Choosing between emerald, Asscher and radiant cuts

An emerald cut and a radiant cut are not the same, although they share a cut-cornered outline: the emerald is a step cut, with long parallel facets that give broad, calm flashes of light, while the radiant is a brilliant cut, with many small facets that break light into lively sparkle. The Asscher is a step cut too, close to a square emerald but usually deeper, so choosing between the three comes down to the kind of light you prefer and how much of the stone's interior you are happy to see.

Step cut or brilliant cut: what is the difference?

Faceting decides how a diamond handles light, and there are two broad families.

A step cut has long, flat facets in parallel rows, running down from the table like the steps of a stair. The facets are fewer and larger, so light moves across them in broad planes, while the large flat table gives a clear view into the stone.

A brilliant cut has many smaller facets, mostly triangles and kites, angled to break light up and return it as quick points of sparkle, with flashes of spectral colour known as fire. The round brilliant is the familiar example.

The emerald and the Asscher are step cuts. The radiant is a brilliant cut given a step cut's outline.

Is an emerald cut the same as a radiant cut?

Across a room they can look alike, but in the hand they behave as different stones. The emerald shows long, clean lines through its table. The radiant's surface is busy with facets, so the eye reads sparkle before it reads geometry.

Grading reports make the difference plain. On a GIA report, the shape and cutting style line describes an emerald as an emerald cut, while a radiant usually appears as a cut-cornered rectangular or square modified brilliant. Neither receives an overall cut grade, because GIA currently gives cut grades only to round brilliant diamonds, so for these shapes you judge the cutting from the polish and symmetry grades, the measurements and, above all, how the stone looks.

If you love the emerald's outline but want more sparkle, the radiant is the natural alternative.

Is an Asscher a square emerald cut?

Both are step cuts, and a grading report will often describe an Asscher as a square emerald cut. The Asscher, though, is usually cut with larger cropped corners, so its outline reads clearly as an octagon, and with a smaller table and deeper proportions. Looking down into it, the eye follows concentric squares towards the centre rather than the long lines of an emerald.

A square step cut with small corners and shallow proportions can look flatter than a true Asscher, so the name on its report is only a starting point. Our page on Asscher cut engagement rings covers the shape in depth.

Which sparkles more?

The radiant does, if by sparkle you mean scintillation and fire. Its brilliant faceting breaks light into many small flashes across the whole face of the stone. The emerald and the Asscher give fewer, larger flashes that switch on and off as the hand moves. Neither is dull when well cut; they are simply quieter, and many people choose a step cut for the deliberate look of its light.

We answer the shape-specific versions of this question on the shape pages themselves: whether emerald cuts sparkle, and whether a radiant sparkles as much as a round brilliant.

What is windowing, and how do you spot it?

A window is an area, usually in the centre of a stone, where light passes straight through instead of returning to the eye. It looks pale and washed out, and it generally comes from a pavilion cut too shallow, often to keep more weight from the rough or to make the stone face up larger.

Emerald cuts are the most exposed of the three. A degree of transparency is part of their character, but a real window reads as a dull, empty panel in the middle of the stone. Radiants can window too, particularly long, shallow ones, although the faceting disguises it better. Asschers, with their deeper proportions, are less prone, though not immune.

Three ways to check a stone:

• Look at it face up in a photograph or video against a light background. A window shows as a pale patch where the facet pattern fades.
• Watch it move. A well-cut step cut flashes light and dark as it tilts; a windowed one stays glassy in the centre.
• Read the measurements as well as the grades. A stone that is shallow for its shape needs a second look, though depth alone does not decide it.

Colour and clarity: which cut forgives more?

On clarity the answer is the radiant. Its many small facets break up the view into the stone, so small inclusions tend to lose themselves in the sparkle. Step cuts do the opposite: an inclusion that would vanish in a radiant can sit plainly visible in an emerald or an Asscher. That is why our guide to diamond clarity sets a higher floor for step cuts than for brilliants. The aim is a stone that looks clean to the eye, which need not mean the highest grade on paper.

Colour is harder to call. The open table of a step cut shows body colour clearly, so a warmth that a brilliant would mask can read in an emerald or an Asscher, especially in larger stones. A radiant's sparkle can draw the eye away from a faint tint, but its faceting also concentrates colour, which is why the shape suits fancy yellows and champagnes. In a white radiant, and particularly an elongated one, look at the ends and corners, where any colour tends to gather. Neither family forgives colour outright, so judge each stone as it faces up. Our guide to diamond colour explains the grading scale.

Which looks bigger for its carat weight?

A carat is a unit of weight, and how large a stone looks depends on where that weight sits. Of the three, the emerald generally faces up largest for its weight, because it is elongated and cut with a broad, open table. A radiant of the same weight often looks a little smaller, since radiants are frequently cut deeper, with more weight below the girdle where it adds nothing to the view from above. The Asscher, square and deep with a small table, looks the most compact.

The shallower a step cut, the larger it looks, but the more likely it is to window. Compare stones by their length and width in millimetres rather than by weight alone. Our guide to carat weight explains how weight and face-up size relate.

Settings that suit each shape

All three have cropped corners, so there are no sharp points to guard, as there are on a princess cut. Claws usually sit on those corners, where they grip securely and leave the long edges clean.

Emerald. A solitaire on a fine band keeps the attention on its lines. In a three-stone engagement ring, tapered baguettes or trapezoids beside the centre carry the step-cut language across the ring.

Asscher. Square and compact, it wants less around it than the emerald: simple claws, stepped side stones or a slim halo that squares off the outline. It sits naturally in designs with an Art Deco sensibility.

Radiant. It is the most adaptable of the three, because its sparkle holds its own beside a full halo or brilliant-cut side stones, which can compete with the quieter light of a step cut. It works equally well as a solitaire or flanked by smaller radiants or trapezoids.

For any of them, a bezel setting wraps the outline in a fine rim of metal. Its clean frame suits the architecture of a step cut and protects the corners, though a full bezel covers a little of the edge, so if you want the stone to read at its full size, consider a half bezel.

Choosing your stone

Start with the light. If you want sparkle that carries across a room, the radiant is your shape. If you prefer long, calm lines and a stone you look into rather than at, choose the emerald. If you want that same stepped calm in a square, with more depth, choose the Asscher. Then let the practical points settle the detail: step cuts ask for more clarity and closer attention to colour, while the radiant gives you more room on clarity within a budget, though its colour still needs checking.

Each shape page carries our ring builder, where you choose a setting and then a diamond of that shape: see emerald cut engagement rings, radiant cut engagement rings and the Asscher page above. If you would rather begin with the stone, you can start with a diamond. For the shapes not covered here, read our guide to diamond shapes.

Sourcing the stone and drawing the setting

We work by appointment from our studio inside The Goldsmiths' Centre, Unit 1.02, 42 Britton Street, London EC1M 5AD, and consultations take place in the studio, by phone or by WhatsApp.

We begin with the look you are drawn to, your budget and the proportions that suit your hand, and source natural or laboratory-grown diamonds to match. A GIA or IGI grading report is available on centre stones, and we share images and video of each stone we put forward, with its report where it has one, so you can judge the light for yourself before you decide.

We draw the setting in CAD and finish it at our own bench; the casting and the stone setting go out to specialist workshops, and every piece above the legal exemption weight is hallmarked at the London Assay Office. A complete bespoke ring starts from £2,000. CAD design is from £300. The fee is non-refundable, and it is credited to the commission if you go ahead. You receive a full, itemised quote before anything is made. When you approve the CAD design, a 50% deposit is due, less the fee already paid, and it is non-refundable once production begins. The balance is payable before collection or delivery.

If you are still deciding between an emerald, an Asscher and a radiant, book a consultation with us. We typically reply within four working hours, Monday to Friday.

Common questions

Which of the three is best for everyday wear?

Any of them wears well day to day. Their cropped corners remove the sharp points that leave some shapes prone to chipping, and claws or a bezel protect the corners that remain. If you work with your hands, a bezel or a low-set design is the more protective choice.

Which shape suits my hand?

Elongated stones, the emerald or a longer radiant, draw the eye along the finger and can make it look longer. Square stones, the Asscher or a square radiant, read compact and balanced, and often sit best on longer, slimmer fingers.

Can I mix step cuts and brilliants in one ring?

Yes. A radiant centre with baguettes or trapezoids either side is a classic pairing, and an emerald centre can sit on a band of small brilliants. The stones should be matched in colour and clarity, because side by side any difference shows.

Does the grading report tell me whether a stone windows?

A report gives measurements, depth and table percentages, but no measure of windowing. Depth is a clue; images and video of the stone face up tell you far more. Our guide to reading a diamond grading report goes through it line by line.