-stone engagement rings.

For a classic Round cut, look for a length-to-width ratio of 1.00 to 1.01. A length-to-width ratio of 1.02 still looks round because the sides of the diamond will create the illusion of a greater width in the center.

Round cut diamond ratio LW – 1.00, 1.05

Is a 2 Carat Round Diamond Big?

2 carats is above the current average for diamond engagement rings, and will look noticeably bigger than the more commonly chosen 1 – 1.5 carat diamonds.

While size depends on proportion, a Round diamond with an Excellent cut grade will generally feature a diameter of around 8mm, whereas a 1 carat diamond will feature a diameter of around 6.5mm.

A 2 carat diamond will create an unmissable focal point on the finger of your future bride, and create a truly dazzling performance of fire, brilliance, and scintillation with every slight movement of her hand. 

Is 2.5 Carat too Big?

No, many people are now favoring larger diamonds – above the national average.

There is, however, one exception to this rule. A diamond is ‘too big’ if, in order to invest in that carat weight, you’ve had to sacrifice the quality of the stone.

In other words, a 2.5 carat diamond will be too big if it features visible and obstructive inclusions that diminish its beauty and sparkle, an unignorable yellow color, or poor cut dimensions that jeopardize its light performance.

Finding the best diamond possible means not prioritizing size – or any single aspect – over the rest of the diamond’s features.

What is the Best Clarity for a Round Diamond?

VS1, but potentially as low as SI1.

While it’s tempting to go for the highest clarity grade possible, Round cut diamonds can appear flawless (we call this eye clean) at much lower clarity grades. The exact clarity grade depends on the size of the diamond (larger diamonds risk showing more inclusions than smaller diamonds, where minor inclusions can be concealed by the many facets and the high level of sparkle).

Do Round Diamonds Show Color?

Round diamonds are pretty good at concealing a minor amount of color, though you’ll still want to limit your search to the Near Colorless grades G, H, I and J.

A noticeable yellow tinge can really impede on the beauty of a diamond. You definitely don’t need to aim for the very highest color grades here, but you do need to exercise caution and, of course, go to see the diamond in-person before you make your decision. It might be that a diamond’s color looks more or less noticeable in pictures and videos online, so don’t put all your faith in a website – always let the jeweler carry you the rest of the way.

What is the Best Cut For a Round Diamond?

A GIA cut grade of Excellent is by far the best choice for anyone browsing Round diamonds.

A grade of Very Good will also look beautiful in a ring setting, but we would never recommend our readers go below this grade on the GIA’s cut scale. You can browse our full range of Round cut Diamonds here, all of which feature cut grades of Excellent or Very Good.

The following cut, color, and clarity guides should be taken into consideration when choosing a Round cut diamond: 

Round Cut Diamond Guide – Cut

The cut attributes of a diamond contribute to its sparkle, brilliance, and bling. Most knowledgeable buyers would choose attributes from the Excellent – Very Good columns.

ExcellentVery GoodGoodFairPoor
Table %56 – 59.954 – 55.9
60 – 60.9
52 – 53.9
61 – 64.9
50 – 51.9 or
65 – 69.9
Depth %59 – 62.358 – 58.9
62.4 – 63.5
57.5 – 57.9 or
63.9 – 64.1
56.5 – 57.4 or
64.2 – 65.9
to Slightly Thick
Very Thin
to Slightly Thick
Very Thin
Very Thin
Very Thick
Extremely Thin
CuletNoneVery SmallSmallMedium>Medium

Round Cut Diamond Length-to-Width Guide

A classic Round Cut diamond has a length-to-width ratio of 1.00 to 1.01.

ExcellentVery GoodGoodFairPoor
L/W Ratio1.00 – 1.0091.01 – 1.0191.02 – 1.0291.03 – 1.033>1.034

Round Cut Diamond Symmetry, Polish, Cut and Fluorescence Guide

Our experience suggests that Cut, Symmetry, Polish, and Fluorescence contributes to a diamond’s brilliance so that most buyers will choose Excellent – Very Good and Fluorescence None – Faint.

ExcellentVery GoodGoodFairPoor
CutExcellentVery GoodGoodFair – Poor
PolishExcellentVery GoodGoodFair – Poor
SymmetryExcellentVery GoodGoodFair – Poor
FluorescenceNoneFaintMediumStrong –
Very Strong

Round Cut Diamond Color Guide

Most buyers prefer size over color hue and will buy a diamond of G color.

ExcellentVery GoodGoodFairPoor
< 0.50 ct.D – GH – IJ – KL – M> N
0.51 – 1.00 ct.D – GH – IIJ – KK> L
1.00 – 2.00 ct.D – GHI – JK> L
>2.00 ct.D – GHI – JK> L

Round Cut Diamond Clarity Guide

Most buyers prefer size over clarity cleanse and will buy a diamond of SI1 Clarity.

ExcellentVery GoodGoodFairPoor
< 0.50 ct.FL – VS2SI1 – SI2I1I2> I3
0.51 – 1.00 ct.FL – VS1VS2 – SI1SI2I1 – I2> I3
1.00 – 2.00 ct.FL – VS1VS2 – SI1SI2I1I2 – I3
>2.00 ct.FL – VS1VS2 – SI1SI2I1I2 – I3

Advantages and Disadvantages

The Round cut diamond is versatile and looks beautiful in almost any engagement ring setting. When placed in intricate settings, they are just as beautiful when set on a simple band like a solitaire. Its design means that it will get you the most sparkle possible, and that your ring will never go out of style even as trends and fashions evolve.

The Round cut diamond is the most expensive diamond cut. This is partly because of the high amount of diamond rough wasted with the cutting process. Due to lower yields, consumer prices rise. It also looks a little smaller than other diamonds that feature the same carat weight, but an elongated shape, such as the Marquise, Pear and Oval.

Our Summary: Is a Round Brilliant Cut Diamond Good?

Absolutely. The Round Brilliant has not remained the number one choice for engagement rings for nothing, and it’s not difficult to understand why it will always be a classic.

One of the most remarkable things about the Round cut is the fact that, while it has been popular since the mid-1900s, it doesn’t look vintage or overly-traditional unless you pick out a more old-fashioned style of ring setting. It can look modern, modest, out-there, or highly traditional, however you choose to present it.

Obviously, this is not the most economic choice. It’s possible to get a more affordable diamond of the same quality and carat weight if you simply decide to look at one of the less-popular diamond shapes. Some of these, like the Pear or the Cushion, feature a brilliant facet pattern, while other more affordable options are step cuts. Nevertheless, many, many shoppers consider the Round cut to be worth the higher cost.

And, of course, the conversation will always lead back around to sparkle. Yes, you’re going to get a beautiful and beguiling light performance from any diamond you pick, simply because diamond’s innate features make it so, but, with the Round cut, you’ll know there’s no better.

Hand-Selected Round Cut Diamonds You Should See