A diamond's shape is its outline — the silhouette you see looking straight down at the stone — and it is the most personal choice in the whole selection. There are ten shapes in common use: round brilliant, princess, cushion, oval, emerald, pear, asscher, heart, radiant and marquise. Round brilliant is by far the most popular because it returns the most light; the others, often called fancy shapes, each carry a distinct character, from the vintage calm of an emerald cut to the elongating grace of an oval. None is objectively better — the right shape is the one that speaks to the person who will wear it.
The ten diamond shapes in common use, each with its own character.
Round brilliant — the timeless standard
With fifty-seven or fifty-eight precisely arranged facets, the round brilliant is engineered to maximise sparkle, and it accounts for the majority of diamonds sold. It is the most forgiving shape, hiding inclusions and colour well, and the only one to receive an official cut grade from the major laboratories. If enduring brilliance is your priority, this is the safe and radiant choice.
Step cuts — emerald and asscher
Emerald and asscher cuts are step cuts: their facets run in long, parallel lines like a hall of mirrors, producing broad flashes of light rather than the intense scintillation of a brilliant. The effect is understated and architectural, prized for its clarity and calm. Because these open cuts conceal little, they reward higher colour and clarity — but they offer wonderful presence, an emerald's elegant rectangle appearing larger for its weight, the asscher a near-square with cropped corners and vintage poise.
Elongating shapes — oval, marquise and pear
Oval, marquise and pear diamonds are brilliant cuts stretched along one axis. They flatter the hand, lengthening the finger, and their greater surface area makes them appear larger than a round of the same carat. An oval offers round-like brilliance in a softer, elongated form; a marquise, pointed at both ends, delivers maximum spread for its weight; and a pear, or teardrop, brings a graceful asymmetry that sits beautifully in pendants as well as rings.
Princess, cushion, radiant and heart
The princess is a sharp, contemporary square with brilliant-cut facets and striking fire, second only to the round in popularity. The cushion — a square or rectangle with softened corners — has a romantic, antique warmth and a slightly larger-looking face. The radiant marries a rectangular outline with full brilliant faceting for exceptional sparkle in a modern silhouette. And the heart, the most expressive of all, is a technical showpiece best chosen at half a carat or more so its two lobes and cleft read clearly.
Choosing your shape
Begin with the wearer, not the chart. Consider the styles they already reach for — classic or contemporary, quiet or expressive — and the shape of the hand and finger a ring will sit on. Think, too, about setting: solitaires celebrate a round or oval, while halos and three-stone designs open the door to fancy shapes. Whichever silhouette you choose, insist on a fine cut within it, because craftsmanship, not outline, is what makes any diamond come alive.