Cushion Cut Engagement Rings

A cushion is a square or rectangle with its corners rounded off — the shape that sat on almost every Victorian ring before the round brilliant existed. Modern cushions split into two quite different families, and knowing which one you are looking at matters more than any other decision on this shape.

Build a cushion cut ring See stones in person

The cushion cut in brief

Cut style: Brilliant, in two families. GIA distinguishes brilliant cushions, with larger facets and a softer sparkle that emphasises clarity, from modified cushions, whose extra facets maximise brilliance and produce what the trade calls a crushed-ice effect. Neither is better. GIA's own observer research found opinion widely split on crushed ice, with evidence of both personal and regional preference — so this is genuinely a matter of taste, and anyone telling you otherwise is selling their stock.
Length to width: Square about 1.00 to 1.05, elongated about 1.10 to 1.30. GIA gives no ratio for cushions, so this is trade convention. Square cushions sit at 1.00 to 1.05. Elongated cushions — the ones now competing directly with the oval — are generally cut between 1.10 and 1.30, though they stretch to 1.60 and beyond.
One carat measures: About 5.5 mm across. A useful sanity check — carat is weight, not size, and two stones of the same weight in different shapes cover quite different amounts of finger.

Choosing a cushion cut diamond

General four Cs advice is written for round brilliants. Where it differs for this shape, it differs like this.

Colour shows more than you would expect

Cushions show greater colour saturation than round brilliants and than many other shapes, so this is a shape to spend on colour grade rather than to economise on it.

It faces up smaller

The counter-intuitive one. GIA notes that a cushion's slightly deeper proportions can make it appear smaller than other shapes of the same carat weight — so you may want more carat than you would for an oval to reach the same visual size.

Expect a different sparkle

GIA puts it plainly: do not expect the sparkle of a round brilliant or a princess cut. A cushion has a different pattern of sparkle, and is no less beautiful for it.

Chunky or crushed ice

Hold two cushions side by side and this is the difference you will see first. A chunky cushion returns light in large distinct flashes; a crushed-ice cushion breaks it into many small glittering points. GIA's research found buyers split on which they prefer, which makes this the single thing to decide in person rather than from a certificate — the grading report will not tell you which one you are getting.

Setting a cushion cut

GIA notes that a cushion's girdle is typically thicker at the corners than between them, and that a very thin girdle there can be vulnerable to chipping — which is why it suggests considering a rubover rather than claws on some stones. Four claws on the corners is the usual answer, and a halo suits the soft outline.

The wedding ring beside it

Rounded corners generally sit reasonably with a straight band, and an elongated cushion behaves much like an oval. We will show you both against the ring before deciding.

All ten shapes compared, with profile, width and whether to solder the pair.

Where the shape comes from

The modern cushion descends from the old mine cut, which dates to the 1700s and was the most common diamond cut until the late nineteenth century — named for the Brazilian diamond mines.

Cushion cut diamonds, answered

What is the difference between a chunky and a crushed ice cushion?

How the stone breaks up light. A chunky cushion has larger facets and returns light in big distinct flashes. A crushed-ice cushion is a modified cut with extra facets that scatter light into many small glittering points. GIA's own observer research found preferences genuinely split between the two, with regional differences — so there is no correct answer, only the one you prefer when you see them together.

Do cushion cut diamonds look smaller?

Slightly, yes, and it surprises people. GIA notes that a cushion's deeper proportions can make it appear smaller than other shapes of the same carat weight. It is worth budgeting for a little more carat weight on a cushion than you would on an oval to reach the same face-up size.

Are cushion cut and old mine cut diamonds the same?

Related, not identical. The modern cushion descends directly from the old mine cut, which was the dominant diamond cut from the 1700s until the late nineteenth century. Old mine cuts were cut by eye for candlelight — smaller tables, higher crowns, a large open culet. A modern cushion keeps the outline and is cut for electric light.

What is an elongated cushion cut?

A cushion cut longer than it is wide, usually around 1.10 to 1.30. It is the shape currently competing hardest with the oval: it has the soft rounded corners of a cushion with much of the finger-lengthening effect of an oval, and it tends to be easier to find than a comparable oval.

Why are cushion cut diamonds cheaper than round diamonds?

Less of the rough is thrown away. A round brilliant discards a great deal of the original crystal to reach a circle; a cushion keeps far more of it, so the same rough yields a heavier finished stone. That is a difference in cutting economics, not in the quality of the diamond.

Other shapes

Undecided is a perfectly good place to start — come and see several side by side, which is the only way to settle it. Before that, the natural and laboratory-grown comparison and the ring size guide are the two things worth reading.

Sources

Gemmological claims on this page are from the Gemological Institute of America. Where GIA gives no figure — facet counts for most fancy shapes, several length-to-width ratios — we say so rather than repeat a trade convention as fact.