From the very beginning, Apple Watch was designed with a deep reverence for the art of fine watchmaking. For the raw materials, every choice we made was intended to not merely honor the traditions of the past, but to advance them. From the custom gold alloys to the sapphire crystal, each element comes together with an unrivaled level of care and precision, giving Apple Watch a beauty that is both timeless and thoroughly modern.
Inspired by the inherent beauty of gold, we created Apple Watch Edition in 18-karat solid gold. Since it’s a soft metal, susceptible to nicks and scratches, our metallurgists engineered an entirely new alloy that’s up to twice as hard as standard gold. This allowed us to achieve the exact hues of yellow and rose gold we envisioned, without compromising on durability.
The strength and beauty of stainless steel have long made it a favorite material in fine timepieces. The stainless steel we created for Apple Watch is a modern expression of this tradition. We started with an alloy known for its durability and corrosion resistance. Then we made it even stronger. Through a specialized cold-forging process, it becomes up to 80 percent harder. This same stainless steel is used in the carefully engineered closures that allow Apple Watch to fit so precisely. And we added a diamond-like carbon layer to create the space black stainless steel case and matching band.
For Apple Watch Sport, we started with 7000 Series aluminum — the same used in competition bicycles. We altered it to create a new alloy that’s just as light, yet even more durable — it’s 60 percent stronger than most aluminum, and one-third the density of stainless steel. It has a bright, lustrous color and a uniform structure free of defects and impurities. Each case is machined and polished, then blasted with microscopic zirconia beads to achieve a consistent, satin texture. A special anodizing process creates a hard, clear outer layer that helps protect against scratches and corrosion.
Because the back crystal is vital to the function of the technology encased inside Apple Watch and Apple Watch Edition, we chose zirconia, a type of ceramic, as the primary material. It’s nonconductive, so the antenna can perform without any interference from the crystal. It’s also opaque, which eliminates cross-talk between the components of the heart rate sensor. The manufacturing process begins by heating the zirconia at 2640 degrees Fahrenheit for over 30 hours. Once it cools, we incorporate the sapphire lenses of the sensor. Then we polish the entire back crystal with a grinding stone to an incredibly smooth, precise finish — with a surface roughness of just 3 nanometers — so that it feels comfortable next to your skin.
Sapphire is the second-hardest transparent substance after diamond. That’s why we chose it to cover the Apple Watch and Apple Watch Edition faces, and to make the lenses of the heart rate sensor. Our sapphire crystal comes from the highest-quality boules. Only the purest, clearest, and strongest sapphire crystal is harvested. To ensure a precise fit for the case, the crystal is cut using a diamond-encrusted wire. To make room for an integrated antenna, a tiny groove is laser-ablated around its perimeter. And to create the smoothest possible finish, the crystal is polished with diamond-covered pellets.
Ion-X glass is the same material used in the windows of space shuttles and high-speed trains. This glass is thin and light, yet surprisingly strong — five times stronger than regular glass. Which made it the perfect choice for Apple Watch Sport. There are many ways to strengthen glass at the surface, but Ion-X glass is hardened down to its molecules. During the manufacturing process, the glass is dipped in a 750-degree molten potassium salt bath. That’s when ion exchange takes place, with the smaller sodium ions being removed from the glass and replaced by larger potassium ions. As the glass cools, these larger ions create an extremely hard surface layer that is resistant to scratches and impact.
To make the leather straps for Apple Watch, we start by hand-selecting hides from three of the world’s best-known artisan tanneries. The subtly grained Dutch, pebbled Venezia, and supple Granada leathers are chosen for their superior quality and uniform texture. The dyes we use ensure consistent, long-lasting color. And each design departs from tradition in its own way. The Classic Buckle features the same premium leather on both the interior and the exterior. Magnets concealed within our quilted Leather Loop allow for an infinitely adjustable fit. And the Modern Buckle has a hidden inner layer of stretch-resistant polymer that’s stronger than Kevlar.
Originally developed to withstand the rigors of commercial use, fluoroelastomer is a remarkably high-performance material. It’s thermal and water resistant, flexible, and strong. We knew that if we made fluoroelastomer as beautiful as it is durable, it would be ideal for Apple Watch Sport. So we custom-engineered our own to make it more pliable and gave it five vivid colors. The result is a resilient band with a soft feel and just enough weight to drape smoothly across your wrist.
Explore the technology behind Apple Watch