3D model and faceting diagram · 76 facets · 6.26 x 5.96 mm
A faceted cabochon: seventy-five triangular facets on a five-fold pattern, rising from a flat pentagonal base to a point. It is widest a little below the middle. There, the crown and pavilion triangles meet in a zig-zag, with no girdle band. It is drawn for ruby.
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A faceted cabochon: seventy-five triangular facets on a five-fold pattern, rising from a flat pentagonal base to a point. It is widest a little below the middle. There, the crown and pavilion triangles meet in a zig-zag, with no girdle band. It is drawn for ruby.
Like a cabochon, it has no table. It is made to be seen from above and set on its flat base, but every surface of the dome stays faceted.
Measured from the delivered model, not quoted from a standard.
We do not measure brilliance, fire and scintillation for the DG-Cabochon Cut: our census follows light that enters through the table and returns face up, and this stone has no table.
Also scored, with the same census, in 19 more gemstones: topaz, spinel, demantoid, zircon, tourmaline, peridot, tanzanite, YAG, pyrope, almandine, spessartine, grossular, chrysoberyl, kunzite, iolite, morganite, GGG, strontium titanate and synthetic rutile. Their head-on figures are in the table below.
The same geometry behaves differently in every material. Light that meets a pavilion facet at less than the critical angle of the stone does not reflect. It passes straight out of the back and shows face-up as a window. This stone has no table, so the head-on measure for the other cuts does not apply to it. The table below gives the weight of the model in each stone.
| Stone | Refractive index | Critical angle | Pavilion reflecting head-on light | Weight at this size | Verdict |
|---|---|---|---|---|---|
| Diamond | 2.417 | 24.4° | n/a | 2.00 ct | Not measured: no table |
| Moissanite | 2.648 to 2.691 | 22.2° | n/a | 1.83 ct | Not measured: no table |
| Cubic Zirconia | 2.15 to 2.18 | 27.7° | n/a | 3.30 ct | Not measured: no table |
| Ruby | 1.762 to 1.770 | 34.6° | n/a | 2.27 ct | Not measured: no table |
| Sapphire | 1.762 to 1.770 | 34.6° | n/a | 2.27 ct | Not measured: no table |
| Emerald | 1.577 to 1.583 | 39.4° | n/a | 1.55 ct | Not measured: no table |
| Amethyst | 1.544 to 1.553 | 40.4° | n/a | 1.51 ct | Not measured: no table |
| Topaz | 1.606 to 1.644 | 38.5° | n/a | 2.01 ct | Not measured: no table |
| Spinel | 1.712 to 1.747 | 35.7° | n/a | 2.06 ct | Not measured: no table |
| Demantoid | 1.881 to 1.888 | 32.1° | n/a | 2.19 ct | Not measured: no table |
| Zircon | 1.925 to 1.984 | 31.3° | n/a | 2.65 ct | Not measured: no table |
| Tourmaline | 1.603 to 1.655 | 38.6° | n/a | 1.78 ct | Not measured: no table |
| Peridot | 1.650 to 1.690 | 37.3° | n/a | 1.90 ct | Not measured: no table |
| Tanzanite | 1.685 to 1.707 | 36.4° | n/a | 1.90 ct | Not measured: no table |
| YAG | 1.833 | 33.1° | n/a | 2.59 ct | Not measured: no table |
| Pyrope | 1.730 to 1.766 | 35.3° | n/a | 2.14 ct | Not measured: no table |
| Almandine | 1.750 to 1.830 | 34.8° | n/a | 2.34 ct | Not measured: no table |
| Spessartine | 1.790 to 1.830 | 34.0° | n/a | 2.36 ct | Not measured: no table |
| Grossular | 1.730 to 1.760 | 35.3° | n/a | 2.07 ct | Not measured: no table |
| Chrysoberyl | 1.746 to 1.755 | 34.9° | n/a | 2.12 ct | Not measured: no table |
| Kunzite | 1.660 to 1.676 | 37.0° | n/a | 1.81 ct | Not measured: no table |
| Iolite | 1.542 to 1.551 | 40.4° | n/a | 1.48 ct | Not measured: no table |
| Morganite | 1.572 to 1.600 | 39.5° | n/a | 1.62 ct | Not measured: no table |
| GGG | 1.970 | 30.5° | n/a | 4.01 ct | Not measured: no table |
| Strontium titanate | 2.409 | 24.5° | n/a | 2.91 ct | Not measured: no table |
| Synthetic rutile | 2.616 to 2.903 | 22.5° | n/a | 2.42 ct | Not measured: no table |
Head-on light, first reflection. The 3D Gemstone Simulator traces the full Light Return in each of these gemstones.
Open it in the 3D Gemstone Simulator. Set its carat, color, clarity and cut grade in any of seven gemstones. Turn it under ten kinds of light, and watch its 3D gemstone report change as you go. Free, in your browser.
Six formats. STEP is the exact faceted solid for CAD, and 3DM is for Rhino. STL and OBJ are meshes. FBX is for Blender, 3ds Max, Maya, Cinema 4D, Unity and Unreal. GLB is for the web and AR. All are in millimeters at real-world scale, with 76 planar facets.
Yes. The cutting files contain a GemCad .asc design (76 facets, 120 index, 5-fold mirror-image symmetry) and a printable faceting diagram. They also contain a tier table in CSV, with the angles, indices and cutting order.
This stone has no table, so the head-on light measure that we use for the other cuts does not apply. Light enters and leaves through its steep facets, not through a table. Its Light Return map shows how it behaves in each stone.
We check it facet by facet against the 3D model that it was written from. Every crown and pavilion facet within 0.004° of the 3D model (average under 0.001°). The angles are the ones you set on the machine. The 3D model is the same stone that you render or set.
The model measures 6.26 x 5.96 x 6.73 mm, which is 2.00 ct in diamond. At the same size, it weighs 1.83 ct in moissanite, 3.30 ct in cubic zirconia, 2.27 ct in ruby, 2.27 ct in sapphire, 1.55 ct in emerald, 1.51 ct in amethyst. You can scale it uniformly to any size: the weight follows the cube of the size.
Yes. The mesh is watertight and manifold, with outward normals and no duplicate vertices, so it prints and casts without repair. Use the STEP file when you need the exact faceted solid in CAD.
The DG-Cabochon Cut as exact geometry: 76 planar facets, real-world scale, ready for CAD, rendering, printing and casting.
The DG-Cabochon Cut as a faceting design: 76 facets, 120 index, 5-fold mirror-image symmetry, ready for the machine.
Not sure the files open in your software? Get the cube free: the same six formats, for your email address, used only to send them (privacy).
Questions before you buy? Email us.