Teardrop Cut Spinel: more fire than the T73 in spinel
Brilliance 59 · Fire 70 · Scintillation 81 · in our census, where the T73 scores 94 · 47 · 80 in spinel
How the Teardrop Cut handles light in spinel, measured: brilliance 59, fire 70 and 24% leakage, set against the T73 in the same stone and against the same cut in diamond.
Light Return map of the Teardrop Cut in spinel, face-up, from our own tracer at refractive index 1.712. Red, green and blue return light to the eye; gray leaks.
Teardrop Cut Spinel
Spinel has a refractive index of 1.712 to 1.747 and a dispersion of 0.020. Its critical angle, from the low end of that range, is 35.7°, so a round design needs a pavilion of at least 36.1° for head-on light to reflect off both sides of the pavilion and leave through the table. We trace it with one index, 1.730, the midpoint of the published range, and a fire spread of 0.017, 0.86 of the published dispersion. Every picture here is our Light Return tracer at 1.712, and every figure is from the same light census that scores the other gemstones; the 3D Gemstone Simulator shows the Teardrop Cut in spinel live.
The Teardrop Cut has 74 facets and a total depth of 60.0% of its width; its pavilion mains sit at 38.5°. In spinel, the census returns 59 of 100 for brilliance and 70 for fire, against 94 and 47 for the T73, our benchmark, in the same stone; the same Teardrop Cut in diamond reads 46 and 89.
Is spinel good in a Teardrop? Pros and cons, measured
Compared with the T73 Round Brilliant in spinel and with the Teardrop 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 Teardrop Cut in spinel (white) against the T73 Round Brilliant in spinel (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 spinel: ahead on 3, behind on 5.
Global67, the comparison 81, difference −14
Brilliance59, the comparison 94, difference −35
Fire70, the comparison 47, difference +23
Scintillation81, the comparison 80, difference +1
Spread101, the comparison 100, difference +1
Symmetry98, the comparison 100, difference −2
Shape-norm69, the comparison 101, difference −32
Tilt50, the comparison 75, difference −25
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; these are the same census figures as our Cut Performance Index.
What the Teardrop Cut gains in spinel
More fire than the T73 in spinel
Fire 70 against 47 for the T73 Round Brilliant in spinel: 23 points higher
Fire is the share of the returned light that splits into color at the exit facet: the census traces each exit again at the refractive index minus and plus the fire spread (0.017 in spinel) and counts a ray as fire when the two directions differ by more than 0.6°. The Teardrop Cut reads 70 against 47 for the T73 in spinel. The figure is the census's; the 3D Gemstone Simulator renders spinel's fire live.
The fire figure is the census's, traced at the refractive index minus and plus the fire spread. See the fire in the 3D Gemstone Simulator: the Teardrop Cut in spinel under the sunny-day lighting.
Face-up size 116 against 100 for the T73 Round Brilliant in spinel (T73 = 100): 16% more face-up area for the same weight
Face-up size is the outline's area per carat, measured from each model (T73 = 100): 116 for the Teardrop Cut against 100 for the T73. The same volume spread over a longer or shallower outline shows more face for the weight; it is the same in every stone, because specific gravity scales every cut alike.
Teardrop Cut · 8.56 x 5.92 mm at 1.00 ct · Face-up size 116
T73 Round Brilliant · 6.42 mm at 1.00 ct · Face-up size 100
Both stones weigh 1.00 ct in spinel and are drawn to the same scale in millimeters, 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.
Brilliance 59 against 94 for the T73 Round Brilliant in spinel: 35 points lower
Brilliance is the share of the 3,200 census rays that enter the stone and come back out of the crown towards the viewer. In spinel, whose critical angle is 35.7°, the Teardrop Cut returns 59 of 100 and the T73 94. The Teardrop Cut's pavilion mains sit at 38.5°, the T73's at 40.8°. The maps below show where each stone's light returns from and where it leaks.
Teardrop Cut in spinel · Brilliance 59
T73 Round Brilliant in spinel · Brilliance 94
Red, green and blue = light returning to the eye; gray = leakage, light that leaves heading down or stays inside. 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 DG-M5 reads 100 for brilliance in spinel, the best of the cuts we score there.
Tilt 50 against 80 for the Teardrop Cut in diamond: 30 points lower
Tilt is how much of its face-up brilliance a stone keeps when the census tilts it 20° about its long axis, with 2,200 rays. The Teardrop Cut keeps 50 against 80 for the same cut in diamond. The tilt strips below show the maps at 0°, 10°, 20° and 30°, with each picture's own leak share under it.
Teardrop Cut in spinel · Tilt 50
0° · 22% leak
10° · 31% leak
20° · 42% leak
30° · 49% leak
Teardrop Cut in diamond · Tilt 80
0° · 34% leak
10° · 35% leak
20° · 37% 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; gray is leakage. The share under each frame is that picture's own.
What helps:the DG-Miliano reads 82 for tilt in spinel, the best of the cuts we score there.
Leakage 24 against 6 for the T73 Round Brilliant in spinel: 18 points higher
Leakage is the share of the census rays that enter the stone and leave through the pavilion, or through the crown heading down. The Teardrop Cut leaks 24% in spinel against 6% for the T73 in spinel. Grey in the maps below is leaking light; the share under each picture is that picture's own.
Teardrop Cut in spinel · Leakage 24
0° · 22% leak
10° · 31% leak
20° · 42% leak
30° · 49% leak
T73 Round Brilliant in spinel · Leakage 6
0° · 0% leak
10° · 15% leak
20° · 30% leak
30° · 32% leak
Each frame is the Light Return map with the stone tilted away from you by the angle shown; gray is leakage. The share under each frame is that picture's own.
What helps:the DG-M5 reads 0% for leakage in spinel, the best of the cuts we score there.
Pick the Teardrop Cut in spinel for this: it shows more fire than the T73 and faces up larger for its weight. The catch: it returns less light than the T73, loses more light when tilted than in diamond and leaks more light than the T73.
If that catch matters more to you, the DG-M5 reads 100 for brilliance in spinel, the best of the cuts we score there.
Every figure on this page is from our light census, traced at one refractive index: a simulation of the geometry, not a grading report. The 3D files and cutting files below are the same Teardrop Cut model we traced.
Teardrop Cut Spinel: questions
Is the Teardrop a good cut for spinel?
In our census the Teardrop Cut returns 59 of 100 for brilliance and 70 for fire in spinel, against 94 and 47 for the T73 in the same stone. Against that round and against the same cut in diamond it has 2 pros and 3 cons by our thresholds; the summary above names them.
What pavilion angle does spinel need?
At least 36.1° for a round design: spinel's critical angle is 35.7°, from the low end of its refractive index range, and head-on light has to reflect off both sides of the pavilion and leave through the table. The Teardrop Cut's pavilion mains sit at 38.5°.
How much does a Teardrop weigh in spinel?
At 6.5 mm across, 1.32 ct in spinel, against 1.28 ct for the same cut in diamond (+3%): spinel's specific gravity is 3.62, diamond's 3.52.
Can I see the Teardrop in spinel in 3D?
Yes: the 3D Gemstone Simulator renders it live, with spinel's own refractive index and dispersion. Spinel is traced by the same light census as the other gemstones, with its refractive index and fire spread derived from published values, so its scores are on the same scale; the pictures here are our Light Return tracer, and the Cut Performance Wheel sets it against any other cut and stone.
Get the Teardrop Cut files
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Teardrop Cut 3D files
The Teardrop Cut as exact geometry: 74 planar facets, real-world scale, ready for CAD,
rendering, printing and casting.
