10 Most Common Diamond Shapes

"Cut" and "shape" get used interchangeably, but they're different things. Cut refers to how well a diamond's facets are proportioned to reflect light. Shape refers to its outline, the thing you actually see at a glance. Here are the ten shapes you'll run into most often, and what makes each one distinct.

Round Brilliant

The round brilliant is the standard by which diamond sparkle is measured. Its 58-facet structure is specifically engineered to maximize light return, which is why it consistently outperforms other shapes on brilliance alone. It's also the most researched and refined cut in diamond history, which tends to make round diamonds the most consistent in quality for a given price point.

Princess

A princess cut is square or slightly rectangular with sharp, uncut corners. It holds more of the rough diamond's original weight during cutting than a round brilliant does, which often makes it more efficient for the carat weight you're paying for. The pointed corners do need protective settings, since they're the most vulnerable part of the stone.

Cushion

Cushion cuts combine a square or rectangular outline with rounded corners, giving them a softer silhouette than a princess cut. The facet pattern is typically larger, which produces a warmer, more fire-forward sparkle rather than the sharp brilliance of a round cut.

Oval

An oval diamond is essentially an elongated round brilliant, which means it carries similar fire and brilliance while creating the visual effect of a larger stone on the hand. Ovals are prone to a "bow tie" effect, a shadow that appears across the center of the stone depending on how the cut is proportioned, so cut quality matters more here than in most shapes.

Emerald

The emerald cut uses long, rectangular step facets rather than the triangular facets found in brilliant cuts. Instead of scattering light into sparkle, it produces a clear, mirror-like flash. Because there's less brilliance to hide flaws, emerald-cut diamonds tend to show inclusions more visibly, so clarity matters more with this shape than with most others.

Pear

A pear shape combines a rounded end with a pointed end, essentially a teardrop. It's often worn with the point facing toward the hand's fingertips, though there's no fixed rule. Like the oval, it's prone to the bow tie effect and benefits from careful proportioning.

Marquise

Marquise diamonds are elongated with pointed ends on both sides. The shape was reportedly first cut to resemble the smile of a French noblewoman, and its long, narrow profile makes it one of the most effective shapes for creating the appearance of length and size on the finger.

Radiant

A radiant cut is rectangular or square with cut corners, similar to a princess cut but with more facets, giving it brilliance closer to a round cut while keeping the more angular outline. It's a middle ground for people who want brightness without a fully round shape.

Asscher

The Asscher cut is square with step-cut facets and cropped corners, essentially a squared-off version of the emerald cut. It shares the emerald cut's clear, layered light pattern rather than scattered brilliance, and its symmetry gives it a distinct, almost architectural look.

Heart

A heart-shaped diamond is exactly what it sounds like, and it's one of the more difficult shapes to cut symmetrically. Getting both lobes and the point proportioned evenly requires more skill and more waste from the rough stone, which is part of why well-cut heart shapes carry a premium.

Choosing a Shape

Shape is largely personal preference, but a few practical points are worth knowing. Elongated shapes like oval, pear, and marquise tend to look larger per carat than round or square shapes of the same weight. Step-cut shapes like emerald and Asscher show inclusions more readily, so clarity grade matters more with those. If you're deciding between shapes, it helps to see a few in person under the same lighting rather than comparing photos, since the way each one handles light varies more than most people expect.