Onyx is a banded variety of the oxide mineral chalcedony. The colors of its bands range from white to almost every color (with the exception of some shades, such as purple or blue). Commonly, specimens of onyx contain bands of black and/or white.
Rhodium is a noble metal with a whitish gray appearance, and it is typically applied to metal through electroplating. A plating of rhodium is applied over either sterling silver or alloys to give a piece of jewelry a bright, glossy and long-lasting finish.