The bezel on this vintage Rolex GMT Master was made from Bakelite which tends to crack as it gets older. So rolex went from Bakelite, to screen printed Steel.
Screen printed steel can fade if exposed to UV and other elements. It is hard to scratch, but possible.
In the latest version of the GMT Rolex introduced ceramic bezels, which they claim are as scratch-proof as their synthetic sapphire crystals.
Each generation of Rolex Bezel gets increasingly stronger...
