Rudyard Kipling, 1907 Nobel Prize winner in Literature, begins his poem ‘Cold Iron’ with these lines. Indeed, iron does appear in many diff erent facets of our lives: from the band Iron Maiden to the Ironman championships in triathlon; in history with the Iron Curtain, or when we refer to the Iron Lady, ruling with an iron hand. Iron is a transition metal that melts at 1,539 °C, and its appearance can be described as lustrous and metallic, with a silver–grey tinge. It is the second most abundant metal on our planet — with the fi rst being aluminium — and is mostly present in its dense metal core as an alloy with nickel. It is also ubiquitous in the Earth’s crust, and constitutes about a third of its entire mass.