Emerald Square Cut Sapphire: Pros, Cons & Spread

The emerald square is a step cut: cropped corners, concentric steps and a broad, open table. Our model has 49 facets, 61.0% deep, with a 28.16° pavilion figure.

Step cuts show a stone's colour in broad panes rather than breaking it into flashes, which is why they are often chosen for evenly saturated sapphires and avoided for colour-zoned ones.

Our census gives it two pros, size and tilt, and the usual sapphire cons on light, fire and weight.

Is an emerald square cut good for sapphire? Pros and cons

Pros

Faces up larger for its weight 108 vs 100
Holds its light better than the diamond version when tipped 86 vs 79

Compared with the T73 Round Brilliant in sapphire and with the Emerald Square 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 Emerald Square 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.

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

Global73, the comparison 79, difference −6
Brilliance71, the comparison 94, difference −23
Fire53, the comparison 37, difference +16
Scintillation72, the comparison 80, difference −8
Spread108, the comparison 100, difference +8
Symmetry100, the comparison 100, difference 0
Shape-norm94, the comparison 102, difference −8
Tilt86, the comparison 75, difference +11

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 an emerald square

Faces up larger for its weight

Spread 108 against 100 for the T73 Round Brilliant in sapphire: 8 points higher

Spread 108 against 100: at 1 ct it covers more area than the T73 in sapphire. The outlines under this claim are drawn to the same scale.

Emerald Square Cut · 5.49 mm at 1.00 ct · Spread 108

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

Holds its light better than the diamond version when tipped

Tilt 86 against 79 for the Emerald Square Cut in diamond: 7 points higher

At 20° it keeps 86 of its face-up light, the diamond emerald square 79. Its light, 71, is above the diamond's 64, so this is a real gain, not a dim stone keeping little.

Emerald square cut in sapphire tilted 0 degrees: Light Return map, 25% 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.

Emerald square cut in sapphire tilted 10 degrees: Light Return map, 27% 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

Where the emerald square costs a sapphire

Much less fire than in diamond

Fire 53 against 84 for the Emerald Square Cut in diamond: 31 points lower

53 against 84. Broad step facets and weak dispersion leave little colour to see.

Emerald square cut in sapphire face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 53) — 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.

Emerald square cut in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 84) — 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 cut gives sapphire much fire; the Oval Cut Sapphire leads at 74.

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

Far less light than a round

Brilliance 71 against 94 for the T73 Round Brilliant in sapphire: 23 points lower

Brilliance 71 against 94. Step cuts return light in broad flashes between darker panes.

Emerald square cut in sapphire face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 71) — 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 sapphire face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (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: For a square outline with more light, the Cushion Cut Sapphire returns 88 in sapphire and the Square Cut Sapphire 78.

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

Over a fifth of the light leaks

Leakage 22 against 5 for the T73 Round Brilliant in sapphire: 17 points higher

Our census loses 22% through the pavilion; the T73 in sapphire loses 5%. The pavilion figure, 28.16°, is below even sapphire's critical angle of 34.6°, the angle under which light meets a facet and passes straight out.

What helps: The pavilion is shallower than sapphire's 36.4° guide minimum. With no measurements of a steeper version we promise nothing from changing it; the Square Cut Sapphire leaks 16%.

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

Heavier than diamond

1.66 ct at 6.5 mm, against 1.46 ct for the same cut in diamond (+14%)

Sapphire's extra density shows on the scale: 1.66 ct for this square at 6.5 mm, 1.46 ct in diamond.

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

What helps: Its spread offsets part of this; choose it by width.

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

Who an emerald square sapphire suits

The emerald square suits a sapphire with even, rich colour, in a ring or earrings where its larger face and steady light count for more than sparkle.

If light matters more, the Cushion Cut Sapphire. For a brilliant square, the Square Cut Sapphire.

Emerald Square Cut Sapphire: questions

Is an emerald square cut good for sapphire?

For size and steadiness, yes: Spread 108 and Tilt 86. For light, it trails a round: 71 against 94.

Do step cuts show colour zoning in sapphire?

Their large, open facets can make colour bands easier to see, so cutters orient zoned rough with care. We do not model zoning.

Emerald square or Asscher for a sapphire?

In our census the emerald square edges it: Brilliance 71 against 68, leakage 22% against 29%.

What does a 6.5 mm emerald square sapphire weigh?

1.66 ct; in diamond, 1.46 ct.

Get the Emerald Square Cut files

6 formatsMillimetresWatertight

Emerald Square Cut 3D files

The Emerald Square 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

Emerald Square Cut cutting files

The Emerald Square Cut as a faceting design: 41 + 8 girdles = 49 facets, 96 index, 4-fold 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

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

Emerald Square Cut Sapphire: a step-cut square that faces up larger and steadier