Cushion Cut Gemstones

What a Cushion Cut Is

A cushion is a square or rectangular outline with rounded corners and gently curved sides, named for what it resembles — a pillow seen from above. That description covers the outline and almost nothing else, which is the first thing a buyer needs to understand.

The shape descends from the old mine cut, the dominant diamond cut of the eighteenth and nineteenth centuries. It was cut by hand, without the powered laps and optical modelling a modern cutter takes for granted, and it followed the octahedral shape of diamond rough rather than fighting it: a squarish stone with a small table, a high crown, a deep pavilion and a large flat culet, made to perform under candlelight, where broad slow returns of light read better than fine glitter. Electric light changed what people wanted, and the old mine cut was reworked into the modern cushion brilliant. Both are still cut, and both are still called cushions.

That is the difficulty. Cushion is a family of cuts, not a specification. Round brilliants are held to a tight set of proportions and facet counts; cushions are not. A cushion may have fifty-eight facets or a hundred, a small table or a wide one, a deep belly or a shallow one, corners barely rounded or so soft the stone approaches an oval. Two stones listed identically — cushion, 3.10 carats, fine blue — can look nothing alike in the hand. Everything in our cushion collection is a cushion; no two of them are the same cut.

Antique Versus Modern Cushion

This is the most useful distinction on this page, and the one least often stated on a listing.

The antique or old-mine style keeps the nineteenth-century architecture: a small table, a high crown, a deep pavilion and large open facets, often with a visible culet. Light travels a long way inside the stone and comes back in broad, slow, distinct flashes. The stone appears to breathe rather than sparkle. It also tends to look smaller for its weight, because the depth producing that effect is weight you cannot see face-up.

The modern cushion brilliant runs the other way. The table is larger, the crown lower, the facets smaller and more numerous, and the pavilion is arranged to break light into many small returns. The result is finer, faster scintillation — closer to a round brilliant, in a softer outline.

Neither is better. They are different instruments, and the choice is a matter of taste: some people find the modern cushion busy, and some find the antique sleepy. What matters is that a buyer who wants one and receives the other will be disappointed, and the listing rarely says which it is. Ask, before you buy, which family the stone belongs to.

Crushed Ice Versus Chunky

The trade has its own vocabulary for the same axis, and buyers meet these two words constantly without being told what they mean.

A chunky cushion has fewer, larger facets. Its light return arrives as discrete blocks — you can see the individual facets working, and the stone reads as a few bold reflections that move as a unit when you tilt it. A crushed ice cushion has many small facets, frequently split and offset, which scatter light into a fine granular field. It looks, accurately enough, like sunlight on broken ice.

Crushed ice hides inclusions better: a busy, glittering field gives the eye nowhere to settle, and needles or feathers that would be obvious in a chunky stone disappear into the noise. Chunky shows colour more cleanly, because broader areas of undisturbed body colour let a saturated stone read as one continuous colour rather than a mosaic. If you are buying for colour, chunky serves you better. If you are buying material that is never entirely clean, crushed ice is doing real work rather than disguising a fault.

Why It Suits Coloured Stones

This is the genuinely important argument, and it explains why the cushion is common in coloured stones and less so in diamond.

Colour in a transparent gemstone is a function of the path length light travels through it. A shallow, highly brilliant cut bounces light back quickly, which produces sparkle but gives it little time to pick up colour. A cushion is deeper, with broader facets and a longer internal path, so more body colour is returned to the eye. Saturated stones read richer, and the colour looks like it belongs to the whole stone rather than a few patches of it.

That is why so much fine ruby, sapphire and spinel is cushion cut, and why cushion is close to the default when coloured rough is planned and colour matters more than sparkle. A cutter looking at good corundum rough is not trying to maximise scintillation — that is a diamond problem. They are placing the deepest, most even colour face-up and keeping as much weight as the shape allows. The cushion does both. Much of what is worth looking at in the sapphire collection, the ruby collection and the spinel collection is cushion cut for that reason.

Rounded Corners Are a Durability Feature

The rounded corner is not only an aesthetic decision, and the argument is the one that produced the emerald cut.

A sharp corner is a stress concentrator. Any point where two straight edges meet carries a disproportionate share of any force applied to the stone, and it sits exposed at the edge of the setting where knocks land. A princess or a square outline puts four such points at the four most vulnerable positions. Round those corners and the stress has nowhere to concentrate; the load spreads along a curve instead of piling into a point.

For brittle material, or for species with cleavage, this matters more than a point of Mohs hardness. It is why the cushion suits tanzanite, included emerald, zircon with its vulnerable facet edges, and anything that will chip before it scratches. The same reasoning underlies the emerald cut, whose clipped corners solve the identical problem by a different geometry.

Length-to-Width Ratio

The length-to-width ratio is the long dimension divided by the short one, and on a cushion it changes the character of the stone more than buyers expect.

Square cushions sit at roughly 1.00 to 1.05. They read as compact and substantial, suit a wide finger, and carry weight well in a solitaire. Between 1.05 and 1.15 the eye registers the stone as not-quite-square, which is the least resolved territory and worth avoiding unless the stone is exceptional. From about 1.15 it reads deliberately rectangular; at 1.20 to 1.30 it is an elongated cushion that lengthens the finger as an oval does, while keeping the corner strength an oval lacks. Beyond 1.35 the shape demands a setting designed around it.

None of these is correct in the abstract. What is worth insisting on is that the ratio be intentional rather than accidental, and that you see the millimetres before deciding.

Windowing and Extinction

Two faults account for most disappointing cushions, at opposite ends of the same scale.

Windowing is a transparent, washed-out area in the centre where light passes straight through instead of being reflected back. It happens when the pavilion is too shallow: the angles fall below the critical angle for that material, and the facets stop acting as mirrors. Hold a suspect stone over printed text — if you can read through the middle, that area is window, and it is dead. Shallow cuts are common on cushions because cutting shallow saves weight from flat rough.

Extinction is the opposite fault: dark, lifeless patches, usually central, in a stone cut too deep. The light goes in, takes too long a path, and is absorbed rather than returned. Some extinction is normal and even desirable in a saturated stone — a ruby with no dark areas at all is usually a pale ruby — but a stone that goes black in the middle under ordinary light has been cut for weight.

There is a third thing to check, specific to this shape. Face-up spread is how large a stone appears from above for its weight, and the cushion varies in it more than almost any other cut, because depth percentages across the family range so widely. A deep antique cushion of 3 carats can look smaller than a well-spread modern cushion of 2.4. Millimetres matter more than carats here than almost anywhere, and any serious listing should give both. Ours do, on the standard set out in how SARATTI grades gemstones.

Which Gemstones Suit a Cushion

Four kinds of material argue for this shape, for different reasons.

Saturated corundum and spinel are the obvious case: the depth and broad facets return the colour people are paying for, and neither needs help with brilliance. Pale material is the less obvious case — where colour is weak, a deeper cushion builds it, and a pale sapphire will often face up better as a cushion than as a shallow, sparkly round. Included material is third: crushed-ice facetting is forgiving in a way no other common cut is, which is why so much beryl, Paraiba tourmaline and included ruby is finished this way. Brittle species are fourth, where the rounded corners earn their place whatever the optics are doing.

Setting a Cushion

Four claws at the corners is the standard, since the curve of a corner gives the claw something to seat against. Double claws — eight in pairs — spread the load and suit larger stones or softer material, at the cost of covering slightly more of the outline. A bezel follows the cushion's curves comfortably and gives the most protection available, which makes it the right answer for anything brittle or cleavage-prone, though it makes the stone read slightly smaller and slightly darker.

The halo deserves an honest note, because it became close to ubiquitous on cushions over the past two decades. It does one thing very well: a 1-carat cushion in a halo occupies the visual space of something near double the weight. What it does not do is improve the stone. It can flatter a sleepy antique cushion and it can equally overwhelm a fine one with competing sparkle. A cushion good enough to stand alone is usually better alone.

Judging a Cushion Before You Buy

Ask which family it belongs to — antique or modern, chunky or crushed ice — because the listing will not say and the answer determines how it behaves. Get the millimetre dimensions and the depth, not only the carat weight, and work out the ratio yourself.

Then look for the two faults. Check for a window by trying to read through the centre, and for extinction under ordinary indoor light rather than a jeweller's lamp, which flatters everything. Look at the corners: are all four the same, or has the cutter rounded one harder to remove a flaw? And check the outline for symmetry, since a lopsided cushion shows more than a lopsided oval.

Choosing a Cushion

Decide what you want the stone to do. If you want colour above all — a fine ruby, a rich sapphire, a red spinel — take a chunky cushion of moderate depth and accept a little extinction as the price of saturation. If you are buying material that will never be clean, crushed ice is working for you. If the stone is brittle or cleaved, the rounded corners are the reason you are here, and a bezel finishes the argument. If you want presence for your budget, buy the millimetres rather than the carats.

Every stone here is listed individually, with its own measurements, proportions and photographs, because in this shape more than any other the average tells you nothing.

Only part of what we can reach is listed online. If what you want is not listed — a particular ratio, an antique cut in a given species, a matched pair — describe it, and we will go and look.