Most of the universe is primordial atoms that haven’t fused yet but if you were to take an iron atom, it probably would have been through only one star cycle.

Most of the universe is primordial atoms that haven’t fused yet but if you were to take an iron atom, it probably would have been through only one star cycle. A main sequence star at least ten times the size of the sun goes through several stages as it ages: hydrogen, helium, carbon, neon, oxygen, and finally silicon burning. The silicon burning stage produces abundant iron and the type II supernova that follows spreads it around.