Rectangle Cut Emerald: Pros, Cons & Light Return

The rectangle is a step cut with clean, wide steps and square corners: simpler than the emerald cut, with no cropping. Our model has 45 facets, a 1.506 to 1 outline, a total depth of 62.0% and a pavilion figure of 33.48°.

In diamond this plan returns 50. In emerald it falls to 29 and leaks 68% of its light, against 32% in diamond. The pavilion figure sits under emerald's 39.4° guide minimum and well over diamond's critical angle of about 24°. That fits the gap, but our census does not trace the cause.

Rectangle step cut emerald: worth it? Pros and cons

Pros

Lighter than the diamond rectangle 1.62 vs 2.10 ct
The most face for its weight we measure, level with the marquise 121 vs 100

Cons

Far less light than a round 29 vs 78
Most of the light leaks 68 vs 22
Less fire than the diamond rectangle 55 vs 77
Fewer flashes than a round 63 vs 80

Compared with the T73 Round Brilliant in emerald and with the Rectangle Cut 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 Rectangle 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.

Against the T73 Round Brilliant in emerald: ahead on 2, level on 2, behind on 4.

Global56, the comparison 73, difference −17
Brilliance29, the comparison 78, difference −49
Fire55, the comparison 39, difference +16
Scintillation63, the comparison 80, difference −17
Spread100, the comparison 100, difference 0
Symmetry100, the comparison 100, difference 0
Shape-norm38, the comparison 84, difference −46
Tilt100, the comparison 77, difference +23

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 emerald gains in a rectangle cut

Lighter than the diamond rectangle

1.62 ct at 6.5 mm, against 2.10 ct for the same cut in diamond (−23%)

For a bar or a row of side stones, the saving adds up. A rectangle 6.5 mm wide is 1.62 ct in emerald against 2.10 ct in diamond.

A Rectangle 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 Rectangle Cut page

The most face for its weight we measure, level with the marquise

Face-up size 121 against 100 for the T73 Round Brilliant in emerald (T73 = 100): 21% more face-up area for the same weight

At a given carat weight the rectangle covers more area than the T73, and no cut we measure covers more; the marquise ties it. Its square corners fill the outline and the stone is not deep for its length. The figure is the model's own, so it holds in any gemstone.

Rectangle Cut · 8.32 x 5.53 mm at 1.00 ct · Face-up size 121

T73 Round Brilliant · 7.06 mm at 1.00 ct · Face-up size 100

Both stones weigh 1.00 ct in emerald 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 emerald in the 3D Gemstone Simulator

The catch with a rectangle emerald

Far less light than a round

Brilliance 29 against 78 for the T73 Round Brilliant in emerald: 49 points lower

29 against 78. Emerald costs this cut more than it costs most: the same rectangle in diamond returns 50.

Rectangle cut in emerald face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 29) — 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 emerald face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 78) — 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: We have not measured a steeper rectangle, so we make no promise for one. With cropped corners and more steps, the Emerald Cut Emerald returns 58; the Octagon Cut Emerald 69.

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

Most of the light leaks

Leakage 68 against 22 for the T73 Round Brilliant in emerald: 46 points higher

68% of the light in our census leaves through the pavilion, against 22% for the T73 in emerald and 32% for the rectangle in diamond.

Rectangle cut in emerald tilted 0 degrees: Light Return map, 72% 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.

Rectangle cut in emerald tilted 10 degrees: Light Return map, 64% 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: Size does not change the share. The Emerald Cut Emerald leaks 35% in emerald, the Octagon Cut Emerald 31%.

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

Less fire than the diamond rectangle

Fire 55 against 77 for the Rectangle Cut in diamond: 22 points lower

55 against 77. Emerald's dispersion is about a third of diamond's, and no cut we measure gives it the fire of the same cut in diamond. It does beat the T73 in emerald, which scores 39.

Rectangle cut in emerald face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 55) — 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.

Rectangle cut in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 77) — 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

Fewer flashes than a round

Scintillation 63 against 80 for the T73 Round Brilliant in emerald: 17 points lower

45 facets in wide steps against the T73's 73: scintillation 63 against 80. The score depends only on the plan, and the diamond rectangle shares it.

Rectangle Cut · 45 facets · Scintillation 63

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.

What helps: More steps help: the Emerald Cut Emerald scores 72.

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

Who a rectangle emerald suits

The rectangle suits bars, side stones and minimalist settings in emerald, where a big face for the carat weight and the stone's colour count, and light does not. As a centre stone for light it is one of the weakest we measure here.

For a rectangular step cut with more light, the Emerald Cut Emerald. For the most light of any step-cut outline we measure in emerald, the Octagon Cut Emerald.

Rectangle Cut Emerald: questions

Is a rectangle step cut good for emerald?

It depends what you want from it. Face size per carat is excellent, 121 against 100; light is poor, 29 against 78, with 68% escaping.

Rectangle or emerald cut for an emerald?

The Emerald Cut returns more light in emerald, 58 to the rectangle's 29, and leaks less, 35% to 68%. The rectangle faces up larger (121 against 105), has more fire (55 against 36) and a fully regular plan (Symmetry 100 against 64).

Does a rectangle emerald face up larger than a round?

Yes, per carat: Face-up size 121 against 100 for the T73, level with the marquise for the most we measure. How large it looks on the hand we do not compute.

What does a 6.5 mm rectangle emerald weigh?

1.62 ct, for a stone 1.506 times as long as it is wide; in diamond, 2.10 ct.

Get the Rectangle Cut files

6 formatsMillimetresWatertight

Rectangle Cut 3D files

The Rectangle Cut as exact geometry: 45 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

Rectangle Cut cutting files

The Rectangle Cut as a faceting design: 41 + 4 girdles = 45 facets, 96 index, 2-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

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

Rectangle Cut Emerald: as much face for its weight as any cut we measure