T73 Round Brilliant Cubic Zirconia: Pros, Cons & Fire

The T73 is the 1919 round brilliant finished with a sixteen-facet girdle band: 57 facets plus sixteen. It is the benchmark on every other CZ page on this site, which is why the gaps there look wide: in CZ it returns Brilliance 98.

On its own page the comparison changes. The round baseline here is the T57, the same plan without the girdle facets, and the second comparison is the T73 in diamond.

Against the T57 it gains only sparkle; light, fire and tilt are level. Against diamond, CZ gains light and fire and loses some steadiness when tipped.

Is the T73 the right round for cubic zirconia? Pros and cons

Pros

More fire than the T73 in diamond 87 vs 78
A little more sparkle than the T57 80 vs 72
More light than in diamond 98 vs 93

Cons

Heavier than diamond for its size 1.66 vs 1.01 ct
Loses more light than diamond when tipped 87 vs 92

Compared with the T57 Round Brilliant in cubic zirconia and with the T73 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 T57

At a glance: the T73 Round Brilliant in cubic zirconia (white) against the T57 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.

Against the T57 Round Brilliant in cubic zirconia: ahead on 3, level on 4, behind on 1.

Global93, the comparison 92, difference +1
Brilliance98, the comparison 98, difference 0
Fire87, the comparison 87, difference 0
Scintillation80, the comparison 72, difference +8
Spread100, the comparison 101, difference −1
Symmetry100, the comparison 100, difference 0
Shape-norm106, the comparison 105, 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 T73 gives cubic zirconia

More fire than the T73 in diamond

Fire 87 against 78 for the T73 Round Brilliant in diamond: 9 points higher

With the same angles in both stones, the extra colour comes from the material alone. Set the two renders side by side, under one light, and the CZ carries more of it.

T73 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) — 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.

T73 round brilliant in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 78) — 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

A little more sparkle than the T57

Scintillation 80 against 72 for the T57 Round Brilliant in cubic zirconia: 8 points higher

The girdle band is the only difference between the two plans, and our scintillation score counts those sixteen extra facets. The facet diagrams show where they sit.

T73 Round Brilliant · 73 facets · Scintillation 80

T57 Round Brilliant · 57 facets · Scintillation 72

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.

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

More light than in diamond

Brilliance 98 against 93 for the T73 Round Brilliant in diamond: 5 points higher

Face-up, the CZ map has no grey at all, where the diamond map shows a little. Over the wider cone of light the census averages, CZ comes out ahead as well.

T73 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) — 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.

T73 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 93) — 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

The catch with a T73 CZ

Heavier than diamond for its size

1.66 ct at 6.5 mm, against 1.01 ct for the same cut in diamond (+65%)

CZ's density, about 5.8 against 3.52, makes a T73 of a given width weigh about 65% more than a diamond one. That is the stone; no cut changes it.

A T73 Round Brilliant 6.5 mm across, weighed from the model's measured volume and each stone's specific gravity.

What helps: Size it in millimetres. A 6.5 mm T73 in CZ: 1.66 ct.

Try it yourself: Weights in all seven gemstones on the T73 Round Brilliant page

Loses more light than diamond when tipped

Tilt 87 against 92 for the T73 Round Brilliant in diamond: 5 points lower

The strips tell it: the CZ starts clean and stays nearly clean to 10°, the two are level at 20°, and by 30° the CZ shows more grey than the diamond. A lower refractive index lets more slanting light out.

T73 round brilliant in cubic zirconia tilted 0 degrees: Light Return map, 0% of the face leaking — 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.

T73 round brilliant in cubic zirconia tilted 10 degrees: Light Return map, 1% of the face leaking — 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: In CZ, DG-Miliano Cubic Zirconia keeps 90 when tilted at Brilliance 97: the steadiest of our brightest rounds in this stone.

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

Who a T73 CZ suits

For a CZ round with the published proportions and a girdle any setter knows, this is it, and in CZ it sits close to the top of everything we measure.

For more sparkle at the same light, DG-Vitruvio Cubic Zirconia (98 for scintillation); for the very top of the brilliance scale, DG-Rafaello Cubic Zirconia (100).

If you want the 1919 plan without the girdle band, the T57 Round Brilliant Cubic Zirconia returns the same light.

T73 Round Brilliant Cubic Zirconia: questions

Is the T73 the best round cut for CZ?

It is among the best: Brilliance 98, with only DG-Rafaello higher at 100. DG-Vitruvio and DG-Miliano give nearly the same light with far more sparkle.

T73 or T57 for cubic zirconia?

The same light and fire, 98 and 87. The T73 sparkles a little more, 80 against 72, and has a girdle a setter can seat.

Is a T73 CZ brighter than a T73 diamond?

In our census, yes: Brilliance 98 against 93, and Fire 87 against 78. The diamond holds more light when tipped: 92 against 87.

Does a T73 CZ leak light?

Very little: 1% in our census, and the head-on map shows none.

Get the T73 Round Brilliant Cut files

6 formatsMillimetresWatertight

T73 Round Brilliant Cut 3D files

The T73 Round Brilliant 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

GemCad96 index

T73 Round Brilliant Cut cutting files

The T73 Round Brilliant Cut as a faceting design: 57 + 16 girdles = 73 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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T73 Round Brilliant Cubic Zirconia: nearly all the light back, and more fire than diamond