Buying Guide for “Round Cut” Diamonds

Buying Guide for “Round Cut” Diamonds

Searching for the best place to get comprehensive information about round cut diamonds?

This is it; you have come to the perfect place!

Here, you will learn about:

  • What exactly is a round cut diamond?
  • What the pros and cons of a round cut diamond are?
  • Tips for saving money when purchasing round-cut diamonds
  • The best place to buy round-cut diamonds
  • And a lot more!

When you and your fiancé decide to go for a round cut diamond for your engagement rings, you are selecting the fairytale shape of diamonds.

Most people select round cut diamond cuts when it comes to diamond engagement rings. This is the diamond shape that sparkles to the maximum of all diamond cuts and will attract the most attention from everyone everywhere you go.

You will fall in love with the way a round cut fits well in any ring style and setting.

Professionals who cut diamonds have made sure that round cut diamonds are cut with precise science and mathematical equations in mind such that they acquire the perfect shape.

This shape allows light to pass through the light and give it a sparkle that matches no other shape of diamond. This cut is the best when compared with both ancient and modern ring settings.

The question is, is a round cut diamond ring the right piece for you? We shall help you find out if this cut suits your needs. Let’s start, shall we?

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What is a Round Cut Diamond?

A round cut diamond is a diamond shape that has perfect proportions and symmetry that allows it to show the most brilliance or return of light in a diamond stone. Round diamond cuts are also referred to as brilliant rounds and top the list of the most common diamond shapes you will find in the market. Apart from being the most expensive diamond shape, it was also the first ever diamond shape to be invented.

In the 15th century, diamond cutters discovered that rough diamonds could be faceted into high diamond quality by the use of diamond dust. When they understood that, they started trying out different diamond cuts.

Today, the brilliant-cut is the technique used to arrange the facets in round cut diamonds giving them the fire and brilliance you see. In the past, this technology was not there and thus the diamonds were not as dazzling.

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The first few round cut diamonds were named Old European cut; this was before the brilliant-cut technology came into practice. The Old European cut had deep proportions and the tables were small.

These cuts were far from the pretty ones you see today. In the past, diamonds were not being graded and neither were they sparkling.

The diamond cutters back then had no idea about optimizing diamonds for the return of light, therefore diamonds had a gray color. This is also the reason colored diamonds were commonly used in jewelry pieces meant to be worn by royalties or rich people.

When the brilliant-cut technique was invented, diamonds started to gain popularity as beauty accessories and many people started to buy them. As time passed, gemologists discovered the round cut-the most beautiful shape of a diamond on earth according to diamond professionals.

Pros and Cons of Round Cut Diamonds

Like any other shape of a diamond, a round cut has the good and bad side of it. But is the bad side the deal breakers? Make your decision.


  • Easily available
  • Has the best sparkle and fire among all shapes of diamonds
  • No need for high clarity for it to look attractive
  • Has exact cut symmetry and proportions
  • Ring setting versatility
  • Exact cut grades and grade reporting


  • Most expensive of all diamond shape
  • Requires a high carat weight to be seen
  • Very common (has lost uniqueness)

Choosing a Round Cut Diamond

When Marcel Tolkowsky invented the round cut for diamonds in the 1900s, the diamond industry started to change. Diamond cutters began to acquire knowledge of how to use scintillation and exact symmetry to make ideal cut diamonds.

Ideal cut sets the standard through which all other diamonds get graded. Although the GIA does not recognize “ideal cut” it still uses the same standards (4Cs) for grading its diamonds. The 4Cs represent Color, Clarity, Carat, and Cut.


The one and only diamond cut that has exact symmetry with ideal proportions is the round brilliant cut. Other princess cut diamonds are also branded as ideal but they have not been officially recognized as so.

A round cut diamond has the highest sparkle because it reflects the most light. Marcel Tolkowsky ensured this happens with his mathematical expertise.

When you go shopping for a round cut diamond, the piece you select must have a grading report from GIA or AGS.

These are the two most respected and trusted labs for grading diamonds in the jewelry industry. When you buy a diamond with either of these two grading reports, you can rest assured that the diamond sold to you is exactly the one stated in the report. Other labs that grade diamonds like GSI and IGI are not as reliable as their guidelines for diamond grading are considered loose.

You may have a diamond with a GSI report stating that the round cut diamond is 1 carat with clarity grade SI1, H color grade, and is an Excellent cut. Do not be surprised if you take the same diamond for grading to GIA and it comes back with totally different grades, say I1 clarity, I color grade and Very Good cut.

Honestly, this is not fair to customers. You may end up buying an expensive round cut diamond with lesser quality with such labs. It is only best to rely on AGS and GIA grading reports.

The GIA’s round brilliant diamonds’ grading system is made up of 5 grades: Excellent, Very Good, Good, Fair, and Poor. There are also ideal cut diamonds although GIA does not acknowledge them. The Excellent cut is its equivalent for AGS’s ideal cut grade. In short Excellent cut=Ideal cut.

Ideal cut graded diamonds bear exact symmetries and have the highest sparkle compared to other diamond cuts. There are other terms associated with ideal cut diamonds that you need to get familiar with. One of them is the hearts and arrows pattern, which is common in the diamond industry, especially with online jewelry retailers.

The precision cuts in these diamonds create 900 angles that show hearts and arrows when viewed using a microscope. Some of the diamonds that have the hearts and arrows pattern can display this pattern through a gemscope.

The diamonds may display perfect hearts and arrows but it does not necessarily mean that the diamond has been proportioned properly. Always ask to look at the proportions of the diamond rather than trusting word of mouth.

Do not also fall for the “super ideal cut” diamond story since there is no visible difference between this and the ideal cut diamond, except for the unrealistically high price.

For you to understand what it means for a diamond to have ideal proportions, you need to know the anatomy of a diamond. You do not have to be a diamond expert or a gemologist to know this. A diamond has several parts.


The top of the diamond is called the crown while the bottom is the pavilion. These are the parts that if not cut precisely will make the diamond chip or break easily.

The lower grades of cut like Fair and Poor play a great role in compromising the durability and beauty of diamond rings. Of all the 4Cs, the cut is the most significant as it is the basis of the diamond.


Unlike other fancy shapes, a round cut diamond enables you select a lower clarity. The sparkle in these shapes of a diamond is so much that it hides all the imperfections and blemishes that can be noticed in an emerald cut diamond. While the round cut is a brilliant-cut, emerald is a step cut.

The clarity scale for diamonds used by GIA includes grades such as VS1, VS2, VVS1, and VVS2 among others.

The thing is you do not any diamond shape to be free from flaws. Step cut diamonds do not require high clarity grades since they have wide flashes, but there is no need for a clarity grade as high as VVS2 or VVS1. The lowest acceptable clarity grade for round cut diamonds is SI2, SI1 is also good.

You will be able to tell how clear a diamond is if you view the loose stones, as much as it is just numbers and letters. No diamond does not have natural inclusions, but no two pieces of the diamond are the same.

Look at these two diamonds with SI1 clarity grade. Both diamonds are similar in color, clarity, cut, and carat weight but with a minor difference in their prices, which would you buy? Would you purchase the one with a black inclusion at the center of the table or the one with an inclusion near its girdle?

You cannot base on diamond clarity only to make your pick; you have to look at the diamond using a microscope. James Allen offers the best 360 technique of looking at round cut diamonds.


When we talk about round brilliant cut diamonds, the color grade is not as important a factor as it is in other fancy shapes. The minimum color grade that is acceptable for round cut diamonds is I.

Most diamonds are graded using the color scale D-Z; you will not find any color further than grade K in the retail stores. Most retailers restrict their diamonds to colorless or near-colorless grades.

As much as retailers sell this, if you want a round cut diamond, color grade I is enough, no need for grades D, E, or F. you may also find J colored diamonds that are not yellow in the jewelry shops.

Round cut diamonds in color grades J or K will look whiter than they actually are if put in yellow gold ring settings. If you buy this, you stand to save more.

Color grade H is not something you would want for a round brilliant cut. It is common knowledge in the diamond industry that noticing the difference between two color grades which are adjacent is very difficult.


Carat weight is arguably the least important C of the 4Cs. When it comes to a carat weight, we cannot really recommend a particular figure, it all boils down to what you prefer as an individual.

If you like to draw attention to the center stone or setting of your ring, you are better off picking a different shape of diamond. 1 carat round cut diamond looks smaller than they actually are.

It is important to know that carat weight is totally different from the carat size of a diamond stone. When carat weight goes up, the carat size increases too, provided it is a similar shape. The diamond shapes below are both 1 carat, but their sizes are not the same.

Also, an increase in diamond carat weight leads to a corresponding increase in color, cut, and clarity. This is the reason most retailers sell 2-carat diamonds more expensive than 1-carat diamonds.

It is not easy to get eye-clean diamonds when mining. In fact, only about 20% of the diamonds mined are quality. Diamond miners filter through as much as 250 tons of ore before they can get rough diamonds that may look clean to the human eye.

This simply means they have to dig through 250 tons of ore to find a 1-carat diamond that is free of inclusions when seen by the eye. This is the reason diamonds are very expensive, they are hard to find.

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If it is this hard to find a single carat of diamond, how hard can it get to find 2 or even more carats? What about the cost? It most likely will cost twice as much as the price of a single carat diamond.

You will not escape the high prices, but you can always get a better deal for your money. Most major diamond retailers measure the carat of centerpieces as 2, 1 ½, 1, ¾, ½. ¼, and 1/3.

Carat weight is also measured in points. 1-carat diamond is the same as 100points in a round cut diamond. Not so many diamond retailers mention carat points in their sales but you can find loose diamonds measured using carat points in Blue Nile and James Allen shops.

You can save a lot of money if you buy a round cut diamond ring in points and not whole numbers. For example, instead of buying a 1-carat diamond, think of a 92points diamond. You may not see the difference physically but the price is sure different.

Below is a comparison between a 92 point brilliant diamond and a 1-carat diamond, both from James Allen. Check out the price difference.

0.90 Carat round diamond
0.90 Carat round diamond

1.00 Carat round diamond
1.00 Carat round diamond

Round Cut vs Other Diamond Shapes

round cut
princess cut

Which Lasts Longer

After the round cut diamonds, the princess cut is the commonest. Since the round cut is too popular and traditional, other customers prefer something a bit different. Although they are the second most popular, princess cuts are more fragile. If you look at the Mohs scale of hardness, diamond is the hardest mineral found on earth, however, this does not mean that it cannot chip, break or crack. With right pressure amount, this mineral can break.

Unlike the round cut diamonds, princess and other cut diamonds have sharp corners which put them at a greater risk of getting damaged. This is quite common in rings put in solitaire settings. The round edge on round brilliant cut diamonds makes it less likely for a round diamond to chip, although it can still crack around the girdle.

RECOMMENDED: What is Princess Cut Diamond Shape?

Which is More Adaptable?

Which diamond shape is the best for which ring setting is completely dependent on a customer’s style and preference? While some customers prefer princess cut diamonds for the center stone, some think other cuts make a better option. Maybe customers prefer princess cut because of its square outline that creates straight lines that look more attractive in modern designs. While princess cut diamonds look good in channel set diamonds, round cuts do not.

A round cut diamond looks great in any type of setting but cannot be put with channel set diamonds. Round cut diamonds look great in vintage style, tension, or solitaire setting. A princess-cut also does not do well with a bezel setting.

Round Cut vs Cushion Cut

A cushion cut is a shape in between round and princess and is number three on the list of popularity after round and princess respectively.

Round Cut
cushion cut

Which Sparkles More?

About brilliance and fire, round cut diamonds take the edge. No other diamond cut comes close to the way a round cut sparkles, even when it is a brilliant cut.

Cushion cut and diamond cut diamonds sparkle too. However, round cut diamonds neither have exact symmetry and proportions and neither prince nor cushion is cut with the same mathematics in mind.

Which Diamond Cut is Better?

It is not really easy to say which is better. We already know that round cut diamonds have the utmost sparkle and are found all over. You may also find a flashy cushion cut, but you will have to shop more than you would for a round cut.

When you are shopping for round cut diamonds, you only have to choose between an Excellent cut and an Ideal cut. As for cushion cuts, there are no guidelines on how to find the best quality diamonds.

Different cushion cut diamonds have varying pavilion depths, crown sizes, and other measurements that can help you when choosing diamonds. However, there are no preset standards.

RECOMMENDED: What is Cushion Cut Diamond Shape?

Best Place to Buy Round Cut Diamonds

We already know you can get round cut diamonds in almost every corner you turn to, but where exactly is the best place to get these sparkly pieces? Can you find them in online jewelry stores or brick and mortar stores, perhaps the family-owned jewelry businesses? What about that local jeweler in your neighborhood. Let’s look at which is the better place.

James Allen is the best place to buy round cut diamonds. This is an online shop that specializes in selling high-quality diamonds. When you shop at James Allen, you gain full control of the buying process, from picking the loose diamonds to the craftsmanship of the ring. Their library of loose diamonds is made up of an extensive collection of natural, lab-grown, and fancy colored diamonds.

All the diamond stones in their library have 360 views to help you see exactly how the diamond looks before buying. For a long time, people dreaded buying anything online. Buy today it is the most convenient way of shopping. So, why not shop for diamonds the same way too.

The shopping experience at James Allen is hassle-free and pressure-free; you take enough time to pick the diamond of your choice without any of the staff putting pressure on you.

You will most definitely love a diamond ring that you have personally crafted. If you do not have enough knowledge about diamonds, the staff is available 24/7 to help you with the process and also answer all the questions you may have. James Allen’s gemologists are trained by GIA and can very well go over the diamond grades with you via a live chat.

The staff at James Allen does not depend on commission from sales and therefore, any information you get is none biased. They will not push you to buy a diamond that is not your preference.

When you buy a round cut diamond from James Allen, you get a free lifetime warranty and a free ring resizing in the first year in case the one you ordered does not fit. The warranty will take care of all the costs incurred when you do routine repairs such as stone tightening, prong re-tipping, rhodium plating for white gold rings, cleaning, or polishing. In most corporate retailers, you will pay for such a warranty.

If you are still not convinced about buying a round cut diamond online, I would recommend you go to a family-owned business or a local jeweler. As much as you can, avoid buying from mega jewelry stores as those sell low-quality diamonds for a high price and have staff that is not fully knowledgeable about diamonds.

Best Settings for Round Cut Diamonds

Generally, round cut diamonds can fit in any ring setting. However, there are pros and cons when choosing a setting style. Some kinds of settings such as tension style give the diamond more sparkle. Others like the bezel setting impact negatively on the brilliance. Some of the best round cut diamond settings include the following:


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