In its natural state, zirconium is a silver-grey color. It earns its stark black appearance through our proprietary heating process, in which a layer of hard black oxide grows on the metal. This black layer is much harder than raw zirconium, but it is very thin. Unlike oxidized silver and black rhodium, this layer does not rub off over time. It is also more durable than black-coated rings, such as black titanium and black tungsten.