The rings around Saturn are bodies that have been around for more than 4 billion years, from a time when the solar system was in its infancy, according to NASA. The recent coloring on the rings' surface is due to recent "pollution" from a rain of meteoroids from beyond the solar system.
The data, obtained by the Cassini's visual and infrared mapping spectrometer (VIMS), has now shown how rings made of water and ice are spread across the Saturnian system. The analysis of spectrometer revealed that the color on the rings is limited to the surface.
Source: Nature World News. Read full article. (link)