Portuguese Bird's Nest Cut Moissanite: Pros & Cons

The Portuguese cut stacks five crown tiers over five pavilion tiers, each offset half an index step from the one above, so the facets interlock. Our model has a 48.9% table, a 26.0° crown and a 38.0° pavilion, and is 63.1% deep.

In diamond this cut is weak on fire, 65. In moissanite it has four pros and two small cons, both against the T73 and both by a few points.

Moissanite even leaks less here than diamond does: 10% against 13%. That does not make our list, because the gap to the T73, which runs the other way, is the one we count.

Portuguese cut moissanite: is it a good pairing? Pros and cons

Cons

A little less light than the T73 82 vs 86
Slightly more leakage than the T73 10 vs 7

Compared with the T73 Round Brilliant in moissanite and with the Portuguese Bird's Nest 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 Portuguese Bird's Nest Cut in moissanite (white) against the T73 Round Brilliant in moissanite (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 moissanite: ahead on 3, level on 2, behind on 3.

Global92, the comparison 91, difference +1
Brilliance82, the comparison 86, difference −4
Fire95, the comparison 97, difference −2
Scintillation98, the comparison 80, difference +18
Spread100, the comparison 100, difference 0
Symmetry100, the comparison 100, difference 0
Shape-norm88, the comparison 93, difference −5
Tilt100, the comparison 94, difference +6

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 moissanite gains in a Portuguese cut

Far more fire than in diamond

Fire 95 against 65 for the Portuguese Bird's Nest Cut in diamond: 30 points higher

The same facets give 65 in diamond and 95 in moissanite: the stone's dispersion, more than twice diamond's, does the work. In moissanite the bird's nest sits just behind the T73's 97.

Portuguese bird's nest cut in moissanite face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 95) — 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.

Portuguese bird's nest cut in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 65) — 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

Sparkle at the top of our scale

Scintillation 98 against 80 for the T73 Round Brilliant in moissanite: 18 points higher

With 177 facets interlocking in sixteen-fold tiers, the Portuguese scores 98 for scintillation, where the T73 with 73 scores 80.

Portuguese Bird's Nest Cut · 177 facets · Scintillation 98

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.

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

Lighter than in diamond

1.02 ct at 6.5 mm, against 1.11 ct for the same cut in diamond (−9%)

At 63.1% deep, this cut carries a lot of weight for its width. In moissanite that weight is lower than in diamond, because the material is less dense.

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

Try it yourself: Weights in all seven gemstones on the Portuguese Bird's Nest Cut page

Keeps its light when tipped

Tilt 100 against 94 for the T73 Round Brilliant in moissanite: 6 points higher

Tilt reads 100, the top of our scale for keeping face-up light at 20° of tip. Its brilliance is within a few points of the T73's, so we count this as a pro.

Portuguese bird's nest cut in moissanite tilted 0 degrees: Light Return map, 12% 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.

Portuguese bird's nest cut in moissanite tilted 10 degrees: Light Return map, 8% 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.

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

The catch with a Portuguese cut moissanite

A little less light than the T73

Brilliance 82 against 86 for the T73 Round Brilliant in moissanite: 4 points lower

82 against 86: a small gap. Its pavilion, at 38.0°, sits under moissanite's guide minimum of 39.5° for rounds; we have not measured a steeper version and do not promise one.

Portuguese bird's nest cut in moissanite face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 82) — 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 moissanite face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 86) — 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-Miliano Moissanite has the same facet count and the same scintillation (98) and returns 86. For the most light, DG-M5 Moissanite at 98.

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

Slightly more leakage than the T73

Leakage 10 against 7 for the T73 Round Brilliant in moissanite: 3 points higher

10% of the light in our census leaves through the pavilion, a few points more than the T73's 7% in this stone.

What helps: The share does not change with size. DG-M5 leaks 1% and DG-Anteros 3% in moissanite.

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

Who a Portuguese cut moissanite suits

The bird's nest suits a moissanite meant to show off its facet work, a showpiece for the faceting machine, with fire and sparkle near the top of our scale and light that holds at an angle.

If the last few points of light matter, DG-Miliano Moissanite gives the same sparkle with a little more. For a fiery round with far fewer facets to cut, the T73 Round Brilliant Moissanite.

Portuguese Bird's Nest Cut Moissanite: questions

Is moissanite good in a Portuguese cut?

Yes, on fire, sparkle and tilt: Fire 95, Scintillation 98, Tilt 100. Brilliance is 82.

Portuguese cut moissanite or diamond?

Moissanite has far more fire (95 against 65) and leaks less (10% against 13%); diamond returns a little more light, 85 against 82.

How many facets does the Portuguese cut have?

Our model has 177, in five crown and five pavilion tiers on a sixteen-fold plan.

What does a 6.5 mm Portuguese cut moissanite weigh?

Roughly 1.02 ct; in diamond 1.11 ct.

Get the Portuguese Bird's Nest Cut files

6 formatsMillimetresWatertight

Portuguese Bird's Nest Cut 3D files

The Portuguese Bird's Nest Cut as exact geometry: 177 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

Portuguese Bird's Nest Cut cutting files

The Portuguese Bird's Nest Cut as a faceting design: 161 + 16 girdles = 177 facets, 96 index, 16-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

Moissanite: optical properties and the top ten cuts · The Portuguese Bird's Nest Cut: specifications, model and files

Portuguese Bird's Nest Cut Moissanite: far more fire than in diamond, and steady under tilt