The name is derived from the Greek goddess of the rainbow, Iris, because Iridium salts are highly colored.
Iridium is a hard, silvery metal. It is almost as unreactive as gold. The metal Iridium has no known biological role, and is of low toxicity.
Iridium is one of the rarest elements on Earth. It is found uncombined in nature in sediments that were deposited by rivers. It is commercially recovered as a by-product of nickel refining.
INFORMATION FROM THE CENTER FOR DISEASE CONTROL (CDC)
Radioisotope Brief: Iridium-192 (Ir-192) ; Half-life: 73.83 days
Ir-192 is used in industrial gauges that inspect welding seams and in medicine to treat certain cancers.
External exposure to Ir-192 can cause burns, acute radiation sickness, and even death. Internal exposure could occur only if a person were to swallow one of the Ir-192 seeds or pellets. Internal exposure from Ir-192 could cause burns in the stomach and intestines if the high-energy industrial pellets are swallowed. Ir-192 seeds and pellets would be excreted in the feces. Long-term health effects of internal exposure would depend on how strong the seeds or pellets were and how long they stayed in the body.