Lab-grown diamond shapes – What to know before buying

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Diamonds come in many shapes and forms, and there is no difference between what form a mined and a lab-grown diamond can be shaped into. The only difference is that you’ll get a larger and better stone with your budget if you go with a lab-grown diamond (and doing the environment and its people a service).

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Lab-grown diamond shapes

The most common lab-grown diamond shape is the round diamond which has been perfected to maximize brilliance. It is conveniently referred to as the brilliant shape and is the most popular share for lab-created and mined diamonds. All other forms than round are called “fancy.” This is because they are usually cheaper due to lower market demand and manufacturing costs. In fact, fancy cut diamonds are often cut from the remains not suitable for round diamonds or when it’s more convenient and profitable to cut the raw stone into a fancy shape.

Non-round shapes are divided into modified brilliant shapes and step cuts. Brilliant-like shapes are typically elongated shapes such as the oval as well as the romantic heart shape. They mimic the brilliance of the round diamond and ideal light reflections, and while they do not sparkle nearly as much, they come close – when cut well.

The other type is step cuts which are shapes such as the classic emerald cut. These differ in that they don’t sparkle in quite the same way, and their light reflection is more related to how mirrors reflect light. Some shapes have a larger surface than the round brilliant and are generally cheaper but may not sparkle just as much.

The shape of a diamond thus impacts price as well as brilliance and surface size and is used for different jewelry types. The round shape is the most versatile, while some fancy shapes are used for specific jewelry types or have particular design qualities (and cost less).

3 best places to buy all lab-grown diamond shapes

What is the difference between shape and cut?

While sometimes used interchangeably, shape refers to the outline geometrical shape such as heart, round, or emerald. The cut is concerned with the technical aspects surrounding the reflective qualities and how well the raw diamond is cut into the particular shape’s ideal proportions. So cut is a quality aspect, while shape is about the design and personal preference for form and jewelry settings.

To make matters even more confusing, only the round shape is graded for cut quality while the fancy shapes are (typically) not. Read more about diamond cut and what to look out for in our guide to lab-grown diamond cut.

Why are fancy shaped diamonds not cut graded?

There are two key reasons why some laboratories do not grade fancy-shaped diamond cuts.

  1. Fancy cut diamonds are usually not chosen for their brilliance alone. All other shapes than round will always have less sparkle compared to the brilliant shape. In order to improve the brilliance of a fancy-shaped diamond, you would have to make it more round. So the ideal shape of a cushion-shaped diamond would actually be to get rid of its squareness. Completely.
  2. The second reason is that the number of different shapes and their variations are almost infinite. Unlike the round shape where the ideal shape is, you guessed it, round, fancy-shaped diamonds are shaped in various forms for designs and aesthetic reasons (other than brilliance).

While some “ideal” proportions do exist, there is no consensus on the exact measurements. So how do you evaluate fancy-shaped cuts?

How to evaluate fancy-shaped diamond cut?

One approach is to use an Angular Spectrum Evaluation Tool (ASET) to inspect light reflection. This is a commonly used tool across the diamond industry. However, not for consumers. Unfortunately, very few online sellers offer images taken using the ASET tool. One of these is James Allen, but you will have to ask their gemologists if they have it available.

Some laboratories (notably the inventor of the 4Cs, GIA) are working on standardizing an assessment of cut grade, starting with the more common fancy shapes such as cushion. Other laboratories already grade fancy shapes, including IGI, which incidentally also is the premier grading institute for lab-grown diamonds.

So, great! IGI grades them; what’s the problem? Well, since there is no agreed-upon industry standard, it’s challenging to compare across sellers and graders. For that reason, it’s even more critical that you only purchase fancy-shaped diamonds at reputable sellers where you can inspect the dimensions against what is considered ideal. Second, inspect fancy-shaped diamonds by studying the magnified 360-degree images that they offer. The best and most professional sellers provide this (e.g., Clean Origin and, again, James Allen).

Diamond shape impact on price

Due to manufacturing costs and demand, the brilliant is the most costly. However, it is also the most sparkly and radiant. The cushion shape is often the cheapest, followed by the oval. The prices for princess, emerald, and heart shapes all fall somewhere in between. So despite the brilliant shape being the dearest, if you evaluate brilliance per dollar, it often comes out as the cheapest.

Diamond shape impact on appearance and surface size

To maximize the diamond surface size per dollar, the emerald or princess shape comes out on top. So if you want your diamond to appear larger and people to think you have a higher-carat diamond than you do, then they are the best choice (but will sparkle less). On the other hand, the fancy heart shape will probably attract more attention per dollar just by its unusual appearance alone. So the choice really is yours. But to help you on your journey, read about the common diamond shapes, and their characteristics and get our top buying advice below.

List of diamond shapes and buying tips

The round brilliant lab-grown diamond shape: The most brilliant and sparkly of them all.

Round Brilliant

The round brilliant is the classic and most common diamond shape. Perfected to maximize light reflection and thus brilliance. The round brilliant shape tends to be more expensive due to higher demand, but supply will also be higher. So despite the higher cost, you get a lot more sparkle for your diamond dollar, and should always be considered.

Buying tips:

Most people go for “rounded” carat weights, for example, 0.5 or 1.0. This is particularly the case for round, brilliant-shaped diamonds. So if you can go just below these popular marks, you can save money or get a better quality cut. The size difference will not be noticeable.

The only reason you would pay a marginally high premium to reach a round weight is being able to tell people you have an “X” carat stone (just round up). Rather spend the savings on getting a better cut. Read about this and get more tips in our in-depth guide to diamond carats.

With the brilliant shape, color and clarity are less noticeable and have less of an impact due to the brilliant shape’s already magnificent sparkle (in particular with an excellent or ideal cut). So for most shoppers, the clarity grades SI1 or SI2 will be just fine, and there is no reason to go above VS1.

Color also does not have to be perfect with a brilliant-cut diamond. With white gold or silver jewelry settings, aim for the I or J color grade. If set in yellow or rose gold, J or K grades will be your best bet since the diamond takes some color from the setting anyway. You can learn more in our lab-grown diamond buying guide.

Oval lab-grown diamond shape: The best-known of the fancy shapes.


The oval shape is one of the best-known of the “fancy” shapes and, despite the longer shape, retains a lot of the similar light-emitting qualities and brilliance of the round shape. The upside is that the larger shape makes the diamond appear bigger. The main drawback of the oval shape is that it almost always exhibits some extent of the bow-tie effect.

Buying tips:

On average, the oval shape comes cheaper than its popular round cousin. So expect to get more for your money’s worth. While not as radiant as the round shape, it still hides imperfections and shines nicely through color. Aim for SI1 or SI2 and I or J color grades. Finally, you should search for a stone with an acceptable “bowtie” effect by examining close-up videos of the diamond (see more tips on the bow-tie effect below).

Marquise lab-grown diamond shape: The pointy oval sibling.


Closely related to the oval shape but with more pointy ends. This shape literally has more of an edge. Similar to the oval shape, the marquise shape has excellent brilliance. The extended length results in a larger diamond surface and the appearance of a larger diamond relative to the carat weight. Also, similarly to the oval cut, an issue with the marquise is the presence of the bow-tie effect.

Buying tips:

On average, the marquise shape also comes at a discount compared to the round brilliant. While not as radiant as the round shape, the marquise, similar to the oval shape, hides imperfections and shines through color well. Aim for SI1 or SI2 and I or J color grades. You should search for a stone with an acceptable “bow-tie” effect by examining close-up videos of the diamond (see more tips on the bow-tie effect below).

Pear lab-grown diamond shape: The love child of the round and marquise diamond shapes


The love child of the round and the marquise diamond shapes, the pear is shaped exactly as you would imagine. It works really well with pendant jewelry designs (that “hang”), for example, earrings and necklaces. Or if you want something a bit different for your next ring. Being closely related to the brilliant and marquise cut, the pear shape also has an outstanding sparkle while appearing larger than the brilliant cut with the same carat. As with the oval and marquise, the pear shape is also prone to exhibit bow-tie.

Read our Ultimate Guide to Pear-Shaped Lab Diamonds!

Buying tips:

Just like the marquise, the pear is typically cheaper than the round brilliant. While not as radiant as the round shape, the pear, similar to the marquise shape, hides imperfections and shines through color well. Aim for SI1 or SI2 and I or J color grades. You should search for a stone with an acceptable “bow-tie” effect by examining close-up videos of the diamond (see more tips on the bowtie effect below).

Get more tips in our guide to buying a pear-shaped lab-grown diamond.

Get inspiration for buying pear-shaped lab diamond jewelry in our guide to the best pear-shaped lab-grown diamond jewelry.

What is the bow tie effect and what should I do about it?

The bow tie appears as darker areas across the middle of the diamond, expanding towards the outer side of the stone – much like a bow tie. The reason for the darkening effect is the cut of the stone (and the shape). It only affects the oval, marquise, and pear shapes. Typically, skillful cutters will minimize the bow tie, so its effect on the stone’s appearance is limited. However, bow-tie is not included in grading reports, so you will have to see the diamond up close and from various angles.

Buying tips:

While it is possible to eliminate the bow-tie by adjusting the cut, this comes at a cost – to your wallet, to the carat weight, and to the brilliance of the stone. For those reasons, we don’t recommend trying to avoid the bow tie at all costs. Instead, search for diamonds where the effect is less noticeable and intrusive.

Inspecting a diamond for bow tie requires examining it up close from various angles. This is typically impossible at a physical store (due to lighting and lack of available magnification). And some salespeople will even try to convince you that it’s an attractive feature and you should maximize the effect to unload their lesser-quality cuts (it can be a beautiful effect, but you want to limit it).

We therefore highly recommend that you purchase your lab-grown oval, marquise, and pear-shaped diamonds at one of the sellers that allow you to examine the stone from all angles up close using 360-degree rotation. Both Clean Origin and James Allen offer this feature, and if you’re considering any of these three particular shapes, we highly suggest you buy through them.

Princess lab-grown diamond shape: The most popular and common of the fancy shapes.


The princess diamond cut is the most common of the “fancy” shapes. The reason for its popularity is its impressive brilliance and large appearance due to the diagonal lengths (despite the actual surface area measuring smaller than it looks). The princess shape is very versatile and can be used in most types of jewelry. The biggest drawback is that the prongs attach to the sharp edges, which can lead to chipping.

Buying tips:

While not as radiant as the round shape, the princess has excellent brilliance that helps hide imperfections and color, which have a less negative visual impact on the diamond. Aim for SI1 or SI2 diamond clarity and VS1 at most (unless money is no object). With white gold or silver jewelry settings, aim for the I or J color grade. If set in yellow or rose gold, J or K grades will be your best bet since the diamond takes some color from the setting anyway.

Cushion lab-grown diamond shape: The oldest and a cheaper brilliant shape.


The cushion diamond cut is one of the oldest “fancy” cuts. It has tremendous brilliance while also being cheaper than the round brilliant shape. It has recently risen in popularity due to its exquisite appeal. The biggest drawback is that the visible surface of the diamond is smaller than the round brilliant (at the same carat weight).

Buying tips:

Due to its impressive brilliance, the cushion shape hides inclusions well, and you don’t have to opt for higher clarity than SI1 or SI2, and VS1 at most (unless, again, money is no object). However, unlike the round brilliant and the above cuts, the cushion does not hide color well, and you should probably not go below the H color, or perhaps I if in a gold or rose gold setting.

Radiant lab-grown diamond shape: The most radiant of the fancy shapes.


True to its name, the radiant cut has one of the highest radiance of the fancy cuts – almost on par with the brilliant. While cheaper than the round-shaped diamond, the surface size is also smaller. Optics play in the radiant shape’s favor, though, and the more elongated shape and diagonal length make it appear larger than it is.

Buying tips:

While not nearly as sparkly as the round shape, the radiant shape has extraordinary brilliance, which helps hide inclusions. Therefore, you can settle for SI1 or SI2 diamond clarity and VS1 at most (unless, as always, money is no object). It doesn’t hide color and the brilliant, but you should be fine with H, or I color grade. If set in yellow or rose gold, I or J grades will be your best bet since the diamond takes some color from the setting anyway.

Asscher lab-grown diamond shape: The 20ies retro diamond shape.


The Asscher diamond shape has a distinct look reminiscent of the roaring twenties and art deco style. Therefore, the shape is perfect for retro jewelry and settings. The main drawback is that, similar to the cushion shape, the surface size is smaller than the round brilliant and the smallest of the common fancy cuts (relative to its carat weight).

Buying tips:

Like the cushion shape, the Asscher does not hide color as well as the brilliant, and you should probably not go below the H color grade or perhaps I if in a gold or rose gold setting. Inclusions are also quite visible, so aim for the VS1 or VS2 clarity grades (anything above will likely be prohibitively expensive). Due to the small surface size, you can try to find a shallower diamond, giving more carat weight to the surface area.

Emerald lab-grown diamond shape: More surface and bang for the buck.


The emerald cut is probably the shape that differs most from both the brilliant and other fancy cuts. It does not reflect light in the same way as the other cuts but rather like fancy glass or mirrors. The upside is that the diamond is cheaper and does not have to be very deep, which allows for a much bigger surface and appearance relative to its carat weight. This is fortunate since the actual surface area is smaller than the brilliant shape.

Buying tips:

The emerald cuts do not hide inclusions as well as the brilliant and even the other fancy shapes due to their lack of sparkle. So you probably want to aim for at least a VS1 or VS2. It does not hide color as well either so we recommend at least an I color grade and to aim for H. The upside is that it generally is cheaper, though supply is limited.

Heart-shaped lab-grown diamonds: The most romantic of all diamonds shaped.


The heart shape is the fanciest of the fancy in our view due to its unusual shape. While it does not lack romantic appeal or attention, the surface size is smaller than that of the brilliant and most other fancy cuts. Another drawback is that to appreciate and see the heart shape, the diamond should not be too small.

But it’s the perfect romantic diamond shape – ideal for a Valentine’s Day diamond gift!

Buying tips:

The heart shape has excellent brilliance and will therefore hide imperfections fairly well. As with most brilliant-like cuts, we recommend that you aim for SI1 or SI2 diamond clarity and VS1 at most. With white gold or silver jewelry settings, aim for the H or I color grade. If set in yellow or rose gold, I or J grades will be your best bet since the diamond takes some color from the setting anyway.

Read more about the most romantic shape of all in our in-depth guide to heart-shaped lab-grown diamonds.

Conclusion and concluding buying tips

Our favorite is the timeless and number one sparkler, the round brilliant diamond shape, and we recommend the brilliant-cut simply due to its brilliance. Demand may be higher, but so is the supply. Due to its reflective qualities, it appears larger than other shapes. So unless your jewelry design requires another shape or you want to maximize surface size, go for the round brilliant shape.

Regardless of shape, but perhaps in particular for the shapes prone to bow-tie, you should always inspect prospective diamonds in detail. This includes HD pictures and 360-degree views revealing inclusions, the quality of the cut, and the amount of brilliance under correct lighting and without any undue pressure from commission-motivated salespeople.

Both Clean Origin and James Allen offer these required features, and they both come out on top in our reviews. We highly recommend that you buy your lab-grown diamonds through them whether you’re looking for a round brilliant-shaped diamond or a fancy-shaped stone.

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Rolf Hartmann
Rolf Hartmann

Rolf Hartmann has decades of experience in the jewelry industry. He knows everything you need to know to find the perfect diamond. He's an expert in lab-grown diamonds and has followed the exciting development of lab diamonds from industrial usage to the incredible gemstone quality that lab-grown diamonds are today. Rolf guides you to find the right diamond at the best possible price and expertly and transparently reviews all lab-grown diamond sellers.

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