In this instalment of 'Watch 101', we look at watch cases, specifically what they're made of and what a difference that can make
From comparatively simple stainless steel through to complex carbon composites, watch cases are made from a broad range of materials. And while case materials might seem to operate on a simple spectrum from lowest cost to highest value, the equation isn’t as simple like that. Steel routinely outperforms precious metals, in both demand and price. The new breed of high-tech composites from brands like Richard Mille and Audemars Piguet only complicates the situation. Refined precious dress pieces have their place, but the bold new frontier of watchmaking is the world of sporty, highly complicated watchmaking. Besides aesthetic differences, there's a range of pros and cons to each material. We break it down below.
Steel
Steel is, by far, the most popular material for a watch case, and for good reason. Stainless steel is an alloy that looks good brushed, polished or anywhere in between. It's hard-wearing, with good scratch and corrosion resistance and high tensile strength. All this means that a steel watch case will look good for a long time. Add to this the fact that it's an economical material to work with and you can see why steel shines so bright for watch cases. Of course, that’s the theory. Anyone who’s tried to buy a professional Rolex or steel Patek Philippe knows that sometimes, on the right watch; steel is more precious than gold.
Watch out for: Not all steel is the same. Some brands have their own unique blends, like Rolex's Oystersteel and Chopard's eco-friendly Lucent steel. Some brands will also harden steel cases to make them extra scratch-resistant.
Titanium
Titanium is a metal known for its high strength and low weight. It was these two properties that saw the alloy rise to prominence in the 1950s, with a new, jet-fuelled era of aviation. In addition, titanium is anti-magnetic and heat-resistant. It's also remarkably corrosion-resistant, as the alloy develops an oxidised layer that protects the metal. Its matte grey appearance lends itself to purposeful or utilitarian watch designs.
Watch out for: While the practical benefits of a titanium watch case are many, one downside you need to be aware of is that the material scratches reasonably easily. Many brands will treat the alloy to harden it, but it's still something worth bearing in mind.
Gold
Few materials can rival the cachet of gold. Since antiquity, the heavy, lustrous metal has been synonymous with wealth and status, and that's as true with watches as anything else. Objectively though, gold isn't a great material for watch cases; it's heavy, soft and scratches if you breathe on it funny. Most modern watch cases are made from 18k gold as the full 24k is too soft. On vintage watches you’ll occasionally find more hardwearing 14k cases. For pure prestige though, it's hard to go past gold.
Rose Gold
With a warmer tone achieved thanks to a dash of copper in the alloy, rose gold has enjoyed surging popularity in recent years. It’s easy to see why.
White Gold
The stealthiest of the golds, from a distance white gold could easily be mistaken for simple steel. The weight and the shine tell another story, though.
Yellow Gold
Pure gold has a bright yellow lustre that never goes out of style. There’s no mistaking it on the wrist.
Watch out for: Typically, gold comes in three main flavours: yellow, white and pink/rose/red. The main difference in the last golds comes from the amount of copper in the alloy, which determines the amount of red colouration. Some brands have their own proprietary alloys, like Omega's Sedna gold and Rolex's Everose.
Platinum
Even rarer than gold, platinum is a pretty special material for watch cases. To the casual observer, it can be mistaken for white gold, but up close you will notice it's heavier than gold, as well as more lustrous and a little harder. It also doesn't tarnish as much as gold, making it a longer-lasting material — and why platinum is used in some gold alloys.
Watch out for: If you ever have the pleasure of handling a precious metal Patek Philippe and aren't sure if its white gold or platinum, have a look between the lugs — if there's a single diamond set between them, it's platinum.
Bronze
As far as metal alloys go, bronze hasn't changed too much in the last 4000 or so years. Bronze is something of a catch-all term for a range of alloys that usually include copper and aluminium or nickel. It's corrosion-resistant and fairly tough, but the real reason watchmakers have started using it in recent years is because it develops a distinctive, world-worn patina that works really well on watches. And while bronze has become popular on retro-styled divers from brands like Tudor, the material’s mainstream moment was on the cult hit Panerai Submersible ‘Bronzo’ in 2011.
Watch out for: Most bronze watches don't make the case backs or buckles out of bronze. If they did, that green patina would end up all over your wrist.
Ceramic
The advent of relatively affordable, mass-produced ceramic is one of the most significant developments in the modern era of watchmaking. Modern high-tech ceramic covers a range of inorganic, nonmetallic solids; in watchmaking, that typically means zirconium dioxide or tungsten carbide. These days, ceramic is used in watch cases, bezel inserts and even movement components. It's virtually scratch-proof and resistant to colour-fading caused by ultra-violet light. To see just how varied ceramic cases can be, look that the difference between a brushed case by Blancpain and the highly polished ceramic Speedmaster by Omega.
Watch out for: For all its toughness, ceramic has one real downside; it's brittle. So if you should have the misfortune of dropping a ceramic case onto a hard surface, the case might break or shatter, and that's never a good thing.
Carbon
The distinctive woven pattern of carbon fibre has been a staple in watchmaking for some time. But it's not the only form of carbon. There's a whole raft of carbon composites and proprietary materials such as the NTPT Carbon Richard Mille makes use of. All carbon materials fundamentally consist of a combination of carbon and binding resin. Of all the carbon-cased watches out there, it’s hard to go past the carbon Royal Oak Offshores by Audemars Piguet for sheer wrist appeal.
Watch out for: Aside from its distinct looks, carbon materials are exceptionally light, strong and shock-resistant. Perfect for sports watches.
Sapphire
Primarily the domain of high-end brands like Richard Mille, Greubel Forsey, MB&F and Hublot, sapphire watch cases are exceptional in every way; exceptionally tough and exceptionally hard to produce. That's due to the nature of the material. Sapphire cases are made from corundum, which has a hardness of 9 on the Mohs scale, one below diamond. This strength makes it exceptionally difficult and time-consuming to machine.
Watch out for: While you don't have to worry about scratches, large impacts and sudden drops could be catastrophic.
Regardless of whether or not your watch is made from humble steel or something as rare as sapphire, the most important thing is to pick a case material that works for you, suits your lifestyle and makes you happy.