Sparkle or flash
Every shape sits somewhere on a spectrum between two looks. Brilliant cuts (round, oval, cushion, pear, marquise, princess, radiant, heart) are cut for many small sparkles that dance as the stone moves. Step cuts (emerald, Asscher) are cut for wide, mirror-like flashes and a calmer, more architectural feel.
Neither is better. If you love how a round diamond throws light in a restaurant, brilliant is your family. If you love the quiet drama of a hall-of-mirrors flash, step cuts are yours.
The shapes, honestly
Round brilliant
The reference shape. 57 to 58 facets tuned for maximum light return. Round hides colour slightly better than fancy shapes and reads the largest for its carat when well cut. If sparkle is the priority, start here.
Oval
Elongated round. Reads larger on the finger than a round of the same weight and flatters longer fingers. Watch for a bowtie, the shadow across the middle of the stone. A great oval has a soft bowtie, not a dark bar.
Cushion
A soft square with rounded corners. Older cushions read chunky and romantic; modern brilliant cushions sparkle closer to a round. Both are lovely, they are just different looks.
Emerald
A rectangle with step facets that create long, mirror-like flashes instead of pinpoint sparkle. Elegant and architectural. Clarity matters more here because you can see straight into the stone, so lean toward VS2 or better.
Asscher
A square emerald cut. Same step facets, same clarity considerations, but with an art deco geometry. Timeless in bezel or three-stone settings.
Pear
A teardrop, brilliant on one end and pointed on the other. Elongating and expressive. Symmetry matters most: check that the point aligns with the centre of the round end.
Marquise
A long elliptical shape with points at each end. Reads very large for its weight. Like pears, watch for bowtie shadowing and protect the tips with a bezel or v-prong.
Princess
A square brilliant. Sharper edges and lots of sparkle for the money. Corners need protection — v-prongs are standard.
Radiant
A rectangle with brilliant faceting and cropped corners. The sparkle of a round with the silhouette of an emerald. Handles colour warmth better than most shapes.
Heart
A romantic shape that lives or dies on symmetry. Look for even lobes, a defined cleft, and a well-shaped point. Bigger is better for a heart — small hearts lose their shape.
How each shape wears on the hand
At the same carat weight, elongated shapes (oval, pear, marquise, emerald, radiant) look larger on the finger than round or princess. Rounds hold their weight in depth; elongated shapes spread more of it across the top.
A useful rule: if you want a piece that feels bigger for the price, consider an oval or radiant before jumping to a higher carat. You will likely land somewhere kinder to the budget without giving up presence.
What to look for in the cut
For rounds, ask for Excellent cut and hearts-and-arrows if you can. For fancy shapes, IGI does not always assign a cut grade, so proportion matters more than paperwork. Length-to-width ratio, depth, and table percentage all shape how the stone looks in real life.
If the numbers feel abstract, we're happy to walk you through them on any stone in the Vault.