Octagon Cut Cubic Zirconia: Pros, Cons & Light Return

Our octagon has 49 facets on a regular eight-sided outline: a 60.0% table and a 39.8° crown over a 29.3° pavilion, 61.0% deep. It shares its tier profile with our hexagon.

In CZ it returns more light than the hexagon and than the diamond octagon. It still trails the T73 on light, leakage and sparkle, and like every CZ stone it is heavy.

Is cubic zirconia good in an octagon cut? Pros and cons

Pros

None by our margins: Tilt is high but counts only with near-round light, and fire trails the T73.

Cons

Much heavier than diamond 2.03 vs 1.23 ct
Less light than the T73 76 vs 98
Some light leaks through the back 16 vs 1
Fewer flashes than a round 66 vs 80

Compared with the T73 Round Brilliant in cubic zirconia and with the Octagon Cut in diamond. A difference counts from 3 points (Brilliance, Fire, Tilt, Leakage), 5 (Scintillation, Symmetry), 4% (face-up size per carat) 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 Octagon Cut 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.

Against the T73 Round Brilliant in cubic zirconia: ahead on 1, level on 2, behind on 5.

Global82, the comparison 93, difference −11
Brilliance76, the comparison 98, difference −22
Fire80, the comparison 87, difference −7
Scintillation66, the comparison 80, difference −14
Spread100, the comparison 100, difference 0
Symmetry100, the comparison 100, difference 0
Shape-norm100, the comparison 106, difference −6
Tilt97, the comparison 87, difference +10

Face-up light census, a different measure from the Cut Grading Tool; Spread and Shape-norm above 100 sit on the ring. Spread is the census's estimate from depth alone; the face-up size in the pros and cons is measured from each model's outline.

Open it in the Cut Performance Wheel

What the octagon gives cubic zirconia

We found no pro for the octagon in CZ. Its Tilt of 97 beats the T73's 87, but we count Tilt as a pro only when the light behind it is within a few points of the baseline's, and 76 is not. Its fire leads the diamond octagon, 80 against 76, yet trails the T73's 87 in CZ by more; each score counts once, against the bigger gap. What it does offer is a crisp, regular outline for modern settings.

The catch with an octagon CZ

Much heavier than diamond

2.03 ct at 6.5 mm, against 1.23 ct for the same cut in diamond (+65%)

6.5 mm across, the octagon weighs 2.03 ct in CZ; the same model in diamond weighs 1.23 ct.

A Octagon Cut 6.5 mm across, weighed from the model's measured volume and each stone's specific gravity.

What helps: Order it in millimetres.

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

Less light than the T73

Brilliance 76 against 98 for the T73 Round Brilliant in cubic zirconia: 22 points lower

It returns 76 where the T73 returns 98 in CZ. That is more than the diamond octagon's 71, so CZ suits it a little better than diamond does.

Octagon cut in cubic zirconia face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 76) — 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 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.

What helps: DG-Octagonal Kite Cubic Zirconia keeps an eight-sided outline and returns 93 in CZ.

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

Some light leaks through the back

Leakage 16 against 1 for the T73 Round Brilliant in cubic zirconia: 15 points higher

16% of the light in our census leaves through the pavilion, against 18% for the diamond octagon and 1% for the T73 in CZ.

Octagon cut in cubic zirconia tilted 0 degrees: Light Return map, 15% of the face leaking — 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.

Octagon cut in cubic zirconia tilted 10 degrees: Light Return map, 15% of the face leaking — 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: We have no figures for a steeper octagon. DG-Octagonal Kite Cubic Zirconia leaks 5%.

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

Fewer flashes than a round

Scintillation 66 against 80 for the T73 Round Brilliant in cubic zirconia: 14 points lower

With 49 facets against the T73's 73, the octagon scores 66 to the round's 80; the diamond version scores the same 66.

Octagon Cut · 49 facets · Scintillation 66

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: For finer sparkle on a squarish outline, the Cushion Cut Cubic Zirconia scores 85.

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

Who an octagon CZ suits

Choose the octagon in CZ for a crisp geometric centre stone, or a coloured-stone design where the eight sides are the point. It holds its light steadily when tipped, but it starts from less than a round's.

For the most light in eight sides, DG-Octagonal Kite Cubic Zirconia. For a six-sided version of the same profile, the Hexagon Cut Cubic Zirconia, which returns less (64).

Octagon Cut Cubic Zirconia: questions

Is an octagon cut good for cubic zirconia?

It is a fair one: Brilliance 76 and Fire 80, against 98 and 87 for the T73 in CZ, with 16% leakage.

Octagon or DG-Octagonal Kite in CZ?

DG-Octagonal Kite is the brighter stone, 93 to 76, with more fire and less leakage. The octagon sparkles a little more, 66 against 60, and holds steadier when tipped.

Octagon CZ or octagon diamond?

CZ returns more light (76 against 71) and a little more fire; both keep 97 of their light when tipped. Diamond is far lighter and harder.

What does a 6.5 mm octagon CZ weigh?

2.03 ct, where the diamond octagon weighs 1.23 ct.

Get the Octagon Cut files

6 formatsMillimetresWatertight

Octagon Cut 3D files

The Octagon Cut as exact geometry: 49 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

Octagon Cut cutting files

The Octagon Cut as a faceting design: 41 + 8 girdles = 49 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.

More gemstones and cuts

Cubic Zirconia: optical properties and the top ten cuts · The Octagon Cut: specifications, model and files

Octagon Cut Cubic Zirconia: an eight-sided cut that trails the round on light