What is this element?

for you smart people out there, Ive got a brain teaser. This is an element that is rare, has a whitish color and has something to do with the dinosaurs getting extinct. Gold is about 4 0r 5 times more common than this element is. It is found in the earth's crust, but is believed to have much more in asteroids. It is not a noble gas. I am pretty sure that the element is iridium, but not quite certain... any guesses???