Cushion Cut Amethyst: Pros, Cons & Sparkle

The cushion is a square with rounded corners and a brilliant facet plan, descended from the old mine cut. The cushion model behind these figures is a deep one, 65.0%, carrying 85 facets above and below a 39.56° pavilion.

In amethyst it returns 69 against the T73's 72: apart from the rounds, no cut we measure in this stone comes as close. It also sparkles more than the T73.

Its weak points are fire, which quartz cannot supply, and how it holds light when tipped. The pavilion is just under the 40.4° guide minimum for rounds.

Is a cushion cut good for amethyst? Pros and cons

Pros

Lighter than diamond 0.96 vs 1.27 ct
More sparkle than the T73 85 vs 80

Cons

A third of the diamond cushion's fire 24 vs 73
Loses more light when tipped 67 vs 92
More leakage than in diamond 31 vs 9
Less light than the diamond cushion 69 vs 80

Compared with the T73 Round Brilliant in amethyst and with the Cushion Cut 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 Cushion Cut in amethyst (white) against the T73 Round Brilliant in amethyst (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 amethyst: ahead on 2, behind on 6.

Global64, the comparison 70, difference −6
Brilliance69, the comparison 72, difference −3
Fire24, the comparison 36, difference −12
Scintillation85, the comparison 80, difference +5
Spread98, the comparison 100, difference −2
Symmetry97, the comparison 100, difference −3
Shape-norm80, the comparison 77, difference +3
Tilt67, the comparison 80, difference −13

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 amethyst gains in a cushion

Lighter than diamond

0.96 ct at 6.5 mm, against 1.27 ct for the same cut in diamond (−25%)

A cushion 6.5 mm across is 0.96 ct in amethyst; in diamond, 1.27 ct.

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

Try it yourself: Weights in all seven gemstones on the Cushion Cut page

More sparkle than the T73

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

85 facets on a square outline give our facet-based scintillation score more to count than the T73's 73.

Cushion Cut · 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 catch with a cushion amethyst

A third of the diamond cushion's fire

Fire 24 against 73 for the Cushion Cut in diamond: 49 points lower

In diamond the cushion is generous with colour. Quartz, at under a third of diamond's dispersion, leaves it with less fire than even the T73 here.

Cushion cut in amethyst face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 24) — 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.

Cushion cut in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 73) — 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: In a square outline, the Asscher Cut Amethyst reaches 52 in amethyst; the Oval Cut Amethyst 69.

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

Loses more light when tipped

Tilt 67 against 92 for the Cushion Cut in diamond: 25 points lower

Tipped by 20°, the amethyst cushion keeps 67 of its face-up light against 92 in diamond.

Cushion cut in amethyst tilted 0 degrees: Light Return map, 29% 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.

Cushion cut in amethyst tilted 10 degrees: Light Return map, 39% 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: The Square Cut Amethyst brilliant keeps 84 when tipped, at 65 brilliance.

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

More leakage than in diamond

Leakage 31 against 9 for the Cushion Cut in diamond: 22 points higher

31% of the light in our census leaves through the back, where the diamond cushion loses 9%. In amethyst that is only a few points more than the T73.

What helps: The Square Cut Amethyst leaks 29%, DG-M5 Amethyst 15%.

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

Less light than the diamond cushion

Brilliance 69 against 80 for the Cushion Cut in diamond: 11 points lower

The cushion returns 80 in diamond. Quartz's index near 1.55 costs it part of that, as it costs every cut.

Cushion cut in amethyst face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 69) — 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.

Cushion cut in diamond face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 80) — 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.

What helps: No square outline we measure in amethyst returns more. Only a round does, and DG-M5 Amethyst leads them with 85.

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

Who a cushion amethyst suits

For a square amethyst with plenty of light, this is the cut we would choose. It suits vintage-style rings and pendants seen mostly face-up.

A cushion's rounded corners are kinder to quartz's hardness of 7 than sharp ones, and its deep pavilion holds colour well in a pale stone.

For fire in a square outline, the Asscher Cut Amethyst; for the most light of all, DG-M5 Amethyst.

Cushion Cut Amethyst: questions

Is cushion a good cut for amethyst?

One of the best non-round choices: Brilliance 69 against 72 for the T73, with 31% leakage.

Cushion or square amethyst?

The cushion returns more light (69 against 65) and sparkles more; the square holds better when tipped (84 against 67).

Does a cushion amethyst have fire?

Little: Fire 24, against 36 for the T73 in amethyst and 73 for a diamond cushion.

What does a 6.5 mm cushion amethyst weigh?

0.96 ct, where a diamond cushion of that size would come to 1.27 ct.

Get the Cushion Cut files

6 formatsMillimetresWatertight

Cushion Cut 3D files

The Cushion 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

Cushion Cut cutting files

The Cushion Cut as a faceting design: 69 + 16 girdles = 85 facets, 96 index, 2-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.

More gemstones and cuts

Amethyst: optical properties and the top ten cuts · The Cushion Cut: specifications, model and files

Cushion Cut Amethyst: more sparkle than a round, and the most light of any square shape