T57 Round Brilliant Cubic Zirconia: the 1919 round, brighter here than in diamond

Brilliance 98 · Fire 87 · Scintillation 72 · in our census, where the T73 scores 98 · 87 · 80 in cubic zirconia

The knife-edge 1919 round gives CZ all the light the T73 does. It gives less sparkle, because it has fewer facets.

See it in the simulatorGet the files
The T57 Round Brilliant in cubic zirconia, rendered at an angle in our 3D Gemstone Simulator under studio light
Rendered in our 3D Gemstone Simulator from the T57 Round Brilliant model, 1.00 ct, studio light.

T57 Round Brilliant Cubic Zirconia

The T57 is the round brilliant cut to the proportions published in 1919: table, eight stars, eight bezels, sixteen upper halves, eight pavilion mains and sixteen lower halves, meeting at a knife-edge girdle. In our model the knife-edge stone stands 59.2% deep over a 40.75° pavilion.

In CZ those proportions return Brilliance 98, level with the T73 and higher than the same plan reaches in diamond. The cost of the bare plan is sparkle: with no girdle band it has 57 facets, and our scintillation score counts them.

Should you cut cubic zirconia as a T57? Pros and cons

Pros

Cons

Compared with the T73 Round Brilliant in cubic zirconia and with the T57 Round Brilliant 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 T57 Round Brilliant in cubic zirconia (white) against the T73 Round Brilliant in cubic zirconia (dashed): solid white where it reaches further, hatched where it falls short. Each pro and con is explained, with pictures, below.

Performance wheel: T57 Round Brilliant in cubic zirconia, against the T73 Round Brilliant in cubic zirconia as an outline. Solid white marks where it reaches further, hatching where it falls short. The scores are listed below.50100Global−1Brilliance0Fire0Scintillation−8Spread+1Symmetry0Shape-norm−1Tilt0

Against the T73 Round Brilliant in cubic zirconia: ahead on 1, level on 4, behind on 3.

  • Global92, the comparison 93, difference −1
  • Brilliance98, the comparison 98, difference 0
  • Fire87, the comparison 87, difference 0
  • Scintillation72, the comparison 80, difference −8
  • Spread101, the comparison 100, difference +1
  • Symmetry100, the comparison 100, difference 0
  • Shape-norm105, the comparison 106, difference −1
  • Tilt87, the comparison 87, difference 0
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 the T57 gives cubic zirconia

More fire than the T57 in diamond

Fire 87 against 79 for the T57 Round Brilliant in diamond: 8 points higher

Put the two renders side by side and the CZ's flashes carry more colour. With identical facets, that comes down to dispersion: 0.060 for CZ, 0.044 for diamond.

T57 round brilliant in cubic zirconia face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 87)

T57 Round Brilliant in cubic zirconia · Fire 87

T57 round brilliant in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 79)

T57 Round Brilliant in diamond · Fire 79

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.

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

More light than in diamond

Brilliance 98 against 92 for the T57 Round Brilliant in diamond: 6 points higher

A lower refractive index often costs light. Here it does not: CZ returns more than diamond through these angles, and as much as the T73 does in CZ.

T57 round brilliant in cubic zirconia face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 98)

T57 Round Brilliant in cubic zirconia · Brilliance 98

T57 round brilliant in diamond face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 92)

T57 Round Brilliant in diamond · Brilliance 92

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.

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

Where the T57 falls short in CZ

Heavier than diamond

1.51 ct at 6.5 mm, against 0.92 ct for the same cut in diamond (+65%)

At 59.2% deep it is lighter for its width than the T73. The material still adds 65% over a diamond of the same size.

Cubic Zirconia1.51 ctDiamond0.92 ct
A T57 Round Brilliant 6.5 mm across, weighed from the model's measured volume and each stone's specific gravity.

What helps: Measure, don't weigh: a 6.5 mm T57 in CZ is 1.51 ct.

Try it yourself: Weights in all seven gemstones on the T57 Round Brilliant page

Less sparkle than the T73

Scintillation 72 against 80 for the T73 Round Brilliant in cubic zirconia: 8 points lower

Without girdle facets the plan has 57 against the T73's 73, and the score rises with the count. The facet diagrams show the plainer division.

T57 Round Brilliant · 57 facets · Scintillation 72

T73 Round Brilliant · 73 facets · Scintillation 80

Scintillation follows the number of facets: more facets, more and smaller flashes as the stone moves. Count the facets in each crown. Drawn from each cut's own model.

What helps: This is the plan, not the angles. The T73 Round Brilliant Cubic Zirconia adds a girdle band and scores 80; DG-Vitruvio Cubic Zirconia reaches 98.

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

A little less steady than in diamond

Tilt 87 against 90 for the T57 Round Brilliant in diamond: 3 points lower

Tipped, the CZ keeps 87 of its face-up light against 90 for the diamond: a small gap, and the same 87 the T73 manages in CZ.

T57 Round Brilliant in cubic zirconia · Tilt 87

T57 round brilliant in cubic zirconia tilted 0 degrees: Light Return map, 0% of the face leaking0° · 0% leak
T57 round brilliant in cubic zirconia tilted 10 degrees: Light Return map, 2% of the face leaking10° · 2% leak
T57 round brilliant in cubic zirconia tilted 20 degrees: Light Return map, 9% of the face leaking20° · 9% leak
T57 round brilliant in cubic zirconia tilted 30 degrees: Light Return map, 21% of the face leaking30° · 21% leak

T57 Round Brilliant in diamond · Tilt 90

T57 round brilliant in diamond tilted 0 degrees: Light Return map, 4% of the face leaking0° · 4% leak
T57 round brilliant in diamond tilted 10 degrees: Light Return map, 2% of the face leaking10° · 2% leak
T57 round brilliant in diamond tilted 20 degrees: Light Return map, 10% of the face leaking20° · 10% leak
T57 round brilliant in diamond tilted 30 degrees: Light Return map, 16% of the face leaking30° · 16% 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; grey is light leaving through the pavilion. The share under each frame is that picture's own.

What helps: DG-Miliano Cubic Zirconia holds 90 tipped, at 97 brilliance.

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

Who a T57 CZ suits

The T57 suits period work, teaching and comparison, where the bare 1919 plan is the point. In CZ it gives up no light to the T73, only sparkle.

For a girdle a setter can seat, the T73 Round Brilliant Cubic Zirconia; for more facets and still no girdle band, the T105 Round Brilliant Cubic Zirconia, at 90 for scintillation.

A knife edge is fragile in any stone, and CZ at 8 to 8.5 on the Mohs scale is softer than diamond: keep the girdle covered in the setting.

T57 Round Brilliant Cubic Zirconia: questions

Is the T57 good for cubic zirconia?

For light, yes: Brilliance 98, level with the T73. For sparkle it trails, 72 against 80.

Why does the T57 sparkle less than the T73?

It has no girdle facets: 57 against 73, and our scintillation score follows the count.

Is a T57 CZ brighter than a T57 diamond?

Yes, 98 against 92 in our census, with more fire too. Diamond keeps more of its light when tilted: 90 against 87.

How much does a 6.5 mm T57 CZ weigh?

About 1.51 ct; the diamond equivalent is 0.92 ct.

Get the T57 Round Brilliant Cut files

6 formatsMillimetresWatertight

T57 Round Brilliant Cut 3D files

The T57 Round Brilliant Cut as exact geometry: 57 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

T57 Round Brilliant Cut cutting files

The T57 Round Brilliant Cut as a faceting design: 57 facets, 96 index, 8-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.

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Cubic Zirconia: optical properties and the top ten cuts · The T57 Round Brilliant: specifications, model and files

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