Brilliance 97 · Fire 61 · Scintillation 85 · in our census, where the T73 scores 96 · 54 · 80 in YAG
How the DG-M5 handles light in YAG, measured: brilliance 97, fire 61 and 3% leakage, set against the T73 in the same stone and against the same cut in diamond.
Light Return map of the DG-M5 in YAG, face-up, from our own tracer at refractive index 1.833. Red, green and blue return light to the eye; gray leaks.
DG-M5 YAG
YAG has a refractive index of 1.833 and a dispersion of 0.028. Its critical angle, from the low end of that range, is 33.1°, so a round design needs a pavilion of at least 36.7° for head-on light to reflect off both sides of the pavilion and leave through the table. We trace it with one index, 1.833, the midpoint of the published range, and a fire spread of 0.024, 0.86 of the published dispersion. Every picture here is our Light Return tracer at 1.833, and every figure is from the same light census that scores the other gemstones; the 3D Gemstone Simulator shows the DG-M5 in YAG live.
The DG-M5 has 85 facets and a total depth of 60.6% of its width; its pavilion mains sit at 41.5°. In YAG, the census returns 97 of 100 for brilliance and 61 for fire, against 96 and 54 for the T73, our benchmark, in the same stone; the same DG-M5 in diamond reads 97 and 67.
Compared with the T73 Round Brilliant in YAG and with the DG-M5 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 DG-M5 in YAG (white) against the T73 Round Brilliant in YAG (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 yag: ahead on 6, level on 2.
Global87, the comparison 83, difference +4
Brilliance97, the comparison 96, difference +1
Fire61, the comparison 54, difference +7
Scintillation85, the comparison 80, difference +5
Spread100, the comparison 100, difference 0
Symmetry100, the comparison 100, difference 0
Shape-norm105, the comparison 103, difference +2
Tilt83, the comparison 78, difference +5
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 DG-M5 gains in YAG
More fire than the T73 in YAG
Fire 61 against 54 for the T73 Round Brilliant in YAG: 7 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 (0.024 in YAG) and counts a ray as fire when the two directions differ by more than 0.6°. The DG-M5 reads 61 against 54 for the T73 in YAG. The figure is the census's; the 3D Gemstone Simulator renders YAG'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 DG-M5 in YAG under the sunny-day lighting.
Tilt 83 against 78 for the T73 Round Brilliant in YAG: 5 points higher
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 DG-M5 keeps 83 against 78 for the T73. The tilt strips below show the maps at 0°, 10°, 20° and 30°, with each picture's own leak share under it.
DG-M5 in YAG · Tilt 83
0° · 5% leak
10° · 3% leak
20° · 22% leak
30° · 28% leak
T73 Round Brilliant in YAG · Tilt 78
0° · 1% leak
10° · 6% leak
20° · 19% leak
30° · 29% 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.
Scintillation 85 against 80 for the T73 Round Brilliant in YAG: 5 points higher
Scintillation follows the number of facets the stone shows: 100 × (1 − e^(−facets / 45)). The DG-M5 has 85 facets and the T73 73, so 85 against 80. It depends on the geometry alone, so it is the same in every stone.
Scintillation follows the number of facets: more facets, more and smaller flashes as the stone moves. Compare the facet counts under the drawings; each drawing shows only the crown. Drawn from each cut's own model.
1.27 ct at 6.5 mm, against 0.98 ct for the same cut in diamond (+29%)
Weight follows specific gravity: 4.55 for YAG against 3.52 for diamond, so the same model at the same size weighs 1.27 ct here and 0.98 ct in diamond, 6.5 mm across. Nothing about the light changes with it.
A DG-M5 6.5 mm across, weighed from the model's measured volume and each stone's specific gravity.
Pick the DG-M5 in YAG for this: it shows more fire than the T73, keeps its light when tilted and has more facets to sparkle with. The catch: it weighs more than in diamond.
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 DG-M5 model we traced.
DG-M5 YAG: questions
Is the DG-M5 a good cut for YAG?
In our census the DG-M5 returns 97 of 100 for brilliance and 61 for fire in YAG, against 96 and 54 for the T73 in the same stone. Against that round and against the same cut in diamond it has 3 pros and 1 con by our thresholds; the summary above names them.
What pavilion angle does YAG need?
At least 36.7° for a round design: YAG's critical angle is 33.1°, 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 DG-M5's pavilion mains sit at 41.5°.
How much does a DG-M5 weigh in YAG?
At 6.5 mm across, 1.27 ct in YAG, against 0.98 ct for the same cut in diamond (+29%): YAG's specific gravity is 4.55, diamond's 3.52.
Can I see the DG-M5 in YAG in 3D?
Yes: the 3D Gemstone Simulator renders it live, with YAG's own refractive index and dispersion. YAG 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 DG-M5 Cut files
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DG-M5 Cut 3D files
The DG-M5 Cut as exact geometry: 85 planar facets, real-world scale, ready for CAD,
rendering, printing and casting.
