Trilliant Cut Topaz: what our light census measures
Brilliance 76 · Fire 39 · Scintillation 79 · in our census, where the T73 scores 86 · 35 · 80 in topaz
How the Trilliant Cut handles light in topaz, measured: brilliance 76, fire 39 and 23% leakage, set against the T73 in the same stone and against the same cut in diamond.
Light Return map of the Trilliant Cut in topaz, face-up, from our own tracer at refractive index 1.606. Red, green and blue return light to the eye; gray leaks.
Trilliant Cut Topaz
Topaz has a refractive index of 1.606 to 1.644 and a dispersion of 0.014. Its critical angle, from the low end of that range, is 38.5°, so a round design needs a pavilion of at least 38.5° for head-on light to reflect off both sides of the pavilion and leave through the table. We trace it with one index, 1.625, the midpoint of the published range, and a fire spread of 0.012, 0.86 of the published dispersion. Every picture here is our Light Return tracer at 1.606, and every figure is from the same light census that scores the other gemstones; the 3D Gemstone Simulator shows the Trilliant Cut in topaz live.
The Trilliant Cut has 70 facets and a total depth of 58.9% of its width; its pavilion mains sit at 39.0°. In topaz, the census returns 76 of 100 for brilliance and 39 for fire, against 86 and 35 for the T73, our benchmark, in the same stone; the same Trilliant Cut in diamond reads 78 and 83.
Is topaz good in a Trilliant? Pros and cons, measured
Compared with the T73 Round Brilliant in topaz and with the Trilliant 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 Trilliant Cut in topaz (white) against the T73 Round Brilliant in topaz (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 topaz: ahead on 2, behind on 6.
Global67, the comparison 75, difference −8
Brilliance76, the comparison 86, difference −10
Fire39, the comparison 35, difference +4
Scintillation79, the comparison 80, difference −1
Spread101, the comparison 100, difference +1
Symmetry62, the comparison 100, difference −38
Shape-norm88, the comparison 92, difference −4
Tilt71, the comparison 74, 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 Trilliant Cut gains in topaz
Against the T73 in topaz and the same cut in diamond, no figure of the Trilliant Cut is ahead by the thresholds above. Its figures are in the wheel and the FAQ; Topaz ranks every cut we score in topaz.
What the Trilliant Cut gives up in topaz
Less fire in topaz than in diamond
Fire 39 against 83 for the Trilliant Cut in diamond: 44 points lower
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 (0.012 in topaz) and counts a ray as fire when the two directions differ by more than 0.6°. The Trilliant Cut reads 39 against 83 for the same cut in diamond. The figure is the census's; the 3D Gemstone Simulator renders topaz'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 Trilliant Cut in topaz under the sunny-day lighting.
What helps:the Oval Cut reads 68 for fire in topaz, the best of the cuts we score there.
Symmetry 62 against 100 for the T73 Round Brilliant in topaz: 38 points lower
Symmetry reads how evenly the pavilion facets of each design family are cut: 100 − 6 × their scatter in degrees. The Trilliant Cut reads 62, the T73 100. It depends on the geometry alone, so it is the same in every stone.
Trilliant Cut · 70 facets · Symmetry 62
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.
Tilt 71 against 89 for the Trilliant Cut in diamond: 18 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 Trilliant Cut keeps 71 against 89 for the same cut in diamond. The tilt strips below show the maps at 0°, 10°, 20° and 30°, with each picture's own leak share under it.
Trilliant Cut in topaz · Tilt 71
0° · 16% leak
10° · 27% leak
20° · 38% leak
30° · 38% leak
Trilliant Cut in diamond · Tilt 89
0° · 12% leak
10° · 16% leak
20° · 20% leak
30° · 24% 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 T105 Round Brilliant reads 78 for tilt in topaz, the best of the cuts we score there.
Leakage 23 against 11 for the Trilliant Cut in diamond: 12 points higher
Leakage is the share of the census rays that enter the stone and leave through the pavilion, or through the crown heading down. The Trilliant Cut leaks 23% in topaz against 11% for the same cut in diamond. Grey in the maps below is leaking light; the share under each picture is that picture's own.
Trilliant Cut in topaz · Leakage 23
0° · 16% leak
10° · 27% leak
20° · 38% leak
30° · 38% leak
Trilliant Cut in diamond · Leakage 11
0° · 12% leak
10° · 16% leak
20° · 20% leak
30° · 24% 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.
What helps:the DG-M5 reads 4% for leakage in topaz, the best of the cuts we score there.
Against the T73 in topaz and the same cut in diamond, no figure of the Trilliant Cut is ahead by our thresholds. The catch: it shows less fire than in diamond, has a less regular pavilion than the T73, loses more light when tilted than in diamond and leaks more than in diamond.
If that catch matters more to you, the Oval Cut reads 68 for fire in topaz, 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 Trilliant Cut model we traced.
Trilliant Cut Topaz: questions
Is the Trilliant a good cut for topaz?
In our census the Trilliant Cut returns 76 of 100 for brilliance and 39 for fire in topaz, against 86 and 35 for the T73 in the same stone. Against that round and against the same cut in diamond it has 0 pros and 4 cons by our thresholds; the summary above names them.
What pavilion angle does topaz need?
At least 38.5° for a round design: topaz's critical angle is 38.5°, 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 Trilliant Cut's pavilion mains sit at 39.0°.
How much does a Trilliant weigh in topaz?
At 6.5 mm across, 0.96 ct in topaz, against 0.96 ct for the same cut in diamond, the same weight to the per cent: topaz's specific gravity is 3.535, diamond's 3.52.
Can I see the Trilliant in topaz in 3D?
Yes: the 3D Gemstone Simulator renders it live, with topaz's own refractive index and dispersion. Topaz 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 Trilliant Cut files
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Trilliant Cut 3D files
The Trilliant Cut as exact geometry: 72 planar facets, real-world scale, ready for CAD,
rendering, printing and casting.
