Radiant Cut Diamond: one of the largest faces for its weight we measure
Brilliance 32 · Fire 77 · Scintillation 74 · in our census, where the T73 scores 93 · 78 · 80 in diamond
A brilliant facet plan on a cropped rectangle. Our radiant faces up far larger than the T73 for its weight, and in diamond it returns about a third of the light.
Rendered in our 3D Gemstone Simulator from the Radiant Cut model, 1.00 ct, studio light.
Radiant Cut Diamond
Under the cropped corners of a step-cut outline, our radiant runs a full brilliant facet plan: 74 facets on a rectangle 1.284 times as long as it is wide, 53.8% deep.
Set against the T73 Round Brilliant in diamond, it wins on face-up size by a wide margin. Light is another matter: its brilliance is the lowest we measure in diamond after DG-Bowtie and DG-Elongated Hexagon, and only DG-Elongated Hexagon leaks more.
Fire is level with the round, 77 against 78. Tilt reads 100, which we leave out of the pros: it counts there only when brilliance is near the round's.
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 Radiant 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 2, behind on 6.
Global65, the comparison 90, difference −25
Brilliance32, the comparison 93, difference −61
Fire77, the comparison 78, difference −1
Scintillation74, the comparison 80, difference −6
Spread105, the comparison 100, difference +5
Symmetry99, the comparison 100, difference −1
Shape-norm37, the comparison 100, difference −63
Tilt100, the comparison 92, difference +8
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 118 against 100 for the T73 Round Brilliant in diamond (T73 = 100): 18% more face-up area for the same weight
At the same carat weight the radiant's outline covers far more area than the T73's, measured from each model. Only the marquise and the rectangle face up larger in diamond. Our model's shallow profile, 53.8% against the T73's 61.7%, likely helps.
Radiant Cut · 6.91 x 3.77 mm at 1.00 ct · Face-up size 118
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.
Brilliance 32 against 93 for the T73 Round Brilliant in diamond: 61 points lower
This is the radiant's heaviest cost. Our model is 53.8% deep, shallow for a radiant, and we have not measured a deeper one, so we cannot say how much depth would recover.
Radiant Cut in diamond · Brilliance 32
T73 Round Brilliant in diamond · 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.
Leakage 41 against 2 for the T73 Round Brilliant in diamond: 39 points higher
In our census 41% of the light leaves through the pavilion, against 2% for the T73. Of the cuts we measure in diamond, only DG-Elongated Hexagon loses more.
Radiant Cut in diamond · Leakage 41
0° · 50% leak
10° · 47% leak
20° · 44% leak
30° · 42% leak
T73 Round Brilliant in diamond · Leakage 2
0° · 4% leak
10° · 2% leak
20° · 9% leak
30° · 14% 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.
Scintillation 74 against 80 for the T73 Round Brilliant in diamond: 6 points lower
The gap is small, just past our threshold. Scintillation is read from the facets that reach the model's surface; the radiant's design lists one facet more than the T73's, yet its score lands a few points lower.
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.
Choose our radiant when face-up size for the weight is what you are after: it is among the three largest per carat we measure. Accept that it returns about a third of a round's light and loses two-fifths through the back.
