thumb|upright=1.7|alt=Graph sowing on the x axis the elements by atomic number and on y-axis the amount in earth's crust compared to Si abundance. There is a green area with high abundance for the lighter elements between oxygen and iron. The yellow area with lowest abundant elements includes the heavier platinum group metals, tellurium and gold. The lowest abundance is clearly iridium. |Iridium is one of the least abundant elements in Earth's crust. thumb|upright|The Willamette Meteorite, the sixth-largest meteorite found in the world, has 4.7 ppm iridium.|alt=A large black egg-shaped boulder of porous structure standing on its top, tilted Iridium is one of the nine least abundant stable elements in Earth's crust, having an average mass fraction of 0.001 ppm in crustal rock; gold is 4 times more abundant, platinum is 10 times more abundant, silver and mercury are 80 times more abundant. Osmium, tellurium, ruthenium, rhodium and rhenium are about as abundant as iridium. In contrast to its low abundance in crustal rock, iridium is relatively common in meteorites, with concentrations of 0.5 ppm or more. The overall concentration of iridium on Earth is thought to be much higher than what is observed in crustal rocks, but because of the density and siderophilic ("iron-loving") character of iridium, it descended below the crust and into Earth's core when the planet was still molten.
thumb|upright=17|alt=graph sowing on the x axis the elements by atomic number and on y-axis the amount in earth's crust compared to si abundance there is a green area with high abundance for the lighter elements between oxygen and iron the yellow area with lowest abundant elements includes the heavier platinum group metals tellurium and gold the lowest abundance is clearly iridium |iridium is one of the least abundant elements in earth's crust thumb|upright|the willamette meteorite the sixth-largest meteorite found in the world has 47 ppm iridium|alt=a large black egg-shaped boulder of porous structure standing on its top tilted iridium is one of the nine least abundant stable elements in earth's crust having an average mass fraction of 0001 ppm in crustal rock; gold is 4 times more abundant platinum is 10 times more abundant silver and mercury are 80 times more abundant osmium tellurium ruthenium rhodium and rhenium are about as abundant as iridium in contrast to its low abundance in crustal rock iridium is relatively common in meteorites with concentrations of 05 ppm or more the overall concentration of iridium on earth is thought to be much higher than what is observed in crustal rocks but because of the density and siderophilic ("iron-loving") character of iridium it descended below the crust and into earth's core when the planet was still molten