Diamond shapes and cuts: oval, brilliant, and princess

Choosing the shape of a diamond means defining the character of an engagement ring for decades to come. The round brilliant accounts for 75% of diamonds sold worldwide, yet each of the nine other popular shapes offers its own distinct visual identity. Here is the complete guide to the ten most sought-after diamond shapes: their technical characteristics, their brilliance, their effect on the hand, and how to choose between them based on your personal style.

The round brilliant is the undisputed benchmark of diamond cutting. 57 or 58 facets arranged according to a geometry optimised for light reflection. It is the shape that delivers maximum brilliance: every facet is calculated to return as much light as possible to the eye. Demand is such that the round brilliant typically commands a premium of 20 to 30% more than fancy shapes of equivalent quality, simply because the cutting process results in greater loss of rough material. The round brilliant suits every mounting style: classic solitaire, pave halo, trilogy, vintage. It is the timeless shape par excellence.

The oval is an elongated brilliant. It retains a brilliance close to that of the round (similar facets, comparable arrangement), yet its elongated format creates a slimming visual effect on the hand. At equal carat weight, an oval often appears larger than a round, simply because its table surface is more extensive. The modern oval dates from the 1960s, popularised by cutter Lazare Kaplan. Be mindful of the bow-tie effect: a dark, bow-tie-shaped shadow at the centre of the diamond, visible on certain poorly proportioned ovals. A well-cut oval features a length-to-width ratio between 1.35 and 1.50.

The princess is the most brilliant square shape. A modern cut invented in the 1980s, it combines V-shaped facets arranged from the corners toward the centre, generating intense scintillation comparable to that of the round brilliant. The princess requires a mounting that protects its four pointed corners, which are naturally vulnerable. Worth noting: the princess loses less rough material during cutting than the round brilliant. This is one of the reasons it costs 20 to 30% less per carat.

The cushion evokes a rounded pillow with softened corners. It is an historic shape, popularised in the nineteenth century, that has experienced a remarkable resurgence over the past fifteen years. The cushion exists in two variations: classic cushion (broad facets, a soft, lustrous glow) and modified brilliant cushion (additional facets, more intense scintillation). The cushion cut lends itself particularly well to vintage settings and pave halos. Its soft, almost organic appearance contrasts beautifully with the precise lines of the round brilliant.

The Emerald (or emerald cut) is a rectangular shape with parallel step facets. Unlike brilliant cuts, which prioritise scintillation, the emerald cut relies on clarity and a mirror effect. The broad, flat facets act like windows: any inclusions become immediately visible. An emerald cut diamond demands high clarity (VS2 minimum recommended). The emerald cut exudes an Art Deco elegance. Simple settings, often flanked by two lateral baguette cut stones, highlight its geometric lines.

The pear combines a rounded end with a pointed tip. A hybrid between the round brilliant and the marquise, the pear visually elongates the fingers and offers brilliance comparable to a round. Traditionally worn with the point toward the nail, it suits both engagement rings and pendants. Symmetry is critical: a poorly cut pear will show uneven shoulders or a pronounced bow-tie effect. The ideal length-to-width ratio falls between 1.45 and 1.75.

The marquise is a boat-shaped cut, elongated to two pointed ends. It maximises the apparent carat weight: at equal weight, a marquise appears larger than any other shape. The elongating effect on the hand is spectacular. Historically, the marquise is said to have been created for Louis XV, inspired by the lips of Madame de Pompadour. Today, it evokes a dramatic, vintage or bohemian style. Like the pear, the marquise requires a setting that protects its points.

The Asscher is a square emerald cut, created in 1902 by Joseph Asscher in Amsterdam. A step-faceted shape with cropped corners, the Asscher presents a unique optical effect: a "hall of mirrors", a play of deep reflections that mesmerises under the light. The Asscher demands the same high clarity as the emerald cut. It is a rare shape, prized by connoisseurs and Art Deco enthusiasts alike.

The radiant is a hybrid: rectangular or square in shape (like the emerald cut), but with brilliant facets combining the strict geometry of step cuts with the scintillation of brilliant cuts. Invented in the 1970s, the radiant cut bridges clean geometric lines and maximum brilliance. It is ideal for those who love straight lines but desire an exceptional sparkle. It conceals inclusions more effectively than the Emerald cut, thanks to its fragmented facet arrangement.

The heart is the most symbolic of all diamond shapes. A variation of the round brilliant featuring a distinctive upper cleft, the heart requires expert cutting to preserve perfect symmetry and avoid a central bow-tie effect. It is rarely chosen for an engagement ring, appearing more often as a pendant, yet it remains an unmistakable declaration of intent. A heart-shaped diamond should be at least 0.50 carat for the shape to read clearly. Below that weight, the cleft becomes difficult to distinguish.

The shape refers to the diamond's external outline (round, oval, princess). The cut quality (cut grade) refers to the precision of proportions, angles, and polish. A perfectly cut round brilliant reflects incoming light directly back to the observer's eye, producing brilliance.

The facets are the polished flat surfaces of the diamond. The number of facets varies by shape: 58 for the round brilliant, 76 for the radiant, 71 for the princess. Yet the number alone guarantees nothing. The angle and arrangement of the facets determine the brilliance, fire, and scintillation.

Brilliance: the quantity of white light reflected. Fire: the dispersion of light into spectral colours. Scintillation: flashes of light visible as the diamond moves. Brilliant-cut shapes (round, oval, pear, marquise, modified cushion brilliant, princess, radiant) are designed to maximise these three qualities. Step-cut shapes (Emerald, Asscher) favour clarity and a mirror-like effect.

Le solitaire met le diamant seul en scène. Toutes les formes fonctionnent, mais le brillant rond reste la référence : sa brillance maximale ne nécessite aucun artifice. L'ovale, la poire et la marquise créent un effet plus personnel, moins conventionnel.

Un halo de petits diamants entoure la pierre centrale. Les formes arrondies (rond, ovale, coussin) se prêtent naturellement au halo circulaire. La princess et le radiant demandent un halo carré ou rectangulaire pour respecter leurs lignes.

Le trilogy aligne trois pierres, souvent un diamant central flanqué de deux plus petits. Le brillant rond est classique, mais l'émeraude en trilogy (avec deux baguettes latérales) dégage une élégance Art déco incomparable.

Le pavage couvre l'anneau de petits diamants. La forme de la pierre centrale importe moins que sa capacité à se détacher du pavage. Les formes hautes (brillant rond, coussin) créent plus de contraste que les formes plates (émeraude).

Les formes anciennes (coussin, asscher, émeraude) évoquent naturellement les décennies passées. Associées à des montures ciselées, elles recréent l'esthétique des années 1920-1940.

L'or jaune 18 carats (75 % d'or pur) réchauffe les diamants de couleur légèrement teintée (grades H à K). Les formes vintage (coussin, asscher) s'harmonisent naturellement avec l'or jaune, évoquant les bijoux anciens.

L'or blanc 18 carats (or + palladium) et le platine (95 % pur) sont les métaux de référence pour les diamants incolores (grades D à G). Leur neutralité ne masque aucune teinte. Le platine, hypoallergénique, est la référence des implants médicaux : aucun risque allergène. À noter : certaines formulations d'or blanc (anciennes ou hors UE) contiennent du nickel, allergène potentiel. L'or jaune 18k Mayuri est formulé sans nickel (argent + cuivre uniquement).

L'or rose (or + 20 à 25 % de cuivre) crée un contraste chaleureux avec les diamants blancs. Les formes rondes et douces (brillant rond, ovale, coussin) s'harmonisent particulièrement bien avec la douceur de l'or rose.

The round brilliant commands a higher price per carat. The reason: its cut generates significant raw material loss (up to 50% of the original stone). Fancy shapes (oval, princess, cushion, Emerald cut, pear, marquise, Asscher, radiant, heart) cost 20 to 30% less at equivalent quality.

In practical terms: with a budget of $3,600, you can obtain a round brilliant of 0.70 carat or an oval of 0.90 carat, at comparable clarity and colour grades.

The shapes that maximise apparent carat size are the marquise, oval, and pear. Their extended table surface makes them appear larger at equal weight. The shapes that demand higher clarity are the Emerald cut and Asscher. Their broad, flat facets reveal every inclusion, making a VS2 grade the minimum recommended, or even VS1. The shapes that conceal inclusions are the round brilliant, modified brilliant cushion, radiant, and princess. Their fragmented facets scatter light and disguise internal flaws, meaning a well-selected SI1 grade (with the inclusion positioned away from the centre) can be entirely sufficient.

Le brillant rond coûte plus cher à carat égal. Raison : la taille génère une perte de matière brute importante (jusqu'à 50 % de la pierre d'origine). Les formes fantaisie (ovale, princess, coussin, émeraude, poire, marquise, asscher, radiant, cœur) coûtent 20 à 30 % moins cher à qualité équivalente.

Conséquence pratique : avec un budget de 3 000 EUR, vous pouvez obtenir un brillant rond de 0,70 carat ou un ovale de 0,90 carat, à clarté et couleur comparables.

Les formes qui maximisent le carat apparent sont la marquise, l'ovale et la poire. Leur surface de table étendue les fait paraître plus grandes à poids égal. Les formes qui exigent une pureté élevée sont l'émeraude et l'asscher. Leurs facettes larges et plates révèlent toute inclusion. Budget à prévoir : un diamant VS2 minimum, voire VS1. Les formes qui masquent les inclusions sont le brillant rond, le coussin brillant modifié, le radiant et la princess. Leurs facettes fragmentées dispersent la lumière et camouflent les défauts internes. Un grade SI1 bien choisi (inclusion positionnée hors du centre) peut suffire.

Choosing a diamond shape means defining the visual identity of a ring worn for decades. The round brilliant remains the benchmark for its unmatched brilliance, yet each of the nine other shapes offers a distinct personality: the oval elongates the hand, the princess cut sparkles with intensity, the emerald cut radiates Art Deco elegance, and the marquise maximises the appearance of carat weight.

Several factors come into play: your budget (fancy shapes typically cost 20 to 30% less), your preferred setting style (solitaire, halo, trilogy), the visual effect on your hand (elongating versus compact shapes), and simply what speaks to you. A well-chosen diamond is not the one that ticks every technical box, but the one you will never tire of looking at.

Our creations incorporate shapes suited to each design, always set in 18K gold, always individually selected by our gemologists. Form follows function, never the other way around.

Choisir la forme d'un diamant, c'est définir l'identité visuelle d'une bague portée des décennies. Le brillant rond reste la référence pour sa brillance maximale, mais les neuf autres formes offrent chacune une personnalité distincte : l'ovale affine la main, la princess scintille intensément, l'émeraude dégage une élégance Art déco, la marquise maximise le carat apparent.

Les critères de choix se croisent : votre budget (les formes fantaisie coûtent 20 à 30 % moins cher), le style de monture souhaité (solitaire, halo, trilogy), l'effet visuel sur votre main (formes allongeantes vs compactes), et simplement ce qui vous parle. Un diamant bien choisi n'est pas celui qui coche toutes les cases techniques, mais celui que vous ne vous lasserez pas de regarder.

Nos créations intègrent les formes adaptées à chaque design, toujours serties sur or 18 carats, toujours sélectionnées individuellement par nos gemmologues. La forme suit la fonction, jamais l'inverse.