Aquamarine that is not so clean
The Geometry of Rain: Faceting a Hexagonal Aquamarine with Challenging Inclusions
In the world of gem cutting, we are often taught that inclusions are flaws to be cut away. But every so often, nature provides a "flaw" so poetic it demands to be the star of the show. I recently sat down at the mast with a piece of rough Aquamarine (Beryl) featuring stunning penetrating tube inclusions—long, hollow channels that run parallel through the crystal.
When these inclusions are dense enough, they create what collectors call a "rain" effect. To honor the stone’s mineralogical roots, I chose a geometric hexagon design, mirroring the natural six-sided crystal structure of the Beryl family.
However, as any faceting pro knows, those beautiful tubes are essentially microscopic straws, and they present a unique set of technical hurdles during the polishing stage.
The Polishing Pitfall: The 60k paste Trap
When you move to the final polish, the standard operating procedure is often a 60,000-grit diamond compound. While this produces a mirror-like finish on the facets, it creates a nightmare for stones with open tubes.
The oil-based diamond paste is easily pulled into the inclusions via capillary action. Once that 60k diamond grit is embedded deep within those needle-thin channels, it sits there like dark, stubborn silt, ruining the "frozen rain" aesthetic and making the stone look muddy.
The Professional Alternative: The Hyper Edge 25k
If you want to avoid this headache entirely, the "pro move" is to use a Hyper Edge 25k lap with water. Because this method relies on water rather than oil-based pastes, the grit doesn't "stick" inside the tubes in the same way.
It is a cleaner process, but it demands:
Extra Time: 25k takes longer to move the surface than 60k and requires knowledge and practice to use.
Higher Skill: Managing the moisture and heat on a Hyper Edge lap requires a delicate touch to avoid roll over from the penetrating inclusions and edges of the facets.
The "Oops" Moment and the 10-Minute Save
In this particular instance, I didn't take the Hyper Edge route. I went with the 60k diamond grit, and as predicted, the tubes were immediately packed with gray polishing residue. From the outside, the stone looked like it had been filled with lead pencil shavings.
If you find yourself in this position, don't panic. You don't have to re-cut or live with a dirty stone.
The Solution: An ultrasonic cleaner.
I placed the finished Aquamarine in the ultrasonic bath with clean water. The high-frequency sound waves create cavitation bubbles—tiny bursts of energy that can penetrate where a brush or cloth cannot. After 10 minutes in the tank, the vibration successfully "scrubbed" the diamond paste out of the microscopic tubes.
The result? The "rain" was clear again, reflecting light perfectly against the sharp, hexagonal facets.
Final Thoughts
Faceting is a constant balance between artistic intent and mechanical reality. By choosing a cut that matched the stone's natural geometry and knowing how to navigate the "grit-in-the-tubes" crisis, I was able to turn a challenging piece of rough into a 2.13ct masterpiece.
