The name iridium comes from the Greek word "iris" meaning rainbow.

The "iridium theory" has been used to explain the exticntion of dinasours as resulting from the impact of a meteor that led to catestrophic climate changes on Earth. The theory is based on evidence indicating high concentrations of the element iridium in layers of the earth's crust dating back to the time of extinction. The iridium content in asteroids and meteors is higher than that normaly found on Earth.