Rhodium
rho·di·um | ˈrō-dē-əm
noun
A metal that is a member of the platinum family of metals, but is liquid in its raw, natural state, not solid like platinum
Rhodium is an element on the periodic table located between ruthenium and palladium, and holding an atomic number of 45. It is a member of the platinum family of metals, but unlike platinum which is solid in its natural state, it is liquid. Due to the unique, corrosion-resistant nature of rhodium, and the fact that it is more common than gold or platinum, it is used as a coating that can be applied to other precious metals. It is used as a coating for gold commonly to create “white gold”, simulating the shiny white surface of platinum without the cost of pure platinum. It is also used on other alloys, including sterling silver, to provide corrosion resistance. These coatings have to be reapplied over time.