Trilliant Cut Grossular: more fire than the T73 in grossular

Brilliance 85 · Fire 74 · Scintillation 79 · in our census, where the T73 scores 94 · 58 · 80 in grossular

How the Trilliant Cut handles light in grossular, measured: brilliance 85, fire 74 and 13% leakage, set against the T73 in the same stone and against the same cut in diamond.

The Trilliant Cut in grossular, face-up Light Return map from our tracer at refractive index 1.73: red, green and blue show where the light returns from, gray shows where it leaks
Light Return map of the Trilliant Cut in grossular, face-up, from our own tracer at refractive index 1.73. Red, green and blue return light to the eye; gray leaks.

Trilliant Cut Grossular

Grossular has a refractive index of 1.730 to 1.760 and a dispersion of 0.028. Its critical angle, from the low end of that range, is 35.3°, so a round design needs a pavilion of at least 36.2° for head-on light to reflect off both sides of the pavilion and leave through the table. We trace it with one index, 1.745, the midpoint of the published range, and a fire spread of 0.024, 0.86 of the published dispersion. Every picture here is our Light Return tracer at 1.730, and every figure is from the same light census that scores the other gemstones; the 3D Gemstone Simulator shows the Trilliant Cut in grossular 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 grossular, the census returns 85 of 100 for brilliance and 74 for fire, against 94 and 58 for the T73, our benchmark, in the same stone; the same Trilliant Cut in diamond reads 78 and 83.

Is grossular good in a Trilliant? Pros and cons, measured

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

Performance wheel: Trilliant Cut in grossular, against the T73 Round Brilliant in grossular as an outline. Solid white marks where it reaches further, hatching where it falls short. The scores are listed below.50100Global−5Brilliance−9Fire+16Scintillation−1Spread+1Symmetry−38Shape-norm−2Tilt−1

Against the T73 Round Brilliant in grossular: ahead on 2, behind on 6.

  • Global78, the comparison 83, difference −5
  • Brilliance85, the comparison 94, difference −9
  • Fire74, the comparison 58, difference +16
  • Scintillation79, the comparison 80, difference −1
  • Spread101, the comparison 100, difference +1
  • Symmetry62, the comparison 100, difference −38
  • Shape-norm99, the comparison 101, difference −2
  • Tilt73, the comparison 74, difference −1
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 grossular

More fire than the T73 in grossular

Fire 74 against 58 for the T73 Round Brilliant in grossular: 16 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 (0.024 in grossular) and counts a ray as fire when the two directions differ by more than 0.6°. The Trilliant Cut reads 74 against 58 for the T73 in grossular. The figure is the census's; the 3D Gemstone Simulator renders grossular'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 grossular under the sunny-day lighting.

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

What the Trilliant Cut gives up in grossular

A less regular pavilion than the T73

Symmetry 62 against 100 for the T73 Round Brilliant in grossular: 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.

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

Loses more light when tilted than in diamond

Tilt 73 against 89 for the Trilliant Cut in diamond: 16 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 73 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 grossular · Tilt 73

Trilliant cut in grossular tilted 0 degrees: Light Return map, 15% of the face leaking0° · 15% leak
Trilliant cut in grossular tilted 10 degrees: Light Return map, 24% of the face leaking10° · 24% leak
Trilliant cut in grossular tilted 20 degrees: Light Return map, 26% of the face leaking20° · 26% leak
Trilliant cut in grossular tilted 30 degrees: Light Return map, 35% of the face leaking30° · 35% leak

Trilliant Cut in diamond · Tilt 89

Trilliant cut in diamond tilted 0 degrees: Light Return map, 12% of the face leaking0° · 12% leak
Trilliant cut in diamond tilted 10 degrees: Light Return map, 16% of the face leaking10° · 16% leak
Trilliant cut in diamond tilted 20 degrees: Light Return map, 20% of the face leaking20° · 20% leak
Trilliant cut in diamond tilted 30 degrees: Light Return map, 24% of the face leaking30° · 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 DG-Miliano reads 83 for tilt in grossular, the best of the cuts we score there.

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

Returns less light than the T73 in grossular

Brilliance 85 against 94 for the T73 Round Brilliant in grossular: 9 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 grossular, whose critical angle is 35.3°, the Trilliant Cut returns 85 of 100 and the T73 94. The Trilliant Cut's pavilion mains sit at 39.0°, the T73's at 40.8°. The maps below show where each stone's light returns from and where it leaks.

Trilliant cut in grossular face-up Light Return map: red, green and blue show where the light returns from, gray shows where it leaks (Brilliance 85)

Trilliant Cut in grossular · Brilliance 85

T73 round brilliant in grossular face-up Light Return map: red, green and blue show where the light returns from, gray shows where it leaks (Brilliance 94)

T73 Round Brilliant in grossular · Brilliance 94

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 100 for brilliance in grossular, the best of the cuts we score there.

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

Leaks more light than the T73 in grossular

Leakage 13 against 5 for the T73 Round Brilliant in grossular: 8 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 13% in grossular against 5% for the T73 in grossular. Grey in the maps below is leaking light; the share under each picture is that picture's own.

Trilliant Cut in grossular · Leakage 13

Trilliant cut in grossular tilted 0 degrees: Light Return map, 15% of the face leaking0° · 15% leak
Trilliant cut in grossular tilted 10 degrees: Light Return map, 24% of the face leaking10° · 24% leak
Trilliant cut in grossular tilted 20 degrees: Light Return map, 26% of the face leaking20° · 26% leak
Trilliant cut in grossular tilted 30 degrees: Light Return map, 35% of the face leaking30° · 35% leak

T73 Round Brilliant in grossular · Leakage 5

T73 round brilliant in grossular tilted 0 degrees: Light Return map, 0% of the face leaking0° · 0% leak
T73 round brilliant in grossular tilted 10 degrees: Light Return map, 14% of the face leaking10° · 14% leak
T73 round brilliant in grossular tilted 20 degrees: Light Return map, 28% of the face leaking20° · 28% leak
T73 round brilliant in grossular tilted 30 degrees: Light Return map, 31% of the face leaking30° · 31% 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 0% for leakage in grossular, the best of the cuts we score there.

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

Our verdict on the Trilliant Cut in grossular

Pick the Trilliant Cut in grossular for this: it shows more fire than the T73. The catch: it has a less regular pavilion than the T73, loses more light when tilted than in diamond, returns less light than the T73 and leaks more light than the T73.

If that catch matters more to you, the DG-Miliano reads 83 for tilt in grossular, 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 Grossular: questions

Is the Trilliant a good cut for grossular?

In our census the Trilliant Cut returns 85 of 100 for brilliance and 74 for fire in grossular, against 94 and 58 for the T73 in the same stone. Against that round and against the same cut in diamond it has 1 pro and 4 cons by our thresholds; the summary above names them.

What pavilion angle does grossular need?

At least 36.2° for a round design: grossular's critical angle is 35.3°, 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 grossular?

At 6.5 mm across, 0.99 ct in grossular, against 0.96 ct for the same cut in diamond (+3%): grossular's specific gravity is 3.64, diamond's 3.52.

Can I see the Trilliant in grossular in 3D?

Yes: the 3D Gemstone Simulator renders it live, with grossular's own refractive index and dispersion. Grossular 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

6 formatsMillimetersWatertight

Trilliant Cut 3D files

The Trilliant Cut as exact geometry: 72 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 modeling and rendering
  • FBXBlender, 3ds Max, Maya, Cinema 4D, Unity, Unreal
  • GLBWeb, AR and quick previews
GemCad96 index

Trilliant Cut cutting files

The Trilliant Cut as a faceting design: 58 + 12 girdles = 70 facets, 96 index, 3-fold mirror-image symmetry, ready for the machine.

  • .ascGemCad design file, 96 index gear
  • .csvTier table: angles, indices and cutting order
  • DiagramPrintable faceting diagram

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).

Questions before you buy? Email us.

More gemstones and cuts

Grossular: optical properties and the top ten cuts · The Trilliant Cut: specifications, model and files

Other cuts in grossular

The Trilliant Cut in other gemstones