Ahead of the 1919 ideal in diamond and in cubic zirconia. A quarter of a point behind it in moissanite.
Global score against Tolkowsky 1919, measured the same way in the same material.
Diamondn = 2.417+1.80Ahead
Moissaniten = 2.65−0.25Behind
Cubic zirconian = 2.16+0.75Slightly ahead
−2Tolkowsky 1919 = 0+2
The short version
In lab-grown diamond, BL-Miliano holds the largest margin over Tolkowsky of any cut in the registry: 93.45 against 91.65. It earns that margin twice over: more light returned through the crown (95.1% against 92.6%) and more fire (82.9 against 78.7), each worth almost exactly the same 0.85 points.
In cubic zirconia it leads the table as well. In moissanite it finishes a quarter of a point behind the standard. A small deficit is still a deficit.
The ledger
Where the points come from
Global is a weighted sum of six terms. Subtract the standard's figure from this cut's,
term by term, and the six differences add back up to the published gap. Nothing is hidden in the total,
so you can see exactly which part of the stone is doing the work.
In diamond n = 2.417
Ahead
93.45 against the standard's 91.65. Brightness and fire in near-equal measure: +0.85 and +0.84 of a +1.80 margin. Tilt, scintillation and leak contribute 0.11 between them. An angles result, not a facet-count result.
TermThis cut / standardPoints
Useful lightweight 0.3495.192.6+0.85
Fireweight 0.2082.978.7+0.84
Tiltweight 0.1692.792.5+0.03
Scintillationweight 0.1098.998.4+0.05
Symmetryweight 0.10100.0100.0+0.00
Leakweight 0.10 ↓1.832.17+0.03
Sum of the six terms+1.81
Published Global gap +1.80. The six terms reconstruct it to
0.01 of a point. The difference is rounding in the source figures, not a second method.
In moissanite n = 2.65
Behind
92.61 against the standard's 92.86. Fire is the whole story: 92.8 against the standard's 97.2, worth −0.88. Brightness and tilt return +0.59 between them. What is left is a quarter of a point, below the engine's resolution.
TermThis cut / standardPoints
Useful lightweight 0.3486.586.1+0.14
Fireweight 0.2092.897.2−0.88
Tiltweight 0.1696.894.0+0.45
Scintillationweight 0.1098.998.4+0.05
Symmetryweight 0.10100.0100.0+0.00
Leakweight 0.10 ↓7.327.46+0.01
Sum of the six terms−0.23
Published Global gap −0.25. The six terms reconstruct it to
0.02 of a point. The difference is rounding in the source figures, not a second method.
In cubic zirconia n = 2.16
Slightly ahead
95.34 against the standard's 94.59. Top of the table, and built differently from the diamond win: fire (+0.70) and tilt (+0.43) carry it, while useful light sits a full point behind the standard.
TermThis cut / standardPoints
Useful lightweight 0.3497.498.4−0.34
Fireweight 0.2090.587.0+0.70
Tiltweight 0.1689.887.1+0.43
Scintillationweight 0.1098.998.4+0.05
Symmetryweight 0.10100.0100.0+0.00
Leakweight 0.10 ↓1.160.58−0.06
Sum of the six terms+0.78
Published Global gap +0.75. The six terms reconstruct it to
0.03 of a point. The difference is rounding in the source figures, not a second method.
What it's doing
Miliano carries 201 facets, sixteen more than the standard and the most in the registry. It would be easy to read the margin as a facet count, and it isn't one. Scintillation moves from 98.4 to 98.9, worth 0.05 points of Global. The other 1.75 comes from the angles.
That distinction matters because of what the control set on the standard's page shows: by 185 facets, Tolkowsky's design has already banked nearly everything facet count has to give. Anything above that line has to be won optically. Miliano wins it by keeping more light inside the stone (1.83% leaks away against the standard's 2.17%) and returning more of what it keeps through the crown, while raising dispersion at the same time.
Most cuts buy one of those and pay in the other. Cinderella buys fire and pays in leak. Rafaello buys stability and pays in leak. Miliano is the only cut in the registry that is at or ahead of the standard on every measured term in diamond.
Where it gives ground
Moissanite, and not for the reason you would expect. At n = 2.65 Miliano actually leaks marginally less than the standard (7.32% against 7.46%) and returns marginally more light. What it loses is fire: 92.8 against 97.2, worth −0.88 of a point.
The crown geometry that lifts dispersion 4.2 points in diamond lifts it not at all in moissanite, where the standard's own angles already reach 97.2. Tilt repays most of the deficit and the stone still finishes a quarter-point short of the standard. If the stone is moissanite, BL-M5 is the cut solved for it.
How to read this
The protocol
Monte-Carlo ray census on exact facet geometry: 3,200 rays face-up plus 2,200 at
20° tilt, cosine-weighted from a 7° near-vertical cone. Every cut is scored against Tolkowsky's 1919 ideal,
measured the same way in the same material.
These are engine estimates, ± 2 points, not lab-certified grades.
A lead of under half a point sits inside the engine's resolution, so we don't claim it as a win. A deficit is reported as a deficit, however small.
Symmetry
Reads 100 for every cut, because each is modelled from exact geometry rather than
a finished stone. It contributes nothing to any comparison here: it cancels, and we show the row anyway.
The rest of the registry
Ahead of the standard in diamond and cubic zirconia.