Princess Cut Diamond Buying Guide

What is a princess cut?

The princess cut is a square or slightly rectangular diamond with sharp, uncropped corners and a brilliant-style faceting pattern underneath. Modern princess cuts typically carry between 57 and 76 facets — the same fire-and-brilliance optical strategy as the round brilliant, applied to a square outline. Viewed face-up, the outline is a near-perfect square; viewed in profile, the stone is deep, with most of its weight tucked below the girdle.

The shape was developed in the 1960s and popularised through the 1980s as buyers looked for a modern alternative to the round brilliant that retained brilliant-style sparkle. Unlike the emerald or asscher (which are step cuts emphasising clarity and the “hall of mirrors” effect), the princess is a brilliant cut — designed to maximise light return and scintillation rather than reveal the stone's internal structure.

Practically, this matters in two ways. First, a princess returns light across its whole face the way a round does — you see sparkle, not the body colour. Second, because the cut is deep, a princess weighs more for its face-up size than an equivalent round — so a 1.00ct princess looks slightly smaller from above than a 1.00ct round. Buyers prioritising visible size at a given carat sometimes pick a slightly heavier princess as a workaround.

How do the 4Cs apply to princess-cut diamonds?

Cut: the princess is not graded with a single overall cut grade by GIA the way rounds are, so cut quality has to be read from the certificate's measurements (table %, depth %, length-to-width ratio) plus polish and symmetry. A well-cut princess shows uniform brilliance across the table; a poorly-cut one has dim corners or a visible “dead zone” in the centre. For a square princess, aim for a length-to-width ratio between 1.00 and 1.05.

Colour: princess cuts hide body colour better than step cuts (emerald, asscher) because brilliant faceting fragments light into white flashes that mask tint. We offer D–H colour grades. Compare individual stones across that range in your preferred metal and lighting, because apparent warmth varies with the stone, setting and viewer.

Clarity: the sharp corners of a princess concentrate stress and any inclusions sitting near a corner can become structural risk points. VS2 can be a useful starting point, but inspect the type and position of inclusions, the corner condition and the proposed setting independently. A plot helps locate features where one is provided; it does not replace examination of the stone.

Carat: because a princess is deep, the face-up spread per carat is roughly 10% smaller than a round of equivalent weight. A 1.00ct round measures about 6.4mm across the table; a 1.00ct square princess measures about 5.5mm on each side. Buyers wanting a visibly larger stone for the budget sometimes pick a 1.20–1.30ct princess instead of a 1.00ct round — the face-up size is similar and the per-carat cost on a princess is lower.

Does colour matter on a princess cut?

Yes, but less than on step cuts. Brilliant faceting masks colour effectively in the G–H range, and even I-colour stones often face up bright when set in warm-metal designs. The GIA grades princess-cut colour on the same D–Z scale used for all white diamonds; the scale below is the reference.

Princess vs round — how do they compare?

The round brilliant is the benchmark for white-diamond sparkle. Its 58-facet pattern has been optimised over a century to maximise light return, and GIA grades round cut with a single overall grade (Excellent / Very Good / Good / Fair / Poor) that captures the full light-performance picture. A princess, by contrast, has no overall cut grade — you read cut from polish, symmetry, and proportions individually.

In raw sparkle, a well-cut round generally edges out a well-cut princess: rounds throw broader, whiter flashes; princess cuts throw smaller, more concentrated flashes with crisp edges. Both shapes are highly brilliant; the character of the sparkle differs. For a side-by-side feel, a round shows softer, blended scintillation and a princess shows angular, geometric scintillation.

A princess can cost less than a comparable round, but the difference varies between individual stones. Compare current like-for-like quotes rather than relying on a fixed percentage. The saving may let you consider a larger stone or a higher individual grade within your budget.

What setting suits a princess cut?

The most important consideration for a princess setting is corner protection. Those sharp 90-degree corners are the highest-risk part of the stone — a knock to a corner can chip the diamond. A well-designed setting covers each corner with a prong or a bezel lip so the corner never bears a direct impact.

Four-prong solitaire: the classic princess setting, with one prong wrapping each corner. Clean, modern, and structurally sound. Make sure each prong covers the full corner rather than tucking against one side — a half-covered corner still bears impact.

Bezel setting: a full metal rim around the stone offers maximum corner protection and gives the ring an architectural, contemporary look. The trade-off is slightly less light entering the stone from the sides — you lose a touch of sparkle for a meaningful gain in durability.

Halo with princess centre: a halo of melee diamonds around the centre stone visually enlarges the princess and adds extra sparkle, while the melee themselves contribute to corner protection. Particularly flattering on princess centre stones below 1.00ct where the halo adds noticeable visual presence.

Three-stone with princess centre and tapered baguette sides: the geometry harmonises — square centre, elongated rectangular sides. A symmetrical, formal look. This style suits buyers wanting a ring with visual weight without stepping up to a much larger centre stone.

We can build any of these in 18ct yellow, white, or rose gold, or in platinum. Yellow and rose metals can add warmth to stones within our D–H range; platinum and white gold provide a cool background that lets the centre stone read at its brightest.

How does princess-cut clarity affect price?

The traditional clarity scale runs from FL through I3, but the read on the certificate matters more on a princess than on a round because of the corner-stress risk described above. The scale below is the reference.

Where does the budget work hardest?

VVS inclusions are very or extremely difficult for a trained grader to see at 10×. Higher clarity grades may or may not offer a visible difference that matters to you. G/VS2 with Excellent polish and symmetry can be a useful shortlist starting point, then compare actual appearance, inclusion position and corner condition before choosing how to spend the budget.

Princess cut diamond size chart

What a princess cut's measurements mean in carat weight. This is where the depth penalty above becomes concrete: read the millimetre column against the round chart and the same weight buys you visibly less face-up. Every row from 0.30ct up is the median of real certified princess cuts in our own inventory, with the sample size beside it; the smaller sizes come from our diamond supplier's own book.

Length and width give an indicative weight range. Depth, girdle thickness and other proportions also affect weight, so this table is an estimate. Use the individual grading report or a measured loose-stone weight for an exact figure. For every other shape, and a converter that works both ways, see the full diamond size chart.

Compare other shapes

Princess sits in the square-outline family. If you'd prefer the step-cut look in a square outline, read the Asscher Buying Guide; for a softer pillow outline with similar brilliant-cut sparkle, see the Cushion Buying Guide. For a single-page side-by-side across all ten shapes, see our Diamond Shape Comparison. Or jump straight to our engagement ring designs when you're ready to choose a setting.