Iron

Items made of iron weighs one and one half times as much as the same item made from steel. Cursed iron ore does exist and the only known cases come from the hollows
Iron armor
Can be any Medium or Heavy armor, but not hide. Medium armor imposes a -1 penalty to the DEX modifier for calculating the Armor Class (AC). Heavy armor requires a STR score 2 points higher than that listed in the PHB.
Iron weapons
Items without metal parts cannot be made from iron. An arrow could be made of iron, but a standard quarterstaff could not. Iron weapons lose all Light and Finesse properties.
Cost
Armor and Weapons made from Iron cost the same as those made from steel.