Trillion Cut Sapphire: a triangle that faces up larger than a round of its weight

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

A shallow, curved-sided triangle: in sapphire it looks larger than a round of the same weight, and lets more of its light out of the back.

See it in the simulatorGet the files
The Trillion Cut in sapphire, 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 Sapphire

Our trillion is a shallow stone: 50.7% deep, with a 56.6% table, a 36.0° crown and a 31.91° pavilion. Its sides bow outward, so it reads rounder than the straight-sided trilliant.

That shallow build is where its pro comes from: more face-up area for the weight. The pavilion is also below sapphire's guide minimum of 36.4° and below its critical angle of 34.6°, which fits the leakage we measure.

The trillion is a popular solitaire shape for coloured stones.

Is a trillion cut right for a sapphire? Pros and cons

Pros

Cons

Compared with the T73 Round Brilliant in sapphire 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 sapphire (white) against the T73 Round Brilliant in sapphire (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 sapphire, against the T73 Round Brilliant in sapphire 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 sapphire: 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 a sapphire gains as a trillion

Faces up larger for its weight

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

At 1 ct it spans more than the T73 in sapphire: Spread 107 against 100. Put the other way, a 6.5 mm trillion weighs just 0.91 ct.

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 sapphire 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 sapphire

Much less fire than in diamond

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

Fire 59 against 87 for the diamond trillion, though still well above the T73 in sapphire, 37.

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

Trillion Cut in sapphire · 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: No triangle we sell does much better; for fire in sapphire the Oval Cut Sapphire tops our census at 74.

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

Less light than the T73

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

Brilliance 72 against 94. In diamond the same trillion returns 67, so here the shape, not the stone, is what holds it back.

Trillion cut in sapphire 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 sapphire · Brilliance 72

T73 round brilliant in sapphire 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 sapphire · 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: Among triangles in sapphire, the Trilliant Cut Sapphire returns 86.

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

Heavier than diamond, even when shallow

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

Sapphire's density still adds about 14%: a diamond trillion 6.5 mm across would be 0.80 ct.

Sapphire0.91 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: Its spread already offsets some of this: buy it by width.

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

Over three times the T73's leakage

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

17% in our census against 5% for the T73 in sapphire, and 13% for the trillion in diamond.

Trillion Cut in sapphire · Leakage 17

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

T73 Round Brilliant in sapphire · Leakage 5

T73 round brilliant in sapphire tilted 0 degrees: Light Return map, 1% of the face leaking0° · 1% leak
T73 round brilliant in sapphire tilted 10 degrees: Light Return map, 10% of the face leaking10° · 10% leak
T73 round brilliant in sapphire tilted 20 degrees: Light Return map, 29% of the face leaking20° · 29% leak
T73 round brilliant in sapphire 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: Its pavilion, 31.91°, is under sapphire's 36.4° guide minimum. We have not measured a steeper trillion, so we cannot say how much a change would recover. The Trilliant Cut Sapphire leaks 12%.

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

Who a trillion sapphire suits

The trillion suits a sapphire solitaire or pendant where face-up size matters more than light. A shallow stone gives light a shorter path, so it can lift a dark blue that would look inky in a deeper cut.

For more light in a triangle, the Trilliant Cut Sapphire; for the most light, DG-M5 Sapphire.

As a solitaire its three points need covering: sapphire's hardness of 9 protects the faces from scratches, not the tips from knocks.

Trillion Cut Sapphire: questions

Is a trillion cut good for sapphire?

For size, yes: Spread 107 against 100. For light it trails a round: Brilliance 72 against 94.

Trillion or trilliant for a sapphire?

For face-up size and an even pavilion, the trillion: Spread 107 against 101, Symmetry 100 against 62. For light, the trilliant: 86 against 72.

What does a 6.5 mm trillion sapphire weigh?

About 0.91 ct; the same diamond would be 0.80 ct.

Does a trillion sapphire leak light?

Yes: 17% leaves through the pavilion in our census, where the T73 loses 5%. Its 31.91° pavilion is shallower than sapphire's guide minimum.

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

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

Other cuts in sapphire

The Trillion Cut in other gemstones