Radiant Cut Morganite: Pros, Cons and Scores

Morganite has a refractive index of 1.572 to 1.600 and a dispersion of 0.014. Its critical angle, from the low end of that range, is 39.5°, so a round design needs a pavilion of at least 39.5° for head-on light to reflect off both sides of the pavilion and leave through the table. We trace it with one index, 1.586, the midpoint of the published range, and a fire spread of 0.012, 0.86 of the published dispersion. Every picture here is our Light Return tracer at 1.572, and every figure is from the same light census that scores the other gemstones; the 3D Gemstone Simulator shows the Radiant Cut in morganite live.

The Radiant Cut has 74 facets and a total depth of 53.8% of its width. In morganite, the census returns 22 of 100 for brilliance and 55 for fire, against 79 and 39 for the T73, our benchmark, in the same stone; the same Radiant Cut in diamond reads 32 and 77.

Is morganite good in a Radiant? Pros and cons, measured

Pros

Lighter than the same cut in diamond 1.27 vs 1.56 ct
Faces up larger for its weight 118 vs 100

Cons

Returns less light than the T73 in morganite 22 vs 79
Leaks more light than the T73 in morganite 74 vs 21
Less fire in morganite than in diamond 55 vs 77
Fewer facets, less sparkle 74 vs 80

Compared with the T73 Round Brilliant in morganite and with the Radiant 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 Radiant Cut in morganite (white) against the T73 Round Brilliant in morganite (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 morganite: ahead on 3, behind on 5.

Global54, the comparison 73, difference −19
Brilliance22, the comparison 79, difference −57
Fire55, the comparison 39, difference +16
Scintillation74, the comparison 80, difference −6
Spread105, the comparison 100, difference +5
Symmetry99, the comparison 100, difference −1
Shape-norm26, the comparison 85, difference −59
Tilt100, the comparison 77, difference +23

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 Radiant Cut gains in morganite

Lighter than the same cut in diamond

1.27 ct at 6.5 mm, against 1.56 ct for the same cut in diamond (−19%)

Weight follows specific gravity: 2.855 for morganite against 3.52 for diamond, so the same model at the same size weighs 1.27 ct here and 1.56 ct in diamond, 6.5 mm across. Nothing about the light changes with it.

A Radiant Cut 6.5 mm across, weighed from the model's measured volume and each stone's specific gravity.

Try it yourself: Weights in every gemstone on the Radiant Cut page

Faces up larger for its weight

Face-up size 118 against 100 for the T73 Round Brilliant in morganite (T73 = 100): 18% more face-up area for the same weight

Face-up size is the outline's area per carat, measured from each model (T73 = 100): 118 for the Radiant 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.

Radiant Cut · 7.41 x 4.04 mm at 1.00 ct · Face-up size 118

T73 Round Brilliant · 6.94 mm at 1.00 ct · Face-up size 100

Both stones weigh 1.00 ct in morganite 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.

Try it yourself: See its size at 1.00 ct in morganite in the 3D Gemstone Simulator

What the Radiant Cut gives up in morganite

Returns less light than the T73 in morganite

Brilliance 22 against 79 for the T73 Round Brilliant in morganite: 57 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 morganite, whose critical angle is 39.5°, the Radiant Cut returns 22 of 100 and the T73 79. The maps below show where each stone's light returns from and where it leaks.

Radiant cut in morganite face-up Light Return map: red, green and blue show where the light returns from, gray shows where it leaks (Brilliance 22) — 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.

T73 round brilliant in morganite face-up Light Return map: red, green and blue show where the light returns from, gray shows where it leaks (Brilliance 79) — 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 91 for brilliance in morganite, the best of the cuts we score there.

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

Leaks more light than the T73 in morganite

Leakage 74 against 21 for the T73 Round Brilliant in morganite: 53 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 Radiant Cut leaks 74% in morganite against 21% for the T73 in morganite. Grey in the maps below is leaking light; the share under each picture is that picture's own.

Radiant cut in morganite tilted 0 degrees: Light Return map, 75% of the face leaking — 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.

Radiant cut in morganite tilted 10 degrees: Light Return map, 70% of the face leaking — 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 9% for leakage in morganite, the best of the cuts we score there.

Try it yourself: Tilt it yourself in the simulator's light map

Less fire in morganite than in diamond

Fire 55 against 77 for the Radiant Cut in diamond: 22 points lower

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 (0.012 in morganite) and counts a ray as fire when the two directions differ by more than 0.6°. The Radiant Cut reads 55 against 77 for the same cut in diamond. The figure is the census's; the 3D Gemstone Simulator renders morganite'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 Radiant Cut in morganite under the sunny-day lighting.

What helps: the Oval Cut reads 70 for fire in morganite, the best of the cuts we score there.

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

Fewer facets, less sparkle

Scintillation 74 against 80 for the T73 Round Brilliant in morganite: 6 points lower

Scintillation follows the number of facets the stone shows: 100 × (1 − e^(−facets / 45)). The Radiant Cut has 74 facets and the T73 73, so 74 against 80. It depends on the geometry alone, so it is the same in every stone.

Radiant Cut · 74 facets · Scintillation 74

T73 Round Brilliant · 73 facets · Scintillation 80

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.

What helps: the DG-Miliano reads 98 for scintillation in morganite, the best of the cuts we score there.

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

Our verdict on the Radiant Cut in morganite

Pick the Radiant Cut in morganite for this: it weighs less than in diamond and faces up larger for its weight. The catch: it returns less light than the T73, leaks more light than the T73, shows less fire than in diamond and has fewer facets to sparkle with.

If that catch matters more to you, the DG-M5 reads 91 for brilliance in morganite, 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 Radiant Cut model we traced.

Radiant Cut Morganite: questions

Is the Radiant a good cut for morganite?

In our census the Radiant Cut returns 22 of 100 for brilliance and 55 for fire in morganite, against 79 and 39 for the T73 in the same stone. Against that round and against the same cut in diamond it has 2 pros and 4 cons by our thresholds; the summary above names them.

What pavilion angle does morganite need?

At least 39.5° for a round design: morganite's critical angle is 39.5°, 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.

How much does a Radiant weigh in morganite?

At 6.5 mm across, 1.27 ct in morganite, against 1.56 ct for the same cut in diamond (-19%): morganite's specific gravity is 2.855, diamond's 3.52.

Can I see the Radiant in morganite in 3D?

Yes: the 3D Gemstone Simulator renders it live, with morganite's own refractive index and dispersion. Morganite 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 Radiant Cut files

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Radiant Cut 3D files

The Radiant Cut as exact geometry: 74 planar facets, real-world scale, ready for CAD, rendering, printing and casting.

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In preparation

Radiant Cut cutting files

The faceting design for the Radiant Cut is in preparation. It will include the GemCad file, the tier table and a printable diagram.

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Save with a bundle: the Radiant Cut 3D files are also in Jewelry Essentials 3D, 10 cuts for €29.99 until 1 December, then €39.99 (€99.90 as single files). Buy the bundle.

Not sure the files open in your software? Get the cube free: the same six formats, for your email address, used only to send them (privacy).

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More gemstones and cuts

Morganite: optical properties and the top ten cuts · The Radiant Cut: specifications, model and files

Radiant Cut Morganite: lighter than the same cut in diamond