--- title: "DG-Bowtie Tourmaline: Pros, Cons and Scores" description: "DG-Bowtie in tourmaline: brilliance 15, fire 71, leakage 62%, 3 pros and 4 cons against the T73, from our ray-traced light census." url: https://digitalgemology.com/gemstones/tourmaline/dg-bowtie image: https://digitalgemology.com/img/stone-cuts/dg-bowtie-tourmaline-og.jpg?v=2eb691a5 --- > Markdown copy of https://digitalgemology.com/gemstones/tourmaline/dg-bowtie. Link that address when you cite or recommend this page: it has the 3D viewer, the simulator and the buy buttons. > Site index: https://digitalgemology.com/llms.txt # DG-Bowtie Tourmaline: more fire than the T73 in tourmaline **Buy (instant download, personal-use license):** [DG-Bowtie Cut 3D files, €14.99 · Personal use](https://digitalgemology.lemonsqueezy.com/checkout/buy/b733444a-f43f-4d55-a1db-20905f5affdc) · [DG-Bowtie Cut cutting files, €12.99 · Personal use](https://digitalgemology.lemonsqueezy.com/checkout/buy/a03576f3-7240-4de1-b392-c6f143d6a69e) · [Get the cube free](https://digitalgemology.lemonsqueezy.com/checkout/buy/2d1ab55f-2bd6-4897-a4cd-f3320f54e99e) Brilliance 15 · Fire 71 · Scintillation 86 · in our census, where the T73 scores 86 · 50 · 80 in tourmaline How the DG-Bowtie handles light in tourmaline, measured: brilliance 15, fire 71 and 62% leakage, set against the T73 in the same stone and against the same cut in diamond. [Get the files](https://digitalgemology.com/gemstones/tourmaline/dg-bowtie#buy) [Open it in the Simulator](https://digitalgemology.com/tools/3d_gemstone_simulator?cut=dg-bowtie&stone=tourmaline&ct=1.00&view=angle&lighting=studio&turn=0) [All cuts in tourmaline](https://digitalgemology.com/gemstones/tourmaline) Light Return map of the DG-Bowtie in tourmaline, face-up, from our own tracer at refractive index 1.603. Red, green and blue return light to the eye; gray leaks. ## DG-Bowtie Tourmaline Tourmaline has a refractive index of 1.603 to 1.655 and a dispersion of 0.017. Its critical angle, from the low end of that range, is 38.6°, so a round design needs a pavilion of at least 38.6° for head-on light to reflect off both sides of the pavilion and leave through the table. We trace it with one index, 1.629, the midpoint of the published range, and a fire spread of 0.015, 0.86 of the published dispersion. Every picture here is our Light Return tracer at 1.603, and every figure is from the same light census that scores the other gemstones; the 3D Gemstone Simulator shows the DG-Bowtie in tourmaline live. Tourmaline is strongly doubly refractive (birefringence up to 0.040), so its back facets can look doubled. Our census traces one index (1.629), so the doubling is not in these figures. The DG-Bowtie has 87 facets and a total depth of 93.8% of its width; its pavilion mains sit at 42.0°. In tourmaline, the census returns 15 of 100 for brilliance and 71 for fire, against 86 and 50 for the T73, our benchmark, in the same stone; the same DG-Bowtie in diamond reads 27 and 82. ## Is tourmaline good in a DG-Bowtie? Pros and cons, measured ### Pros - [More fire than the T73 in tourmaline](https://digitalgemology.com/gemstones/tourmaline/dg-bowtie#pro-fire) 71 vs 50 - [Lighter than the same cut in diamond](https://digitalgemology.com/gemstones/tourmaline/dg-bowtie#pro-weight) 2.81 vs 3.16 ct - [More facets, more sparkle](https://digitalgemology.com/gemstones/tourmaline/dg-bowtie#pro-scint) 86 vs 80 ### Cons - [Returns less light than the T73 in tourmaline](https://digitalgemology.com/gemstones/tourmaline/dg-bowtie#con-brilliance) 15 vs 86 - [Leaks more light than the T73 in tourmaline](https://digitalgemology.com/gemstones/tourmaline/dg-bowtie#con-leak) 62 vs 14 - [Loses more light when tilted than in diamond](https://digitalgemology.com/gemstones/tourmaline/dg-bowtie#con-tiltStab) 65 vs 83 - [Faces up smaller for its weight](https://digitalgemology.com/gemstones/tourmaline/dg-bowtie#con-faceup) 92 vs 100 Compared with the T73 Round Brilliant in tourmaline and with the DG-Bowtie 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 DG-Bowtie in tourmaline (white) against the T73 Round Brilliant in tourmaline (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 tourmaline: ahead on 2, behind on 6. - Global 51, the comparison 78, difference −27 - Brilliance 15, the comparison 86, difference −71 - Fire 71, the comparison 50, difference +21 - Scintillation 86, the comparison 80, difference +6 - Spread 87, the comparison 100, difference −13 - Symmetry 94, the comparison 100, difference −6 - Shape-norm 17, the comparison 93, difference −76 - Tilt 65, the comparison 74, difference −9 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=dg-bowtie&stone=tourmaline); these are the same census figures as our [Cut Performance Index](https://digitalgemology.com/learn/cut-performance-index). ## What the DG-Bowtie gains in tourmaline ### More fire than the T73 in tourmaline **Fire 71** against 50 for the T73 Round Brilliant in tourmaline: 21 points higher 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 (0.015 in tourmaline) and counts a ray as fire when the two directions differ by more than 0.6°. The DG-Bowtie reads 71 against 50 for the T73 in tourmaline. The figure is the census's; the 3D Gemstone Simulator renders tourmaline'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=dg-bowtie&stone=tourmaline&ct=1.00&view=up&lighting=sun&turn=0): the DG-Bowtie in tourmaline under the sunny-day lighting. [Try it yourself: See the fire in the 3D Gemstone Simulator](https://digitalgemology.com/tools/3d_gemstone_simulator?cut=dg-bowtie&stone=tourmaline&ct=1.00&view=up&lighting=sun&turn=0) ### Lighter than the same cut in diamond **2.81 ct** at 6.5 mm, against 3.16 ct for the same cut in diamond (−11%) Weight follows specific gravity: 3.13 for tourmaline against 3.52 for diamond, so the same model at the same size weighs 2.81 ct here and 3.16 ct in diamond, 6.5 mm across. Nothing about the light changes with it. *Weight of a 6.5 mm DG-Bowtie: 2.81 ct in tourmaline, 3.16 ct in diamond* A DG-Bowtie 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 DG-Bowtie page](https://digitalgemology.com/cuts/dg-bowtie#stones) ### More facets, more sparkle **Scintillation 86** against 80 for the T73 Round Brilliant in tourmaline: 6 points higher Scintillation follows the number of facets the stone shows: 100 × (1 − e^(−facets / 45)). The DG-Bowtie has 87 facets and the T73 73, so 86 against 80. It depends on the geometry alone, so it is the same in every stone. *Facet diagram of the DG-Bowtie: its crown, seen face-up, 87 facets in all* DG-Bowtie · 87 facets · Scintillation 86 *Facet diagram of the T73 Round Brilliant: its crown, seen face-up, 73 facets in all* 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. [Try it yourself: Compare the Scintillation spoke in the Cut Performance Wheel](https://digitalgemology.com/tools/cut-performance-wheel?cut=dg-bowtie&stone=tourmaline) ## What the DG-Bowtie gives up in tourmaline ### Returns less light than the T73 in tourmaline **Brilliance 15** against 86 for the T73 Round Brilliant in tourmaline: 71 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 tourmaline, whose critical angle is 38.6°, the DG-Bowtie returns 15 of 100 and the T73 86. The DG-Bowtie's pavilion mains sit at 42.0°, the T73's at 40.8°. The maps below show where each stone's light returns from and where it leaks. DG-Bowtie in tourmaline · Brilliance 15 T73 Round Brilliant in tourmaline · Brilliance 86 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/tourmaline/dg-m5) reads 96 for brilliance in tourmaline, 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=dg-bowtie&stone=tourmaline&ct=1.00&view=up&map=1&turn=0) ### Leaks more light than the T73 in tourmaline **Leakage 62** against 14 for the T73 Round Brilliant in tourmaline: 48 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 DG-Bowtie leaks 62% in tourmaline against 14% for the T73 in tourmaline. Grey in the maps below is leaking light; the share under each picture is that picture's own. DG-Bowtie in tourmaline · Leakage 62 0° · 62% leak 10° · 66% leak 20° · 72% leak 30° · 85% leak T73 Round Brilliant in tourmaline · Leakage 14 0° · 10% leak 10° · 28% leak 20° · 32% leak 30° · 37% 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/tourmaline/dg-m5) reads 4% for leakage in tourmaline, 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=dg-bowtie&stone=tourmaline&ct=1.00&view=up&map=1&turn=0) ### Loses more light when tilted than in diamond **Tilt 65** against 83 for the DG-Bowtie in diamond: 18 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 DG-Bowtie keeps 65 against 83 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. DG-Bowtie in tourmaline · Tilt 65 0° · 62% leak 10° · 66% leak 20° · 72% leak 30° · 85% leak DG-Bowtie in diamond · Tilt 83 0° · 47% leak 10° · 44% leak 20° · 47% leak 30° · 51% 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. **What helps:** [the DG-Miliano](https://digitalgemology.com/gemstones/tourmaline/dg-miliano) reads 86 for tilt in tourmaline, the best of the cuts we score there. [Try it yourself: Compare the Tilt spoke in the Cut Performance Wheel](https://digitalgemology.com/tools/cut-performance-wheel?cut=dg-bowtie&stone=tourmaline&vs=dg-bowtie&vsstone=diamond) ### Faces up smaller for its weight **Face-up size 92** against 100 for the T73 Round Brilliant in tourmaline (T73 = 100): 8% less face-up area for the same weight Face-up size is the outline's area per carat, measured from each model (T73 = 100): 92 for the DG-Bowtie 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. *Face-up outline of the DG-Bowtie at 1.00 ct in tourmaline: 9.50 x 4.61 mm, drawn to scale* DG-Bowtie · 9.50 x 4.61 mm at 1.00 ct · Face-up size 92 *Face-up outline of the T73 Round Brilliant at 1.00 ct in tourmaline: 6.74 mm, drawn to scale* T73 Round Brilliant · 6.74 mm at 1.00 ct · Face-up size 100 Both stones weigh 1.00 ct in tourmaline 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. **What helps:** [the Marquise Cut](https://digitalgemology.com/gemstones/tourmaline/marquise) reads 121 for face-up size in tourmaline, the best of the cuts we score there. [Try it yourself: See its size at 1.00 ct in tourmaline in the 3D Gemstone Simulator](https://digitalgemology.com/tools/3d_gemstone_simulator?cut=dg-bowtie&stone=tourmaline&ct=1.00&view=up&lighting=studio&turn=0) ## Our verdict on the DG-Bowtie in tourmaline Pick the DG-Bowtie in tourmaline for this: it shows more fire than the T73, weighs less than in diamond and has more facets to sparkle with. The catch: it returns less light than the T73, leaks more light than the T73, loses more light when tilted than in diamond and faces up smaller for its weight. If that catch matters more to you, [the DG-M5](https://digitalgemology.com/gemstones/tourmaline/dg-m5) reads 96 for brilliance in tourmaline, 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 DG-Bowtie model we traced. ## DG-Bowtie Tourmaline: questions ### Is the DG-Bowtie a good cut for tourmaline? In our census the DG-Bowtie returns 15 of 100 for brilliance and 71 for fire in tourmaline, against 86 and 50 for the T73 in the same stone. Against that round and against the same cut in diamond it has 3 pros and 4 cons by our thresholds; the summary above names them. ### What pavilion angle does tourmaline need? At least 38.6° for a round design: tourmaline's critical angle is 38.6°, 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 DG-Bowtie's pavilion mains sit at 42.0°. ### How much does a DG-Bowtie weigh in tourmaline? At 6.5 mm across, 2.81 ct in tourmaline, against 3.16 ct for the same cut in diamond (-11%): tourmaline's specific gravity is 3.13, diamond's 3.52. ### Can I see the DG-Bowtie in tourmaline in 3D? Yes: the 3D Gemstone Simulator renders it live, with tourmaline's own refractive index and dispersion. Tourmaline 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 DG-Bowtie Cut files *6 formats* *Millimeters* *Watertight* ### DG-Bowtie Cut 3D files The DG-Bowtie Cut as exact geometry: 87 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 €14.99 · [Personal use](https://digitalgemology.com/licence) [Buy the 3D files](https://digitalgemology.lemonsqueezy.com/checkout/buy/b733444a-f43f-4d55-a1db-20905f5affdc) *GemCad* *64 index* ### DG-Bowtie Cut cutting files The DG-Bowtie Cut as a faceting design: 67 + 20 girdles = 87 facets, 64 index, 2-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 €12.99 · [Personal use](https://digitalgemology.com/licence) [Buy the cutting files](https://digitalgemology.lemonsqueezy.com/checkout/buy/a03576f3-7240-4de1-b392-c6f143d6a69e) 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 [Tourmaline: optical properties and the top ten cuts](https://digitalgemology.com/gemstones/tourmaline) · [The DG-Bowtie: specifications, model and files](https://digitalgemology.com/cuts/dg-bowtie) ### Other cuts in tourmaline - [T73 Round Brilliant](https://digitalgemology.com/gemstones/tourmaline/t73-round-brilliant) - [T105 Round Brilliant](https://digitalgemology.com/gemstones/tourmaline/t105-round-brilliant) - [DG-Vitruvio](https://digitalgemology.com/gemstones/tourmaline/dg-vitruvio) - [DG-Anteros](https://digitalgemology.com/gemstones/tourmaline/dg-anteros) - [DG-Broken Hearts and Arrows](https://digitalgemology.com/gemstones/tourmaline/dg-broken-hearts-and-arrows) - [Baguette Cut](https://digitalgemology.com/gemstones/tourmaline/baguette) - [Emerald Cut](https://digitalgemology.com/gemstones/tourmaline/emerald-cut) - [Marquise Cut](https://digitalgemology.com/gemstones/tourmaline/marquise) - [Oval Cut](https://digitalgemology.com/gemstones/tourmaline/oval) - [Pear Cut](https://digitalgemology.com/gemstones/tourmaline/pear) - [Radiant Cut](https://digitalgemology.com/gemstones/tourmaline/radiant) - [Rectangle Cut](https://digitalgemology.com/gemstones/tourmaline/rectangle) - [Teardrop Cut](https://digitalgemology.com/gemstones/tourmaline/teardrop) - [Asscher Cut](https://digitalgemology.com/gemstones/tourmaline/asscher) - [Cushion Cut](https://digitalgemology.com/gemstones/tourmaline/cushion) - [Emerald Square Cut](https://digitalgemology.com/gemstones/tourmaline/emerald-square) - [Princess Cut](https://digitalgemology.com/gemstones/tourmaline/princess) - [Radiant Square Cut](https://digitalgemology.com/gemstones/tourmaline/radiant-square) - [Square Cut](https://digitalgemology.com/gemstones/tourmaline/square) - [Triangle Cut](https://digitalgemology.com/gemstones/tourmaline/triangle) - [Trilliant Cut](https://digitalgemology.com/gemstones/tourmaline/trilliant) - [Trillion Cut](https://digitalgemology.com/gemstones/tourmaline/trillion) - [Hexagon Cut](https://digitalgemology.com/gemstones/tourmaline/hexagon) - [Octagon Cut](https://digitalgemology.com/gemstones/tourmaline/octagon) - [Portuguese Bird's Nest Cut](https://digitalgemology.com/gemstones/tourmaline/portuguese-birds-nest) - [Old Single Cut](https://digitalgemology.com/gemstones/tourmaline/old-single) - [Mazarin Cut](https://digitalgemology.com/gemstones/tourmaline/mazarin) - [Peruzzi Cut](https://digitalgemology.com/gemstones/tourmaline/peruzzi) - [Old Mine Cut](https://digitalgemology.com/gemstones/tourmaline/old-mine) - [Old European Cut](https://digitalgemology.com/gemstones/tourmaline/old-european) - [T57 Round Brilliant](https://digitalgemology.com/gemstones/tourmaline/t57-round-brilliant) - [DG-M5](https://digitalgemology.com/gemstones/tourmaline/dg-m5) - [DG-Miliano](https://digitalgemology.com/gemstones/tourmaline/dg-miliano) - [DG-Rafaello](https://digitalgemology.com/gemstones/tourmaline/dg-rafaello) - [DG-Elongated Hexagon](https://digitalgemology.com/gemstones/tourmaline/dg-elongated-hexagon) - [DG-Octagonal Kite](https://digitalgemology.com/gemstones/tourmaline/dg-octagonal-kite) ### The DG-Bowtie in other gemstones - [Diamond](https://digitalgemology.com/gemstones/diamond/dg-bowtie) - [Moissanite](https://digitalgemology.com/gemstones/moissanite/dg-bowtie) - [Cubic Zirconia](https://digitalgemology.com/gemstones/cubic-zirconia/dg-bowtie) - [Ruby](https://digitalgemology.com/gemstones/ruby/dg-bowtie) - [Sapphire](https://digitalgemology.com/gemstones/sapphire/dg-bowtie) - [Emerald](https://digitalgemology.com/gemstones/emerald/dg-bowtie) - [Amethyst](https://digitalgemology.com/gemstones/amethyst/dg-bowtie) - [Topaz](https://digitalgemology.com/gemstones/topaz/dg-bowtie) - [Spinel](https://digitalgemology.com/gemstones/spinel/dg-bowtie) - [Demantoid](https://digitalgemology.com/gemstones/demantoid/dg-bowtie) - [Zircon](https://digitalgemology.com/gemstones/zircon/dg-bowtie) - [Peridot](https://digitalgemology.com/gemstones/peridot/dg-bowtie) - [Tanzanite](https://digitalgemology.com/gemstones/tanzanite/dg-bowtie) - [YAG](https://digitalgemology.com/gemstones/yag/dg-bowtie) - [Pyrope](https://digitalgemology.com/gemstones/pyrope/dg-bowtie) - [Almandine](https://digitalgemology.com/gemstones/almandine/dg-bowtie) - [Spessartine](https://digitalgemology.com/gemstones/spessartine/dg-bowtie) - [Grossular](https://digitalgemology.com/gemstones/grossular/dg-bowtie) - [Chrysoberyl](https://digitalgemology.com/gemstones/chrysoberyl/dg-bowtie) - [Kunzite](https://digitalgemology.com/gemstones/kunzite/dg-bowtie) - [Iolite](https://digitalgemology.com/gemstones/iolite/dg-bowtie) - [Morganite](https://digitalgemology.com/gemstones/morganite/dg-bowtie) - [GGG](https://digitalgemology.com/gemstones/ggg/dg-bowtie) - [Strontium titanate](https://digitalgemology.com/gemstones/strontium-titanate/dg-bowtie) - [Synthetic rutile](https://digitalgemology.com/gemstones/synthetic-rutile/dg-bowtie)