Cushion Cut Synthetic rutile: more fire in synthetic rutile than in diamond
Brilliance 73 · Fire 94 · Scintillation 85 · in our census, where the T73 scores 81 · 94 · 80 in synthetic rutile
How the Cushion Cut handles light in synthetic rutile, measured: brilliance 73, fire 94 and 11% leakage, set against the T73 in the same stone and against the same cut in diamond.
Light Return map of the Cushion 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.
Cushion 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 Cushion 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 Cushion Cut has 85 facets and a total depth of 65.0% of its width; its pavilion mains sit at 39.6°. In synthetic rutile, the census returns 73 of 100 for brilliance and 94 for fire, against 81 and 94 for the T73, our benchmark, in the same stone; the same Cushion Cut in diamond reads 80 and 73.
Is synthetic rutile good in a Cushion? Pros and cons, measured
Compared with the T73 Round Brilliant in synthetic rutile and with the Cushion 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 Cushion 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 1, level on 1, behind on 6.
Global85, the comparison 88, difference −3
Brilliance73, the comparison 81, difference −8
Fire94, the comparison 94, difference 0
Scintillation85, the comparison 80, difference +5
Spread98, the comparison 100, difference −2
Symmetry97, the comparison 100, difference −3
Shape-norm85, the comparison 87, difference −2
Tilt91, the comparison 94, difference −3
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 Cushion Cut gains in synthetic rutile
More fire in synthetic rutile than in diamond
Fire 94 against 73 for the Cushion Cut in diamond: 21 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 Cushion Cut reads 94 against 73 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 Cushion Cut in synthetic rutile under the sunny-day lighting.
Scintillation 85 against 80 for the T73 Round Brilliant in synthetic rutile: 5 points higher
Scintillation follows the number of facets the stone shows: 100 × (1 − e^(−facets / 45)). The Cushion Cut has 85 facets and the T73 73, so 85 against 80. It depends on the geometry alone, so it is the same in every stone.
Scintillation follows the number of facets: more facets, more and smaller flashes as the stone moves. Compare the facet counts under the drawings; each drawing shows only the crown. Drawn from each cut's own model.
1.54 ct at 6.5 mm, against 1.27 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 1.54 ct here and 1.27 ct in diamond, 6.5 mm across. Nothing about the light changes with it.
A Cushion Cut 6.5 mm across, weighed from the model's measured volume and each stone's specific gravity.
Returns less light than the T73 in synthetic rutile
Brilliance 73 against 81 for the T73 Round Brilliant in synthetic rutile: 8 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 Cushion Cut returns 73 of 100 and the T73 81. The Cushion Cut's pavilion mains sit at 39.6°, the T73's at 40.8°. The maps below show where each stone's light returns from and where it leaks.
Cushion Cut in synthetic rutile · Brilliance 73
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.
Tilt 91 against 94 for the T73 Round Brilliant in synthetic rutile: 3 points lower
Tilt is how much of its face-up brilliance a stone keeps when the census tilts it 20° about its long axis, with 2,200 rays. The Cushion Cut keeps 91 against 94 for the T73. The tilt strips below show the maps at 0°, 10°, 20° and 30°, with each picture's own leak share under it.
Cushion Cut in synthetic rutile · Tilt 91
0° · 18% leak
10° · 14% leak
20° · 18% leak
30° · 24% leak
T73 Round Brilliant in synthetic rutile · Tilt 94
0° · 10% leak
10° · 6% leak
20° · 10% leak
30° · 15% leak
Tilt is how much of its own face-up light a stone keeps when tilted. 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.
What helps:the Old European Cut reads 100 for tilt in synthetic rutile, the best of the cuts we score there.
Our verdict on the Cushion Cut in synthetic rutile
Pick the Cushion Cut in synthetic rutile for this: it shows more fire than in diamond and has more facets to sparkle with. The catch: it weighs more than in diamond, returns less light than the T73 and loses more of its light when tilted.
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 Cushion Cut model we traced.
Cushion Cut Synthetic rutile: questions
Is the Cushion a good cut for synthetic rutile?
In our census the Cushion Cut returns 73 of 100 for brilliance and 94 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 3 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 Cushion Cut's pavilion mains sit at 39.6°.
How much does a Cushion weigh in synthetic rutile?
At 6.5 mm across, 1.54 ct in synthetic rutile, against 1.27 ct for the same cut in diamond (+21%): synthetic rutile's specific gravity is 4.26, diamond's 3.52.
Can I see the Cushion 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 Cushion Cut files
6 formatsMillimetersWatertight
Cushion Cut 3D files
The Cushion Cut as exact geometry: 85 planar facets, real-world scale, ready for CAD,
rendering, printing and casting.
Save with a bundle: the Cushion Cut 3D files are also in Jewelry Essentials 3D, 10 cuts for €29.99 until 1 December, then €39.99 (€99.90 as single files). Buy the bundle.
Save with a bundle: the Cushion Cut cutting files are also in Faceter's Classics, 10 cuts for €22.49 until 1 December, then €29.99 (€69.90 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).
