Trilliant Cut Amethyst: a bold three-sided brilliant, lighter in weight than diamond

Brilliance 63 · Fire 34 · Scintillation 79 · in our census, where the T73 scores 72 · 36 · 80 in amethyst

Straight sides, sharp corners and a bold outline. In amethyst it is a little brighter than the trillion, and leakier.

See it in the simulatorGet the files
The Trilliant Cut in amethyst, rendered at an angle in our 3D Gemstone Simulator under studio light
Rendered in our 3D Gemstone Simulator from the Trilliant Cut model, 1.00 ct, studio light.

Trilliant Cut Amethyst

The trilliant is a three-sided brilliant with straight sides, often set in pairs beside a centre stone. Our model has 70 facets, a 39.0° pavilion and a depth of 58.9%.

Against the T73 in amethyst it is close on several counts: Brilliance 63 against 72, Fire 34 against 36, scintillation level. The cons come mostly from the diamond trilliant, which does far better, and from its pavilion's irregular facets.

The pavilion sits under the 40.4° guide minimum for rounds; we have not measured a steeper trilliant.

Is a trilliant cut good for amethyst? Pros and cons

Pros

Cons

Compared with the T73 Round Brilliant in amethyst and with the Trilliant Cut in diamond. A difference counts from 3 points (Brilliance, Fire, Tilt, Leakage), 5 (Scintillation, Symmetry), 2 (Spread) 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 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.

Performance wheel: Trilliant Cut in amethyst, against the T73 Round Brilliant in amethyst as an outline. Solid white marks where it reaches further, hatching where it falls short. The scores are listed below.50100Global−9Brilliance−9Fire−2Scintillation−1Spread+1Symmetry−38Shape-norm−3Tilt−4

Against the T73 Round Brilliant in amethyst: ahead on 1, behind on 7.

  • Global61, the comparison 70, difference −9
  • Brilliance63, the comparison 72, difference −9
  • Fire34, the comparison 36, difference −2
  • Scintillation79, the comparison 80, difference −1
  • Spread101, the comparison 100, difference +1
  • Symmetry62, the comparison 100, difference −38
  • Shape-norm74, the comparison 77, difference −3
  • Tilt76, the comparison 80, difference −4
Face-up light census, a different measure from the Cut Grading Tool; Spread and Shape-norm above 100 sit on the ring.
Open it in the Cut Performance Wheel

What amethyst gains in a trilliant

Lighter than diamond

0.72 ct at 6.5 mm, against 0.96 ct for the same cut in diamond (−25%)

A 6.5 mm trilliant is 0.72 ct in amethyst; in diamond, 0.96 ct.

Amethyst0.72 ctDiamond0.96 ct
A Trilliant Cut 6.5 mm across, weighed from the model's measured volume and each stone's specific gravity.

Try it yourself: Weights in all seven gemstones on the Trilliant Cut page

The catch with a trilliant amethyst

Far less fire than the diamond version

Fire 34 against 83 for the Trilliant Cut in diamond: 49 points lower

The diamond trilliant scores 83, high for its shape. In quartz the same facets carry far less colour: dispersion is the limit, not the plan.

Trilliant cut in amethyst face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 34)

Trilliant Cut in amethyst · Fire 34

Trilliant cut in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 83)

Trilliant Cut in diamond · Fire 83

Look at the coloured flashes: those are fire. Same light, same size, same face-up angle; rendered by our 3D Gemstone Simulator from each cut's own model.

What helps: Among three-sided cuts, the Triangle Cut reaches 61 in amethyst.

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

An irregular pavilion

Symmetry 62 against 100 for the T73 Round Brilliant in amethyst: 38 points lower

Three straight sides do not divide into repeating facets the way a circle does, and our symmetry score, which measures that repetition, reads 62. Set as a mirrored pair of side stones, the two irregular pavilions still match each other.

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.

What helps: The Trillion Cut Amethyst, with gently bowed sides, scores 100.

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

More leakage than in diamond

Leakage 36 against 11 for the Trilliant Cut in diamond: 25 points higher

The census counts 36% of the light lost through the trilliant's pavilion in quartz; in diamond, 11%. Sharp corners give light more places to slip out than a rounded outline.

Trilliant Cut in amethyst · Leakage 36

Trilliant cut in amethyst tilted 0 degrees: Light Return map, 34% of the face leaking0° · 34% leak
Trilliant cut in amethyst tilted 10 degrees: Light Return map, 40% of the face leaking10° · 40% leak
Trilliant cut in amethyst tilted 20 degrees: Light Return map, 38% of the face leaking20° · 38% leak
Trilliant cut in amethyst tilted 30 degrees: Light Return map, 46% of the face leaking30° · 46% leak

Trilliant Cut in diamond · Leakage 11

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
Each frame is the Light Return map with the stone tilted away from you by the angle shown; grey is light leaving through the pavilion. The share under each frame is that picture's own.

What helps: The Trillion Cut Amethyst leaks 30% in amethyst; size does not change the share.

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

Less light than the diamond trilliant

Brilliance 63 against 78 for the Trilliant Cut in diamond: 15 points lower

Quartz holds less of the light the trilliant sends down than diamond does, its critical angle being about 40.4°.

Trilliant cut in amethyst face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 63)

Trilliant Cut in amethyst · Brilliance 63

Trilliant cut in diamond face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 78)

Trilliant Cut in diamond · Brilliance 78

Red, green and blue = light returning to the eye; grey = light leaving through the pavilion. 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: No three-sided cut we measure in quartz returns more; DG-M5 Amethyst, a round, returns 85.

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

Who a trilliant amethyst suits

Choose the trilliant in amethyst for side stones or a graphic solitaire, where a bold outline matters more than every point of light. Its sharp corners need protecting in a setting, the more so in quartz.

Pairs of side stones need matching colour, and amethyst's colour zoning makes matched pairs a matter of careful orientation in the rough.

For less leakage and a regular pavilion, the Trillion Cut Amethyst; for more fire in three sides, the Triangle Cut.

Trilliant Cut Amethyst: questions

Is a trilliant cut good for amethyst?

Fair: Brilliance 63 against 72 for the T73, with 36% leakage. It trails the diamond trilliant by more.

Trilliant or trillion amethyst?

The trilliant returns a little more light (63 against 60); the trillion leaks less (30% against 36%) and faces up larger.

Does a trilliant amethyst have fire?

Fire 34 in our census: a little under the T73's 36 in amethyst, and far under 83 for the diamond trilliant.

What does a 6.5 mm trilliant amethyst weigh?

0.72 ct, against 0.96 ct in diamond.

Get the Trilliant Cut files

6 formatsMillimetresWatertight

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 modelling and rendering
  • FBXBlender, 3ds Max, Maya, Cinema 4D, Unity, Unreal
  • GLBWeb, AR and quick previews
€9.99 · Personal useBuy the 3D files
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
€9.99 · Personal useBuy the cutting files

Questions before you buy? Email us.

More gemstones and cuts

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

Other cuts in amethyst

The Trilliant Cut in other gemstones