Trillion Cut Ruby: a larger face for its weight than a round

Brilliance 72 · Fire 59 · Scintillation 80 · in our census, where the T73 scores 94 · 37 · 80 in ruby

Curved sides and a shallow pavilion: the trillion shows more ruby face per carat than the T73, and lets more light through.

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

Trillion Cut Ruby

A trillion bows its three sides gently outward, softer in the hand than a trilliant. Our model is shallow for a brilliant, 50.7% deep, with a 56.6% table, a 36.0° crown, a 31.91° pavilion and 73 facets.

That pavilion is below ruby's guide minimum of 36.4°, and below its critical angle of 34.6° too. Light coming straight down through the table meets it at an angle it can pass through, which fits the leakage we measure. That shallowness is also what spreads a red trillion so wide for its weight.

Trillions are a familiar solitaire shape for coloured stones, rubies included.

Is a trillion a good cut for ruby? Pros and cons

Pros

Cons

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

Performance wheel: Trillion Cut in ruby, against the T73 Round Brilliant in ruby as an outline. Solid white marks where it reaches further, hatching where it falls short. The scores are listed below.50100Global−3Brilliance−22Fire+22Scintillation0Spread+7Symmetry0Shape-norm−19Tilt+12

Against the T73 Round Brilliant in ruby: ahead on 3, level on 2, behind on 3.

  • Global76, the comparison 79, difference −3
  • Brilliance72, the comparison 94, difference −22
  • Fire59, the comparison 37, difference +22
  • Scintillation80, the comparison 80, difference 0
  • Spread107, the comparison 100, difference +7
  • Symmetry100, the comparison 100, difference 0
  • Shape-norm83, the comparison 102, difference −19
  • Tilt87, the comparison 75, difference +12
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 ruby gains in a trillion

A wider face for its weight

Spread 107 against 100 for the T73 Round Brilliant in ruby: 7 points higher

At 50.7% deep, much of the stone's volume sits in its face, so a trillion of a given carat weight spans more than a T73. For a ruby that means more red on show for the weight.

Trillion Cut · 6.72 mm at 1.00 ct · Spread 107

T73 Round Brilliant · 6.21 mm at 1.00 ct · Spread 100

Both stones weigh 1.00 ct in ruby and are drawn to the same scale, from each cut's own model. Spread is face-up size per carat: a deeper stone carries more weight below the girdle and looks smaller for its weight.

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

The catch with a trillion ruby

Less fire than a diamond trillion

Fire 59 against 87 for the Trillion Cut in diamond: 28 points lower

A diamond trillion scores 87 for fire and the ruby 59. In ruby it is the most colourful three-sided cut we measure, but corundum's dispersion holds it well below diamond.

Trillion cut in ruby face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 59)

Trillion Cut in ruby · Fire 59

Trillion cut in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 87)

Trillion Cut in diamond · Fire 87

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: For more colour than this, only the elongated cuts help; the Oval Cut Ruby leads at 74.

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

Less light than a round ruby

Brilliance 72 against 94 for the T73 Round Brilliant in ruby: 22 points lower

Brilliance 72 against 94: the light that slips through the shallow pavilion is light the crown never returns.

Trillion cut in ruby face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 72)

Trillion Cut in ruby · Brilliance 72

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

T73 Round Brilliant in ruby · Brilliance 94

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: For a three-sided ruby with more light, the Trilliant Cut Ruby returns 86. We have no measurements of a steeper trillion, so we cannot say how much a deeper pavilion would recover.

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

Heavier than the diamond version

0.91 ct at 6.5 mm, against 0.80 ct for the same cut in diamond (+14%)

At 6.5 mm across the ruby trillion weighs 0.91 ct and a diamond one 0.80 ct. The ruby figure is the lightest for its width on our ruby pages, thanks to the shallow outline.

Ruby0.91 ctDiamond0.80 ct
A Trillion Cut 6.5 mm across, weighed from the model's measured volume and each stone's specific gravity.

What helps: Nothing to fix in the cut: choose it by millimetres.

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

More leakage than the T73

Leakage 17 against 5 for the T73 Round Brilliant in ruby: 12 points higher

17% of the light escapes the ruby trillion in our census; the T73 lets out 5%.

Trillion Cut in ruby · Leakage 17

Trillion cut in ruby tilted 0 degrees: Light Return map, 17% of the face leaking0° · 17% leak
Trillion cut in ruby tilted 10 degrees: Light Return map, 18% of the face leaking10° · 18% leak
Trillion cut in ruby tilted 20 degrees: Light Return map, 30% of the face leaking20° · 30% leak
Trillion cut in ruby tilted 30 degrees: Light Return map, 43% of the face leaking30° · 43% leak

T73 Round Brilliant in ruby · Leakage 5

T73 round brilliant in ruby tilted 0 degrees: Light Return map, 1% of the face leaking0° · 1% leak
T73 round brilliant in ruby tilted 10 degrees: Light Return map, 10% of the face leaking10° · 10% leak
T73 round brilliant in ruby tilted 20 degrees: Light Return map, 29% of the face leaking20° · 29% leak
T73 round brilliant in ruby tilted 30 degrees: Light Return map, 30% of the face leaking30° · 30% 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: A smaller trillion leaks the same share. The straight-sided Trilliant Cut Ruby lets out 12%.

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

Who a trillion ruby suits

The trillion suits a ruby solitaire where face-up size and a soft triangular outline matter most, and some light can be given up for them.

The straight-sided Trilliant Cut Ruby is the brighter triangle in ruby, and DG-M5 Ruby the brightest cut of all. For an even wider face, the step-cut Emerald Square Cut Ruby spreads 108.

Trillion Cut Ruby: questions

Does a trillion ruby look bigger?

Carat for carat, yes. Its Spread is 107 against 100 for the T73 in ruby, and a stone 6.5 mm across weighs only about 0.91 ct.

Is a trillion ruby bright?

Moderately. It returns 72 against the T73's 94, and 17% of the light slips out of its shallow pavilion.

Why does a trillion ruby leak light?

Its 31.91° pavilion is below ruby's 34.6° critical angle, so light from straight above can pass through it.

Get the Trillion Cut files

6 formatsMillimetresWatertight

Trillion Cut 3D files

The Trillion Cut as exact geometry: 73 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
GemCad120 index

Trillion Cut cutting files

The Trillion Cut as a faceting design: 61 + 12 girdles = 73 facets, 120 index, 3-fold symmetry, ready for the machine.

  • .ascGemCad design file, 120 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

Ruby: optical properties and the top ten cuts · The Trillion Cut: specifications, model and files

Other cuts in ruby

The Trillion Cut in other gemstones