Iridium is a member of the Platinum family. The family includes, platinum, iridium, osmium, palladium, and ruthenium. Iridium was alloyed frequently in fine jewelry of the Art Nouveau and Art Deco periods, (1900 to the mid 1930’s) employing 10% iridium and 90% platinum. It was quite common in the finer pieces of jewelry of the times. During World War II, platinum and the members of its family were declared to be “essential” commodities used in the war effort. It was at this time that if became popular (and necessary) to alloy gold with nickel and zinc to create 18karat, 14karat and 10karat “white” gold for those desiriing the look of platinum jewelty. White gold is still very popular today. Today platinum is again a popular metal in the construction of jewelry, however it is more commonly alloyed with cobalt at present.