Square Cut Emerald: the square brilliant, lighter in weight here than in diamond

Brilliance 68 · Fire 38 · Scintillation 78 · in our census, where the T73 scores 78 · 39 · 80 in emerald

The square counterpart of the round brilliant: in emerald it holds its light well when tipped, and returns less of it than the diamond version.

See it in the simulatorGet the files
The Square Cut in emerald, rendered at an angle in our 3D Gemstone Simulator under studio light
Rendered in our 3D Gemstone Simulator from the Square Cut model, 1.00 ct, studio light.

Square Cut Emerald

Our square brilliant has a full facet set, 69 facets, a 41.39° pavilion and a depth of 65.0%. The pavilion is about two degrees steeper than emerald's 39.4° guide minimum.

In emerald it keeps 85 of its face-up light when tipped, more than the T73's 77. With Brilliance 68 against 78, we do not count that as a pro, but it is a steady stone.

Against the same square in diamond the gap is largest on fire, and roughly half that on light and leakage. The cut is the same in both, so those gaps belong to emerald: its 39.4° critical angle and its 0.014 dispersion.

Square brilliant emerald: worth choosing? Pros and cons

Pros

Cons

Compared with the T73 Round Brilliant in emerald and with the 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 Square Cut in emerald (white) against the T73 Round Brilliant in emerald (dashed): solid white where it reaches further, hatched where it falls short. Each pro and con is explained, with pictures, below.

Performance wheel: Square Cut in emerald, against the T73 Round Brilliant in emerald as an outline. Solid white marks where it reaches further, hatching where it falls short. The scores are listed below.50100Global−3Brilliance−10Fire−1Scintillation−2Spread−2Symmetry0Shape-norm+6Tilt+8

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

  • Global70, the comparison 73, difference −3
  • Brilliance68, the comparison 78, difference −10
  • Fire38, the comparison 39, difference −1
  • Scintillation78, the comparison 80, difference −2
  • Spread98, the comparison 100, difference −2
  • Symmetry100, the comparison 100, difference 0
  • Shape-norm90, the comparison 84, difference +6
  • Tilt85, the comparison 77, difference +8
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 emerald gains in a square cut

Lighter than a square diamond

0.88 ct at 6.5 mm, against 1.14 ct for the same cut in diamond (−23%)

A 6.5 mm square brilliant weighs 0.88 ct in emerald; cut in diamond, the same stone weighs 1.14 ct.

Emerald0.88 ctDiamond1.14 ct
A Square 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 Square Cut page

The catch with a square emerald

Half the diamond version's fire

Fire 38 against 72 for the Square Cut in diamond: 34 points lower

Fire 38 against 72. Emerald disperses light weakly, and the square plan adds none back: it is level with the T73 in emerald, 39.

Square cut in emerald face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 38)

Square Cut in emerald · Fire 38

Square cut in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 72)

Square Cut in diamond · Fire 72

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: Not in a square outline: emerald's fire peaks in the Oval Cut Emerald, at 71.

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

Less light than the diamond square

Brilliance 68 against 85 for the Square Cut in diamond: 17 points lower

68 against 85. Light that diamond turns back at 24.4° needs 39.4° in emerald, and some of it never gets there.

Square cut in emerald face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 68)

Square Cut in emerald · Brilliance 68

Square cut in diamond face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 85)

Square Cut in diamond · Brilliance 85

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: Of the square outlines, the Cushion Cut Emerald returns 74 in emerald.

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

About a quarter of the light leaks

Leakage 26 against 10 for the Square Cut in diamond: 16 points higher

26% of the light in our census, against 10% for the square in diamond.

Square Cut in emerald · Leakage 26

Square cut in emerald tilted 0 degrees: Light Return map, 17% of the face leaking0° · 17% leak
Square cut in emerald tilted 10 degrees: Light Return map, 33% of the face leaking10° · 33% leak
Square cut in emerald tilted 20 degrees: Light Return map, 34% of the face leaking20° · 34% leak
Square cut in emerald tilted 30 degrees: Light Return map, 38% of the face leaking30° · 38% leak

Square Cut in diamond · Leakage 10

Square cut in diamond tilted 0 degrees: Light Return map, 7% of the face leaking0° · 7% leak
Square cut in diamond tilted 10 degrees: Light Return map, 11% of the face leaking10° · 11% leak
Square cut in diamond tilted 20 degrees: Light Return map, 16% of the face leaking20° · 16% leak
Square cut in diamond tilted 30 degrees: Light Return map, 22% of the face leaking30° · 22% leak
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: A steeper pavilion is not the remedy: this one is already above 39.4°. The Cushion Cut Emerald leaks 25%.

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

Slightly smaller for its weight

Spread 98 against 100 for the T73 Round Brilliant in emerald: 2 points lower

At 65.0% deep the square carries extra weight under the girdle, so for a given carat weight it is a little narrower than a T73.

Square Cut · 6.78 mm at 1.00 ct · Spread 98

T73 Round Brilliant · 7.06 mm at 1.00 ct · Spread 100

Both stones weigh 1.00 ct in emerald 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.

What helps: Buy by millimetres; at 6.5 mm the square is 0.88 ct.

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

Who a square emerald suits

The square brilliant suits an emerald centre or accent stone that should look much the same from many angles: it keeps its light well when tipped.

For more light in a square outline, the Cushion Cut Emerald. For the traditional step-cut square, the Asscher Cut Emerald or Emerald Square Cut Emerald, with less light.

Square Cut Emerald: questions

Is a square cut good for emerald?

A sound choice: Brilliance 68 against 78 for the T73, 26% leakage, and Tilt 85.

Square brilliant or cushion for an emerald?

The cushion returns more light (74 against 68); the square holds it better when tipped (85 against 68).

Square brilliant or Asscher for an emerald?

The brilliant returns more light (68 against 62) and leaks less (26% against 37%); the Asscher faces up larger and has more fire.

Does a square emerald have fire?

Little: Fire 38, level with the T73's 39 in emerald and about half the diamond square's 72.

Get the Square Cut files

6 formatsMillimetresWatertight

Square Cut 3D files

The Square Cut as exact geometry: 69 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
GemCad64 index

Square Cut cutting files

The Square Cut as a faceting design: 57 + 12 girdles = 69 facets, 64 index, 4-fold mirror-image symmetry, ready for the machine.

  • .ascGemCad design file, 64 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

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

Other cuts in emerald

The Square Cut in other gemstones