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The round-cut diamond is by far the most popular diamond shape, making up over half of all diamonds sold today. With their classic style and breathtaking brilliance, it’s easy to see why round diamonds are so beloved. But if you want to pick the best round diamond for you, what should you look for? Find out below as we go over everything you need to know about picking out a round-cut diamond.

Understanding The Round Cut Diamond

Before buying any diamond, you should understand what you’re shopping for, so we’ll start our guide with some basic information on round-cut diamonds.

Round Brilliant Cut Diamonds

When people talk about round diamonds today, they’re usually referring to a specific round diamond cut: the round brilliant cut. This incredibly popular modern diamond cut was invented by Marcel Tolkowsky, a mathematician from a family with a long history in diamond cutting.

In 1919, Marcel Tolkowsky began exploring the idea of creating a round diamond with an ideal cut that would optimize the diamond’s brilliance. He determined that a cut pattern with 58 perfectly proportioned facets is what would maximize the brilliance of a round-cut diamond. Tolkowsky’s faceting pattern consists of 33 crown facets, 24 pavilion facets, and a culet facet at the diamond’s tip. When paired with perfect symmetry and specific ideal proportions for a diamond’s pavilion angle, table size, crown angle, and crown height, Tolkowsky’s perfectly designed faceting pattern creates incredible light performance, unlike any other cut.

Tolkowsky’s invention is largely responsible for the incredible popularity of round diamonds today. Round brilliant-cut diamonds passed cushion cut diamonds in popularity after their invention and, today, remain more popular than every other diamond shape. Additionally, a large percentage of modern fancy diamond shapes now feature a modified version of Tolkowsky's brilliant cut. For example, most modern oval cut, cushion cut, pear-shaped, and princess cut diamonds feature an adapted version of the round brilliant cut.

Other Types of Round Diamonds

While round brilliant cut diamonds are the most common and popular type of round diamond, the brilliant-cut isn’t the only option for round diamonds.

Before the invention of the round brilliant cut diamond, most round diamond gemstones featured an Old European Cut. Like the round brilliant cut, the Old European Cut has 58 facets, but these facets are larger and less uniform due to hand cutting. The Old European Cut also has different proportions that are designed to enhance color and draw the eye in, rather than reflect sparkle out.

Another notable round diamond cut is the rose cut diamond, which looks very different compared to round brilliant and Old European Cut diamonds. Born in the 1700s, rose-cut diamonds have a flat base and a domed top set with triangular facets. There is no standard number of facets for a rose-cut diamond, which may feature anywhere from 3 to 24 facets. Due to their antique origins and dreamy look, rose-cut diamonds are sometimes used in modern vintage-inspired diamond jewelry.

A Note On Round Diamond Pricing

When you’re shopping for a round diamond, it’s good to be armed with the knowledge that you’re shopping for the most expensive diamond shape. Round diamonds are more expensive than other diamond shapes because of their popularity and their high manufacturing cost. Because round diamonds are so highly desired, people charge more for them. Then, the baseline cost of creating a round diamond is simply always high due to the large amount of rough diamond waste involved in creating a round shape.

Even the most skilled diamond cutter usually loses over 50% of rough diamond stone weight when cutting a round shape. So, how much more expensive is a round diamond? A round diamond can cost up to 30% more than a fancy-shaped diamond with comparable qualities. Many people find that the timeless style and unmatched brilliance of a round-cut diamond is worth this higher price tag. Then, others may ultimately decide that they’d be happy to switch to a fancy shape for the price advantage. Whatever the case may be for you, it’s good to prepare yourself for this price difference when you start seriously shopping for your diamond.

Always Look For a Diamond Grading Report

One thing you should always look for when buying a diamond is a diamond grading report, also sometimes referred to as diamond certification. After a diamond is cut and polished, it should be sent to a reputable diamond grading lab for inspection. Gemologists at the lab will weigh the diamond, measure the diamond, and grade the diamond’s qualities. Then, they will provide a grading report that details these qualities.

When you buy a round diamond from a jeweler or other retailer, it’s wise to make sure that the diamond comes with a grading report that verifies it has the qualities the seller says it does. Grading reports may come from different labs. Two highly respected gemstone grading laboratories that we recommend are the Gemological Institute of America (GIA) and the American Gem Society (AGS). Whether you would prefer a diamond that comes with a GIA diamond grading report, an AGS diamond grading report or a report from another reputable lab is up to you. Whatever you decide, some type of grading report is a must.

A Simple Guide To The 4Cs of Round Cut Diamonds

Most people have heard of the 4Cs of diamonds: diamond cut, diamond color, diamond clarity, and diamond carat. These are four elements of a diamond that can tell you quite a lot about a diamond’s appearance and beauty. In this section, we’ll give a brief overview of what you should look for when inspecting the 4Cs of round cut diamonds. We’ll start by going over the most important of the 4Cs: diamond cut.

Diamond Cut Grade

Diamond cut is a grading of how well a diamond has been cut into its shape. Diamond cut is extremely important for the beauty of a round brilliant cut diamond, as it determines not only its symmetry, but also its light performance. A well cut round diamond will have beautiful scintillation. A poorly cut round diamond will have poor light performance, making it look dull, dim, and lifeless, as well as a bit smaller than it actually is.

The GIA diamond grading scale from best to worst is:


Very Good




The AGS has a slightly more detailed scale that uses numbers within the GIA scale:

Excellent: 0, 1

Very Good: 2

Good, 3, 4

Fair: 5, 6, 7

Poor: 8, 9, 10

The AGS refers to their 0 diamonds as Ideal Cut diamonds.

So, what cut grade should you choose for your round diamond? Put simply, the higher, the better. Cut quality is not something you should skimp on if you want your diamond to look brilliant and bright. With that said, an AGS Ideal Cut or well-proportioned GIA Excellent Cut is not always feasible if you have a smaller budget. If you are working within a smaller budget, we suggest choosing a diamond with a Very Good cut grade or better. Once you move into the Good cut range, you will see a noticeable difference in light performance.

Diamond Color Grade

Diamond color is a grading of how colorless a diamond is. Colorless diamonds, also sometimes referred to as white diamonds, can range from being completely colorless to having a noticeable yellow tint.

The GIA diamond color scale uses the letters D through Z for color grades. These letters fall into categories as follows:

Colorless: D, E, F

Near Colorless: G, H, I, J

Faint Color: K, L, M

Very Light Color: N, O, P, Q, R

Light Color: S, T, U, V, W, X, Y, Z

What to look for in terms of diamond color is very much about your personal preference. If you have a strong opinion about diamond color, you may want to make sure you get a colorless diamond in the D to F range. If you want a diamond that generally looks colorless but is a bit more affordable, a G or H color diamond may work well for you.

One thing to note about diamond color grade is that it can look different depending on the color of your setting. For example, if you set a completely colorless diamond in a ring setting made of white gold or platinum, it will still look completely colorless. Yet, if you put that same colorless diamond into a yellow gold or rose gold setting, it may look a bit yellow due to light reflection. This can make paying more for a D-color diamond feel unnecessary. On the other side of the coin, you can put a diamond with a color grade as low as J or K into a yellow gold or rose gold setting and hardly notice the diamond’s faint yellow color. Warm precious metals can often mask a faint yellow tint and make a faintly colored diamond look harmonious. But if you put that same J or K grade diamond into a platinum setting, its yellow tint will be all too apparent.

To summarize, what you should look for in a diamond’s color is a matter of personal preference, but remember to keep your jewelry setting in mind when choosing your diamond color grade. The same diamond center stone may look very different in a yellow gold halo setting than it would in a white gold prong solitaire.

Diamond Clarity Grade

Diamond clarity is a grading of how flawless a diamond is. Diamonds can have internal flaws (inclusions) and external flaws (blemishes).

The GIA diamond clarity is as follows:

Flawless (FL)

Internally Flawless (IF)

Very, Very Slightly Included (VVS1, VVS2)

Very Slightly Included (VS1, VS2)

Slightly Included (SI1, SI2)

Included (I1, I2, I3)

Diamond clarity grades are assigned after the grader looks at the diamond under varying levels of magnification. Often, diamonds can look flawed under magnification, but look flawless to the naked eye. Diamonds that have flaws that cannot be seen without using magnification are what jewelers call “eye clean.”

An eye clean diamond is what most people want, but note that round brilliant cut diamonds graded as low as VS2 clarity and even SI1 clarity can sometimes be eye clean. So, if you’re shopping on a budget, looking at diamonds with these clarity grades can help you save money on clarity grade and still get a diamond that looks flawless to the naked eye.

Diamond Carat Weight

Diamond carat weight is different from the other 4Cs in that it’s not a subjective grade. Instead, it’s an objective weight measurement. Carat is simply a weight measurement that’s used specifically for diamonds and other gemstones.

People often think diamond carat means diamond size. While it does not, diamond carat weight can certainly give you an idea of a diamond’s size, since diamonds that weigh more will be larger.

So, is there something you should look for in a round diamond’s carat weight? Not really. Diamond carat weight is usually a matter of budget and preference. Generally, people choose the highest diamond carat weight that works for their budget and quality concerns.

If you’re shopping for a round diamond on a budget, here’s a tip: look at diamonds with carat weights that are just a bit under what industry insiders call “magic numbers.” Diamond magic numbers are highly desirable carat weights such as 0.50, 1, 1.25, 1.50, 1.75, and 2. Diamond price tags jump up around these diamond carat sizes. So, for example, if you were thinking of getting a 1-carat diamond but want to maximize your budget, consider looking at diamonds that are closer to 0.90 carats. Diamonds that are close in carat weight and exactly the same in quality can look extremely similar. Yet, if they’re on opposite sides of a magic number, they may have very different price tags.

Balancing Carat and Quality Within Your Budget

Most people who are buying a diamond do not have an unlimited budget. Whether you’re shopping for a loose diamond, a diamond engagement ring, or any other piece of diamond jewelry, you probably have a certain budget you need to stay within.

The key to finding a high-quality diamond you love while staying within your budget is balance. Decide on what you want to prioritize and what’s less important to you. Then, find the right balance for you within your budget. As we mentioned above, we strongly recommend prioritizing diamond cut grade and sticking with a grade of at least Very Good or better, especially if you’re shopping for an important piece like a round cut engagement ring. But, apart from that, be as flexible as your heart desires.

Final Thoughts on Shopping For a Round Diamond

We hope this buying guide has been helpful as you hunt for your perfect round diamond. If you have any questions about round diamonds or if you need assistance with picking out a round diamond, please don’t hesitate to reach out. You can get in touch with a member of the Global Rings team by messaging us through our website, calling us at (888) 774-4367, or stopping by our showroom in downtown Los Angeles.

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