Princess Cut Sapphire: sharp corners and a deep pavilion, at a cost in light

Brilliance 68 · Fire 52 · Scintillation 78 · in our census, where the T73 scores 94 · 37 · 80 in sapphire

The princess keeps weight from the rough and puts sharp corners on the finger. In sapphire it lets over a quarter of its light out of the back.

See it in the simulatorGet the files
The Princess Cut in sapphire, rendered at an angle in our 3D Gemstone Simulator under studio light
Rendered in our 3D Gemstone Simulator from the Princess Cut model, 1.00 ct, studio light.

Princess Cut Sapphire

Our princess has chevron pavilion facets under a square face: 85 facets, 68.5% deep, with a steep 41.94° pavilion.

That depth makes it heavy for its width, 1.68 ct at 6.5 mm, and it does not buy light: in sapphire it trails the T73 by a wide margin and leaks more than the square brilliant beside it.

Is a princess cut good for a sapphire? Pros and cons

Pros

None by our margins. Its fire beats the T73's but trails the diamond princess by more.

Cons

Compared with the T73 Round Brilliant in sapphire and with the Princess Cut in diamond. A difference counts from 3 points (Brilliance, Fire, Tilt, Leakage), 5 (Scintillation, Symmetry), 2 (Spread) or 5% (weight); Tilt counts as a pro only for a stone within 5 points of the brilliance it is compared with. How we measure.

All eight scores against the T73

At a glance: the Princess Cut in sapphire (white) against the T73 Round Brilliant in sapphire (dashed): solid white where it reaches further, hatched where it falls short. Each pro and con is explained, with pictures, below.

Performance wheel: Princess Cut in sapphire, against the T73 Round Brilliant in sapphire as an outline. Solid white marks where it reaches further, hatching where it falls short. The scores are listed below.50100Global−8Brilliance−26Fire+15Scintillation−2Spread−5Symmetry0Shape-norm+4Tilt+1

Against the T73 Round Brilliant in sapphire: ahead on 3, level on 1, behind on 4.

  • Global71, the comparison 79, difference −8
  • Brilliance68, the comparison 94, difference −26
  • Fire52, the comparison 37, difference +15
  • Scintillation78, the comparison 80, difference −2
  • Spread95, the comparison 100, difference −5
  • Symmetry100, the comparison 100, difference 0
  • Shape-norm106, the comparison 102, difference +4
  • Tilt76, the comparison 75, difference +1
Face-up light census, a different measure from the Cut Grading Tool; Spread and Shape-norm above 100 sit on the ring.
Open it in the Cut Performance Wheel

What a sapphire gains as a princess

Nothing clears our margins once each score is counted against its larger gap. Fire, 52, is well above the T73's 37 in sapphire, but the diamond princess reaches 83. Tilt, 76, is level with the T73. What it offers is the outline: crisp corners and a modern square.

The catch with a princess sapphire

Well short of the diamond princess on fire

Fire 52 against 83 for the Princess Cut in diamond: 31 points lower

Fire 52 in sapphire, 83 in diamond: corundum's weak dispersion once more.

Princess cut in sapphire face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 52)

Princess Cut in sapphire · Fire 52

Princess cut in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 83)

Princess Cut in diamond · Fire 83

Look at the coloured flashes: those are fire. Same light, same size, same face-up angle; rendered by our 3D Gemstone Simulator from each cut's own model.

What helps: Sapphire caps fire; the most we measure is the Oval Cut Sapphire's 74.

Try it yourself: See the fire in the 3D Gemstone Simulator

Over a quarter less light than the T73

Brilliance 68 against 94 for the T73 Round Brilliant in sapphire: 26 points lower

Brilliance 68 against 94. The diamond princess returns less still, 57, so the shape is part of the cost.

Princess cut in sapphire face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 68)

Princess Cut in sapphire · Brilliance 68

T73 round brilliant in sapphire face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 94)

T73 Round Brilliant in sapphire · Brilliance 94

Red, green and blue = light returning to the eye; grey = light leaving through the pavilion. This is the head-on view; the Brilliance score averages a wider cone of light, so the score can differ from what one picture shows.

What helps: For a square in sapphire, the Square Cut Sapphire returns 78, the Cushion Cut Sapphire 88.

Try it yourself: Open this Light Return map in the simulator

Over a quarter of the light leaks

Leakage 27 against 5 for the T73 Round Brilliant in sapphire: 22 points higher

27% in our census, against 5% for the T73 in sapphire and 18% for the princess in diamond. The pavilion is far above sapphire's 36.4° guide minimum, so a steeper one is not the cure.

Princess Cut in sapphire · Leakage 27

Princess cut in sapphire tilted 0 degrees: Light Return map, 27% of the face leaking0° · 27% leak
Princess cut in sapphire tilted 10 degrees: Light Return map, 29% of the face leaking10° · 29% leak
Princess cut in sapphire tilted 20 degrees: Light Return map, 35% of the face leaking20° · 35% leak
Princess cut in sapphire tilted 30 degrees: Light Return map, 41% of the face leaking30° · 41% leak

T73 Round Brilliant in sapphire · Leakage 5

T73 round brilliant in sapphire tilted 0 degrees: Light Return map, 1% of the face leaking0° · 1% leak
T73 round brilliant in sapphire tilted 10 degrees: Light Return map, 10% of the face leaking10° · 10% leak
T73 round brilliant in sapphire tilted 20 degrees: Light Return map, 29% of the face leaking20° · 29% leak
T73 round brilliant in sapphire tilted 30 degrees: Light Return map, 30% of the face leaking30° · 30% leak
Each frame is the Light Return map with the stone tilted away from you by the angle shown; grey is light leaving through the pavilion. The share under each frame is that picture's own.

What helps: The Square Cut Sapphire leaks 16% and the Cushion Cut Sapphire 11%.

Try it yourself: Tilt it yourself in the simulator's light map

Heavier than diamond, and deep

1.68 ct at 6.5 mm, against 1.48 ct for the same cut in diamond (+14%)

A 6.5 mm princess would be 1.48 ct in diamond; sapphire's extra density takes the same stone to 1.68 ct.

Sapphire1.68 ctDiamond1.48 ct
A Princess Cut 6.5 mm across, weighed from the model's measured volume and each stone's specific gravity.

What helps: Buy by edge length; carats flatter a deep princess.

Try it yourself: Weights in all seven gemstones on the Princess Cut page

Who a princess sapphire suits

Choose a princess sapphire for the sharp, modern outline, set with protected corners: sapphire's hardness of 9 resists scratches, but points chip more easily than edges.

If light matters, the Square Cut Sapphire or the Cushion Cut Sapphire keep a squarish outline and lose much less: 16% and 11% leakage against 27% here.

Its chevron pavilion breaks colour into a busy pattern, which can hide mild zoning in a blue but also scatters the saturated face a step cut would show.

Princess Cut Sapphire: questions

Is a princess cut good for sapphire?

Not for light: Brilliance 68 against 94 for the T73, and 27% leakage.

Why is a princess sapphire heavy for its size?

It is deep, 68.5%, and sapphire is denser than diamond: 1.68 ct at 6.5 mm against 1.48 ct in diamond.

Princess or cushion for a sapphire?

The cushion: Brilliance 88 against 68, leakage 11% against 27%.

Does a princess sapphire have fire?

Some: 52, more than the T73's 37 in sapphire, but far from the diamond princess at 83.

Get the Princess Cut files

6 formatsMillimetresWatertight

Princess Cut 3D files

The Princess Cut as exact geometry: 93 planar facets, real-world scale, ready for CAD, rendering, printing and casting.

  • STEPExact faceted solid for CAD
  • 3DMRhino, closed mesh on its own layer
  • STLWatertight mesh for printing and casting
  • OBJMesh for modelling and rendering
  • FBXBlender, 3ds Max, Maya, Cinema 4D, Unity, Unreal
  • GLBWeb, AR and quick previews
€9.99 · Personal useBuy the 3D files
GemCad96 index

Princess Cut cutting files

The Princess Cut as a faceting design: 81 + 4 girdles = 85 facets, 96 index, 4-fold mirror-image symmetry, ready for the machine.

  • .ascGemCad design file, 96 index gear
  • .csvTier table: angles, indices and cutting order
  • DiagramPrintable faceting diagram
€9.99 · Personal useBuy the cutting files

Questions before you buy? Email us.

More gemstones and cuts

Sapphire: optical properties and the top ten cuts · The Princess Cut: specifications, model and files

Other cuts in sapphire

The Princess Cut in other gemstones