Asscher Cut Diamond
By Jared James ยท Last updated 21 May 2026
Quick answer
An asscher cut diamond is a square step cut with cropped corners and long, parallel facets that draw the eye down into the stone, giving the deep, concentric hall of mirrors look the shape is known for. It is essentially a square version of the emerald cut, so the same things matter most: clarity sits on show through the open facets, body colour can be visible, and you want a ratio close to square at around 1.00 to 1.05.
Shape at a glance
| Detail | Typical detail | Buying note |
|---|---|---|
| Facet pattern | Square step cut with cropped corners and parallel facets. | The open step facets create the hall of mirrors look, and they also put clarity and colour on show. |
| Typical ratio | Close to square, usually 1.00 to 1.05. | An asscher should read square. Much above 1.05 and it starts to look like an emerald cut. |
| Sparkle | Broad, mirror-like flashes rather than fast brilliant sparkle. | Judge the pattern of light and dark down the centre, not just the grading report. |
| Best for | Art Deco solitaires, bezel settings and vintage-inspired engagement rings. | Choose asscher when you want a square stone with quiet, geometric character. |
What is an Asscher Cut Diamond?
An asscher cut diamond has a square outline with cropped corners and step-cut facets, which means the facets run in long, straight rows rather than the many small facets of a brilliant cut. Look straight down into one and you see a series of concentric squares falling away towards the centre, an effect people often call the hall of mirrors.
It is closely related to the emerald cut, and the easiest way to picture it is as an emerald cut squared off. The Asscher family of Amsterdam patented the cut in 1902, and it became a signature of Art Deco jewellery in the 1920s, which is still the era it tends to call to mind today.
The story behind the asscher cut
The asscher cut is one of the few diamond shapes you can trace to a single family and a single date. The Asscher family had been cutting diamonds in Amsterdam since 1854, and in 1902 Joseph Asscher patented a new square step cut with cropped corners, the shape that still carries the family name.
The Asschers were trusted with some of the most important rough diamonds of their day. In 1908 Joseph Asscher was given the task of cleaving the Cullinan, the largest rough diamond ever found, into workable pieces for the British Crown Jewels. The cut had its great moment of fashion in the Art Deco 1920s, faded for much of the twentieth century, and then came back with the revival of vintage and step-cut styles. The company was later granted a royal title and is known today as Royal Asscher.
What to check before choosing
Best clarity for an asscher cut diamond
The step facets behave like a window, so an asscher hides very little. VS1 or VS2 is a sensible place to start, and you should always look at the exact stone, because a dark inclusion near the centre is hard to miss once light is travelling straight down through those open facets.
Best colour grade for an asscher cut diamond
Body colour shows more readily in an asscher than in a brilliant cut, much as it does in an emerald cut. G or better is a safe starting point in platinum or white gold, while a yellow or rose gold setting lets you drop a grade or two and still look balanced.
Check the symmetry and the windmill
Look straight down into the stone and check that the concentric squares are even and the cropped corners match each other. A well cut asscher has a crisp, symmetrical windmill at its centre, and any twist or unevenness there is easy to see.
Settings that suit this shape
- A bezel or a four-prong solitaire keeps the geometry clean and lets the step facets do the work.
- Asscher cuts pair beautifully with Art Deco details, milgrain and geometric side stones like trapezoids or baguettes.
- A three-stone ring with step-cut or cadillac-cut side stones echoes the squared-off lines of the centre diamond.
Who does asscher suit?
Asscher cut suits anyone drawn to Art Deco and vintage style, and to quiet, architectural geometry rather than fast sparkle. It rewards a cleaner clarity grade, so it works best when you would rather spend on a stone that looks crisp and clear than on sheer size.
Watch for
- Inclusions and body colour are harder to hide than they are in a brilliant cut.
- A poorly cut asscher can look flat or dark down the centre instead of showing clear, concentric squares.
- Stones that stray far from square start to read as emerald cuts, so check the ratio if a true square is what you want.
Watch: thinking of buying an asscher diamond?
A quick look at what to weigh up before you choose an asscher cut diamond.
Other diamond shapes
- #01
Round
If you want the most sparkle and the easiest stones to compare, the round brilliant is the shape to reach for. It is also the only common diamond shape that comes with a proper cut grade, so settle on cut quality first and then choose colour and clarity grades that still look clean and bright once the stone is set.
- #02
Oval
An oval diamond gives you a larger, more lengthening look than a round diamond of a similar weight, and it keeps the bright sparkle pattern of a brilliant cut. There is no single cut grade that tells you whether an oval is a good one, so the things to look at are the bow tie, the length-to-width ratio, the shape of the shoulders and how evenly the two ends mirror each other.
- #03
Emerald Cut
An emerald cut diamond is a step cut, which means it has long, open facets and neatly clipped corners, and it gives you a rectangular outline with broad flashes of light rather than the fast glitter of a brilliant cut. Clarity, colour and ratio all show up more clearly here than in other shapes, so most buyers start at VS1 or VS2 clarity, G colour or better, and a length-to-width ratio somewhere between 1.40 and 1.55 for a balanced, classic look.
- #04
Cushion Cut
A cushion cut diamond has a square or rectangular outline with soft, rounded corners, and depending on the facet pattern it can look antique, modern, chunky or crushed ice. Many buyers find themselves choosing between a true square cushion at a ratio close to 1.00 and an elongated cushion somewhere around 1.15 to 1.30, so it helps to decide the sparkle style and the outline you want first, then compare colour, depth and setting from there.
- #05
Marquise
A marquise diamond is a long brilliant-cut shape with two gently pointed tips, and it gives you one of the largest face-up looks you can get for the carat weight, so it always makes a statement. The trade-off is that it needs excellent symmetry, a bow tie you can live with and tips that are properly protected, so choose it when you want length, drama and presence.
- #06
Pear
A pear shaped diamond, sometimes called a teardrop diamond, has one rounded end and one gently pointed tip. The things worth checking are the length-to-width ratio, which most buyers like somewhere between 1.50 and 1.70, the point alignment, the bow tie effect through the centre, and the prongs that keep the tip protected. Choose pear if you want an elongated shape with a little more softness than a marquise.
- #07
Princess Cut
A princess cut diamond is a square brilliant cut with sharp, uncut corners and plenty of sparkle. It is often called a square diamond, and it is a popular modern alternative to a round brilliant that usually costs a little less per carat. The one practical catch is that the sharp corners need protecting from chips, so look for V-prongs or a bezel, and keep an eye on face-up size, symmetry and colour near the edges.
- #08
Radiant Cut
A radiant cut diamond pairs a square or rectangular outline with cropped corners and brilliant-style facets. It gives more sparkle than an emerald cut and has softer corners than a princess cut, so it suits anyone who wants geometry without giving up brightness. The first thing to decide is whether you want a square radiant at a ratio close to 1.00 or an elongated one at 1.15 to 1.35, and from there you can check the centre brightness and the facet pattern.
- #09
Old Mine
An old mine cut diamond is an antique cushion-shaped cut, hand-cut from roughly the early 1700s through to the late 1800s, long before electric light and modern faceting. It has a soft, squarish outline, a tall crown, a small table and a large open culet that shows as a little circle in the centre, and it was cut to glow under candlelight rather than to throw out the bright sparkle of a modern brilliant. No two are quite alike, so each stone is judged on its own.
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View asscher ringsFrequently asked questions
- What is an asscher cut diamond?
- An asscher cut diamond is a square step-cut diamond with cropped corners and long, parallel facets. Looking down into it, you see concentric squares that create a deep, mirrored effect, and the shape was patented by the Asscher family of Amsterdam in 1902.
- What is the difference between an asscher cut and an emerald cut?
- They use the same step-cut faceting and both have cropped corners, so the main difference is the outline. An emerald cut is rectangular, while an asscher is square, with a ratio close to 1.00, and an asscher tends to have a deeper, more concentric hall of mirrors look. You can think of an asscher as a square emerald cut.
- What is the best clarity for an asscher cut diamond?
- VS1 or VS2 is a sensible starting point. The open step facets make inclusions easier to see than they are in a brilliant cut, so always inspect the exact stone for dark inclusions near the centre before you buy.
- Are asscher cut diamonds expensive?
- Asscher cuts often cost a little less per carat than round brilliants, because the cut keeps more weight from the rough diamond. The trade-off is that they need a cleaner clarity and colour grade to look their best, which can bring the total cost back up.
- Why is it called an asscher cut?
- It is named after the Asscher family, diamond cutters in Amsterdam, who patented the square step cut in 1902. The same family famously cleaved the Cullinan diamond in 1908, and the firm is known today as Royal Asscher.
- Are asscher cut diamonds good for engagement rings?
- Yes. Asscher cuts are hard-wearing for daily wear, and their cropped corners are less vulnerable than the sharp corners of a princess cut. They suit Art Deco, bezel and vintage-inspired engagement rings where the clean geometry is the point.
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