--- title: "Old Mine Cut Topaz: Pros, Cons and Scores" description: "Old Mine Cut in topaz: brilliance 43, fire 25, leakage 56%, 0 pros and 4 cons against the T73, from our ray-traced light census." url: https://digitalgemology.com/gemstones/topaz/old-mine image: https://digitalgemology.com/img/stone-cuts/old-mine-topaz-og.jpg?v=03fa5280 --- > Markdown copy of https://digitalgemology.com/gemstones/topaz/old-mine. 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 # Old Mine Cut Topaz: what our light census measures **Buy (instant download, personal-use license):** [Old Mine Cut 3D files, €9.99 · Personal use](https://digitalgemology.lemonsqueezy.com/checkout/buy/5b3b75f2-db63-4e1c-8acc-ed119e91984a) · [Old Mine Cut cutting files, €6.99 · Personal use](https://digitalgemology.lemonsqueezy.com/checkout/buy/54ae00b8-0467-47be-a84f-354652bd5c37) · [Buy the bundle](https://digitalgemology.lemonsqueezy.com/checkout/buy/dcf2c236-6e04-4292-8040-9d21ac6446d1?checkout%5Bdiscount_code%5D=HISTORIC25) · [Get the cube free](https://digitalgemology.lemonsqueezy.com/checkout/buy/2d1ab55f-2bd6-4897-a4cd-f3320f54e99e) Brilliance 43 · Fire 25 · Scintillation 81 · in our census, where the T73 scores 86 · 35 · 80 in topaz How the Old Mine Cut handles light in topaz, measured: brilliance 43, fire 25 and 56% leakage, set against the T73 in the same stone and against the same cut in diamond. [Get the files](https://digitalgemology.com/gemstones/topaz/old-mine#buy) [Open it in the Simulator](https://digitalgemology.com/tools/3d_gemstone_simulator?cut=old-mine&stone=topaz&ct=1.00&view=angle&lighting=studio&turn=0) [All cuts in topaz](https://digitalgemology.com/gemstones/topaz) Light Return map of the Old Mine Cut in topaz, face-up, from our own tracer at refractive index 1.606. Red, green and blue return light to the eye; gray leaks. ## Old Mine Cut Topaz Topaz has a refractive index of 1.606 to 1.644 and a dispersion of 0.014. Its critical angle, from the low end of that range, is 38.5°, so a round design needs a pavilion of at least 38.5° for head-on light to reflect off both sides of the pavilion and leave through the table. We trace it with one index, 1.625, 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 1.606, and every figure is from the same light census that scores the other gemstones; the 3D Gemstone Simulator shows the Old Mine Cut in topaz live. The Old Mine Cut has 74 facets, a table of 60.3% of its width and a total depth of 65.6% of its width; its pavilion mains sit at 44.4°. In topaz, the census returns 43 of 100 for brilliance and 25 for fire, against 86 and 35 for the T73, our benchmark, in the same stone; the same Old Mine Cut in diamond reads 59 and 72. ## Is topaz good in an Old Mine? Pros and cons, measured ### Pros No figure ahead by our thresholds ### Cons - [Less fire in topaz than in diamond](https://digitalgemology.com/gemstones/topaz/old-mine#con-fire) 25 vs 72 - [Returns less light than the T73 in topaz](https://digitalgemology.com/gemstones/topaz/old-mine#con-brilliance) 43 vs 86 - [Leaks more light than the T73 in topaz](https://digitalgemology.com/gemstones/topaz/old-mine#con-leak) 56 vs 14 - [A less regular pavilion than the T73](https://digitalgemology.com/gemstones/topaz/old-mine#con-symm) 90 vs 100 Compared with the T73 Round Brilliant in topaz and with the Old Mine 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 Old Mine Cut in topaz (white) against the T73 Round Brilliant in topaz (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 topaz: ahead on 2, behind on 6. - Global 57, the comparison 75, difference −18 - Brilliance 43, the comparison 86, difference −43 - Fire 25, the comparison 35, difference −10 - Scintillation 81, the comparison 80, difference +1 - Spread 98, the comparison 100, difference −2 - Symmetry 90, the comparison 100, difference −10 - Shape-norm 67, the comparison 92, difference −25 - Tilt 100, the comparison 74, difference +26 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=old-mine&stone=topaz); these are the same census figures as our [Cut Performance Index](https://digitalgemology.com/learn/cut-performance-index). ## What the Old Mine Cut gains in topaz Against the T73 in topaz and the same cut in diamond, no figure of the Old Mine Cut is ahead by the thresholds above. Its figures are in the wheel and the FAQ; [Topaz](https://digitalgemology.com/gemstones/topaz) ranks every cut we score in topaz. ## What the Old Mine Cut gives up in topaz ### Less fire in topaz than in diamond **Fire 25** against 72 for the Old Mine Cut in diamond: 47 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 topaz) and counts a ray as fire when the two directions differ by more than 0.6°. The Old Mine Cut reads 25 against 72 for the same cut in diamond. The figure is the census's; the 3D Gemstone Simulator renders topaz'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=old-mine&stone=topaz&ct=1.00&view=up&lighting=sun&turn=0): the Old Mine Cut in topaz under the sunny-day lighting. **What helps:** [the Oval Cut](https://digitalgemology.com/gemstones/topaz/oval) reads 68 for fire in topaz, 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=old-mine&stone=topaz&ct=1.00&view=up&lighting=sun&turn=0) ### Returns less light than the T73 in topaz **Brilliance 43** against 86 for the T73 Round Brilliant in topaz: 43 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 topaz, whose critical angle is 38.5°, the Old Mine Cut returns 43 of 100 and the T73 86. The Old Mine Cut's pavilion mains sit at 44.4°, the T73's at 40.8°. The maps below show where each stone's light returns from and where it leaks. Old Mine Cut in topaz · Brilliance 43 T73 Round Brilliant in topaz · 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/topaz/dg-m5) reads 96 for brilliance in topaz, 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=old-mine&stone=topaz&ct=1.00&view=up&map=1&turn=0) ### Leaks more light than the T73 in topaz **Leakage 56** against 14 for the T73 Round Brilliant in topaz: 42 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 Old Mine Cut leaks 56% in topaz against 14% for the T73 in topaz. Grey in the maps below is leaking light; the share under each picture is that picture's own. Old Mine Cut in topaz · Leakage 56 0° · 61% leak 10° · 57% leak 20° · 53% leak 30° · 41% leak T73 Round Brilliant in topaz · 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/topaz/dg-m5) reads 4% for leakage in topaz, 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=old-mine&stone=topaz&ct=1.00&view=up&map=1&turn=0) ### A less regular pavilion than the T73 **Symmetry 90** against 100 for the T73 Round Brilliant in topaz: 10 points lower Symmetry reads how evenly the pavilion facets of each design family are cut: 100 − 6 × their scatter in degrees. The Old Mine Cut reads 90, the T73 100. It depends on the geometry alone, so it is the same in every stone. *Facet diagram of the Old Mine Cut: its pavilion, seen from below, 74 facets in all* Old Mine Cut · 74 facets · Symmetry 90 *Facet diagram of the T73 Round Brilliant: its pavilion, seen from below, 73 facets in all* T73 Round Brilliant · 73 facets · Symmetry 100 Symmetry scores how regular the pavilion facets are within the design. Compare how evenly the facets repeat around each pavilion. Drawn from each cut's own model. [Try it yourself: Compare the Symmetry spoke in the Cut Performance Wheel](https://digitalgemology.com/tools/cut-performance-wheel?cut=old-mine&stone=topaz) ## Our verdict on the Old Mine Cut in topaz Against the T73 in topaz and the same cut in diamond, no figure of the Old Mine 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 has a less regular pavilion than the T73. If that catch matters more to you, [the Oval Cut](https://digitalgemology.com/gemstones/topaz/oval) reads 68 for fire in topaz, 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 Old Mine Cut model we traced. ## Old Mine Cut Topaz: questions ### Is the Old Mine a good cut for topaz? In our census the Old Mine Cut returns 43 of 100 for brilliance and 25 for fire in topaz, against 86 and 35 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 topaz need? At least 38.5° for a round design: topaz's critical angle is 38.5°, 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. The Old Mine Cut's pavilion mains sit at 44.4°. ### How much does a Old Mine weigh in topaz? At 6.5 mm across, 1.21 ct in topaz, against 1.21 ct for the same cut in diamond, the same weight to the per cent: topaz's specific gravity is 3.535, diamond's 3.52. ### Can I see the Old Mine in topaz in 3D? Yes: the 3D Gemstone Simulator renders it live, with topaz's own refractive index and dispersion. Topaz 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 Old Mine Cut files *6 formats* *Millimeters* *Watertight* ### Old Mine Cut 3D files The Old Mine Cut as exact geometry: 74 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/5b3b75f2-db63-4e1c-8acc-ed119e91984a) *GemCad* *96 index* ### Old Mine Cut cutting files The Old Mine Cut as a faceting design: 58 + 16 girdles = 74 facets, 96 index, 4-fold mirror-image symmetry, ready for the machine. - **.asc** GemCad design file, 96 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/54ae00b8-0467-47be-a84f-354652bd5c37) Save with a bundle: the Old Mine Cut 3D and cutting files are also in [Historic Cuts Complete](https://digitalgemology.com/cuts/#bundles), 6 cuts for €29.99 until 1 December, then €39.99 (€101.88 as single files). [Buy the bundle](https://digitalgemology.lemonsqueezy.com/checkout/buy/dcf2c236-6e04-4292-8040-9d21ac6446d1?checkout%5Bdiscount_code%5D=HISTORIC25). 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 [Topaz: optical properties and the top ten cuts](https://digitalgemology.com/gemstones/topaz) · [The Old Mine Cut: specifications, model and files](https://digitalgemology.com/cuts/old-mine) ### Other cuts in topaz - [T73 Round Brilliant](https://digitalgemology.com/gemstones/topaz/t73-round-brilliant) - [T105 Round Brilliant](https://digitalgemology.com/gemstones/topaz/t105-round-brilliant) - [DG-Vitruvio](https://digitalgemology.com/gemstones/topaz/dg-vitruvio) - [DG-Anteros](https://digitalgemology.com/gemstones/topaz/dg-anteros) - [DG-Broken Hearts and Arrows](https://digitalgemology.com/gemstones/topaz/dg-broken-hearts-and-arrows) - [Baguette Cut](https://digitalgemology.com/gemstones/topaz/baguette) - [Emerald Cut](https://digitalgemology.com/gemstones/topaz/emerald-cut) - [Marquise Cut](https://digitalgemology.com/gemstones/topaz/marquise) - [Oval Cut](https://digitalgemology.com/gemstones/topaz/oval) - [Pear Cut](https://digitalgemology.com/gemstones/topaz/pear) - [Radiant Cut](https://digitalgemology.com/gemstones/topaz/radiant) - [Rectangle Cut](https://digitalgemology.com/gemstones/topaz/rectangle) - [Teardrop Cut](https://digitalgemology.com/gemstones/topaz/teardrop) - [Asscher Cut](https://digitalgemology.com/gemstones/topaz/asscher) - [Cushion Cut](https://digitalgemology.com/gemstones/topaz/cushion) - [Emerald Square Cut](https://digitalgemology.com/gemstones/topaz/emerald-square) - [Princess Cut](https://digitalgemology.com/gemstones/topaz/princess) - [Radiant Square Cut](https://digitalgemology.com/gemstones/topaz/radiant-square) - [Square Cut](https://digitalgemology.com/gemstones/topaz/square) - [Triangle Cut](https://digitalgemology.com/gemstones/topaz/triangle) - [Trilliant Cut](https://digitalgemology.com/gemstones/topaz/trilliant) - [Trillion Cut](https://digitalgemology.com/gemstones/topaz/trillion) - [Hexagon Cut](https://digitalgemology.com/gemstones/topaz/hexagon) - [Octagon Cut](https://digitalgemology.com/gemstones/topaz/octagon) - [Portuguese Bird's Nest Cut](https://digitalgemology.com/gemstones/topaz/portuguese-birds-nest) - [Old Single Cut](https://digitalgemology.com/gemstones/topaz/old-single) - [Mazarin Cut](https://digitalgemology.com/gemstones/topaz/mazarin) - [Peruzzi Cut](https://digitalgemology.com/gemstones/topaz/peruzzi) - [Old European Cut](https://digitalgemology.com/gemstones/topaz/old-european) - [T57 Round Brilliant](https://digitalgemology.com/gemstones/topaz/t57-round-brilliant) - [DG-M5](https://digitalgemology.com/gemstones/topaz/dg-m5) - [DG-Miliano](https://digitalgemology.com/gemstones/topaz/dg-miliano) - [DG-Rafaello](https://digitalgemology.com/gemstones/topaz/dg-rafaello) - [DG-Bowtie](https://digitalgemology.com/gemstones/topaz/dg-bowtie) - [DG-Elongated Hexagon](https://digitalgemology.com/gemstones/topaz/dg-elongated-hexagon) - [DG-Octagonal Kite](https://digitalgemology.com/gemstones/topaz/dg-octagonal-kite) ### The Old Mine Cut in other gemstones - [Diamond](https://digitalgemology.com/gemstones/diamond/old-mine) - [Moissanite](https://digitalgemology.com/gemstones/moissanite/old-mine) - [Cubic Zirconia](https://digitalgemology.com/gemstones/cubic-zirconia/old-mine) - [Sapphire](https://digitalgemology.com/gemstones/sapphire/old-mine) - [Ruby](https://digitalgemology.com/gemstones/ruby/old-mine) - [Emerald](https://digitalgemology.com/gemstones/emerald/old-mine) - [Amethyst](https://digitalgemology.com/gemstones/amethyst/old-mine) - [Spinel](https://digitalgemology.com/gemstones/spinel/old-mine) - [Demantoid](https://digitalgemology.com/gemstones/demantoid/old-mine) - [Zircon](https://digitalgemology.com/gemstones/zircon/old-mine) - [Tourmaline](https://digitalgemology.com/gemstones/tourmaline/old-mine) - [Peridot](https://digitalgemology.com/gemstones/peridot/old-mine) - [Tanzanite](https://digitalgemology.com/gemstones/tanzanite/old-mine) - [YAG](https://digitalgemology.com/gemstones/yag/old-mine) - [Pyrope](https://digitalgemology.com/gemstones/pyrope/old-mine) - [Almandine](https://digitalgemology.com/gemstones/almandine/old-mine) - [Spessartine](https://digitalgemology.com/gemstones/spessartine/old-mine) - [Grossular](https://digitalgemology.com/gemstones/grossular/old-mine) - [Chrysoberyl](https://digitalgemology.com/gemstones/chrysoberyl/old-mine) - [Kunzite](https://digitalgemology.com/gemstones/kunzite/old-mine) - [Iolite](https://digitalgemology.com/gemstones/iolite/old-mine) - [Morganite](https://digitalgemology.com/gemstones/morganite/old-mine) - [GGG](https://digitalgemology.com/gemstones/ggg/old-mine) - [Strontium titanate](https://digitalgemology.com/gemstones/strontium-titanate/old-mine) - [Synthetic rutile](https://digitalgemology.com/gemstones/synthetic-rutile/old-mine)