The Bench · N° 57

Ceramic trades scratches for chips

Watch ceramic is exceptionally hard and keeps its finish through abrasion that marks metal. Its low tolerance for deformation means a sharp impact can produce a chip or fracture instead.

Hen & Mills Editorial · 4 min read · 4 November 2026

Watch ceramic resists scratches exceptionally well, but it achieves that hardness without the ductility that lets metal dent or bend. A severe, concentrated impact can therefore chip an edge or fracture a component that still looked new before it met the floor.

Hardness answers one question

Hardness describes resistance to local indentation and scratching. Rado quotes around 1,250 Vickers for its high-tech ceramic, far above ordinary case steel. Everyday metal objects that leave bright lines on a steel clasp often cannot cut the ceramic surface. Years of careful wear can pass with remarkably little visible change.

A mark on ceramic is not always a scratch in the ceramic. Softer material can transfer onto the hard surface, leaving a streak that may clean away. The useful test is not to attack it with a stronger abrasive. Gentle cleaning can distinguish deposited material from a groove without adding a new problem.

Toughness answers another

Fracture toughness describes a material's resistance to crack growth. Metals can yield around a concentrated load, absorbing energy through plastic deformation. Ceramic allows little plastic movement at ordinary temperatures. When stress at a flaw exceeds what the material can tolerate, a crack can travel quickly.

This is why “harder than steel” should not be translated as “stronger in every accident”. A ceramic bezel can ignore countless encounters with sleeves and desktops, then lose a small corner when a sharp tile concentrates impact at its edge. The two outcomes measure different properties.

It begins as powder

High-tech watch ceramic is made from fine mineral powders, binders and colourants formed into an initial shape. The component is sintered at high temperature, which burns away binder and fuses the particles into a dense body. It shrinks during this process, so tooling and dimensions must anticipate the change.

After sintering, the material is difficult to machine by conventional cutting because the finished surface is so hard. Diamond tools, grinding and specialised polishing are used where precise holes, interfaces and finishes are needed. A ceramic case is therefore not a lump of kitchen crockery carved into a watch shape.

Colour can run through the material

Pigments can be incorporated into the ceramic body, allowing colour to extend below the surface rather than sitting as paint on top. A shallow mark is less likely to expose a contrasting substrate. Polished and matte finishes can be created on the same fundamental material, and neither depends on a thin coloured skin in the way many coated metals do.

Colour consistency is technically demanding. Sintering conditions and composition affect shade, density and dimensions. White, black, plasma-treated and coloured ceramics may use related processes with different recipes. The broad word “ceramic” does not specify all of them.

Composite cases manage the risk

Brands often pair ceramic with metal. A steel or titanium inner structure can carry threads, movement supports and case-back loads, while ceramic forms the visible outer case or bezel. Metal inserts can protect screw interfaces and distribute pressure that would be unkind to a brittle thread.

Construction details matter when judging durability. A slim ceramic bezel insert supported around its circumference behaves differently from a solid ceramic bracelet link with exposed corners. The location of joints, pins and metal sleeves determines how impact travels.

Bracelet links live a difficult life

Ceramic bracelets offer a surface that stays clean-looking, but each link contains holes and bears contact at pins. Good designs use sleeves and shapes that distribute load. Dropping the watch while open can still put a sharp impact through one edge, and replacing a broken link may require brand-specific parts.

Sizing deserves the correct tools and support. Hammering a stubborn pin while the link rests poorly turns a routine adjustment into a fracture test. The bracelet's scratch resistance gives no protection from careless point loading on a workbench.

Scratches can still happen

Rado correctly notes that material harder than the ceramic can scratch it. Diamond is the obvious example, but abrasive particles can contain very hard minerals. A diamond ring rubbing directly against a ceramic case is a more credible threat than a shirt cuff.

The surface can also be damaged by another piece of ceramic. Hardness comparisons are not absolute guarantees because contact pressure, particle shape and surface flaws affect the event. “Scratch resistant” remains the honest phrase. “Scratch proof” asks the material to defeat every harder object in nature.

Repair is different from metal

A dented steel case can sometimes be refinished or rebuilt by a specialist. A chipped ceramic component generally cannot be polished until the missing corner returns. Replacement is the normal remedy, subject to parts availability and the case construction.

Polishing ceramic is itself specialised. The hard surface that resists wear also resists easy refinishing. An owner should avoid generic abrasives and ask the manufacturer or an experienced service centre what is possible for the exact material.

Wear it for its real advantage

Ceramic is excellent where surface appearance matters and normal wear is dominated by abrasion. It can keep black deep, white clean and polished planes sharp without the web of hairlines familiar on steel. It is also light, corrosion-resistant and comfortable against the skin in well-designed components.

The sensible concession is impact care. Do not assume a pristine surface has made the object invulnerable, and be cautious around stone floors, exposed edges and bracelet adjustment. Ceramic trades the gradual visible softening of metal for a smaller chance of more decisive damage. That is not a flaw hidden by hardness. It is the material bargain.