"Black rhodium" is a term used to describe a dark metallic coating made from the precious metal rhodium. It is used to give a black or dark finish to jewelry or other objects, adding a unique and luxurious look. Full definition
Gold Cora drop earrings made in 18 karat yellow gold with black rhodium (platinum family), and finished with signature proprietary metalwork that creates an illusion of a diamond inlay... (1stdibs.com)
A delicate chain in 925 sterling silver Vermeil and Black Rhodium Chain accentuated by a Fronay Collection signature Evil Eye Plaque sparkled with a brilliant cubic zirconia. (tokalene-jewelry.com)
Sparkle and shine wearing this 18kt white gold Stasia triple star diamond ear cuff from ALINKA featuring three black rhodium finish graduating stars in a curved line to follow the shape of the ear, each star is embellished with pavé set black diamonds (0.32 ct) and a hook and a butterfly fastening. (polyvore.com)