The diamond shape guide

Shape is the most personal call in a diamond purchase. Cut grade, color, and clarity all have correct answers within your budget. Shape only has the answer that suits the wearer. Here’s what each one does — and the practical wear notes that don’t make it onto most websites.

Round brilliant

The benchmark. 57 or 58 facets engineered for maximum return of light. About 75 % of engagement-ring center stones globally are round, which means: highest demand, highest price per carat, and the most polished secondary market. If you don’t have a strong instinct otherwise, round is the answer.

Oval

Round brilliant’s elongated cousin. Visually larger than a round of the same carat weight — about 10 % more crown surface — which is why it’s been the runaway favorite of the last five years. Watch for the “bowtie”: a dark shadow across the middle of poorly cut ovals. Insist on an Excellent / Very Good cut grade or commit to seeing the stone in person.

Princess

Square with pointed corners. Modern, sharp, and one of the most sparkle-efficient cuts after round. Corners are vulnerable — protect them with a setting that covers them (four corner prongs or a partial bezel).

Cushion

Square-ish with rounded corners. Reads vintage, holds light beautifully, and forgives slight inclusions because the broad facets break them up visually. The cushion family is wide — “cushion brilliant” sparkles like a round; “old mine cushion” reads more antique. Look at both before you commit.

Emerald

Step-cut rectangle with clipped corners. Not sparkly in the traditional sense — emerald cuts produce broad flashes (the “hall of mirrors” look) rather than scintillation. Demands a high clarity grade because inclusions show. Stunning on a long finger.

Asscher

The square sibling of the emerald cut. Same step facets, same need for clarity, more art-deco character. Looks like the diamond itself is a geometric object rather than a sparkling one.

Marquise

Elongated with two pointed ends. Maximum perceived size per carat — a 1.0 ct marquise looks bigger than a 1.0 ct round. Polarizing; either you love the silhouette or you don’t. Both points are fragile, so set them in V-prongs.

Pear

Round on one end, point on the other. Best worn point-out toward the fingertip — it visually elongates the finger. Like the oval, watch for a bowtie.

Radiant

Rectangular with cropped corners and brilliant-cut faceting (not step cut). Combines the silhouette of an emerald with the sparkle of a round. Underrated.

Heart

Self-explanatory. Cutting a clean heart is harder than it looks — the “cleft” at the top of the heart has to be symmetric, and the lobes have to mirror exactly. Buy with a Very Good or better symmetry grade.