Asscher Cut Amethyst: Pros, Cons & Spread

The Asscher is a square step cut with deeply cropped corners and a stepped pavilion. The one we measure has 58 facets; its steps descend at a shallow 27.6° on the pavilion, and it is 60.4% deep.

A step cut shows the inside of the stone plainly, and in amethyst that includes colour zoning: bands of deeper and paler purple that a brilliant's many facets tend to mix. Rough with even colour suits it best.

Our maps tell the light story. Head-on, nearly half the amethyst Asscher's map is grey, and tipping it barely changes that; the diamond version starts with far less grey and gains some as it tips.

Is an Asscher a good cut for amethyst? Pros and cons

Pros

Lighter than diamond 1.01 vs 1.34 ct
A larger face for its weight 107 vs 100

Cons

Much less fire than in diamond 52 vs 80
Much more leakage than in diamond 39 vs 11
Less light than the T73 60 vs 72
Fewer flashes than a round 72 vs 80

Compared with the T73 Round Brilliant in amethyst and with the Asscher 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 Asscher 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 4, level on 1, behind on 3.

Global68, the comparison 70, difference −2
Brilliance60, the comparison 72, difference −12
Fire52, the comparison 36, difference +16
Scintillation72, the comparison 80, difference −8
Spread107, the comparison 100, difference +7
Symmetry100, the comparison 100, difference 0
Shape-norm79, the comparison 77, difference +2
Tilt84, the comparison 80, difference +4

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 an Asscher

Lighter than diamond

1.01 ct at 6.5 mm, against 1.34 ct for the same cut in diamond (−25%)

A 6.5 mm Asscher in amethyst is 1.01 ct; in diamond, 1.34 ct.

A Asscher 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 Asscher Cut page

A larger face for its weight

Spread 107 against 100 for the T73 Round Brilliant in amethyst: 7 points higher

A square of a given width covers more area than a circle, so at the same carat weight the Asscher shows more face than the T73.

Asscher Cut · 6.48 mm at 1.00 ct · Spread 107

T73 Round Brilliant · 7.12 mm at 1.00 ct · Spread 100

Both stones weigh 1.00 ct in amethyst and are drawn to the same scale, from each cut's own model. Spread is face-up size per carat: a deeper stone carries more weight below the girdle and looks smaller for its weight.

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

The catch with an Asscher amethyst

Much less fire than in diamond

Fire 52 against 80 for the Asscher Cut in diamond: 28 points lower

Step facets return light in broad flashes, and quartz gives them little colour to carry. Its fire is still above the T73's in amethyst, 52 against 36.

Asscher cut in amethyst face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 52) — 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.

Asscher cut in diamond face-up under a single bright light: a render from our simulator, its coloured flashes are the fire (score 80) — 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: No step cut does much better; the brilliant Oval Cut Amethyst reaches 69 in quartz.

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

Much more leakage than in diamond

Leakage 39 against 11 for the Asscher Cut in diamond: 28 points higher

39% of the light in our census leaves through the back. In the strip the amethyst's grey stays at about the same share from face-up to 30°, while the diamond's, starting far lower, grows as it tips.

Asscher cut in amethyst tilted 0 degrees: Light Return map, 45% of the face leaking — 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.

Asscher cut in amethyst tilted 10 degrees: Light Return map, 38% of the face leaking — 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: We have not measured a deeper Asscher, so we promise none. In a square outline, the Square Cut Amethyst brilliant leaks 29% in amethyst.

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

Less light than the T73

Brilliance 60 against 72 for the T73 Round Brilliant in amethyst: 12 points lower

The 27.6° step pavilion is far below the angles that suit quartz in a round, and the face-up map shows grey across much of the stepped pavilion.

Asscher cut in amethyst face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 60) — 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 amethyst face-up Light Return map: red, green and blue show where the light returns from, grey shows where it leaks (Brilliance 72) — 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: In a square outline, the Cushion Cut Amethyst returns 69 and the Square Cut Amethyst 65.

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

Fewer flashes than a round

Scintillation 72 against 80 for the T73 Round Brilliant in amethyst: 8 points lower

Our scintillation score follows the facet plan: 58 long step facets against the T73's 73.

Asscher Cut · 58 facets · Scintillation 72

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.

What helps: The Cushion Cut Amethyst keeps a square outline with 85.

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

Who an Asscher amethyst suits

Choose the Asscher in amethyst for an Art Deco design, a clean, evenly coloured stone, and a face that looks big for its weight.

Large, clean amethyst rough is easier to find than most coloured stones, which suits a step cut's open view.

For more light in a square outline, the Cushion Cut Amethyst; for a step cut with an even larger face, the Emerald Square Cut Amethyst.

Asscher Cut Amethyst: questions

Is an Asscher cut good for amethyst?

For face-up size, yes: Spread 107 against 100. For light, it trails the round: 60 against 72, with 39% leakage.

Does an Asscher amethyst show colour zoning?

Step cuts show the inside of a stone plainly, so zoning in the rough tends to show. We do not measure colour.

Asscher or emerald square cut amethyst?

The Asscher has more fire (52 against 40); the Emerald Square leaks a little less (36% against 39%) and faces up slightly larger.

What does a 6.5 mm Asscher amethyst weigh?

1.01 ct; in diamond, 1.34 ct.

Get the Asscher Cut files

6 formatsMillimetresWatertight

Asscher Cut 3D files

The Asscher Cut as exact geometry: 58 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

Asscher Cut cutting files

The Asscher Cut as a faceting design: 58 facets, 96 index, 4-fold 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 Asscher Cut: specifications, model and files

Asscher Cut Amethyst: faces up larger than a round of the same weight