Rhodium is a chemical element that is a rare, silvery-white, hard, and chemically inert transition metal and a member of the platinum group. Naturally occurring rhodium is usually found as the free metal, alloyed with similar metals, and rarely as a chemical compound in minerals such as bowieite and rhodplumsite. It is one of the rarest and most valuable precious metals.

It was discovered in 1803 by William Hyde Wollaston. It is used as a finish for jewelry, mirrors, and search lights. It is also used in electric connections and is alloyed with platinum for aircraft turbine engines.

Another use is manufacturing of nitric acid and used in hydrogenation of organic compounds. Rhodium usage is dominated by automotive catalyst applications where it is used together with platinum and palladium to control exhaust emissions.

South Africa is the major source, accounting for almost 60% of the world's rhodium supply. Russia is the second largest producer, although its sales are, as with the other PGMs, volatile and subject to political intervention.

High rhodium prices during the late 1980s led to increased rhodium production from South Africa. This increased supply was primarily responsible for a declining rhodium price during the 1990s.

Interruptions to Russian supply since early 1997 have helped the rhodium price to recover strongly.

Most metal (85%) goes into catalytic converters for cars. The major use of the metal is in alloys with platinum and iridium, giving improved high-temperature strength and oxidation resistance.

These alloys are used in furnace windings, pen nibs, phonograph needles, high-temperature thermocouple and resistance wires, electrodes for aircraft spark plugs, bearings and electrical contacts. 

The metal itself,is used to plate jewelry and the reflectors of searchlights, due to its brilliance and resistance to tarnish. It is also a highly useful catalyst in a number of industrial processes, such as the BP-Monsanto process.

There are significant improvements in rhodium processing and mining, therefore there has actually been a growth in rhodium supply (2.6%), while demand for rhodium has risen (1.3%). There is an overall general trend of decreasing supply and increasing demand.