Princess Cut
Princess Cut
A square modified brilliant developed for weight retention from octahedral diamond rough
The princess cut is a square or rectangular modified brilliant cutting style with a four-sided inverted-pyramid pavilion and a step-cut crown facet pattern, generally executed with fifty-seven, sixty-five, or seventy-six facets depending on the variant. The cut is the most successful of the square brilliants developed in the second half of the twentieth century, and remains the second most widely produced diamond cut after the round brilliant. The form is also applied to a range of coloured stones where the design's brilliance and weight retention are valuable.
Origins and refinement
The princess cut as currently understood emerged in stages between the 1960s and the 1980s. Earlier square brilliants — including Arpad Nagy's Profile cut of the early 1960s and Basil Watermeyer's Barion cut of 1971 — established the design principles of an inverted-pyramid pavilion combined with a brilliant crown. The cut associated specifically with the name princess took shape in the work of Israeli cutters in the 1980s, with Ygal Perlman, Betzalel Ambar, and Israel Itzkowitz typically credited with the version that became standard in the international market.
The design's commercial success rested on a single property: it preserves more of the original octahedral diamond crystal than a round brilliant of equivalent face-up size. A round brilliant cut from typical diamond octahedron rough yields about forty per cent of the rough weight; a princess cut from the same rough can yield fifty to sixty per cent. For the cutter, this translates directly into higher value per carat of rough.
Geometry and proportions
The princess cut is square in outline (length-to-width ratio close to 1.00) or rectangular (typical ratios from 1.00 to 1.10 for stones marketed as square, 1.15 and above for stones described as rectangular). The pavilion has either two, three, or four chevron rows depending on the variant; the more chevrons, the smaller and more numerous the light returns. The crown is shallow, often around twelve to fifteen per cent of total depth, with a shallow table of seventy to seventy-five per cent and a thin to medium girdle.
Total depth of a well-cut princess is typically sixty-five to seventy-five per cent of the average width, somewhat deeper than the ideal round brilliant. The geometry produces strong scintillation in the centre of the stone and a characteristic pattern of square or kite-shaped light returns visible face-up.
Setting and durability
The four sharp ninety-degree corners are the cut's structural weak point. Diamond's directional hardness varies, and the corners are exposed to chipping during wear, particularly in single-prong settings. Standard practice is to protect each corner with a V-prong, a chevron prong, or a bezel, all of which distribute pressure across the corner and shield it from impact. Single round prongs at the corners are not appropriate for princess-cut diamonds intended for daily wear.
Coloured-stone princess cuts in softer materials — sapphire, ruby, tourmaline, garnet — face similar issues at the corners and benefit from the same protective settings. The hardness of the stone shifts the risk profile; sapphire at 9 on the Mohs scale tolerates exposure better than emerald at 7.5 to 8.
Variants
Closely related square brilliants include the Barion cut (which differs in pavilion facet arrangement and is licensed under specific patents), the Quadrillion cut (a proprietary square brilliant marketed by Ambar Diamonds), the Radiant cut (a corner-cut rectangular brilliant developed by Henry Grossbard in 1977), and the Asscher cut (a square step-cut, structurally distinct rather than a brilliant). The princess cut differs from each in pavilion architecture and corner geometry, but the family of square brilliants shares the underlying principle of weight retention from octahedral rough.
In the trade
For diamonds, the princess cut occupies a substantial share of the bridal market and is offered across the colour and clarity range. Because the four corners and the pavilion's cross of internal facets concentrate light at the centre and edges, colour and inclusions are often more visible in princess cuts than in rounds of equivalent grade; trade preference therefore tilts toward higher colour and clarity grades, particularly in larger stones. For coloured stones, the princess cut is one option among many; faceters often select the cut for clean rough where the square outline allows recovery from particular crystal habits.
Care
For diamond princess cuts, ultrasonic and steam cleaning are generally safe except where the stone has internal stress fractures or laser-drilled inclusions. For coloured-stone princess cuts, cleaning depends on species: ultrasonic and steam are not appropriate for emerald, opal, pearl, or any treated stone with surface fillers, and warm soapy water with a soft brush is the conservative default.