Brilliance 26 · Fire 13 · Scintillation 81 · in our census, where the T73 scores 72 · 36 · 80 in amethyst
In diamond the Peruzzi is the brightest historic cushion we measure, at 75. In quartz it returns about a third of that light, and nearly three quarters leaks out of the back.
Known as the triple cut, the Peruzzi splits its crown into bezels, stars and upper halves and repeats the scheme under the girdle. Our model has 74 facets with its girdle, a tall 46.0° crown, a steep 46.22° pavilion and 69.1% depth.
Its pavilion is well past amethyst's 40.4° guide minimum. Between the diamond and the amethyst only the stone changes, and the census shows the cost: about a third of the light and under a fifth of the fire survive.
Compared with the T73 Round Brilliant in amethyst and with the Peruzzi Cut in diamond. A difference counts from 3 points (Brilliance, Fire, Tilt, Leakage), 5 (Scintillation, Symmetry), 4% (face-up size per carat) 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.
At a glance: the Peruzzi Cut in amethyst (white) against the T73 Round Brilliant in amethyst (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 amethyst: ahead on 2, behind on 6.
0.99 ct at 6.5 mm, against 1.32 ct for the same cut in diamond (−25%)
Specific gravity 2.65 for quartz, 3.52 for diamond. This deep cushion, 69.1% from table to culet, weighs a quarter less in amethyst at the same size.
Try it yourself: Weights in all seven gemstones on the Peruzzi Cut page
Fire 13 against 68 for the Peruzzi Cut in diamond: 55 points lower
Tall crown facets that throw colour in diamond carry little in quartz, whose dispersion is under a third of diamond's. Only the Portuguese Bird's Nest scores lower for fire in amethyst.
Peruzzi Cut in amethyst · Fire 13
Peruzzi Cut in diamond · Fire 68
What helps: Amethyst cuts within ten points of the T73's brilliance top out at 54 for fire, in DG-Anteros Amethyst.
Leakage 73 against 19 for the Peruzzi Cut in diamond: 54 points higher
Only the Old Single and the radiant leak more in amethyst. In the picture, the diamond's strip holds at about a quarter grey in every frame: a steady, modest loss that quartz multiplies.
Peruzzi Cut in amethyst · Leakage 73
Peruzzi Cut in diamond · Leakage 19
What helps: We have no steeper Peruzzi in our census and promise none. The modern Cushion Cut Amethyst leaks 31% in amethyst.
Try it yourself: Tilt it yourself in the simulator's light map
Brilliance 26 against 75 for the Peruzzi Cut in diamond: 49 points lower
Steep facets top and bottom work in diamond, where light that meets the pavilion almost always reflects. In quartz, with its 40.4° critical angle, much of it meets a facet it can pass through.
Peruzzi Cut in amethyst · Brilliance 26
Peruzzi Cut in diamond · Brilliance 75
What helps: For a cushion in amethyst, the modern Cushion Cut Amethyst returns 69; among the historic cushions, the Mazarin Cut Amethyst returns 43.
Try it yourself: Open this Light Return map in the simulator
Symmetry 85 against 100 for the T73 Round Brilliant in amethyst: 15 points lower
Symmetry, as we score it, asks how alike each pavilion facet is to its repeats. The Peruzzi's pavilion mixes facets of different sizes and repeats fewer times around the stone than the T73's.
Peruzzi Cut · 74 facets · Symmetry 85
T73 Round Brilliant · 73 facets · Symmetry 100
What helps: This is the design, not poor cutting. The Old European Cut Amethyst, also a historic cut, has a regular pavilion: Symmetry 100.
Try it yourself: Compare the Symmetry spoke in the Cut Performance Wheel
In amethyst the Peruzzi is for collectors and reproduction pieces, where the triple-cut pattern matters more than how much light comes back. Its facet plan scores 81 for sparkle, a point above the T73's 80.
For a historic cushion that keeps more light in quartz, the Mazarin Cut Amethyst; for a bright cushion, the modern Cushion Cut Amethyst. In diamond the same cut returns nearly three times the light: see the Peruzzi Cut Diamond.
Not for light: Brilliance 26 in our census, against 75 for the same cut in diamond and 72 for the T73 in amethyst. Its sparkle, set by the facet plan, scores 81.
The Old Mine returns more light (38 against 26), leaks less (62% against 73%) and has more fire; sparkle is level.
Our census measures 73% leaving through the pavilion, against 19% in diamond. The angles stay the same; quartz's larger critical angle, 40.4°, holds less.
0.99 ct; the diamond Peruzzi, 1.32 ct.
The Peruzzi Cut as exact geometry: 74 planar facets, real-world scale, ready for CAD, rendering, printing and casting.
The Peruzzi Cut as a faceting design: 58 + 16 girdles = 74 facets, 96 index, 4-fold mirror-image symmetry, ready for the machine.
Questions before you buy? Email us.
Amethyst: optical properties and the top ten cuts · The Peruzzi Cut: specifications, model and files