Natural crystals are formed within the earth's crust over millions of years. Raw minerals are liquefied by magma flowing from the earth's core. These molten minerals can begin to crystallize as they slowly cool.

All crystals are formed from one point, this happens by chance in natural settings. In the same way that an ice cube in water grows outwards, crystals grow from this single structure known as the seed crystal.

These conditions can be replicated in the lab to cultivate crystals with a great deal more control. By liquifying an exact ratio of minerals inside a vacuum chamber and precisely introducing a perfect seed crystal. What naturally takes millions of years, we can perfect in a month.

Emerald REC is a proprietary form of the synthetic gem YAG (Yttrium Aluminium Garnet), a gem that is not found anywhere in nature but formed using the same principles. With a technique called crystal pulling, it is possible to grow Emerald REC with the rich and vivid colours of Colombian Emerald whilst delivering a greater degree of hardness.

In a quartz crucible, polycrystalline silicon is heated to over 1400°C (2550°F). This temperature is hotter than magma (1300°C). It is performed in an airtight chamber with a controlled atmosphere of argon gas in order to prevent contamination from oxidizing. Liquid Silicon is precisely infused with trace elements of Chromium and other proprietary minerals. Chromium is a lustrous metal that is one of the primary ingredients in stainless steel, as it is capable of producing a high polish with excellent resistance to tarnishing. Furthermore, this mineral produces rich green colors when suspended in crystal form.

In this process, a rotating crystal seed is precisely introduced into the molten liquid to jump-start the crystallization process and eliminate the random effect of natural crystallisation. Slowly lowering the temperature in the chamber simulates the cooling of the earth's crust, initiating the crystallisation of the liquid silicon on the seed crystal.

A cylindrical silicon crystal hanging on the seed is formed as the seed crystal is slowly pulled upwards. The chamber temperature and the rate at which the crystal is pulled are both carefully regulated so that a constant diameter is obtained.

The equivalent of millions of years of growth in the space of 4 weeks.

To begin the production process, the large piece of Emerald REC has to be carved into smaller pieces. When working with stainless steel or titanium, this is as easy as cutting a block from a larger sheet. The use of unconventional methods is required when working with crystals.

EDM (Electrical Discharge Machining) is a process that involves tensioning a thin wire, in our case tungsten, between two electrically charged diodes and putting it in contact with a conductive material. A spark of electricity is created when this wire contacts a conductive material, causing the material to vaporize and slowly cut without causing vibrations or abrasions. To prevent shorting, the entire process must be performed within a dielectric (non-conductive) fluid, like deionized water.

Wire EDM enables us to cut perfect REC blanks that are ready for the delicate machine process while also preserving the most precious material and reducing the possibility of breakage. Emerald REC is now ready to start the delicate process of being carved into the distinctive Aventi shape.

Turning a rectangular piece of Emerald REC into the most complex watch case in the world.

After the Emerald REC is cut to size, it is taken to a five-axis CNC machine to begin a 72 step CNC process that will take eight weeks to complete. Using CNC (Computerized Numerical Control) machining results in higher levels of accuracy than is possible by hand, since a single mistake can be disastrous.

We slowly remove micron thin layers of the case with diamond-tipped cutting tools as small as 0.3mm. Carefully carving out the 68 facets and 110 edges of the Aventi case within a 0.01mm tolerance. This tolerance is crucial for both the aesthetic finish of the piece and to ensure the water-resistance of at least 50 meters.

REC Emerald cases are cut in the following stages:

• To create the tapered shape of the Aventi case, an outer edge is cut into the REC blank.
• Each of the ten edges of the case's unique interior are cut, ready to house the dual barrel tourbillon.
• As the outer facets of the case are cut, the signature shape of the Aventi case emerges. It is one of the most complex and time-consuming steps. In order to ensure accuracy and symmetry, each facet requires the CNC machine to be calibrated and measured in a process that takes at least four hours.
• The underside of the case is cut out, except for screw holes.
• The watch glass groove is cut; this step is essential for the piece's water resistance as it prevents the Sapphire Crystal from sitting unevenly in the case.
• A recessed groove cut for the band includes the attachment points for the spring bar.
• The last step is to drill the holes for the proprietary screws on the back of the case.

What could go wrong?

• A movement or mistake as small as 0.01mm can cause cracking or shattering of the crystal, losing hundreds of hours of work and months.
• All 72 steps of the CNC process must be carefully monitored at all times to ensure no excess pressure is applied to the material.
• Each case must be carefully secured in a dampening clamp system as the high-frequency vibrations of the machining process can cause the Crystal to shatter.

Due to abrasions and vibrations caused by the cutting machines, the surface of the REC can appear foggy after eight weeks of intricate machining. To restore the vivid green colour we spent so long developing, each case must be polished and buffed. Each facet must be impeccable. It is a process that must be done entirely by hand by a single craftsman.

While pressure is needed to polish the crystal case, it is the amount of pressure that can cause disaster. Too little pressure prevents the abrasives from cutting through the hard variations on the crystal's surface. In the case of too much pressure, the crystal can shatter, edge details can be lost, and the symmetry and sharp design of the piece will be distorted.

It can be devastating and expensive to lose a REC crystal case at this stage. To prevent this, a single craftsperson polishes the case by hand from beginning to end. Only the touch of a knowledgeable craftsman can ensure the correct amount of pressure is applied to every surface.

Polishing occurs in two stages:

STAGE 1: Fine Sandpaper

After the machining process, the polishing process begins using fine sandpaper to even out any inconsistency or marks on the material.

STAGE 2: Wax and Lambs wool

Wax is applied to a lambs wool polishing wheel and is used to perfect each facet of the REC case; buffing the crystal to its most brilliant form. The wax acts as a gentle cutting compound between the lambs wool and crystal to remove an extremely thin layer. Within the wax, there are microscopic abrasive particles capable of cutting and perfecting the surface of the crystal to a perfectly flat finish.

What are the risks?

• Before polishing, it is challenging to see any micro-cracks or splits in the crystal material. Polishing can expose any of these faults, or the faults can cause shattering caused by the high-frequency vibrations of the polishing wheel.
• The Perfect amount of pressure must be applied to each facet of the case; too little and it won’t polish, too much... and disaster!