DG-M5 Diamond: Pros, Cons & Light Return

DG-M5 is a house round on a twelve-fold plan. Twelve stars and twenty-four crown mains surround the table, and one tier of twenty-four mains, every one at 41.49°, forms the pavilion down to a pointed culet. There are no upper or lower halves, which leaves 85 facets on a stone 60.6% deep.

It was drawn for moissanite. In diamond the result splits sharply: two pros, two cons, and both cons larger than the pros. Leakage stays low at 3%, against 2% for the T73 Round Brilliant, so the light it returns face-up is not bought by losing it elsewhere.

Is DG-M5 a good diamond cut? Pros and cons

Pros

More scintillation than the T73 85 vs 80
The most light we measure in diamond 97 vs 93

Cons

Much less fire than the T73 67 vs 78
Keeps less of its light when tipped 83 vs 92

Compared with the T73 Round Brilliant in diamond. A difference counts from 3 points (Brilliance, Fire, Tilt, Leakage), 5 (Scintillation, Symmetry), 2 (Spread) 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 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 3, level on 2, behind on 3.

Global88, the comparison 90, difference −2
Brilliance97, the comparison 93, difference +4
Fire67, the comparison 78, difference −11
Scintillation85, the comparison 80, difference +5
Spread100, the comparison 100, difference 0
Symmetry100, the comparison 100, difference 0
Shape-norm104, the comparison 100, difference +4
Tilt83, the comparison 92, difference −9

Face-up light census, a different measure from the Cut Grading Tool; Spread and Shape-norm above 100 sit on the ring.

Open it in the Cut Performance Wheel

What DG-M5 gives a diamond

More scintillation than the T73

Scintillation 85 against 80 for the T73 Round Brilliant in diamond: 5 points higher

Twelve-fold, with 85 facets against the T73's 73: more, narrower facets around the stone, and our scintillation score rises with them. The gain is modest next to DG-Miliano or DG-Rafaello.

DG-M5 · 85 facets · Scintillation 85

T73 Round Brilliant · 73 facets · Scintillation 80

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.

Try it yourself: Compare the Scintillation spoke in the Cut Performance Wheel

The most light we measure in diamond

Brilliance 97 against 93 for the T73 Round Brilliant in diamond: 4 points higher

No other cut in our diamond census returns more. With one pavilion angle and no halves, light that enters meets broad, evenly angled mains and comes back up.

Dg-m5 in diamond face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 97) — 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.

T73 round brilliant in diamond face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (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.

Try it yourself: Open this Light Return map in the simulator

What DG-M5 costs a diamond

Much less fire than the T73

Fire 67 against 78 for the T73 Round Brilliant in diamond: 11 points lower

Fire is where DG-M5 pays most. The light comes back, but less of it is split into colour. Of the round brilliants we measure in diamond, DG-M5 shows the least fire.

Dg-m5 in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 67) — 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.

T73 round brilliant in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 78) — 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: A different round, not different angles: DG-Miliano Diamond scores 82 for fire and still returns 95 brilliance.

Try it yourself: See the fire in the 3D Gemstone Simulator

Keeps less of its light when tipped

Tilt 83 against 92 for the T73 Round Brilliant in diamond: 9 points lower

At 20° it keeps 83 of its face-up light, against 92 for the T73. A pavilion cut at a single angle has one way to return light; tip the stone and much of it goes past the eye at once.

Dg-m5 in diamond tilted 0 degrees: Light Return map, 0% of the face leaking — 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.

Dg-m5 in diamond tilted 10 degrees: Light Return map, 4% of the face leaking — 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: Steepening is not the answer: the 41.49° pavilion is already above diamond's 38.9° guide minimum. DG-Rafaello Diamond, another twelve-fold round, holds 97 when tipped.

Try it yourself: Compare the Tilt spoke in the Cut Performance Wheel

Who a DG-M5 diamond suits

Choose DG-M5 when face-up light is what matters: a diamond seen straight on, in a setting that keeps it level, with crisp twelve-fold sparkle. It returns the most light of any cut we measure.

If you want colour as well, DG-Miliano Diamond gives up a little light for much more fire. For a twelve-fold round that holds its light when tipped, DG-Rafaello Diamond. In moissanite, the stone it was drawn for, see DG-M5 Moissanite.

DG-M5 Diamond: questions

Which diamond cut returns the most light?

In our census, DG-M5: Brilliance 97, against 93 for the T73 Round Brilliant and 95 for DG-Miliano.

Does DG-M5 have less fire than a round brilliant?

Yes: Fire 67 against 78 for the T73, the lowest of the rounds we measure in diamond.

Why does DG-M5 have no halves?

It is cut in one tier: twenty-four pavilion mains at 41.49° from girdle to culet, with no upper or lower halves. That keeps the plan to 85 facets.

What does a 6.5 mm DG-M5 diamond weigh?

Our model weighs 0.98 ct at that width.

Get the DG-M5 Cut files

6 formatsMillimetresWatertight

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.

STEPExact faceted solid for CAD
3DMRhino, closed mesh on its own layer
STLWatertight mesh for printing and casting
OBJMesh for modelling and rendering
FBXBlender, 3ds Max, Maya, Cinema 4D, Unity, Unreal
GLBWeb, AR and quick previews

€9.99 · Personal useBuy the 3D files

GemCad96 index

DG-M5 Cut cutting files

The DG-M5 Cut as a faceting design: 61 + 24 girdles = 85 facets, 96 index, 12-fold mirror-image symmetry, ready for the machine.

.ascGemCad design file, 96 index gear
.csvTier table: angles, indices and cutting order
DiagramPrintable faceting diagram

€9.99 · Personal useBuy the cutting files

Questions before you buy? Email us.

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Diamond: optical properties and the top ten cuts · The DG-M5: specifications, model and files

DG-M5 Diamond: the most brilliance of any cut we measure