According this video 9 Shocking Facts from the Quran!
Iron is not natural to the Earth. It did not form on the Earth but came down to Earth from outer space. This may sound strange but it is true. Scientists have found that billions of years ago the Earth was stuck (sic) by meteorites. These meteorites were carrying iron from distant stars which has exploded.
The presenter then relates this fact with a verse from the Quran.
We sent down Iron with it's great inherent strength and its many benefits for humankind.
Did iron form on the Earth? Did it come from outer space? Was it all added after the Earth formed?