What is an Asscher cut diamond
The Asscher cut belongs to the step-cut family, alongside the emerald cut and the baguette. Step cuts use large, parallel rectangular facets arranged in rows rather than the triangular and kite-shaped facets of brilliant cuts. The result is a stone that reflects light in large, slow planes rather than scattering it in all directions.
What distinguishes the Asscher from other step cuts is its square outline and its very deeply cropped corners. Where the emerald cut has a moderately cropped rectangular outline, the Asscher has corners cropped so deeply that the shape appears almost octagonal from above. This deep cropping gives the Asscher a different visual quality at the corners: instead of the relatively narrow angled facets of an emerald cut corner, an Asscher corner has wide, prominent facet surfaces that contribute considerably to the stone's overall reflection pattern.
The high crown angle and small table of the traditional Asscher cut (compared to the emerald cut's lower crown and larger table) concentrate light entering the stone into a tighter central pool, creating the characteristic deep, tunnel-like view into the stone and the windmill pattern at its centre.
A square step-cut diamond with deeply cropped corners, a high crown, a small table, and step-cut facets in three rows on crown and pavilion. GIA designation: "square emerald cut." Created by Joseph Asscher, Royal Asscher Diamond Company, Amsterdam, 1902. Distinguished from other step cuts by its square outline, deeply cropped corners (creating a near-octagonal silhouette), and the windmill or X-shaped reflection pattern at the stone's centre. Demands high colour and clarity grades. No standardised GIA cut grade.
The Asscher family and a shape born from the world's most famous diamond
The Royal Asscher Diamond Company was founded in Amsterdam in 1854 by Joseph Isaac Asscher. The company rose to international fame in 1902 and 1908, when it was entrusted with cleaving and cutting the Cullinan diamond, then the largest gem-quality rough diamond ever found, discovered in the Premier Mine in what is now South Africa. The Cullinan weighed 3,106.75 carats in the rough. Joseph Asscher and his team cleaved it into nine major stones, all of which now form part of the British Crown Jewels and the royal collection.
It was in 1902, the same year the Asscher company received the Cullinan commission, that Joseph Asscher developed and patented the step-cut shape that now bears his name. The original patent expired in the 1940s, after which other cutters began producing similar square step-cut shapes. The Royal Asscher Diamond Company continued to produce its version and in 2001 introduced the Royal Asscher Cut, an updated version with 74 facets (compared to the original's 58), which creates a more brilliant variation of the original design while preserving the characteristic windmill pattern.
The shape became closely associated with Art Deco jewellery of the 1920s and 1930s. The Asscher cut's geometric precision, deep corners, and architectural character made it the ideal centre stone for the bold, symmetrical designs of the Art Deco period. Many of the most celebrated Art Deco engagement rings and brooches use Asscher cuts, and original period stones are sought after in the estate and antique jewellery market.
The Asscher cut was developed by the same family and in the same year they were preparing to receive the world's largest diamond for cutting. The Royal Asscher Diamond Company's expertise with large, high-quality rough diamonds informed the precision and deliberateness of the Asscher cut's design. The shape's history is inseparable from the most famous act of diamond cutting in recorded history. Source: Ogden, J. (2018). Diamonds: An Early History of the King of Gems. Yale University Press.
The windmill pattern: what it is and why it matters
The windmill, also called the X pattern, is the visual signature of the Asscher cut. When an Asscher cut diamond is viewed face-up, the deeply cropped corners and the high crown combine to create a specific reflection pattern at the centre of the stone: four elongated triangular reflections arranged around the culet point, like the blades of a windmill or the arms of an X. This pattern rotates as the stone tilts, giving it a mesmerising depth that is unique among diamond shapes.
The windmill pattern is directly related to cut quality. A well-cut Asscher with symmetrically cropped corners, a properly centred table, and precisely calibrated step rows shows a clear, even windmill with four equal arms. A poorly cut Asscher, with uneven corners or an off-centre table, shows an uneven or distorted windmill that lacks the hypnotic quality of the ideal pattern.
The windmill is not a defect or a flaw. It is the shape's defining optical characteristic. Buyers who view an Asscher cut for the first time and see the windmill pattern should understand that what they are seeing is the stone performing exactly as intended. The pattern intensifies when the stone is viewed in a slightly dimmer light, which is one reason Asscher cuts are particularly striking in candlelight and warm indoor light.
Face-up view of an Asscher cut diamond. The deeply cropped corners create a near-octagonal silhouette. Three concentric step rows surround the table. The windmill or X pattern at the centre is the shape's signature optical characteristic and a quality indicator: a well-cut Asscher shows four even arms; an uneven windmill indicates symmetry problems.
Ideal proportions for Asscher cut diamonds
No GIA cut grade exists for Asscher cuts. The certificate describes the shape as "square emerald cut." These ranges represent industry consensus for well-performing Asscher cuts.
| Proportion | Recommended range | Why it matters |
|---|---|---|
| Total depth percentage | 60–68% | Asscher cuts run deeper than emerald cuts. The high crown adds depth relative to total stone height. Below 60% risks windowing. Above 70% the stone looks notably small. 62–66% is typical for well-proportioned Assche cuts. |
| Table percentage | 53–65% | Asscher cuts have smaller tables than emerald cuts. This is by design: the smaller table and higher crown create the tunnel-like depth and windmill pattern. Very large tables (67%+) in an Asscher reduce the characteristic depth and windmill effect. |
| Length-to-width ratio | 1.00–1.05 | The Asscher is designed to be square. A ratio above 1.08 makes the stone read as rectangular rather than square, at which point a radiant or emerald cut is typically a better choice. The square identity of the Asscher is part of its design intent. |
| Girdle thickness | Thin to Slightly Thick | Asscher cuts have cropped corners with no sharp points, making them more durable at the corners than princess cuts. Medium girdle is ideal. |
| Culet | None or Very Small | In a step-cut shape, the culet is directly visible through the table as a circle or octagon at the stone's centre. It also affects the windmill pattern. None or Very Small is essential. |
| Symmetry | Excellent only | The windmill pattern requires perfectly even corner cropping and a centred table. Any asymmetry is visible in the uneven arms of the windmill. Excellent symmetry only. |
Colour and clarity: step-cut demands apply fully
The Asscher cut is a step-cut shape and carries the same colour and clarity demands discussed in the emerald cut guide. The large parallel facets act as mirrors that reflect colour and inclusions more clearly than brilliant-cut facets. For an Asscher cut in white gold or platinum, F or G colour is the minimum for a reliably colourless appearance. H colour Asscher cuts often show a perceptible warm tint in white metal settings.
One Asscher-specific nuance on colour: the deeply cropped corners of the Asscher create more corner facet area than the shallower corners of an emerald cut. This means colour can concentrate slightly more at the corners in an Asscher than in an emerald cut of the same colour grade. For buyers particularly sensitive to any colour tint at the corners, F colour provides the most reliable assurance.
Clarity in the Asscher follows the same rule as the emerald cut: VS2 minimum, VS1 or VVS2 preferred. The step facets show inclusions clearly. There is an additional consideration specific to the Asscher's windmill pattern: an inclusion positioned near the centre of the stone, around the culet zone, can appear multiplied by the windmill reflection, making a single inclusion appear as four in the face-up view. Always check the GIA clarity plot for inclusions near the culet or centre of the table before purchasing an Asscher cut.
In a well-cut Asscher, an inclusion near the culet or at the centre of the pavilion can be reflected four times by the windmill pattern, appearing as a four-fold image in the face-up view. A VS2 stone with a small crystal inclusion positioned at the centre could face-up like an SI1 or worse due to this multiplication. When purchasing an Asscher, confirm clarity by direct face-up inspection or video, not just by the stated clarity grade. Check the GIA plot for central inclusions specifically.
Original Asscher vs Royal Asscher Cut
Two versions of the Asscher cut exist in the market, with meaningfully different characteristics.
The original Asscher cut, also called the standard Asscher cut, has 58 facets, a high crown, a small table, and the three-row step arrangement that defines the shape. It was the only version available from 1902 until 2001. Antique and estate Asscher cuts are almost always the original version. The original produces a deeper, more intense windmill pattern and a somewhat quieter overall light return than the Royal version.
The Royal Asscher Cut, introduced in 2001 by the Royal Asscher Diamond Company to mark the centenary of the original, has 74 facets. The additional facets are achieved through splitting some of the original step facets and adding extra faceting on the crown. The result is a stone that retains the windmill pattern and deep character of the original while producing more brilliance overall. The Royal Asscher Cut is a trademark of the Royal Asscher Diamond Company; other cutters produce standard Asscher cuts but cannot use the "Royal Asscher Cut" designation.
On a GIA certificate, both versions are described as "square emerald cut." There is no GIA distinction between original and Royal Asscher cuts. Buyers who specifically want a Royal Asscher Cut should purchase through authorised Royal Asscher dealers and verify the stone's provenance through the company's own certificate or documentation.
Asscher vs emerald cut: the step-cut comparison
| Factor | Asscher cut | Emerald cut |
|---|---|---|
| Outline | Square, near-octagonal due to deep corner cropping. | Rectangular, with moderate corner cropping. |
| Optical character | Deep tunnel-like view into stone. Windmill/X pattern at centre. Intense, hypnotic depth. | Hall-of-mirrors: long, rectangular reflections. Elegant lateral drama. |
| Crown height | Higher crown than emerald. Creates deeper visual entry and more pronounced windmill. | Lower crown. Creates a flatter, more horizontal optical effect. |
| Table size | Smaller table. Concentrates light into the depth of the stone. | Larger table. More direct window into the stone. |
| Colour sensitivity | Very high. Corner colour concentration adds to centre colour. F–G minimum. | Very high. F–G minimum. Slightly less corner concentration than Asscher. |
| Clarity sensitivity | Very high. Central inclusion multiplication by windmill pattern is specific risk. | Very high. Large step facets show inclusions clearly without the multiplication risk. |
| Historical character | Art Deco (1920s–1930s). The most specifically historical shape still in production. | Art Deco and mid-century. More generic historical association. |
| Finger coverage | Square. Does not elongate the finger. | Rectangular. Provides some elongation along the finger's length. |
Settings for Asscher cut diamonds
The Asscher cut's square, near-octagonal outline and its strong geometric character suit settings that complement rather than compete with the shape's precision.
A four-prong solitaire with prongs at the four cropped corners is the most natural and secure setting. The prongs sit at the corners' angled facets, holding the stone firmly while exposing the full face. Four prongs at the corners are structurally sound because the corners are cropped and the prongs have good surface contact. Some Asscher solitaires use eight prongs (at all eight sides of the near-octagonal outline) for extra security and a more decorative look.
The Asscher cut is the shape most closely associated with Art Deco jewellery design. Settings with geometric millgrain edges, filigree metalwork, or baguette side stones echo the period aesthetic and frame the Asscher beautifully. A platinum Art Deco-inspired setting with tapered baguette side stones flanking the centre Asscher is one of the most celebrated ring designs in the antique and estate jewellery tradition.
Halo settings around Asscher cuts work well when the halo follows the near-octagonal outline of the stone rather than being perfectly square or round. A halo that echoes the Asscher's octagonal silhouette creates a cohesive design. A round halo around a square Asscher creates an interesting contrast. Both approaches amplify the apparent size of the stone.
Buying an Asscher cut diamond in India
The Asscher cut is a niche shape in India. Most mainstream retail brands carry little or no Asscher inventory. The specialist diamond dealer market in Mumbai and the antique and estate jewellery market in cities like Mumbai, Delhi, and Jaipur offer the best access to well-cut Asscher diamonds. For buyers specifically seeking a Royal Asscher Cut, authorised dealers are limited; the Royal Asscher Diamond Company website lists authorised dealers globally.
The shape's Art Deco character makes it particularly sought after in India's growing vintage and antique jewellery segment. Estate Asscher cuts from the 1920s and 1930s occasionally appear at auction houses and specialist dealers. These period stones may not have GIA certification and should be assessed by an independent GIA-certified gemologist before purchase.
| Carat weight | Approx. Asscher price range | Equivalent round price range | Approx. saving |
|---|---|---|---|
| 0.50 ct | ₹36,000–₹88,000 | ₹45,000–₹1,10,000 | 15–20% |
| 0.70 ct | ₹64,000–₹1,50,000 | ₹80,000–₹1,80,000 | 15–20% |
| 1.00 ct | ₹1,80,000–₹4,20,000 | ₹1,80,000–₹4,50,000 | Minimal, step-cut colour/clarity uplift offsets shape discount |
| 1.50 ct | ₹4,20,000–₹9,50,000 | ₹4,00,000–₹9,00,000 | Similar cost once specs aligned |
| 2.00 ct | ₹9,80,000–₹23,00,000 | ₹9,00,000–₹22,00,000 | Comparable, step-cut premium specs |
Prices approximate for mid-2026, natural diamonds, GIA certified, Excellent symmetry, F–G colour, VS1–VS2 clarity (as required for comparable face-up appearance to round). Add GST (1.5%) and setting/making charges.
1. Certificate: GIA. Note GIA designates Asscher cuts as "square emerald cut."
2. Symmetry: Excellent only. The windmill pattern must have four even arms.
3. Windmill quality: view face-up. Four even arms from the centre indicate a well-cut stone. Uneven arms indicate symmetry problems.
4. Clarity plot: check specifically for inclusions near the culet or table centre. Central inclusions multiply in the windmill pattern.
5. Colour: F or G for white gold. G minimum. H often shows tint in Asscher cuts.
6. Clarity: VS2 minimum. VS1 preferred. Do not accept SI1 without confirmed eye-clean face-up inspection.
7. L/W ratio: 1.00–1.05. Calculate from mm measurements on certificate.
8. Royal Asscher Cut: if specifically desired, purchase only from authorised dealers with Royal Asscher documentation.
Sources and data integrity note
The history of the Royal Asscher Diamond Company and the Cullinan diamond cutting is documented in: Ogden, J. (2018). Diamonds: An Early History of the King of Gems. Yale University Press; and the Royal Asscher Diamond Company's published corporate history (royalasscher.com). The Royal Asscher Cut trademark and the 2001 introduction are sourced from Royal Asscher Diamond Company records. Price ranges are approximate estimates for mid-2026.
Frequently asked questions
What makes an Asscher cut different from a princess cut?
The two shapes look superficially similar from a distance, both are square, but are completely different in facet structure, optical character, and practical considerations. A princess cut uses brilliant-cut chevron facets and produces the scattered sparkle of a brilliant-cut diamond. An Asscher cut uses step-cut facets and produces the deep, calm reflections characteristic of step cuts, including the windmill pattern. A princess cut has sharp 90-degree corners that are vulnerable to chipping. An Asscher cut has deeply cropped corners that are much more durable. An Asscher requires higher colour and clarity grades than a princess for comparable face-up appearance. The two shapes suit completely different aesthetic preferences.
Does an Asscher cut look bigger or smaller than other square shapes?
An Asscher cut tends to look slightly smaller than a princess cut or square radiant of the same carat weight. Two reasons: the Asscher runs deeper (62–66% vs 68–72% for princess), meaning more weight is below the girdle. And the deeply cropped corners reduce the stone's maximum diagonal measurement compared to a sharp-cornered princess cut. The near-octagonal outline is visually smaller than a perfect square of the same carat weight. For buyers who want maximum apparent size in a square shape, the princess cut or square radiant cut will look larger. For buyers who value the windmill pattern and Art Deco character, the Asscher's slightly smaller face-up area is an accepted trade-off.
Can I find an Asscher cut from the Art Deco period?
Yes. Original Art Deco period Asscher cuts from the 1920s and 1930s occasionally appear in estate jewellery sales, specialist antique dealers, and auction houses. These period stones are cut to the original 1902 specifications with the high crown and small table of the traditional design. They may show the larger culet typical of pre-1940s cutting. Period stones are often not GIA certified. Before purchasing any estate Asscher cut, have it assessed by a GIA-certified gemologist who can confirm the stone's quality, identify any treatments, and provide a written appraisal. The period stones can be exceptional, but the absence of a modern laboratory certificate means independent verification is essential.
Is the Asscher cut suitable as an engagement ring for everyday wear?
Yes, with appropriate setting choice. The Asscher's cropped corners make it more durable than the princess cut (no sharp corners to chip) and similar in durability to the radiant cut. A four or eight-prong setting at the corners secures the stone well. The main practical consideration is clarity: because the step facets show inclusions clearly, buyers on clarity budgets need to invest more than they would in a brilliant cut. For buyers who accept the VS2 minimum (or VS1 preferred) and choose a secure prong setting, an Asscher cut is an entirely practical daily-wear ring.
Continue exploring diamond shapes