---
title: "Square Cut Spinel: Pros, Cons and Scores"
description: "Square Cut in spinel: brilliance 77, fire 54, leakage 16%, 0 pros and 4 cons against the T73, from our ray-traced light census."
url: https://digitalgemology.com/gemstones/spinel/square
image: https://digitalgemology.com/img/stone-cuts/square-spinel-og.jpg?v=740bf1ad
---

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# Square Cut Spinel: what our light census measures

**Buy (instant download, personal-use license):** [Square Cut 3D files, €9.99 · Personal use](https://digitalgemology.lemonsqueezy.com/checkout/buy/879ca486-10d4-46a9-bc7b-ec539f36b4b3) · [Square Cut cutting files, €6.99 · Personal use](https://digitalgemology.lemonsqueezy.com/checkout/buy/bf64b861-2dd3-4090-8cf9-cf1ba36b2a1f) · [Get the cube free](https://digitalgemology.lemonsqueezy.com/checkout/buy/2d1ab55f-2bd6-4897-a4cd-f3320f54e99e)

Brilliance 77 · Fire 54 · Scintillation 78 · in our census, where the T73 scores 94 · 47 · 80 in spinel

How the Square Cut handles light in spinel, measured: brilliance 77, fire 54 and 16% leakage, set against the T73 in the same stone and against the same cut in diamond.

[Get the files](https://digitalgemology.com/gemstones/spinel/square#buy) [Open it in the Simulator](https://digitalgemology.com/tools/3d_gemstone_simulator?cut=square&stone=spinel&ct=1.00&view=angle&lighting=studio&turn=0) [All cuts in spinel](https://digitalgemology.com/gemstones/spinel)

Light Return map of the Square Cut in spinel, face-up, from our own tracer at refractive index 1.712. Red, green and blue return light to the eye; gray leaks.

## Square Cut Spinel

Spinel has a refractive index of 1.712 to 1.747 and a dispersion of 0.020. Its critical angle, from the low end of that range, is 35.7°, so a round design needs a pavilion of at least 36.1° for head-on light to reflect off both sides of the pavilion and leave through the table. We trace it with one index, 1.730, the midpoint of the published range, and a fire spread of 0.017, 0.86 of the published dispersion. Every picture here is our Light Return tracer at 1.712, and every figure is from the same light census that scores the other gemstones; the 3D Gemstone Simulator shows the Square Cut in spinel live.

The Square Cut has 69 facets and a total depth of 65.0% of its width; its pavilion mains sit at 41.4°. In spinel, the census returns 77 of 100 for brilliance and 54 for fire, against 94 and 47 for the T73, our benchmark, in the same stone; the same Square Cut in diamond reads 85 and 72.

## Is spinel good in a Square? Pros and cons, measured

### Pros

No figure ahead by our thresholds

### Cons

- [Less fire in spinel than in diamond](https://digitalgemology.com/gemstones/spinel/square#con-fire) 54 vs 72
- [Returns less light than the T73 in spinel](https://digitalgemology.com/gemstones/spinel/square#con-brilliance) 77 vs 94
- [Leaks more light than the T73 in spinel](https://digitalgemology.com/gemstones/spinel/square#con-leak) 16 vs 6
- [Loses more light when tilted than in diamond](https://digitalgemology.com/gemstones/spinel/square#con-tiltStab) 82 vs 86

Compared with the T73 Round Brilliant in spinel and with the Square 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](https://digitalgemology.com/about/how-we-measure).

## All eight scores against the T73

At a glance: the Square Cut in spinel (white) against the T73 Round Brilliant in spinel (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 spinel: ahead on 2, level on 2, behind on 4.

- Global 76, the comparison 81, difference −5
- Brilliance 77, the comparison 94, difference −17
- Fire 54, the comparison 47, difference +7
- Scintillation 78, the comparison 80, difference −2
- Spread 98, the comparison 100, difference −2
- Symmetry 100, the comparison 100, difference 0
- Shape-norm 101, the comparison 101, difference 0
- Tilt 82, the comparison 75, difference +7

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](https://digitalgemology.com/tools/cut-performance-wheel?cut=square&stone=spinel); these are the same census figures as our [Cut Performance Index](https://digitalgemology.com/learn/cut-performance-index).

## What the Square Cut gains in spinel

Against the T73 in spinel and the same cut in diamond, no figure of the Square Cut is ahead by the thresholds above. Its figures are in the wheel and the FAQ; [Spinel](https://digitalgemology.com/gemstones/spinel) ranks every cut we score in spinel.

## What the Square Cut gives up in spinel

### Less fire in spinel than in diamond

**Fire 54** against 72 for the Square Cut in diamond: 18 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 (0.017 in spinel) and counts a ray as fire when the two directions differ by more than 0.6°. The Square Cut reads 54 against 72 for the same cut in diamond. The figure is the census's; the 3D Gemstone Simulator renders spinel'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](https://digitalgemology.com/tools/3d_gemstone_simulator?cut=square&stone=spinel&ct=1.00&view=up&lighting=sun&turn=0): the Square Cut in spinel under the sunny-day lighting.

**What helps:** [the DG-Elongated Hexagon](https://digitalgemology.com/gemstones/spinel/dg-elongated-hexagon) reads 80 for fire in spinel, the best of the cuts we score there.

[Try it yourself: See the fire in the 3D Gemstone Simulator](https://digitalgemology.com/tools/3d_gemstone_simulator?cut=square&stone=spinel&ct=1.00&view=up&lighting=sun&turn=0)

### Returns less light than the T73 in spinel

**Brilliance 77** against 94 for the T73 Round Brilliant in spinel: 17 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 spinel, whose critical angle is 35.7°, the Square Cut returns 77 of 100 and the T73 94. The Square Cut's pavilion mains sit at 41.4°, the T73's at 40.8°. The maps below show where each stone's light returns from and where it leaks.

Square Cut in spinel · Brilliance 77

T73 Round Brilliant in spinel · Brilliance 94

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](https://digitalgemology.com/gemstones/spinel/dg-m5) reads 100 for brilliance in spinel, the best of the cuts we score there.

[Try it yourself: Open this Light Return map in the simulator](https://digitalgemology.com/tools/3d_gemstone_simulator?cut=square&stone=spinel&ct=1.00&view=up&map=1&turn=0)

### Leaks more light than the T73 in spinel

**Leakage 16** against 6 for the T73 Round Brilliant in spinel: 10 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 Square Cut leaks 16% in spinel against 6% for the T73 in spinel. Grey in the maps below is leaking light; the share under each picture is that picture's own.

Square Cut in spinel · Leakage 16

0° · 17% leak

10° · 19% leak

20° · 30% leak

30° · 35% leak

T73 Round Brilliant in spinel · Leakage 6

0° · 0% leak

10° · 15% leak

20° · 30% leak

30° · 32% leak

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](https://digitalgemology.com/gemstones/spinel/dg-m5) reads 0% for leakage in spinel, the best of the cuts we score there.

[Try it yourself: Tilt it yourself in the simulator's light map](https://digitalgemology.com/tools/3d_gemstone_simulator?cut=square&stone=spinel&ct=1.00&view=up&map=1&turn=0)

### Loses more light when tilted than in diamond

**Tilt 82** against 86 for the Square Cut in diamond: 4 points lower

Tilt is how much of its face-up brilliance a stone keeps when the census tilts it 20° about its long axis, with 2,200 rays. The Square Cut keeps 82 against 86 for the same cut in diamond. The tilt strips below show the maps at 0°, 10°, 20° and 30°, with each picture's own leak share under it.

Square Cut in spinel · Tilt 82

0° · 17% leak

10° · 19% leak

20° · 30% leak

30° · 35% leak

Square Cut in diamond · Tilt 86

0° · 7% leak

10° · 11% leak

20° · 16% leak

30° · 22% leak

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; gray is leakage. The share under each frame is that picture's own.

[Try it yourself: Compare the Tilt spoke in the Cut Performance Wheel](https://digitalgemology.com/tools/cut-performance-wheel?cut=square&stone=spinel&vs=square&vsstone=diamond)

## Our verdict on the Square Cut in spinel

Against the T73 in spinel and the same cut in diamond, no figure of the Square Cut is ahead by our thresholds. The catch: it shows less fire than in diamond, returns less light than the T73, leaks more light than the T73 and loses more light when tilted than in diamond.

If that catch matters more to you, [the DG-Elongated Hexagon](https://digitalgemology.com/gemstones/spinel/dg-elongated-hexagon) reads 80 for fire in spinel, 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 Square Cut model we traced.

## Square Cut Spinel: questions

### Is the Square a good cut for spinel?

In our census the Square Cut returns 77 of 100 for brilliance and 54 for fire in spinel, against 94 and 47 for the T73 in the same stone. Against that round and against the same cut in diamond it has 0 pros and 4 cons by our thresholds; the summary above names them.

### What pavilion angle does spinel need?

At least 36.1° for a round design: spinel's critical angle is 35.7°, 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. The Square Cut's pavilion mains sit at 41.4°.

### How much does a Square weigh in spinel?

At 6.5 mm across, 1.17 ct in spinel, against 1.14 ct for the same cut in diamond (+3%): spinel's specific gravity is 3.62, diamond's 3.52.

### Can I see the Square in spinel in 3D?

Yes: the 3D Gemstone Simulator renders it live, with spinel's own refractive index and dispersion. Spinel 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 Square Cut files

*6 formats* *Millimeters* *Watertight*

### Square Cut 3D files

The Square Cut as exact geometry: 69 planar facets, real-world scale, ready for CAD, rendering, printing and casting.

- **STEP** Exact faceted solid for CAD
- **3DM** Rhino, closed mesh on its own layer
- **STL** Watertight mesh for printing and casting
- **OBJ** Mesh for modeling and rendering
- **FBX** Blender, 3ds Max, Maya, Cinema 4D, Unity, Unreal
- **GLB** Web, AR and quick previews

€9.99 · [Personal use](https://digitalgemology.com/licence) [Buy the 3D files](https://digitalgemology.lemonsqueezy.com/checkout/buy/879ca486-10d4-46a9-bc7b-ec539f36b4b3)

*GemCad* *64 index*

### Square Cut cutting files

The Square Cut as a faceting design: 57 + 12 girdles = 69 facets, 64 index, 4-fold mirror-image symmetry, ready for the machine.

- **.asc** GemCad design file, 64 index gear
- **.csv** Tier table: angles, indices and cutting order
- **Diagram** Printable faceting diagram

€6.99 · [Personal use](https://digitalgemology.com/licence) [Buy the cutting files](https://digitalgemology.lemonsqueezy.com/checkout/buy/bf64b861-2dd3-4090-8cf9-cf1ba36b2a1f)

Not sure the files open in your software? [Get the cube free](https://digitalgemology.lemonsqueezy.com/checkout/buy/2d1ab55f-2bd6-4897-a4cd-f3320f54e99e): the same six formats, for your email address, used only to send them ([privacy](https://digitalgemology.com/privacy#free-sample)).

Questions before you buy? [Email us](mailto:support@digitalgemology.com).

## More gemstones and cuts

[Spinel: optical properties and the top ten cuts](https://digitalgemology.com/gemstones/spinel) · [The Square Cut: specifications, model and files](https://digitalgemology.com/cuts/square)

### Other cuts in spinel

- [T73 Round Brilliant](https://digitalgemology.com/gemstones/spinel/t73-round-brilliant)
- [T105 Round Brilliant](https://digitalgemology.com/gemstones/spinel/t105-round-brilliant)
- [DG-Vitruvio](https://digitalgemology.com/gemstones/spinel/dg-vitruvio)
- [DG-Anteros](https://digitalgemology.com/gemstones/spinel/dg-anteros)
- [DG-Broken Hearts and Arrows](https://digitalgemology.com/gemstones/spinel/dg-broken-hearts-and-arrows)
- [Baguette Cut](https://digitalgemology.com/gemstones/spinel/baguette)
- [Emerald Cut](https://digitalgemology.com/gemstones/spinel/emerald-cut)
- [Marquise Cut](https://digitalgemology.com/gemstones/spinel/marquise)
- [Oval Cut](https://digitalgemology.com/gemstones/spinel/oval)
- [Pear Cut](https://digitalgemology.com/gemstones/spinel/pear)
- [Radiant Cut](https://digitalgemology.com/gemstones/spinel/radiant)
- [Rectangle Cut](https://digitalgemology.com/gemstones/spinel/rectangle)
- [Teardrop Cut](https://digitalgemology.com/gemstones/spinel/teardrop)
- [Asscher Cut](https://digitalgemology.com/gemstones/spinel/asscher)
- [Cushion Cut](https://digitalgemology.com/gemstones/spinel/cushion)
- [Emerald Square Cut](https://digitalgemology.com/gemstones/spinel/emerald-square)
- [Princess Cut](https://digitalgemology.com/gemstones/spinel/princess)
- [Radiant Square Cut](https://digitalgemology.com/gemstones/spinel/radiant-square)
- [Triangle Cut](https://digitalgemology.com/gemstones/spinel/triangle)
- [Trilliant Cut](https://digitalgemology.com/gemstones/spinel/trilliant)
- [Trillion Cut](https://digitalgemology.com/gemstones/spinel/trillion)
- [Hexagon Cut](https://digitalgemology.com/gemstones/spinel/hexagon)
- [Octagon Cut](https://digitalgemology.com/gemstones/spinel/octagon)
- [Portuguese Bird's Nest Cut](https://digitalgemology.com/gemstones/spinel/portuguese-birds-nest)
- [Old Single Cut](https://digitalgemology.com/gemstones/spinel/old-single)
- [Mazarin Cut](https://digitalgemology.com/gemstones/spinel/mazarin)
- [Peruzzi Cut](https://digitalgemology.com/gemstones/spinel/peruzzi)
- [Old Mine Cut](https://digitalgemology.com/gemstones/spinel/old-mine)
- [Old European Cut](https://digitalgemology.com/gemstones/spinel/old-european)
- [T57 Round Brilliant](https://digitalgemology.com/gemstones/spinel/t57-round-brilliant)
- [DG-M5](https://digitalgemology.com/gemstones/spinel/dg-m5)
- [DG-Miliano](https://digitalgemology.com/gemstones/spinel/dg-miliano)
- [DG-Rafaello](https://digitalgemology.com/gemstones/spinel/dg-rafaello)
- [DG-Bowtie](https://digitalgemology.com/gemstones/spinel/dg-bowtie)
- [DG-Elongated Hexagon](https://digitalgemology.com/gemstones/spinel/dg-elongated-hexagon)
- [DG-Octagonal Kite](https://digitalgemology.com/gemstones/spinel/dg-octagonal-kite)

### The Square Cut in other gemstones

- [Diamond](https://digitalgemology.com/gemstones/diamond/square)
- [Moissanite](https://digitalgemology.com/gemstones/moissanite/square)
- [Cubic Zirconia](https://digitalgemology.com/gemstones/cubic-zirconia/square)
- [Ruby](https://digitalgemology.com/gemstones/ruby/square)
- [Sapphire](https://digitalgemology.com/gemstones/sapphire/square)
- [Emerald](https://digitalgemology.com/gemstones/emerald/square)
- [Amethyst](https://digitalgemology.com/gemstones/amethyst/square)
- [Topaz](https://digitalgemology.com/gemstones/topaz/square)
- [Demantoid](https://digitalgemology.com/gemstones/demantoid/square)
- [Zircon](https://digitalgemology.com/gemstones/zircon/square)
- [Tourmaline](https://digitalgemology.com/gemstones/tourmaline/square)
- [Peridot](https://digitalgemology.com/gemstones/peridot/square)
- [Tanzanite](https://digitalgemology.com/gemstones/tanzanite/square)
- [YAG](https://digitalgemology.com/gemstones/yag/square)
- [Pyrope](https://digitalgemology.com/gemstones/pyrope/square)
- [Almandine](https://digitalgemology.com/gemstones/almandine/square)
- [Spessartine](https://digitalgemology.com/gemstones/spessartine/square)
- [Grossular](https://digitalgemology.com/gemstones/grossular/square)
- [Chrysoberyl](https://digitalgemology.com/gemstones/chrysoberyl/square)
- [Kunzite](https://digitalgemology.com/gemstones/kunzite/square)
- [Iolite](https://digitalgemology.com/gemstones/iolite/square)
- [Morganite](https://digitalgemology.com/gemstones/morganite/square)
- [GGG](https://digitalgemology.com/gemstones/ggg/square)
- [Strontium titanate](https://digitalgemology.com/gemstones/strontium-titanate/square)
- [Synthetic rutile](https://digitalgemology.com/gemstones/synthetic-rutile/square)