Emerald Square Cut Ruby: Pros & Cons

Concentric steps, cropped corners and a square outline make the emerald square. Ours has just 49 facets, with a shallow 28.16° pavilion and 61.0% total depth.

Step cuts show a ruby's colour in broad, flat planes rather than in sparkle. In our census this one spreads wide for its weight and keeps more light than the diamond version when tilted. It returns less light than a round, and more of it leaks.

Its pavilion is well below ruby's guide minimum of 36.4°, which is set for round designs; a step cut's long pavilion steps behave differently, and we have not measured a steeper version.

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

Pros

Faces up wider than a round of the same weight 108 vs 100
Holds its light better than a diamond emerald square 86 vs 79

Cons

Less fire than in diamond 53 vs 84
Less light than a round ruby 71 vs 94
Over a fifth of the light leaks 22 vs 5
Heavier than diamond 1.66 vs 1.46 ct

Compared with the T73 Round Brilliant in ruby 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 ruby (white) against the T73 Round Brilliant in ruby (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 ruby: 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 ruby gains in an emerald square cut

Faces up wider than a round of the same weight

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

Spread 108 against 100: the shallow pavilion keeps the stone's weight in its face, so a given carat covers more area.

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 ruby 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 a diamond emerald square

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

Tipped 20°, the ruby keeps 86 of its face-up light, against 79 for the diamond version. Its brilliance is above the diamond's too, 71 against 64, so this is a real gain.

Emerald square cut in ruby 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 ruby 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

The catch with an emerald square ruby

Less fire than in diamond

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

Fire 53 against 84. Broad step facets show colour in occasional large flashes, and corundum gives fewer of them than diamond.

Emerald square cut in ruby 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: A brilliant-cut elongated shape shows more colour in corundum: the Oval Cut Ruby scores 74.

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

Less light than a round ruby

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

Brilliance 71 against 94. A step cut has no brilliant pavilion to send light back in many small reflections.

Emerald square cut in ruby 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 ruby 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: A brilliant-cut Cushion Cut Ruby returns 88 in ruby on a similar square footprint. We have no measurements of this step cut with a steeper pavilion, so we cannot say what one would recover.

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 ruby: 17 points higher

The census counts 22% of the light leaving through the back, where the T73 in ruby loses 5%. With the pavilion at 28.16°, below ruby's 34.6° critical angle, light from straight above can pass through.

What helps: Shrinking the stone keeps the same share. The Cushion Cut Ruby loses 11% in ruby.

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%)

Square corners carry weight even over a shallow pavilion: 1.66 ct at 6.5 mm in ruby, 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: Choose by millimetres.

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

Who an emerald square ruby suits

The emerald square suits a ruby where a calm, architectural face and steady light matter more than brilliance: earrings, or a centre stone in a clean modern setting.

For more light in a square, the Cushion Cut Ruby; for a brilliant square with steady light, the Square Cut Ruby.

A step cut shows inclusions more openly than a brilliant, and many rubies carry fine rutile silk. Choose the rough with that in mind.

Emerald Square Cut Ruby: questions

Does an emerald square ruby look bigger?

Per carat, it covers more area than a round: Spread 108 against 100 for the T73 in ruby.

Is an emerald square cut good for ruby?

For face-up size and steady light, yes; for light return, no: Brilliance 71 against 94, with 22% leakage.

Emerald square or square brilliant for a ruby?

The square brilliant returns more light (78 against 71) and leaks less; the emerald square faces up wider (108 against 98).

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

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

Emerald Square Cut Ruby: a wide step-cut face with steady light