Cut registry › Jewellery cuts › Princess
Jewellery cuts · Square brilliant
The square brilliant.
Everything anyone tells you about a princess cut concerns its four corners. They are right to, and for one more reason than they give.
The short version
A princess cut diamond is a square brilliant with sharp, uncut corners and brilliant-style faceting, carrying either 57 or 76 facets depending on how its pavilion is arranged.
It was designed to keep as much of the original octahedral rough as possible, which is why it is usually the least expensive way to buy a given weight of well-cut diamond.
Definition
The princess is a brilliant cut in a square outline. Its crown carries a table and bezel-style facets; its pavilion carries rows of chevron-shaped facets running from the corners toward the centre. Those chevron rows are what produce the X pattern you can see when you look straight down into a well-cut princess.
The number of chevron rows changes the sparkle in a way you can predict. Two chevrons give larger facets and bolder, broader flashes of light and colour. Four chevrons give smaller facets and a finer, denser scintillation. Neither is better; they are different stones, and the count is worth asking for.
The cut dates from the 1960s and 1970s and reached its modern form as the profile cut developed by Betzalel Ambar and Israel Itzkowitz in 1980. Its commercial logic has never changed: a square outline maps onto a diamond octahedron with very little waste.
Proportions
Commonly cited ranges against our measured reference stone. Princess depth runs far higher than any other shape here, which is a consequence of how the shape is cut from the rough rather than a fault.
| Measure | Commonly cited | Our reference stone | What it does |
|---|---|---|---|
| Length-to-width | 1.00 to 1.05 | 1.00 | Anything longer reads as a rectangle rather than a square. |
| Depth | 68% to 75%, often narrowed to 69% to 72% | 68.5% | Below about 68% it leaks; above about 76% it darkens. |
| Table | 67% to 72% | 80.0% | The flat top, as a share of the width. |
| Pavilion angle | not commonly published | 41.9° | Decides whether light returns or escapes. |
| Facets | 57 or 76, by chevron count | 69 | Counted as facets that actually reach the surface. |
GIA issues no cut-quality grade for princess cuts, which is the single most consequential absence in this shape’s buying process. Depth of 68% to 75% is doing the work a cut grade would otherwise do, and it is a much blunter instrument.
Light
The same census that measures every cut on this site: 3,200 rays face-up, 2,200 at a 20° tilt, on exact facet geometry, against T57 as the standard.
| Material | Useful light | Leak | Fire | Scintillation | Global | vs the standard |
|---|---|---|---|---|---|---|
| Diamond | 56.92% | 18.08% | 82.99 | 78.42 | 76.20 | −12.40 |
| Moissanite | 51.15% | 17.13% | 95.28 | 78.42 | 77.74 | −12.08 |
| Cubic zirconia | 63.39% | 22.48% | 91.89 | 78.42 | 79.14 | −12.63 |
| T57 standard, diamond | 92.28% | 1.88% | 78.85 | 71.82 | 88.61 | 0.00 |
Our reference princess returns 56.92% of entering light usefully and leaks 18.08%, for 76.20 Global against the standard’s 88.61. It carries 69 active facets for 78.42 on scintillation, above the round brilliant’s 71.82.
Its fire reads 82.99, which is high, and its tilt retention 88.86 against the standard’s 90.41, which is very nearly as good as a round. A princess holds up well when the hand moves, and that is a real virtue that gets lost in the corner-chipping conversation.
The corners are the whole story, though, and they are worse than the durability advice suggests.
Where the light is: useful return across the stone
Five equal bands across the outline, each returning ray binned by where it leaves the crown. Our reference princess returns around 40.7% at the two edge bands against 66.2% across the middle, a spread of 25.5 points, where the round-brilliant control reads 1.0. The corners of a princess are not only the part that chips. They are also the part that is dark. Every guide covers the first fact. We have not found one that covers the second.
Against the standard
Light return. 92.28% for the round against 56.92% for the princess, on identical protocol, for a Global gap of 12.40 points.
Sparkle character. 69 facets against 57, so 78.42 on scintillation against 71.82. A princess produces a denser flash pattern than a round, with a readable X through the middle that a round does not have.
Movement. The princess holds 88.86 of its face-up return at a 20° tilt against the round’s 90.41, a difference of well under two points. A princess holds its light about as well as a round brilliant does when the hand moves.
Colour. A princess shows body colour more readily than a round, because its faceting disperses colour less effectively and because colour concentrates in the corners and pavilion. Buying one colour grade higher than you would for a round is normal practice.
Durability. The princess is the least robust common shape. Its four sharp corners sit where diamond’s cleavage planes leave the atomic bonding weakest, so they chip. V-prongs or wrapping claws are not optional.
Price. Usually the cheapest way to buy a given weight, because the square outline wastes the least rough.
The baseline for all of this is the round brilliant itself. Its facet plan is set out in the anatomy of a round brilliant, and the measured standard we compare against is T57, the stone Tolkowsky published in 1919.
Materials
In moissanite the princess returns 51.15% for 77.74 Global, with fire climbing to 95.28 from 82.99 in diamond. Moissanite’s hardness of 9.25 is lower than diamond’s, which matters more on a shape whose corners are already the weak point.
In cubic zirconia it returns 63.39% for 79.14 Global. Zirconia at Mohs 8.25 is softer again, and a sharp-cornered square is the least forgiving outline to put it in.
Compare the three for this shape in the Index.
Trade-offs
Questions
The questions buyers actually ask, answered in full. Where the answer is ours to prove, the figure is measured on the Index; where it is an established gemological fact, it is stated as one.
A princess cut diamond is a square brilliant with sharp uncut corners and chevron-shaped pavilion facets, carrying either 57 or 76 facets depending on the number of chevron rows. It reached its modern form as the profile cut developed by Betzalel Ambar and Israel Itzkowitz in 1980.
Yes, at the corners, and there is a gemological reason. GIA notes that the sharp corners sit where diamond’s cleavage planes leave the carbon atoms less tightly bonded, so those four points are the weakest part of the stone. The remedy is specific: V-prongs or wrapping claw prongs that cup each corner. Ordinary round prongs sit beside the corner rather than over it and do not protect it.
The commonly cited range is 68% to 75% depth, often narrowed to 69% to 72%, with a table of 67% to 72%. Below roughly 68% depth a princess leaks light; above roughly 76% it looks dark and carries weight where it cannot be seen. Our reference princess measures 68.5% depth and 80.0% table.
Either 57 or 76, depending on how many chevron rows the pavilion carries. Our reference princess measures 69 facets that actually reach the surface, which is the count behind its scintillation figure of 78.42.
Chevrons are the rows of angled facets running across the pavilion of a princess cut, and they are what create the X pattern visible through the table. Two chevrons give larger facets and bolder, broader flashes. Four give smaller facets and finer, denser sparkle. Neither is better, but they produce visibly different stones, so it is worth asking which you are looking at.
No. GIA issues cut grades for round brilliants only. A princess report carries symmetry and polish grades, which describe finish rather than light performance, and depth percentage ends up carrying more weight in buying decisions than it really should.
Usually one grade higher than you would accept in a round of the same size. The princess’s faceting disperses body colour less effectively than a round brilliant’s, and colour tends to concentrate at the corners and in the pavilion, where it is easiest to see.
Yes, and usually by more than any other shape. A square outline maps onto a diamond octahedron with very little waste, where cutting a round discards a great deal more of the rough, and that difference reaches the price directly.
Corners and pattern. A princess has sharp uncut corners and shows a readable X through the table. A radiant has cut, truncated corners, which makes it considerably more durable, and its many small pavilion facets produce a continuous crushed-ice glitter with no pattern in it.
Measurably, yes. Binning every returning ray by where it leaves the crown, our reference princess returns about 40.7% in the two corner bands against 66.2% across the middle, a spread of 25.5 points where a round brilliant measures 1.0. The corners of a princess are the part that chips and also the part that is dimmest.
Next
See the whole set on the jewellery cuts index, or the measured house and historic cuts in the cut registry.
Method
Monte-Carlo on exact facet geometry: 3,200 rays face-up plus 2,200 at 20° tilt, cosine-weighted from a 7° near-vertical cone. Useful light is what exits through the crown within 64° of vertical. The same protocol runs on every cut on this site, so the figures are comparable to each other.
They measure our reference geometry for the shape at the proportions listed above, not an average of stones on the market. A princess cut to different proportions will read differently. Treat them as a like-for-like comparison between shapes, not as a grade for any individual stone.
Engine estimates, ±2 points, not lab-certified grades. We do not publish the Index symmetry axis on these pages: it scores facet regularity within each pavilion family, which is meaningful for a round brilliant and misleading for a shape whose pavilion is deliberately irregular.
78.42 here against the standard’s 71.82. The term is 100(1−e−n/45) on the count of facets that actually reach the surface, so it is a pure function of facet count and nothing else.