Emerald Cut Sapphire: a long step cut that faces up a little larger for its weight
Brilliance 65 · Fire 47 · Scintillation 72 · in our census, where the T73 scores 94 · 37 · 80 in sapphire
Broad steps on a long outline: in sapphire the emerald cut shows a little more face than a round of its weight, and returns a little over two-thirds of the round's light.
Rendered in our 3D Gemstone Simulator from the Emerald Cut model, 1.00 ct, studio light.
Emerald Cut Sapphire
The emerald cut is a rectangular step cut whose cropped corners protect the stone where it is weakest. Our model runs 1.5 to 1 with 57 facets; it is 68.6% deep, on a 41.0° pavilion figure.
In sapphire it has one pro, and seven scores count as cons; the four largest are shown. The pro is size for weight. Two of the four, fire and tilt, come from the same cut in diamond; the other two, light and symmetry, from the T73 Round Brilliant. Leakage, 25% against the T73's 5%, is among the three not shown.
Its pavilion is steeper than sapphire's 36.4° guide minimum.
Is an emerald cut right for a sapphire? Pros and cons
Compared with the T73 Round Brilliant in sapphire and with the Emerald 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 Emerald 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 1, behind on 7.
Global61, the comparison 79, difference −18
Brilliance65, the comparison 94, difference −29
Fire47, the comparison 37, difference +10
Scintillation72, the comparison 80, difference −8
Spread96, the comparison 100, difference −4
Symmetry64, the comparison 100, difference −36
Shape-norm85, the comparison 102, difference −17
Tilt55, the comparison 75, difference −20
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.
Face-up size 105 against 100 for the T73 Round Brilliant in sapphire (T73 = 100): 5% more face-up area for the same weight
Measured from each model's outline, a carat of this emerald cut covers slightly more area than the T73's round face, though the model is deeper, 68.6% against 61.7%. Both outlines below weigh 1.00 ct and share a scale in millimetres.
Emerald Cut · 7.06 x 4.71 mm at 1.00 ct · Face-up size 105
T73 Round Brilliant · 6.21 mm at 1.00 ct · Face-up size 100
Both stones weigh 1.00 ct in sapphire 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.
Fire 47 against 87 for the Emerald Cut in diamond: 40 points lower
The census changes the whole material, refractive index and dispersion together, so it does not say how much of the gap from 87 to 47 is dispersion. Wide step facets show what colour there is in broad panes. Against the T73 in sapphire it still scores higher, 47 against 37.
Emerald Cut in sapphire · Fire 47
Emerald Cut in diamond · Fire 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.
What helps: Of the cuts that keep close to the T73's light in sapphire, the Trilliant Cut Sapphire has the most fire, 52.
Symmetry 64 against 100 for the T73 Round Brilliant in sapphire: 36 points lower
Our symmetry score reads how regularly the pavilion facets repeat within the design, and in this model they repeat less regularly than in a round. A long outline alone does not explain it: the square-cornered Rectangle is as long and scores 100. Among our sapphire cuts, only the baguette and the trilliant score lower.
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, though not the cropped corners alone: the Emerald Square Cut Sapphire keeps them on a square outline and scores 100.
Brilliance 65 against 94 for the T73 Round Brilliant in sapphire: 29 points lower
Brilliance 65 against 94. The same emerald cut returns less in diamond, 55, so the loss comes with the cut rather than with sapphire.
Emerald Cut in sapphire · Brilliance 65
T73 Round Brilliant in sapphire · 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: The pavilion is already at 41.0°; we have not measured a steeper emerald cut. On a square, the Emerald Square Cut Sapphire returns 71; for the most light, DG-M5 Sapphire at 100.
Darkens faster than the diamond version when tipped
Tilt 55 against 83 for the Emerald Cut in diamond: 28 points lower
Tilted 20°, it keeps 55 of its face-up light, where the diamond emerald cut keeps 83. Only the teardrop holds less in our sapphire census, and the pear is level.
Emerald Cut in sapphire · Tilt 55
0° · 22% leak
10° · 30% leak
20° · 56% leak
30° · 60% leak
Emerald Cut in diamond · Tilt 83
0° · 31% leak
10° · 31% leak
20° · 38% leak
30° · 44% leak
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.
What helps:DG-Rafaello Sapphire keeps 81 when tipped, with 85 brilliance, though it is a round rather than a step cut.
The emerald cut suits a sapphire with even, saturated colour, set where it is seen face-up: its long table shows the body colour in broad panes rather than flashes.
Step facets show inclusions and colour zoning plainly, so this outline asks for clean, evenly coloured rough.
Emerald Cut Sapphire: questions
Is an emerald cut good for sapphire?
For face-up size, a little: 105 against 100 for the T73. For light it trails: Brilliance 65 against 94.
Does an emerald cut sapphire have fire?
Some: Fire 47, above the T73's 37 in sapphire but far below the 87 of the same cut in diamond.
Emerald cut or Asscher for a sapphire?
The Asscher returns a little more light (68 against 65) and holds it far better when tipped (85 against 55); the emerald cut faces up larger, 105 against 102.
What does a 6.5 mm wide emerald cut sapphire weigh?
2.63 ct for our 1.5 to 1 model; the same stone in diamond would be 2.31 ct.
Get the Emerald Cut files
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Emerald Cut 3D files
The Emerald Cut as exact geometry: 57 planar facets, real-world scale, ready for CAD,
rendering, printing and casting.
