Black rhodium refers to plating of the mineral using a chemical process that results in a dark finish. The plating process transforms the coloration of the metal plated with rhodium, which has a rose tint in its natural state.
One of the primary uses of black rhodium is in jewelry making. Precious metals, such as gold and platinum, are coated using a bath-plating solution made with a fine powdered form of the mineral. Black rhodium plating is exceptionally hard, so it also serves for the manufacture of precision equipment. Its corrosion resistance makes rhodium plating well-suited for electrical components, too. While it has multiple uses, rhodium is a very rare mineral in nature.