History

(Gr. rhodon: rose) Wollaston discovered rhodium between 1803 and 1804 in crude platinum ore he presumably obtained from South America.

Sources

Rhodium occurs natively with other platinum metals in river sands of the Urals and in North and South America. It is also found with other platinum metals in the copper-nickel sulfide area of the Sudbury, Ontario region. Although the quantity occurring there is very small, the large tonnages of nickel processed make the recovery commercially feasible. The annual world production of rhodium is only 7 or 8 tons.

Properties

The metal is silvery white and at red heat slowly changes in air to the resquioxide. At higher temperatures it converts back to the element. Rhodium has a higher melting point and lower density than platinum. It is highly reflective, hard, and durable. 
A Periodic Table of the Elements at Los Alamos National Laboratory