Cutting moissanite
Moissanite, silicon carbide, has an even higher refractive index than diamond and more than twice its dispersion, so it shows strong fire. It is lighter than diamond, so the same size weighs less.
It is doubly refractive. Cutters orient the table perpendicular to the optic axis so the facet edges do not appear doubled when viewed through the table.
Cutting a round in moissanite? Diamond proportions lose the arrows and hearts in moissanite. BL-Anteros is re-solved for it and shows both. See the comparison.
Moissanite optical properties
Where a property has a range, angles are calculated from the lower refractive index, which gives the stricter limit.
Every cut, measured in moissanite
For each cut we measured how much of the pavilion, seen face-down, is steeper than moissanite's critical angle of 22.2°, so that head-on light reflects instead of leaking out of the back. Weights are for each model at its reference size.
| Cut | Category | Pavilion reflecting head-on light | Weight | Verdict | Files |
|---|---|---|---|---|---|
| BL-Anteros Cut | Brilliants | 100% | 1.75 ct | Holds head-on light | 3D + cutting |
| BL-Vitruvio Cut | Brilliants | 100% | 1.84 ct | Holds head-on light | 3D + cutting |
| Baguette Cut | Jewellery cuts | 100% | 1.39 ct | Holds head-on light | 3D + cutting |
| Cushion Cut | Jewellery cuts | 100% | 1.38 ct | Holds head-on light | 3D |
| Emerald Cut | Jewellery cuts | 100% | 1.39 ct | Holds head-on light | 3D + cutting |
| Emerald Square Cut | Jewellery cuts | 100% | 1.39 ct | Holds head-on light | 3D + cutting |
| Heart Cut | Jewellery cuts | 100% | 1.39 ct | Holds head-on light | 3D |
| Hexagon Cut | Jewellery cuts | 100% | 1.39 ct | Holds head-on light | 3D + cutting |
| Marquise Cut | Jewellery cuts | 100% | 1.45 ct | Holds head-on light | 3D + cutting |
| Octagon Cut | Jewellery cuts | 100% | 1.83 ct | Holds head-on light | 3D + cutting |
| Oval Cut | Jewellery cuts | 100% | 1.47 ct | Holds head-on light | 3D |
| Pear Cut | Jewellery cuts | 100% | 1.46 ct | Holds head-on light | 3D + cutting |
| Portuguese Bird's Nest Cut | Jewellery cuts | 100% | 1.83 ct | Holds head-on light | 3D + cutting |
| Princess Cut | Jewellery cuts | 100% | 1.33 ct | Holds head-on light | 3D |
| Radiant Square Cut | Jewellery cuts | 100% | 1.39 ct | Holds head-on light | 3D + cutting |
| Rectangle Cut | Jewellery cuts | 100% | 1.43 ct | Holds head-on light | 3D + cutting |
| Square Cut | Jewellery cuts | 100% | 1.42 ct | Holds head-on light | 3D + cutting |
| T105 Round Brilliant Cut | Brilliants | 100% | 1.68 ct | Holds head-on light | 3D + cutting |
| T57 Round Brilliant Cut | Historic cuts | 100% | 1.65 ct | Holds head-on light | 3D + cutting |
| T73 Round Brilliant Cut | Brilliants | 100% | 1.82 ct | Holds head-on light | 3D + cutting |
| Teardrop Cut | Jewellery cuts | 100% | 1.46 ct | Holds head-on light | 3D + cutting |
| Triangle Cut | Jewellery cuts | 100% | 1.83 ct | Holds head-on light | 3D + cutting |
| Trilliant Cut | Jewellery cuts | 100% | 1.41 ct | Holds head-on light | 3D + cutting |
| Trillion Cut | Jewellery cuts | 100% | 1.83 ct | Holds head-on light | 3D + cutting |
| Asscher Cut | Jewellery cuts | 100% | 1.39 ct | Holds head-on light | 3D + cutting |
| Old European Cut | Historic cuts | 100% | 1.83 ct | Holds head-on light | 3D + cutting |
| Old Mine Cut | Historic cuts | 100% | 1.83 ct | Holds head-on light | 3D + cutting |
| Mazarin Cut | Historic cuts | 99% | 1.83 ct | Holds head-on light | 3D + cutting |
| Old Single Cut | Historic cuts | 99% | 1.83 ct | Holds head-on light | 3D + cutting |
| Peruzzi Cut | Historic cuts | 99% | 1.83 ct | Holds head-on light | 3D + cutting |
| Radiant Cut | Jewellery cuts | 96% | 1.83 ct | Minor windowing | 3D |
Moissanite: questions
What pavilion angle should I use for moissanite?
For a round design, about 37.4° or steeper. That is the angle at which head-on light meets both sides of the pavilion above moissanite's critical angle of 22.2° and reflects twice before leaving through the crown. Fancy shapes vary, which is why every cut page lists its own figure.
What is the critical angle of moissanite?
22.2°, from a refractive index of 2.648. Light striking a facet from inside the stone at less than this angle from the facet's normal passes out; above it, it reflects.
Which cuts work best in moissanite?
30 of our 31 cuts reflect head-on light from their whole pavilion in moissanite, including BL-Anteros Cut, BL-Vitruvio Cut, Baguette Cut, Cushion Cut, Emerald Cut, Emerald Square Cut.
How much does moissanite weigh compared with diamond?
Moissanite has a specific gravity of about 3.22 against diamond's 3.52, so a stone of the same size weighs about 0.91 times as much as the diamond.