If you are looking for an easy-to-cut square Barion design that delivers an exceptional pinwheel light return, the Trottola cut designed by Marco Voltolini is a fantastic choice.
Unlike traditional square cushion cuts, Trottola features a 4-fold radial symmetry that creates a unique optical effect. While optimized for Quartz (RI = 1.540), it works extraordinarily well on higher RI gemstones such as Aquamarine, Tourmaline, Topaz, and Sapphire.
Design Specifications
| Parameter | Specification Details |
|---|---|
| Designer | Marco Voltolini |
| Target RI | R.I. = 1.540 (Quartz & higher) |
| Facet Count | 37 facets + 8 girdles = 45 total |
| Symmetry / Index | 4-fold radial | 96 Index Gear |
| Proportions | L/W=1.000 | T/W=0.384 | U/W=0.384 P/W=0.522 | C/W=0.195 |
| Volume Ratio | Vol./W³ = 0.312 |
Step-by-Step Cutting Angles
1. Pavilion Cutting Sequence
| Facet | Angle | 96-Index Settings | Instruction / Meet Point |
|---|---|---|---|
| 1 | 41.50° | 96-06-12-18-24-30-36-42-48-54-60-66-72-78-84-90 | Cut to centerpoint |
| 2 | 90.00° | 96-24-48-72 | Set stone size |
| 3 | 90.00° | 12-36-60-84 | Corner girdles |
| 4 | 60.00° | 96-24-48-72 | Barion wall facet |
2. Crown Cutting Sequence
| Facet | Angle | 96-Index Settings | Instruction / Meet Point |
|---|---|---|---|
| A | 36.19° | 96-24-48-72 | Set girdle thickness |
| B | 30.00° | 01-25-49-73 | Meet girdle |
| C | 22.13° | 03-27-51-75 | Meet A, B |
| E | 40.72° | 12-36-60-84 | Meet A, B, C, girdle |
| T | 0.00° | Table | Meet B, C |
Recommended Gemstones
The Trottola design is versatile and works best on medium to high Refractive Index (RI) rough materials:
- Quartz Family (RI 1.544 - 1.553): Amethyst, Citrine, Smokey Quartz, and Prasiolite.
- Beryl Family (RI 1.577 - 1.583): Aquamarine, Morganite, and Heliodor.
- Higher RI Materials (RI > 1.61): Topaz, Tourmaline, Spinel, and Sapphire for maximum brilliance and sharp pinwheel optical effects.
Pro Cutting Tips & Insights
- E Tier Adjustment Note: As noted by Marco Voltolini, if your cutting precision is slightly off, the E tier (40.72°) may require a tiny angle adjustment to lock into the girdle and meet points smoothly.
- Barion Efficiency: The deep 60° pavilion wall (Facet 4) provides a brilliant Barion effect, maximizing light return even in lighter colored rough without creating a dead center window.
- Pre-Forming: Pre-form the stone carefully into a square shape using the 90° girdle cuts (Facet 2 and 3) to save cutting time on the pavilion main facets.
Looking for more free faceting diagrams and precision gemology tutorials? Explore our full collection on Horizon Gems!
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