Jewelry Guide

How to choose a Round Diamond for Your Engagement Ring

Bride wearing round shape diamond engagement ring

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The round diamond, also known as the round brilliant cut, enjoys the prestigious position of being the most popular shape for diamond engagement rings. In fact, over 75% of all diamond engagement rings bought are round. It is a classic shape that looks great on any type of hand and will never go out of style. Let’s take a look at what makes the round diamond the most loved shaped when it comes to engagement rings.

What is the Round Cut?

Round diamond in channel setting engagement ring

Classic solitaire ring featuring a round diamond. See more here.

The round diamond contains 58 facets, of which 33 can be found on the crown of the diamond while the other 25 are on the pavilion. The stone has a cone shape which funnels light through to the top maximizing the reflection of light from the diamond and causing the diamond to sparkle brilliantly.

This makes the round cut one of the most brilliant of all the diamond cuts and a popular option for solitaire engagement rings. Also, the simplicity of the shape complements the diamond, keeping the focus on the sparkle and quality of the stone itself.

Round Cut Diamond Price

Round shape diamonds are often the priciest of all diamond cuts due to a number of factors. 

First of all, as we mentioned above, round diamonds are the most popular choice for most buyers. High consumer demand often translates to higher prices.

Another factor is the relatively low yield of round diamonds, which results in the stone costing more on a per carat basis. But what do we mean by low yield? A rough diamond is often a cubic shape while the round diamond is a conical shape. In order to cut the diamond rough into the round cut, a lot of rough is wasted. Sometimes as much as up to 60% is lost. This results in the remaining stone being priced higher per carat.

For a quick comparison, compare this round diamond with this princess cut diamond. They both have very similar specifications but the round diamond is noticeably more expensive.

It is estimated that a round diamond can cost up to 35% more than a fancy shape. This may be a price worth paying considering the value of the stone that you will be getting. But if sticking to a particular budget is important to you, then it may be a good idea to consider a different shape.

Round Diamond Cut

Cut is probably the most important factor when it comes to grading a round diamond. After all, it is a diamond’s brilliance that makes it so special and the quality of its light performance is impacted by the quality of the cut. Remember that diamond cut and diamond shape are two different things. The cut refers to the proportion and technical aspects of the faceting, while the shape refers to the geometrical shape of the stone.

GIA has created a grading system that allows labs to give round diamonds a cut grading, ranging from Excellent, Very Good, Good, Fair to Poor. On a side note, only round diamonds are given a cut grade by the GIA (although the AGS grades the cut of both round and princess shapes).

The better the cut grade, the more expensive the diamond, all else being equal.

Cut includes several factors, as this diagram indicates:

Round cut diamond specifications

While the cut grade is important, it’s more important to check out how the stone interacts with light and whether it looks good to the eye. Although cut is one aspect where it’s best not to compromise too much, you could still pick a beautiful diamond low on the cut scale. Check out HD videos and images of the diamond and see how it interacts with light. You don’t want there to be windowing or extinction on your diamond due to poor light performance.

Round shape astor ideal shape diamond from blue nile

Blue Nile’s Astor Ideal Diamonds have impeccable cut quality. See this diamond here.

Most retailers have their signature cut grade that goes beyond GIA’s Excellent. If you’re looking for the best cut, check out James Allen’s True Hearts diamonds, which are some of the best cut diamonds available. Blue Nile offers Astor Ideal diamonds which are also among the best cut diamonds. You can also check out Whiteflash and Brian Gavin, two online retailers known for the quality of their diamond cuts. Their diamonds can be more expensive than the competition, but the quality of cut and brilliance is undeniable.

Round Diamond Color Grade

Choosing your diamond’s color is often based on personal preference. The D-F (colorless) diamonds are highly-sought after and are the most popular choice. Due to the laws of supply and demand, D-F color grades are the most expensive as buyers are willing to pay more for them. However, while the visual difference between these grades can be undetectable, there is often a big price difference.

Some people prefer warm toned diamonds that are on the lower end of the scale – K grade and below. This is also a good idea if you’re opting for rose or yellow gold metals for your ring, as the tints in the stone will not be very clear when placed next to these metals.

If you’re on a budget, drop down on the color scale as far as you’re comfortable to go. The savings will be significant. Check out these two diamonds below, that are very similar in every way except that one is a D and the other a K. The difference in price? $4,360!

Round cut diamond K color

K color grade diamond. See it here.

Round cut diamond color D

D color grade diamond. See it here.

The size of the diamond should also be taken into consideration when deciding on the color. Larger diamonds tend to show more color. For an Excellent grading for color, here are the specifications to look for:

  • If the diamond is less than 1.0 carat, a color grade of D-G is considered Excellent. Avoid grades L-M as this will give your diamond a Fair-Poor rating.
  • If the diamond is between 1.0 – 2.0 carats, choose grades D-F for an Excellent grading and avoid K-L which will give you a Fair-Poor grade.
  • If your diamond is over 2.0 carats, D-F will give you an Excellent rating while I-J will be Fair – Poor.

Round Diamond Clarity

Round shape engagement ring close up on girls finger

Choosing the clarity grade of your round diamond depends on your preference. All diamonds have inclusions, even those that are graded as flawless. The difference is that these inclusions are so tiny you don’t see them.

The higher the clarity grade, the more expensive the diamond is. Bearing in mind that you will already be paying a premium for choosing a round diamond, you could compensate on this by choosing a lower clarity grade. Most inclusions cannot be seeing by the naked eye, except for the Slightly Included and Included grades. As you can see, if you pay more for one category of the 4C’s (in this case, cut), you can compensate for this by playing around with the other C’s.

For an Excellent grading for clarity, here is what you need to look for:

  • If the diamond is less than 1.0 carat, a clarity grade of FL – VS2 will give you an Excellent rating. Avoid a grade over I1 as this will give you a Fair to Poor rating.
  • If the diamond is between 1.0 – 2.0 carats, choose grades FL – VVS2 for an Excellent grading and avoid I1 and above.
  • If your diamond is over 2.0 carats, FL –VVS2 will give you an Excellent rating. Avoid grades past SI2. As the stone is bigger, the inclusions may be more visible.

When purchasing your diamond, it is imperative that you see the actual stone before you buy. Some retailers simply provide a sample photo rather than a photo of the actual stone, but it’s never a good idea to buy a diamond blind.

It’s true that the diamond should come with a grading report, which will detail all the useful specifications of the diamond. However, when it comes to clarity, what’s important is not just if the stone has inclusions but where the inclusions are located, and this is not detailed in lab reports.

Take a look at this random selection of similar diamonds. They all have a clarity grading of SI1 and on a grading report would appear very similar. But looking at the images of these diamonds, it’s clear that some have less visible inclusions, while others are highly visible to the naked eye.

clarity round diamonds


The rule of thumb with clarity is to opt for a stone that contains no visible inclusions, regardless of the grading.

Where to Buy Online

There are many excellent places to purchase a round diamond online, be it a loose diamond or a pre-set engagement ring. Whichever retailer you decide to go with, always make sure that they are reputable, are specialized in what they do and will provide you with certification.

Check that the certifying laboratory is reputable, such as GIA, AGS and EGL. The report should be complete with information on clarity, color, carat and cut.

It is best to choose a professional retailer like James Allen, who have high quality photos and special Diamond Display Technology, which will allow you to inspect your diamond closely and make an informed choice. Also check the after-sales policies, especially the returns policy, in case of any issues. If you want to try out how a round diamond ring looks on your finger before you commit to buying one, check out With Clarity’s Home Preview Service which is completely free. Find out more here.

Check out our quick comparison of the top online engagement ring retailers for more information.

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