A diamond's shape is one of the most personal decisions in the jewellery-buying process, it defines the ring's entire visual identity and is the first thing anyone notices. But with so many shapes available, from the timelessly popular round brilliant to the geometric elegance of an emerald cut or the romantic softness of a pear, knowing how to navigate the options can feel overwhelming. This guide explains every major diamond shape, how each one differs in brilliance, size, appearance, and flattering effect, and how to match the right shape to your style, hand, and budget.
For guidance on cut grades and the full 4Cs, see our diamond grading guide. For the full engagement ring buying process, see our complete engagement ring guide.
Key Takeaways
- Shape refers to a diamond's physical outline (round, oval, pear, etc.); cut refers to how well the diamond has been faceted and how effectively it reflects light. They are distinct qualities.
- A round brilliant diamond has 58 facets and produces more brilliance than any other shape; it is the most popular choice for engagement rings worldwide.
- Elongated shapes (oval, marquise, pear) appear larger per carat weight than round diamonds and have a flattering, finger-lengthening effect.
- Emerald and Asscher cuts have large, open facets that showcase a diamond's clarity, higher clarity grades are recommended for these shapes.
- Cut grade (Excellent, Very Good, Good, Fair, Poor) affects all shapes equally, a diamond's brilliance depends on how well it has been cut, regardless of shape.
- Poh Heng's diamond jewellery collection and engagement ring collection span the full range of shapes and settings.
Shape vs Cut: Understanding the Difference
Shape and Cut
The nuance of shapes and cut can greatly influence the brilliance of your diamond, so discovering what speaks to you can help you make an informed decision. Though often used interchangeably, shape and cut refer to distinct characteristics of a diamond.
Shape is the diamond's physical outline as seen from above: round, square, oval, pear, and so on. It is an aesthetic decision that determines the ring's overall visual character.
Cut is a technical assessment of how well the diamond has been faceted from its rough form, the precision of its angles, proportions, symmetry, and polish. Cut determines how effectively the diamond gathers and returns light, producing brilliance, fire, and scintillation.
Two diamonds of the same shape can have very different cut grades and therefore very different levels of sparkle. A round diamond with an Excellent cut will far outshine a round diamond of the same size with a Fair cut. Choosing a shape you love is important, but never at the expense of cut quality. For a full explanation of cut grades, see our diamond grading guide
The Diamond Shapes: A Complete Guide
Round Brilliant Diamond
The round brilliant is the most popular diamond shape in the world, and for good reason. Engineered specifically for maximum light performance, the round brilliant's 58 precisely arranged facets are designed to return the greatest possible amount of light back through the top of the stone, producing unmatched brilliance, fire, and scintillation. Its perfectly symmetrical, circular outline suits virtually every ring setting, band style, and hand type, making it the most versatile of all diamond shapes.
For those drawn to timeless elegance and confident in the enduring appeal of the classic, the round brilliant is the benchmark against which every other shape is compared. Explore our engagement ring collection for a beautiful selection of round diamond rings across a range of settings.
Cushion Cut Diamond
The cushion cut diamond is characterised by its softly rounded corners and pillow-like silhouette, available in square or rectangular proportions depending on the stone's length-to-width ratio. One of the oldest diamond shapes, the cushion cut combines a romantic, vintage aesthetic with larger facets that create a distinctive, chunky sparkle different from the fine scintillation of a round brilliant.
The rounded corners also offer a practical advantage: they are less prone to chipping than sharp-cornered cuts such as princess or Asscher. For buyers who love the idea of a square diamond but prefer something softer and more romantic than a princess cut, the cushion is an excellent middle ground. Browse our engagement rings for cushion cut options.
Princess Cut Diamond
The princess cut is a square or rectangular diamond with sharp, pointed corners and a brilliant-style facet arrangement that produces exceptional light performance, second only to the round brilliant in sparkle. Its geometric, modern profile has made it one of the most popular engagement ring choices for those who prefer clean, contemporary lines over the softness of a cushion or the classicism of a round.
Princess cuts are relatively forgiving on clarity, their brilliant-cut faceting pattern does a good job of dispersing inclusions and making them harder to detect. Explore the full range of diamond jewellery in our Poh Heng Trust® collection, where every stone is hand-selected for exceptional brilliance and quality.
Emerald Cut Diamond
The emerald cut diamond is a rectangular shape with cut corners and a distinctive step-cut faceting style, parallel rectangular facets arranged in steps rather than the triangular facets of a brilliant cut. This creates a very different visual effect: instead of scintillation (the flashing sparkle of a brilliant), an emerald cut produces a hall-of-mirrors effect, deep, reflective flashes of light and shadow that are elegant and sophisticated rather than dazzling.
The emerald cut's large, open table (the flat top facet) makes inclusions more visible than in brilliant-cut diamonds, which is why higher clarity grades (VS1 or above) are recommended for this shape. Its origins are in the world of coloured stones, where step cuts were used to show off colour depth; applied to diamonds, the result is a look of understated, architectural elegance with a strong vintage appeal. For certified, clarity-assured diamond pieces, see Poh Heng Trust® Diamonds.
Asscher Cut Diamond
The Asscher cut, sometimes called the square emerald cut, shares the step-cut faceting of the emerald but in a square outline with more deeply cropped corners. Developed in 1902 by the Royal Asscher Diamond Company, it became an icon of Art Deco jewellery and has experienced a strong revival among buyers who love vintage-inspired design.
Its layered step facets create a concentric, almost hypnotic pattern of squares visible through the table, a signature look unlike any other diamond shape. Like the emerald cut, the Asscher's open facets demand higher clarity grades, as inclusions are more readily visible. It is a cut for those who appreciate craftsmanship and history as much as sparkle. Explore our diamond collection for Asscher and step-cut diamond options.
Oval Diamond
The oval cut is a brilliant-cut diamond in an elongated elliptical shape, essentially a stretched version of the round brilliant. It shares the round's excellent light performance and scintillation, while offering several additional advantages: its elongated footprint appears larger face-up than a round diamond of the same carat weight, and its length creates a flattering, slimming effect on the finger.
Oval diamonds have surged in popularity in recent years and are now among the most sought-after shapes for engagement rings, loved for combining classic brilliance with a softer, more distinctive silhouette than the traditional round. Explore our engagement rings for oval diamond options.
Marquise Diamond
The marquise is an elongated diamond with two pointed ends, a boat or eye-shaped outline with a history that traces back to the court of King Louis XV of France, who reportedly commissioned a diamond cut to mimic the shape of the Marquise de Pompadour's smile. Its dramatic elongated form maximises the appearance of carat weight more than almost any other shape, a marquise diamond appears noticeably larger face-up than a round diamond of identical weight.
Like the oval, the marquise creates a strong elongating effect on the finger, making it a particularly flattering choice for shorter fingers. Its pointed ends are more exposed than rounded cuts, however, and benefit from a protective V-prong setting to prevent chipping. Explore our diamond collection for marquise and elongated diamond options.
Pear Diamond
The pear diamond, also called a teardrop diamond, combines elements of the round and marquise into a unique shape: a softly rounded base that tapers to a single elegant point. It is one of the most feminine and distinctive of all diamond shapes, equally at home as a pendant, earring drop, or engagement ring centre stone.
When worn as a ring, the point is traditionally oriented toward the fingertip, creating a graceful elongating effect. Like the oval and marquise, the pear appears larger per carat weight than a round diamond, and its asymmetric beauty lends itself naturally to distinctive, one-of-a-kind designs. Discover pear-shaped diamonds in our pendants and earrings collections, or explore our engagement ring collection for pear diamond rings.
Radiant Cut Diamond
The radiant cut diamond is a rectangular or square shape with trimmed corners and a brilliant-cut faceting pattern, combining the elegant outlines of the emerald cut with the superior light performance of the brilliant cut. It was developed in the 1970s specifically to bring maximum brilliance to rectangular diamonds, and the result is a shape that offers the best of both worlds: the presence and modernity of a rectangular outline with the sparkle and scintillation of a round-style cut.
The radiant cut is more forgiving on inclusions than the emerald or Asscher due to its brilliant-style faceting, and its trimmed corners reduce the chipping risk of a full square or rectangle. It is an excellent choice for buyers who love the idea of an elongated or square diamond but want brilliance to match a round. Explore our diamond collection for radiant cut options.
Heart Diamond
The heart-shaped diamond is the ultimate expression of romantic intent, an unmistakable symbol of love in diamond form. Its silhouette requires exceptional craftsmanship to execute: perfect symmetry between the two lobes is essential, as any asymmetry is immediately visible in a shape defined by its regularity. When well-cut, a heart diamond delivers both emotional impact and genuine brilliance from its brilliant-style facet arrangement.
Heart diamonds are particularly meaningful for engagement rings, anniversary gifts, and any occasion where love is the message. For a truly heartfelt gift, explore our gifts for her collection for beautifully crafted diamond jewellery that speaks directly to the heart.
Trillion (Triangular) Diamond
The trillion, also called the trilliant, is a triangular diamond with three equal sides and brilliant-style faceting. As a centre stone, it creates a dramatic, geometric statement; more commonly, trillion-cut diamonds are used as accent stones flanking a larger centre diamond in a three-stone ring setting, where their shape complements and frames the centre stone beautifully. Their wide, flat silhouette maximises face-up size per carat weight, making them appear particularly generous for their actual weight.
Diamond Cut Grades: How Quality of Cut Affects Every Shape
Diamond Cut Grades
Regardless of which shape you choose, the cut grade of your diamond will determine how brilliantly it performs. The GIA grades diamond cut on a five-point scale:
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Excellent: Reflects almost all light entering the stone. Maximum brilliance, fire, and scintillation.
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Very Good: Reflects most light with only minor departures from Excellent proportions. Outstanding visual performance.
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Good: Reflects a good proportion of light with slight compromises in proportion.
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Fair: Noticeably less brilliant. Significant light leakage from the sides or bottom.
- Poor: Visibly dull. Significant defects in proportion that cause dramatic light loss.
For any shape, prioritising an Excellent or Very Good cut grade gives you the most visual beauty per dollar spent. A beautifully cut smaller diamond will always outshine a larger but poorly cut stone. For detailed guidance on cut grades within the full 4Cs framework, see our diamond grading guide.
Which Diamond Shape Is Right For You?
Shape and Hand Proportions
The shape of a diamond interacts with the proportions of the wearer's hand and fingers in ways that are worth considering before choosing:
- Short or wide fingers: Elongated shapes (oval, marquise, pear, radiant) create a flattering lengthening illusion, making fingers appear longer and more slender.
- Long, slender fingers: Almost any shape works well; round and cushion cuts look particularly balanced.
- Average hand proportions: All shapes suit average hand types; personal preference and style are the primary guides.
Shape, Size Appearance, and Budget
Some shapes appear larger face-up per carat weight than others, a useful consideration when maximising the visual impact of your budget:
| Shape | Brillance | Apparent Size vs Round | Best For |
| Round Brillant | ★★★★★ | Benchmark | Maximum sparkle, timeless classic |
| Oval | ★★★★★ | Larger | Finger-elongating, modern classic |
| Marquise | ★★★★ | Largest | Maximum size appearance, dramatic |
| Pear | ★★★★ | Larger | Distinctive, romantic, versatile |
| Radiant | ★★★★ | Similar | Brilliant rectangular, modern |
| Princess | ★★★★ | Similar | Geometric, modern, sleek |
| Cushion | ★★★★ | Slightly smaller | Vintage romantic, chunky sparkle |
| Emerald | ★★★ | Similar | Understated elegance, step-cut |
| Asscher | ★★★ | Slightly Smaller | Art Deco, vintage, step-cut |
| Heart | ★★★ | Similar | Romantic Statement |
For personalised guidance on which shape best suits your priorities, visit any Poh Heng boutique to compare shapes in person.
Closing Thoughts
The diamond shape you choose will define your ring for a lifetime, and the right choice is always the one that resonates most authentically with you or the person who will wear it. Whether you are drawn to the timeless authority of a round brilliant, the vintage romance of a cushion or Asscher, the sleek modernity of a princess cut, or the elongated drama of an oval or marquise, there is no wrong answer, only the one that feels most true to your story.
Explore our full diamond collection and engagement ring collection online to begin your search, or visit any of our Poh Heng boutiques islandwide where our expert team will guide you through every shape, cut, and setting in person.
Frequently Asked Questions
What is the most popular diamond shape for an engagement ring?
The round brilliant is the most popular diamond shape globally and in Singapore, accounting for the majority of engagement ring sales. Its unmatched brilliance, versatility across all settings, and timeless appeal make it the default choice for many buyers. Oval diamonds have grown rapidly in popularity in recent years as a close second, valued for their brilliant-style sparkle and flattering elongated shape.
What is the difference between diamond shape and diamond cut?
Shape refers to the diamond's physical outline, round, oval, pear, princess, and so on. Cut refers to how well the diamond has been faceted from its rough form, assessed across proportions, symmetry, and polish. Cut determines light performance (brilliance and sparkle); shape is an aesthetic preference. Both matter, but cut quality should never be sacrificed for shape preference.
Which diamond shape looks the biggest?
The marquise diamond appears largest face-up for its carat weight, followed by oval and pear shapes. This is because elongated shapes distribute their weight across a larger surface area, creating a bigger visual footprint than a round diamond of identical carat weight. This makes elongated shapes an excellent choice for buyers who want to maximise the apparent size of their diamond within a given budget.
Which diamond shape is best for short or wide fingers?
Elongated shapes, oval, marquise, pear, and radiant, are the most flattering for shorter or wider fingers, as their length creates an optical illusion that makes fingers appear longer and more slender. Round and cushion cuts are well-proportioned for most hand types but do not have the same lengthening effect.
Do emerald and Asscher cuts require a higher clarity diamond?
Yes. The large, open table facets and step-cut style of both the emerald and Asscher cuts make inclusions more visible than in brilliant-cut diamonds. For these shapes, clarity grades of VS1 or above are generally recommended to ensure the diamond appears clean to the naked eye. Our Poh Heng Trust® Diamonds offer independently certified stones with documented clarity grades, making them a reliable choice for these more demanding shapes.
How do I choose a cut grade for my diamond?
Always prioritise Excellent or Very Good cut grades, cut has the greatest impact on how brilliant and beautiful a diamond appears in person. For a full breakdown of cut grades within the 4Cs framework, see our diamond grading guide.