Diamond cut wheels have become incredibly popular in recent years. As the diamond cut process produces a very shiny silver finish (similar to the rear of a CD), a very aesthetically pleasing two-tone effect can be achieved on diamond cut wheels. Black is therefore a very popular choice for the base coat colour of a diamond cut wheel, as it produces a strong contrast with the shiny silver diamond cut areas. This two-tone appearance, combined with some of the creative spoke designs found on modern wheels, can make for some truly fantastic-looking wheels! Whilst they do look fantastic, diamond cut wheels typically tarnish much quicker than wheels which have only been powder coated or painted. This is largely due to a particular form of corrosion - known as filiform corrosion. Filiform corrosion, which generally takes the appearance of white veins and milky spots, occurs when moisture is present between the lacquer and diamond cut parts of the wheel. Underneath the lacquer, the diamond cut areas are actually exposed areas of the bare wheel metal. This moisture then tarnishes and corrodes the bare metal of the wheel, producing the white veiny and spotty look. This can sometimes be frustrating, and even confusing, to owners of diamond cut wheels, as a wheel doesn't always possess noticeable damage when the filiform corrosion begins to appear. The most common  cause of filiform corrosion, in this case, is a tiny pin-prick hole in the lacquer - often caused by a rogue stone chip!