Peruzzi Cut Diamond: Pros, Cons & Light Leakage

The Peruzzi, or triple cut, adds stars and upper halves to the crown: the point where the modern facet plan appears. Our model has 74 facets on a cushion outline, with a tall 46.0° crown, a 46.22° pavilion and a total depth of 69.1%.

In diamond it matches the T73 for sparkle, because it has as many facets. It does not match it anywhere else.

Is a Peruzzi cut diamond a good choice? Pros and cons

Pros

None that we measure. Scintillation ties with the T73: 81 against 80.

Cons

Less light back to the eye 75 vs 93
Nearly a fifth of the light leaks 19 vs 2
A less regular pavilion 85 vs 100
Less fire 68 vs 78

Compared with the T73 Round Brilliant in diamond and with the Peruzzi 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 Peruzzi Cut in diamond (white) against the T73 Round Brilliant in diamond (dashed): solid white where it reaches further, hatched where it falls short. Each pro and con is explained, with pictures, below.

Against the T73 Round Brilliant in diamond: ahead on 2, level on 1, behind on 5.

Global78, the comparison 90, difference −12
Brilliance75, the comparison 93, difference −18
Fire68, the comparison 78, difference −10
Scintillation81, the comparison 80, difference +1
Spread96, the comparison 100, difference −4
Symmetry85, the comparison 100, difference −15
Shape-norm117, the comparison 100, difference +17
Tilt92, the comparison 92, difference 0

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 diamond gains in a Peruzzi cut

Nothing beats the T73 by our margins. Scintillation is level, 81 against 80, because the facet counts are nearly the same. Tilt is level too. The case for it is the outline, a cushion with the modern plan's facet count.

The Peruzzi's costs in diamond

Less light back to the eye

Brilliance 75 against 93 for the T73 Round Brilliant in diamond: 18 points lower

The tall crown and steep pavilion send part of the light out through the back instead of up. In the face-up maps, grey sits in the corners and along the edges.

Peruzzi cut in diamond face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 75) — 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.

T73 round brilliant in diamond face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 93) — 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: Our modern Cushion Cut returns 80 in diamond, the Old European Cut Diamond 90 if a round outline will do.

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

Nearly a fifth of the light leaks

Leakage 19 against 2 for the T73 Round Brilliant in diamond: 17 points higher

Close to a fifth of the light, 19%, goes out of the back in our census; the T73 lets out 2%. The leak is there face-up and stays as it tilts.

Peruzzi cut in diamond tilted 0 degrees: Light Return map, 22% of the face leaking — 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.

Peruzzi cut in diamond tilted 10 degrees: Light Return map, 22% of the face leaking — 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 angles decide the share, not the size. The modern Cushion Cut leaks 9%.

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

A less regular pavilion

Symmetry 85 against 100 for the T73 Round Brilliant in diamond: 15 points lower

Our symmetry score measures how evenly the pavilion facets repeat within the design. The Peruzzi's pavilion mixes facets of different sizes, so it scores 85.

Peruzzi Cut · 74 facets · Symmetry 85

T73 Round Brilliant · 73 facets · Symmetry 100

Symmetry scores how regular the pavilion facets are within the design. Compare how evenly the facets repeat around each pavilion. Drawn from each cut's own model.

What helps: This is the design, not a flaw in cutting. The Old European Cut keeps a regular pavilion and scores 100.

Try it yourself: Compare the Symmetry spoke in the Cut Performance Wheel

Less fire

Fire 68 against 78 for the T73 Round Brilliant in diamond: 10 points lower

Fire 68 against 78: the light that does return carries less colour.

Peruzzi cut in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 68) — 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.

T73 round brilliant in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 78) — 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: The Old Single Cut Diamond gives the most fire of the antique cuts in diamond, 84.

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

Who a Peruzzi cut diamond suits

Choose the Peruzzi for an antique cushion with plenty of sparkle, and accept a darker stone than a modern round. Among antique cushions in diamond it is the brightest we measure: Brilliance 75, against 65 for the Mazarin and 59 for the Old Mine.

For more light in the same outline, the modern Cushion Cut. For an antique look with nearly the T73's light, the Old European Cut Diamond.

Peruzzi Cut Diamond: questions

Is a Peruzzi cut diamond as bright as a round brilliant?

No. Brilliance 75 against 93 for the T73 Round Brilliant, and 19% leakage against 2%.

Does a Peruzzi cut sparkle like a modern diamond?

Yes. With 74 facets its scintillation scores 81, against 80 for the T73.

Peruzzi or Old Mine cut for a diamond?

In our census the Peruzzi returns more light: Brilliance 75 against 59, with 19% leakage against 32%.

Get the Peruzzi Cut files

6 formatsMillimetresWatertight

Peruzzi Cut 3D files

The Peruzzi Cut as exact geometry: 74 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

Peruzzi Cut cutting files

The Peruzzi Cut as a faceting design: 58 + 16 girdles = 74 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

Diamond: optical properties and the top ten cuts · The Peruzzi Cut: specifications, model and files

Peruzzi Cut Diamond: the antique cushion, measured against a modern round