On a recent trip to Malaysia I visited a commercial rubber plantation and was surprised to see that the colour of the raw product was a whitish yellow.
Tyres are black because they contain carbon black.
Carbon black is added to tyres as a reinforcing agent that keeps them from wearing out too quickly. Added carbon will extend the lifetime of a rubber tyre from 8000 kilometres to 100,000 kilometres. Carbon black has been produced for more than 2000 years and has been used as a colorant for most of that time. A common modern method of production involves the controlled burning of a hydrocarbon, such as acetylene. Carbon black is produced in a variety of grades that differ in particle size, and in the size of aggregates of the single particles.