Iron in folklore

Iron has a long and varied tradition in the mythology and folklore of the world.
In Europe.
Cold iron.
"Cold iron" is historically believed to repel, contain, or harm ghosts, fairies, witches, and other malevolent supernatural creatures. This belief continued into later superstitions in a number of forms:
"Cold Iron" is a substitute name used for various animals and incidences considered unlucky by Irish fishermen. A similar phenomenon has been found with Scottish Fishermen.
Horseshoes.
Horseshoes are considered a good luck charm in many cultures, including those of England, Denmark, Lithuania, and Estonia, and its shape, fabrication, placement and manner of sourcing are all important. A common belief is that if a horseshoe is hung on a door with the two ends pointing up then good luck will occur. However, if the two ends point downwards then bad luck will occur. Traditions do differ on this point, however. In some cultures, the horseshoe is hung "points down" (so the luck pours onto a person standing under it); in others, it is hung "points up" (so the luck does not fall out); in others it does not matter so long as the horseshoe has been used (not new), was found (not purchased), and can be touched. In all traditions, luck is "contained" in the shoe and can "pour out" through the ends.
In some traditions, any good or bad luck achieved will only occur to the "owner" of the horseshoe, not the person who hangs it up. Therefore, if the horseshoe was stolen, borrowed or even just found then the "owner", not the person who found or stole the horseshoe, will get any good or bad luck. Other traditions require that the horseshoe be found to be effective.
One reputed origin of the tradition of lucky horseshoes is the story of Saint Dunstan and the Devil. Dunstan, who would become the Archbishop of Canterbury in AD 959, was a blacksmith by trade. The story relates that he once nailed a horseshoe to the Devil's hoof when he was asked to reshoe the Devil's horse. This caused the Devil great pain, and Dunstan only agreed to remove the shoe and release the Devil after the Devil promised never to enter a place where a horseshoe is hung over the door.
Another possible reason for the placing of horseshoes above doorways is to ward off faeries, the supposition being that supernatural beings are repelled by iron and as horseshoes were an easily available source of iron, they could be nailed above a door to prevent such beings entering a house.
Meteoric iron in Tibet.
"Thogcha" () means 'sky-iron' in Tibetan. Meteoric iron was highly prized throughout the Himalayas, where it was included in sophisticated polymetallic alloys for ritual implements such as the singing bowl (Jansen, 1992) and phurba (Müller-Ebeling, "et al.", 2002).
Beer (1999: p. 234) states that:
In fiction.
Cold iron is a poetic term for iron. Francis Grose's "1811 Dictionary of the Vulgar Tongue" defines cold iron as "A sword, or any other weapon for cutting or stabbing." This usage often appears as "cold steel" in modern parlance.
Rudyard Kipling's poem "Cold Iron", found in his 1910 collection of stories "Rewards and Fairies", used the term poetically to mean "weapon".
In his novel "Redgauntlet", the Scottish author Sir Walter Scott wrote, "Your wife's a witch, man; you should nail a horse-shoe on your chamber-door."
In modern fantasy, cold iron may refer to a special type of metal, such as meteoric iron or unworked metal. Weapons and implements made from cold iron are often granted special efficacy against creatures such as fairies and spirits.
In the Disney film "Maleficent", the title character reveals early on that iron is lethal to fairies, and that the metal burns them on contact.
In the "Pokémon" games, Pokémon categorized as Fairy-types are weak against moves that are categorized as Steel-type. Fairy-type moves are also less effective than other types of moves against Pokémon of the Steel-type.