Peruzzi Cut Synthetic rutile: more fire in synthetic rutile than in diamond
Brilliance 69 · Fire 99 · Scintillation 81 · in our census, where the T73 scores 81 · 94 · 80 in synthetic rutile
How the Peruzzi Cut handles light in synthetic rutile, measured: brilliance 69, fire 99 and 13% leakage, set against the T73 in the same stone and against the same cut in diamond.
Light Return map of the Peruzzi Cut in synthetic rutile, face-up, from our own tracer at refractive index 2.616. Red, green and blue return light to the eye; gray leaks.
Peruzzi Cut Synthetic rutile
Synthetic rutile has a refractive index of 2.616 to 2.903 and a dispersion of 0.330. Its critical angle, from the low end of that range, is 22.5°, so a round design needs a pavilion of at least 39.4° for head-on light to reflect off both sides of the pavilion and leave through the table. We trace it with one index, 2.760, the midpoint of the published range, and a fire spread of 0.284, 0.86 of the published dispersion. Every picture here is our Light Return tracer at 2.616, and every figure is from the same light census that scores the other gemstones; the 3D Gemstone Simulator shows the Peruzzi Cut in synthetic rutile live. Synthetic rutile is strongly doubly refractive (birefringence 0.287): its two rays have critical angles of 22.5° and 20.1°. Our census traces one index, so every figure for it is a rough approximation.
The Peruzzi Cut has 74 facets, a table of 56.8% of its width and a total depth of 69.1% of its width; its pavilion mains sit at 46.2°. In synthetic rutile, the census returns 69 of 100 for brilliance and 99 for fire, against 81 and 94 for the T73, our benchmark, in the same stone; the same Peruzzi Cut in diamond reads 75 and 68.
Is synthetic rutile good in a Peruzzi? Pros and cons, measured
Compared with the T73 Round Brilliant in synthetic rutile 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.
All eight scores against the T73
At a glance: the Peruzzi Cut in synthetic rutile (white) against the T73 Round Brilliant in synthetic rutile (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 synthetic rutile: ahead on 4, behind on 4.
Global84, the comparison 88, difference −4
Brilliance69, the comparison 81, difference −12
Fire99, the comparison 94, difference +5
Scintillation81, the comparison 80, difference +1
Spread96, the comparison 100, difference −4
Symmetry85, the comparison 100, difference −15
Shape-norm108, the comparison 87, difference +21
Tilt96, the comparison 94, difference +2
Face-up light census, a different measure from the Cut Grading Tool; Spread and Shape-norm above 100 sit on the ring. Spread is the census's estimate from depth alone; the face-up size in the pros and cons is measured from each model's outline. Open it in the Cut Performance Wheel; these are the same census figures as our Cut Performance Index.
What the Peruzzi Cut gains in synthetic rutile
More fire in synthetic rutile than in diamond
Fire 99 against 68 for the Peruzzi Cut in diamond: 31 points higher
Fire is the share of the returned light that splits into color at the exit facet: the census traces each exit again at the refractive index minus and plus the fire spread (0.284 in synthetic rutile) and counts a ray as fire when the two directions differ by more than 0.6°. The Peruzzi Cut reads 99 against 68 for the same cut in diamond. The figure is the census's; the 3D Gemstone Simulator renders synthetic rutile's fire live.
The fire figure is the census's, traced at the refractive index minus and plus the fire spread. See the fire in the 3D Gemstone Simulator: the Peruzzi Cut in synthetic rutile under the sunny-day lighting.
Leakage 13 against 19 for the Peruzzi Cut in diamond: 6 points lower
Leakage is the share of the census rays that enter the stone and leave through the pavilion, or through the crown heading down. The Peruzzi Cut leaks 13% in synthetic rutile against 19% for the same cut in diamond. Grey in the maps below is leaking light; the share under each picture is that picture's own.
Peruzzi Cut in synthetic rutile · Leakage 13
0° · 16% leak
10° · 17% leak
20° · 21% leak
30° · 25% leak
Peruzzi Cut in diamond · Leakage 19
0° · 20% leak
10° · 22% leak
20° · 24% leak
30° · 25% leak
Each frame is the Light Return map with the stone tilted away from you by the angle shown; gray is leakage. The share under each frame is that picture's own.
1.59 ct at 6.5 mm, against 1.32 ct for the same cut in diamond (+21%)
Weight follows specific gravity: 4.26 for synthetic rutile against 3.52 for diamond, so the same model at the same size weighs 1.59 ct here and 1.32 ct in diamond, 6.5 mm across. Nothing about the light changes with it.
A Peruzzi Cut 6.5 mm across, weighed from the model's measured volume and each stone's specific gravity.
Symmetry 85 against 100 for the T73 Round Brilliant in synthetic rutile: 15 points lower
Symmetry reads how evenly the pavilion facets of each design family are cut: 100 − 6 × their scatter in degrees. The Peruzzi Cut reads 85, the T73 100. It depends on the geometry alone, so it is the same in every stone.
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.
Returns less light than the T73 in synthetic rutile
Brilliance 69 against 81 for the T73 Round Brilliant in synthetic rutile: 12 points lower
Brilliance is the share of the 3,200 census rays that enter the stone and come back out of the crown towards the viewer. In synthetic rutile, whose critical angle is 22.5°, the Peruzzi Cut returns 69 of 100 and the T73 81. The Peruzzi Cut's pavilion mains sit at 46.2°, the T73's at 40.8°. The maps below show where each stone's light returns from and where it leaks.
Peruzzi Cut in synthetic rutile · Brilliance 69
T73 Round Brilliant in synthetic rutile · Brilliance 81
Red, green and blue = light returning to the eye; gray = leakage, light that leaves heading down or stays inside. 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:the DG-M5 reads 97 for brilliance in synthetic rutile, the best of the cuts we score there.
Face-up size 90 against 100 for the T73 Round Brilliant in synthetic rutile (T73 = 100): 10% less face-up area for the same weight
Face-up size is the outline's area per carat, measured from each model (T73 = 100): 90 for the Peruzzi Cut against 100 for the T73. The same volume spread over a longer or shallower outline shows more face for the weight; it is the same in every stone, because specific gravity scales every cut alike.
Peruzzi Cut · 5.57 mm at 1.00 ct · Face-up size 90
T73 Round Brilliant · 6.08 mm at 1.00 ct · Face-up size 100
Both stones weigh 1.00 ct in synthetic rutile and are drawn to the same scale in millimeters, from each cut's own model. Face-up size is the outline's area per carat, with the T73 at 100: a deeper stone, or a rounder outline, spreads less area for its weight.
What helps:the Marquise Cut reads 121 for face-up size in synthetic rutile, the best of the cuts we score there.
Our verdict on the Peruzzi Cut in synthetic rutile
Pick the Peruzzi Cut in synthetic rutile for this: it shows more fire than in diamond and leaks less than in diamond. The catch: it weighs more than in diamond, has a less regular pavilion than the T73, returns less light than the T73 and faces up smaller for its weight.
If that catch matters more to you, the DG-M5 reads 97 for brilliance in synthetic rutile, the best of the cuts we score there.
Every figure on this page is from our light census, traced at one refractive index: a simulation of the geometry, not a grading report. The 3D files and cutting files below are the same Peruzzi Cut model we traced.
Peruzzi Cut Synthetic rutile: questions
Is the Peruzzi a good cut for synthetic rutile?
In our census the Peruzzi Cut returns 69 of 100 for brilliance and 99 for fire in synthetic rutile, against 81 and 94 for the T73 in the same stone. Against that round and against the same cut in diamond it has 2 pros and 4 cons by our thresholds; the summary above names them.
What pavilion angle does synthetic rutile need?
At least 39.4° for a round design: synthetic rutile's critical angle is 22.5°, from the low end of its refractive index range, and head-on light has to reflect off both sides of the pavilion and leave through the table. The Peruzzi Cut's pavilion mains sit at 46.2°.
How much does a Peruzzi weigh in synthetic rutile?
At 6.5 mm across, 1.59 ct in synthetic rutile, against 1.32 ct for the same cut in diamond (+21%): synthetic rutile's specific gravity is 4.26, diamond's 3.52.
Can I see the Peruzzi in synthetic rutile in 3D?
Yes: the 3D Gemstone Simulator renders it live, with synthetic rutile's own refractive index and dispersion. Synthetic rutile is traced by the same light census as the other gemstones, with its refractive index and fire spread derived from published values, so its scores are on the same scale; the pictures here are our Light Return tracer, and the Cut Performance Wheel sets it against any other cut and stone.
Get the Peruzzi Cut files
6 formatsMillimetersWatertight
Peruzzi Cut 3D files
The Peruzzi Cut as exact geometry: 74 planar facets, real-world scale, ready for CAD,
rendering, printing and casting.
Save with a bundle: the Peruzzi Cut 3D and cutting files are also in Historic Cuts Complete, 6 cuts for €29.99 until 1 December, then €39.99 (€101.88 as single files). Buy the bundle.
Not sure the files open in your software? Get the cube free: the same six formats, for your email address, used only to send them (privacy).
