If you’ve started shopping for an engagement ring, you’ve probably asked yourself what is the most popular diamond shape, and for good reason. The shape you choose affects everything from how large the stone appears on the finger to how much it sparkles, and even how much you’ll pay for a given carat weight.

The short answer: the round brilliant cut still dominates. It accounts for roughly 60–70% of all diamonds sold for engagement rings. But popularity doesn’t always mean it’s the right fit for you. Oval, emerald, and cushion cuts have all surged in demand over recent years, and each brings something genuinely different to the table, from elongated elegance to vintage character.

At A Star Diamonds, our gemologists and designers in Hatton Garden work with every major diamond shape daily, helping couples match the right cut to their style, budget, and setting preference. We’ve drawn on that hands-on experience to rank the nine most popular diamond shapes for engagement rings below, covering what makes each one stand out and who it tends to suit best.

1. Round brilliant

The round brilliant has been the dominant choice for engagement rings for decades, and it consistently tops every list when people search for what is the most popular diamond shape. Its mathematically optimised cut produces more light return than any other shape, which is the primary reason it has stayed at the top for so long.

Why it’s the most popular diamond shape

Developed in the early 20th century, the round brilliant cut was formalised by Belgian mathematician Marcel Tolkowsky in 1919, who published the ideal proportions for maximum light performance. Those proportions, a 57 or 58-facet arrangement, maximise both brilliance (white light return) and fire (coloured light dispersion). Cutters have refined that formula ever since, and today’s round brilliants are the most consistently bright diamonds you can buy.

Sparkle profile and face-up size

No other cut matches the round brilliant for pure brilliance, because every facet is angled to reflect light back through the table. The trade-off is face-up size: a round diamond appears smaller than most fancy shapes at the same carat weight. An oval or pear of equal weight will look noticeably larger on the finger, so this is worth factoring into your budget planning.

If maximum sparkle is your priority above all else, the round brilliant is the cut to choose.

Best ring settings for round diamonds

Round diamonds work with virtually every setting style. A classic four or six-claw solitaire remains the most popular choice, as it holds the stone securely while allowing light in from all angles. Pavé, halo, and three-stone settings also complement the round shape well, giving you real flexibility in how you personalise the final ring.

What to prioritise when buying

Cut quality matters more here than with any other shape. Look for a GIA or IGI Excellent cut grade, and pay close attention to symmetry and polish ratings too. Colour and clarity offer slightly more flexibility; an H colour and VS2 clarity will still face up beautifully to the naked eye in most settings.

Who it suits best

The round brilliant flatters any finger shape or length, making it the most versatile option on this list. It works especially well for anyone who wants a timeless result that will not feel dated in 20 years, and for those who value maximum light performance over a more distinctive silhouette.

2. Oval

The oval cut has climbed steadily in popularity over the past decade and now sits firmly as the second most requested shape at A Star Diamonds. If you’re asking what is the most popular diamond shape after the round brilliant, oval is the consistent answer across most UK and US market data.

Why oval keeps trending for engagement rings

Oval diamonds benefit from strong public profiles and a modern aesthetic that still feels timeless. Princess Eugenie, Hailey Bieber, and Blake Lively have all worn oval diamonds publicly, pushing the shape into mainstream demand. Beyond trends, it offers something genuinely practical: more finger coverage at the same carat weight than a round stone.

Sparkle profile and face-up size

The oval cut uses a modified brilliant facet structure, so it delivers sparkle that closely rivals the round brilliant. Its elongated outline means it appears 10 to 15% larger face-up compared to a round of equal carat weight. Watch for the "bow-tie effect," a dark shadow across the centre that appears in poorly proportioned ovals.

Always view an oval diamond via a high-quality video or in person before buying, specifically to assess bow-tie intensity.

Best ring settings for oval diamonds

A four-claw solitaire showcases the full length of the stone cleanly. An east-west setting, where the oval sits horizontally across the finger, gives a more distinctive result if you want something less conventional.

What to prioritise when buying

Focus on a length-to-width ratio between 1.35 and 1.50 for the most flattering silhouette, and always confirm bow-tie visibility is minimal before committing.

Who it suits best

Oval diamonds suit anyone who wants strong visual presence without moving too far from a classic look. The elongated shape also flatters shorter or wider fingers particularly well.

3. Princess

The princess cut sits comfortably in third place when buyers ask what is the most popular diamond shape for an engagement ring. Its square outline and sharp corners give it a bold, geometric look that stands apart from both the round and oval while still producing serious sparkle.

Why princess remains a top fancy shape

Princess cuts emerged in the 1960s and reached peak popularity in the 1990s and early 2000s. The shape has maintained a loyal following because it combines modern geometry with brilliant-cut light performance, making it a strong pick for anyone who wants clean lines without sacrificing brightness.

Sparkle profile and face-up size

The princess cut uses modified brilliant faceting, producing strong brilliance and fire that comes close to the round. Its square outline also offers good face-up size relative to its carat weight, though it will appear slightly smaller than oval or pear cuts of the same weight.

The corners of a princess diamond are vulnerable to chipping, so always choose a setting that protects them.

Best ring settings for princess diamonds

A four-claw setting with prongs at each corner is the standard choice, as it protects the corners and keeps the stone secure. Channel-set and tension settings also complement the princess cut well, giving it a sleek, contemporary finish.

What to prioritise when buying

Focus on a length-to-width ratio close to 1.0 to keep the shape looking genuinely square. Clarity matters slightly more here than with round brilliants, because the princess cut’s facets can make inclusions easier for you to spot through the table.

Who it suits best

The princess cut works well for anyone drawn to modern, architectural aesthetics rather than soft or vintage styles. It suits medium to long fingers particularly well, where its square silhouette sits comfortably in proportion.

4. Cushion

The cushion cut sits in fourth place among buyers comparing what is the most popular diamond shape for an engagement ring. Its rounded corners and pillow-like outline give it a softer look than the princess cut while still delivering strong light performance, which explains why it draws buyers from very different style preferences.

Why cushion appeals to modern and vintage tastes

Cushion cuts have been around for over two centuries, originally known as old mine cuts in the 19th century. Modern cutters have updated the facet structure significantly, but the shape retains its antique charm. That combination of historical character and contemporary refinement makes it genuinely versatile across different ring styles.

Sparkle profile and face-up size

Cushion cuts come in two main variants: standard cushion brilliant and cushion modified brilliant. The modified version produces a crushed-ice effect with smaller, more scattered sparkle, while the standard version delivers chunkier, more defined flashes of light. Both produce good brilliance, though neither quite matches the round for raw light return.

Check which cushion variant you’re buying before committing, as the visual difference between them is significant in real life.

Best ring settings for cushion diamonds

A four-claw solitaire works cleanly with the cushion shape, and a halo setting suits it particularly well by framing those rounded edges. Vintage-inspired settings with milgrain detailing also complement the cushion’s antique character.

What to prioritise when buying

Aim for a length-to-width ratio between 1.0 and 1.05 for a square cushion, or 1.15 to 1.30 for a rectangular one. Clarity grades of VS2 or above are worth prioritising, as the cushion’s open facets can reveal inclusions more readily than brilliant cuts.

Who it suits best

Cushion diamonds suit buyers who want warmth and character in their stone rather than clinical precision. The shape flatters most finger types and pairs naturally with both minimalist and more ornate ring designs.

5. Emerald

The emerald cut sits fifth on the list when buyers research what is the most popular diamond shape, and it earns that place for very different reasons than the shapes above it. Where round and oval diamonds dazzle with brightness and fire, the emerald cut draws attention through clarity, restraint, and an architectural elegance that suits a particular kind of buyer very well.

Why emerald cut stays popular in minimalist design

The emerald cut’s appeal comes from its step-cut facet structure, which produces long, hall-of-mirrors reflections rather than the scattered sparkle of brilliant cuts. That understated look resonates strongly with buyers who prefer clean, design-led jewellery over maximum flash, which is why the shape has grown steadily alongside minimalist design trends.

Sparkle profile and face-up size

Step-cut facets produce less brilliance and fire than brilliant cuts, but the reflections they create are deep and dramatic in their own right. The emerald’s rectangular outline also gives it an excellent face-up size relative to its carat weight, making it one of the most efficient shapes for finger coverage.

Because the emerald cut is so open, clarity becomes a priority: inclusions are far easier to spot here than in any brilliant-cut diamond.

Best ring settings for emerald cut diamonds

A simple solitaire with straight prongs or a bezel setting suits the emerald cut best, keeping the geometric outline clean and uninterrupted. Three-stone settings with trapezoid or baguette side stones also complement its angular character naturally.

What to prioritise when buying

Prioritise clarity at VS2 or above for an emerald cut, as the large open table exposes inclusions plainly. Colour is also more visible here than in brilliant cuts, so staying at G colour or higher gives you a noticeably cleaner result.

Who it suits best

The emerald cut suits buyers who value sophistication over sparkle and want a ring that reads as considered and intentional. It looks particularly strong on longer fingers, where the rectangular outline sits in natural proportion.

6. Pear

The pear cut, sometimes called a teardrop diamond, sits sixth on the list for buyers researching what is the most popular diamond shape. It draws buyers who want something distinctive and elegant without choosing a shape that feels too unusual or niche for a ring they’ll wear every day.

Why pear stands out without feeling "too different"

The pear cut blends a rounded base with a pointed tip, combining elements of the round brilliant and the marquise into a single outline. That hybrid quality is precisely why it holds broad appeal. You get the visual drama of an unusual shape, but the familiar sparkle of a brilliant-cut facet structure underneath it.

Sparkle profile and face-up size

Pear diamonds use modified brilliant faceting, producing strong light return that closely rivals the round cut. Their elongated outline also gives them an impressive face-up size relative to their carat weight, similar to the oval. Like ovals, pear cuts can show a bow-tie shadow across the centre, so always review a video or see the stone in person before buying.

The bow-tie effect varies significantly between pear diamonds, so treat it as a key quality checkpoint.

Best ring settings for pear diamonds

A three-claw setting with one prong protecting the tip is the standard choice. A halo setting also works particularly well, as it frames the teardrop outline and adds visual presence.

What to prioritise when buying

Look for a length-to-width ratio between 1.45 and 1.75 for a balanced silhouette. Check that the tip is well-formed and symmetrical, as poorly cut points affect both durability and appearance.

Who it suits best

Pear diamonds suit buyers who want individuality within a classic framework. The elongated shape also flatters shorter fingers, making the hand appear longer and more slender.

7. Radiant

The radiant cut ranks seventh when buyers compare what is the most popular diamond shape, but it delivers well above that position for visual impact. Its rectangular outline with cropped corners combines the geometry of an emerald cut with brilliant-cut light performance, making it a strong option for buyers who want both qualities in one stone.

Why radiant has become a go-to alternative to emerald

Radiant cuts were developed in the 1970s, introducing brilliant-style faceting to a rectangular shape for the first time. That innovation made it possible to buy a rectangular diamond with serious sparkle, something step-cut shapes cannot offer. Demand has climbed steadily as buyers discover the radiant delivers shape and brightness together in a way the emerald cut simply does not.

Sparkle profile and face-up size

The radiant’s 70-facet structure produces strong brilliance and fire that comfortably outperforms emerald cuts in light return. Its elongated outline also gives it a larger face-up appearance per carat than most buyers expect, which helps stretch a defined budget further.

Cropped corners also make the radiant more durable than a princess cut, reducing chip risk at the edges.

Best ring settings for radiant cut diamonds

A four-prong solitaire suits the radiant’s straight edges cleanly, and a halo setting adds visual presence without competing with the stone’s own sparkle.

What to prioritise when buying

Aim for a length-to-width ratio between 1.0 and 1.35 depending on your preference for square or rectangular. Pay attention to colour grade, as the radiant’s facets reveal warmth more readily than brilliant cuts.

Who it suits best

The radiant suits buyers who want strong sparkle within a geometric outline rather than the quieter look of a step cut. It sits well on medium to long fingers.

8. Marquise

The marquise cut ranks eighth when buyers compare what is the most popular diamond shape, but it consistently surprises people with how much visual presence it delivers for the carat weight. Its elongated oval outline with two pointed tips creates one of the most dramatic silhouettes available in a diamond shape.

Why marquise delivers big impact for the carat

Marquise diamonds originated in 18th-century France, reportedly commissioned by King Louis XV to resemble the lips of his mistress. The shape has never lost that sense of flair. Its extreme length-to-width ratio makes it one of the most distinctive choices on the market, which attracts buyers who want a ring that commands attention.

Sparkle profile and face-up size

The marquise uses a brilliant-cut facet structure, so it produces strong light return and fire comparable to oval and pear diamonds. Its elongated shape also gives it an outstanding face-up size advantage, appearing significantly larger than a round diamond of the same carat weight.

The pointed tips are the most vulnerable part of a marquise diamond, so always confirm your setting protects both ends with secure prongs.

Best ring settings for marquise diamonds

A five-prong solitaire with prongs at both tips and along the sides is the standard and safest choice. A halo setting adds visual weight around the outline without hiding the shape’s distinctive silhouette.

What to prioritise when buying

Focus on a length-to-width ratio between 1.75 and 2.15 for the most balanced look. Check carefully for bow-tie visibility, as poorly proportioned marquise diamonds show a noticeable dark shadow across the centre.

Who it suits best

The marquise suits buyers who want maximum finger coverage and visual drama from a single stone. Its elongating effect also makes it a particularly flattering choice for shorter or wider fingers.

9. Heart

The heart shape rounds out this guide to what is the most popular diamond shape for engagement rings, earning its place through sheer symbolic power rather than conventional appeal. No other diamond communicates romantic intent as directly, which is precisely why it divides opinion so sharply among buyers.

Why heart is a love-it-or-leave-it shape

Heart diamonds sit firmly at the sentimental end of the design spectrum. Buyers either love the shape for its unmistakable meaning, or they find it too literal for a ring they’ll wear every day. That absence of middle ground makes it the most personality-driven choice on this entire list.

Sparkle profile and face-up size

Heart diamonds use a modified brilliant-cut facet structure, producing light return and fire that rivals oval and pear diamonds. The shape offers reasonable face-up size relative to its carat weight, but stones below 0.50 carats can lose their outline definition entirely on the finger.

Go no smaller than 0.70 carats with a heart diamond to keep the shape clearly recognisable.

Best ring settings for heart-shaped diamonds

A three-prong or five-prong solitaire with prongs protecting both lobes and the point keeps the diamond secure without obscuring its outline. A halo setting also works well, as it defines and frames the silhouette with additional clarity.

What to prioritise when buying

Symmetry matters more here than with any other shape on this list. Both lobes must match precisely, since any asymmetry becomes immediately visible face-up. Aim for a length-to-width ratio between 0.90 and 1.10 for a well-balanced result.

Who it suits best

Heart diamonds suit buyers who want their ring to make a clear emotional statement without subtlety. The shape works across most finger types, though wider fingers benefit from a slightly larger stone to maintain visual proportion.

Next steps

Now that you’ve worked through the full list, you have a clear picture of what is the most popular diamond shape and, more importantly, which shapes actually match your priorities. The round brilliant remains the dominant choice for good reason, but the right answer for you depends on how you weigh sparkle, finger coverage, character, and budget against each other.

Your next step is to see these shapes in person or through high-quality video, because every diamond behaves differently in real light. Reading about a bow-tie effect or a crushed-ice cushion only gets you so far. Holding the actual stone in a real setting changes everything.

At A Star Diamonds, our Hatton Garden team works with every shape on this list daily. Whether you already know what you want or you’re still comparing options, book a consultation with our design team and we’ll help you find the right diamond with no pressure and no guesswork.