White Metal is any alloy that is light-colored, and is used especially as a base for plated silverware, ornaments and jewelry. Some of the metals used to create this alloy are antimony, tin, lead, cadmium, bismuth and zinc. Not all of these metals are found in all white metal alloys, but are combined to achieve a desired need, such as being able to be casted and polished.
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.