Which diamond shape is most resistant to chipping in daily wear?

Round brilliant and cushion cuts are the most resistant, since both have rounded outlines with no sharp points exposed. Shapes with distinct corners or points, particularly marquise, pear and heart at their tips, and princess and radiant at their right-angled corners, are more vulnerable to chipping from a knock and generally need protective settings, such as claws placed directly over the vulnerable points, or a bezel or half-bezel around them.

Do fancy diamond shapes need a lower colour grade to look as good as a round brilliant?

Often yes, in the sense that a lower colour grade can be less noticeable in some fancy shapes than in a round brilliant. Step cuts like emerald and asscher, which have fewer, larger facets, show body colour more readily than they hide it, so a warmer colour grade is often more visible there, not less. Brilliant-cut fancy shapes with more facets, such as cushion and oval, tend to mask colour more effectively, similar to a round brilliant, meaning a slightly lower colour grade is usually harder to spot.

Which shape is best for hiding inclusions?

Round brilliant, cushion, and other heavily faceted brilliant cuts are best at hiding inclusions, because their many small facets scatter light in a way that breaks up the visibility of internal flaws. Step cuts such as emerald and asscher, with their broad, mirror-like facets, are the least forgiving, since they act almost like a window into the stone, meaning any inclusion is far more visible and clarity grade matters considerably more when choosing one.

Why are round brilliant diamonds more expensive per carat than other shapes?

Mainly because of cutting yield and demand. Cutting a round brilliant from rough diamond wastes more of the original crystal, since a round shape can't be cut from an irregular rough stone as efficiently as an elongated or cornered shape can, and yield loss drives up the effective cost per carat of the finished stone. Round brilliants are also consistently the most in-demand shape, particularly for engagement rings, which adds a further demand premium on top of the yield-related cost difference.

Can a diamond shape be changed after it has been cut?

Yes, in principle, a diamond can be recut into a different, generally smaller, shape, but this always sacrifices carat weight, sometimes substantially, since material has to be removed to reshape the stone. It is occasionally done to remove a damaged corner or improve a poorly cut stone's proportions, but it is not something to plan around, since it is a one-way process and the weight loss is permanent.

Which diamond shape should I choose?

The decision usually comes down to balancing four things against each other: how much a stone sparkles versus how clearly it shows its internal quality, how big it looks against its actual carat weight, how durable its outline is for daily wear, and what it costs relative to the ever-popular round brilliant. No shape wins on all four counts, which is why this remains one of the more genuinely personal decisions in choosing a stone rather than a straightforwardly technical one.

The brilliant-versus-step distinction

Before looking at individual shapes, it helps to understand the two broad families they fall into. A brilliant cut uses many small, triangular and kite-shaped facets arranged to maximise the amount of light reflected back out through the top of the stone, producing the flashing, sparkling effect most people associate with diamonds. Round brilliant, oval, cushion, princess, radiant, marquise, pear and heart are all, structurally, brilliant cuts, even though their outlines differ considerably.

A step cut uses fewer, larger, rectangular or trapezoidal facets arranged in parallel rows, like steps, running around the stone. This produces a quieter, more understated flash, sometimes described as a hall-of-mirrors effect, with broader, more architectural planes of light rather than a scattering of small sparkles. Emerald and asscher cuts are the two classic step cuts.

Neither is objectively better; they are simply different visual effects, and the choice between them is often the single biggest factor in how a finished ring reads, more than the shape's outline alone.

Round brilliant

The round brilliant is the most popular and most extensively studied diamond shape, and its faceting pattern, 57 or 58 facets arranged with mathematical precision, has been refined over more than a century specifically to maximise brilliance and fire. It hides inclusions and modest colour tints better than almost any other shape, because its dense faceting scatters light in a way that breaks up the visibility of internal characteristics. Its rounded outline has no vulnerable points, making it one of the most durable shapes for daily wear. The trade-off is cost: round brilliants command the highest price per carat of any shape, driven both by cutting yield (a round shape wastes more of the original rough crystal than an elongated one) and by sustained demand, particularly for engagement rings.

Oval

An oval is, structurally, an elongated round brilliant, carrying a similar facet arrangement adapted to a longer outline. It delivers brilliance close to a round's, while its elongated shape gives it noticeably more visual spread, meaning it looks larger, than a round brilliant of the same carat weight, since more of its weight is spread across the visible top surface of the stone rather than depth. Ovals occasionally show a "bow-tie" effect, a dark shadow across the centre of the stone caused by the cutter's own reflection interrupting light return, which varies in intensity between individual stones and is worth checking before buying. Price per carat sits below round brilliant, usually meaningfully so, reflecting both better cutting yield from rough and slightly lower demand.

Emerald

The emerald cut is a rectangular step cut with clipped corners, named for its historical association with emerald gemstones rather than any connection to diamond specifically. Its broad, flat facets produce a quieter, more architectural flash than any brilliant cut, prioritising clarity of line over sparkle. Because step-cut facets act almost like windows into the stone, an emerald cut is considerably less forgiving of inclusions and colour than a brilliant cut, meaning clarity and colour grade both matter more here than they would for the same specification in a round or cushion. Its clipped corners are somewhat protected compared with a true right-angle corner, though the long, straight edges of the stone are still points a setting needs to account for. Price per carat sits well below round brilliant.

Cushion

A cushion cut combines a rounded, pillow-like outline with a brilliant facet pattern, historically the dominant diamond cut before the modern round brilliant was developed in the early twentieth century, and it has returned to strong popularity in recent years. Older-style cushions had larger facets and a softer, more vintage sparkle, sometimes called "chunky" brilliance, while modern cushion cuts are often faceted closer to a round brilliant's precision for more consistent fire. It handles inclusions and colour reasonably well, similar to other brilliant-family shapes, and its rounded corners make it more durable day to day than a sharply cornered shape. Price sits below round brilliant, with older-style antique cushions sometimes commanding a premium of their own for their distinctive look rather than technical rarity.

Pear

A pear shape, sometimes called a teardrop, combines a rounded end with a single point, essentially a hybrid of a round brilliant and a marquise. It delivers strong brilliance and, like other elongated shapes, offers good spread relative to its carat weight when worn with the point aligned along the finger. The single point is a genuine durability concern and needs a protective setting, typically a claw placed directly over the tip, or a small amount of bezel or metal reinforcement at that specific point, since it is the shape's only vulnerable spot. Price per carat is below round brilliant, reflecting reasonable cutting yield from rough.

Princess

A princess cut is a square or rectangular brilliant cut, developed as a way of retaining brilliant-style sparkle within a geometric, cornered outline, unlike the softer lines of a round or cushion. Its four sharp right-angle corners are the most exposed and vulnerable points of any common shape, and a princess cut virtually always needs a setting, most often a four-claw setting with a claw over each corner, to protect them from chipping. It hides inclusions reasonably well given its brilliant faceting, and it typically offers the best cutting yield from rough of any shape after round brilliant, since it can be cut close to the natural rough diamond's crystal form, which keeps its price per carat comparatively low.

Radiant

A radiant cut is a rectangular or square shape with cut, rather than sharp, corners, combining a brilliant facet pattern with a step-cut-influenced outline. It sits as something of a middle ground between princess and emerald, offering more brilliance than an emerald cut while being more forgiving of inclusions than either emerald or asscher, thanks to its brilliant-style faceting. Its trimmed corners are more durable than a true princess cut's sharp right angles, though still worth a protective claw setting. Price per carat sits in the lower-middle of the range, reflecting good cutting yield.

Marquise

A marquise is an elongated shape with two symmetrical points at either end, historically said to have been commissioned to echo the shape of a smile, and it offers the greatest visual spread per carat of any common shape, meaning it looks the largest for its actual weight, since a marquise's long, narrow profile maximises surface area relative to depth. Both of its points are vulnerable and need protective claws. Like pear and oval, it can show a bow-tie effect depending on the individual cut. Price per carat is generally the lowest among the shapes discussed here, driven by strong cutting yield from irregular rough.

Asscher

An asscher cut is, in essence, a square emerald cut, sharing the same broad step-cut facets and clipped corners but in a squarer overall outline. It carries all the same characteristics as emerald in terms of showing inclusions and colour more readily than brilliant cuts, and the same relatively quiet, architectural flash rather than sparkle. Its more compact, symmetrical outline is slightly more durable than a true emerald cut's longer edges, though clarity considerations remain the dominant factor in choosing a high-quality stone in this shape. Price sits below round brilliant, similar to emerald.

Heart

A heart shape is the most distinctive and technically demanding cut to execute well, requiring precise symmetry between its two lobes and a clean, well-defined point at the base and cleft at the top; a poorly cut heart shape is one of the more noticeable cutting failures among fancy shapes. It carries good brilliance from its faceting, similar to a pear or round, but its point at the base is a genuine vulnerability requiring protective setting, and the cleft at the top can also be prone to chipping if not well proportioned. Because it is harder to cut well and there is more rough wastage in achieving the shape, price per carat can sit closer to round brilliant than most other fancy shapes, depending on the specific cutter and quality of execution.

The bottom line

There is no single "best" diamond shape, only the shape that best matches what actually matters to a given buyer. For maximum sparkle and durability with the least compromise, round brilliant remains the benchmark, at the highest price per carat. For more visual size per pound spent, elongated shapes such as oval, pear and marquise offer genuine spread advantages, though pointed ends need protective settings. For those who value quiet, architectural clarity of line over sparkle, emerald and asscher step cuts deliver a distinctive look, at the cost of showing inclusions and colour more readily, meaning clarity and colour grade deserve extra attention when choosing a stone in either shape. Getting the shape right is as much about matching a setting and a wearing style to the stone as it is about the stone in isolation.