Emerald Cut Diamond: Pros, Cons & Fire

The emerald cut is a rectangular step cut: concentric rows of long facets around a long, open table, with the corners cropped. In our model that comes to 57 facets on a 1.5 ratio, over a 41.0° pavilion, 68.6% deep.

Against the T73 Round Brilliant in diamond it wins on fire and on face-up size, and loses on brilliance, symmetry, leakage and tilt. It flashes less often too: Scintillation 72 against 80.

Step facets show the inside of a stone plainly, so the cut is usually kept for clean diamonds.

Is an emerald cut diamond a good choice? Pros and cons

Pros

More fire than a round 87 vs 78
A slightly larger face for its weight 105 vs 100

Compared with the T73 Round Brilliant 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 Emerald Cut in diamond (white) against the T73 Round Brilliant in diamond (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 diamond: ahead on 1, behind on 7.

Global70, the comparison 90, difference −20
Brilliance55, the comparison 93, difference −38
Fire87, the comparison 78, difference +9
Scintillation72, the comparison 80, difference −8
Spread96, the comparison 100, difference −4
Symmetry64, the comparison 100, difference −36
Shape-norm73, the comparison 100, difference −27
Tilt83, the comparison 92, difference −9

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 diamond gains in an emerald cut

More fire than a round

Fire 87 against 78 for the T73 Round Brilliant in diamond: 9 points higher

Among the step cuts we measure in diamond, only DG-Elongated Hexagon shows more. Fire is a share of the light that returns, so the score speaks for the colour in what comes back, not for the amount; for the amount, see the cons.

Emerald cut in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 87) — 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.

T73 round brilliant in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 78) — 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

A slightly larger face for its weight

Face-up size 105 against 100 for the T73 Round Brilliant in diamond (T73 = 100): 5% more face-up area for the same weight

At the same carat weight its outline covers a little more area than the T73's, measured from each model. The margin is small, just past our threshold; the Rectangle Cut Diamond, another step cut, goes much further, at 121.

Emerald Cut · 7.37 x 4.91 mm at 1.00 ct · Face-up size 105

T73 Round Brilliant · 6.48 mm at 1.00 ct · Face-up size 100

Both stones weigh 1.00 ct in diamond and are drawn to the same scale in millimetres, from each cut's own model. Face-up size is the outline's area per carat, with the T73 at 100: a deeper stone, or a rounder outline, spreads less area for its weight.

Try it yourself: See its size at 1.00 ct in diamond in the 3D Gemstone Simulator

The emerald cut's costs in diamond

Much less light than a round

Brilliance 55 against 93 for the T73 Round Brilliant in diamond: 38 points lower

A step-cut pavilion has fewer facets at the angles that send light back to the eye than a brilliant's. Even so, no rectangular step cut we measure in diamond returns more: the rectangle reaches 50, the baguette 40.

Emerald cut in diamond face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 55) — 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 diamond face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 93) — 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 more light with steps, look to outlines as wide as they are long: the Octagon Cut Diamond returns 71, the Asscher Cut Diamond 69. For far more, a brilliant such as the T73 Round Brilliant Diamond.

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

A less regular pavilion

Symmetry 64 against 100 for the T73 Round Brilliant in diamond: 36 points lower

Symmetry here means how evenly the pavilion facets of each angle sit about the centre. On a rectangle with cropped corners, facets of one angle lie at different distances along the sides, the ends and the corners. Only the baguette and the trilliant score lower in diamond.

Emerald Cut · 57 facets · Symmetry 64

T73 Round Brilliant · 73 facets · Symmetry 100

Symmetry scores how regular the pavilion facets are within the design. Compare how evenly the facets repeat around each pavilion. Drawn from each cut's own model.

What helps: This is the design. The Rectangle Cut Diamond drops the cropped corners and scores 100, at a cost in light (50).

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

A quarter of the light leaks

Leakage 25 against 2 for the T73 Round Brilliant in diamond: 23 points higher

The census loses 25% of the emerald cut's light through the pavilion; the T73 loses 2%. The pavilion figure, 41.0°, is above the 38.9° guide minimum we use for rounds.

Emerald cut in diamond tilted 0 degrees: Light Return map, 31% 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.

Emerald cut in diamond tilted 10 degrees: Light Return map, 31% 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: Not by steepening, and not by choosing a smaller stone: the share holds at any size. The Asscher Cut Diamond loses 11%.

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

Darkens more when tipped

Tilt 83 against 92 for the T73 Round Brilliant in diamond: 9 points lower

At a 20° tip the emerald cut holds 83 of the light it shows face-up; the T73 holds 92. It is the smallest of the four cons listed here, but it comes on top of a stone that starts with less light.

What helps: Among cuts with nearly a round's light, those that hold the most when tipped are rounds: DG-Rafaello Diamond keeps 97, and DG-Vitruvio Diamond 93 with the T73's brilliance.

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

Who an emerald cut diamond suits

Choose the emerald cut for a long, quiet diamond with more fire than a round, from less light, and a little more face for its weight. Of the rectangular step cuts we measure, it returns the most light and shows the most fire.

If light comes first, the Asscher Cut Diamond and the Octagon Cut Diamond keep the steps on a shorter outline with more of it. If face-up size comes first, the Rectangle Cut Diamond. For an elongated stone with more light and a larger face for its weight, the Marquise Cut Diamond.

Emerald Cut Diamond: questions

Is an emerald cut diamond less sparkly than a round?

Yes: Scintillation 72 against 80 for the T73, from 57 facets against 73, and less light, 55 against 93.

Does an emerald cut diamond look bigger than a round?

Slightly, for its weight: Face-up size 105 against 100, measured from the outline of each model.

Emerald cut or Asscher for a diamond?

For light, the Asscher: 69 against 55, with 11% leaking to the emerald cut's 25%. For fire, the emerald cut: 87 against 80.

What does a 6.5 mm wide emerald cut diamond weigh?

2.31 ct. Our model is 1.5 times as long as it is wide, so that stone is half as long again.

Get the Emerald Cut files

6 formatsMillimetresWatertight

Emerald Cut 3D files

The Emerald Cut as exact geometry: 57 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

Emerald Cut cutting files

The Emerald Cut as a faceting design: 49 + 8 girdles = 57 facets, 64 index, 2-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

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

Emerald Cut Diamond: more fire than a round, and a slightly larger face for its weight