Iron is found in a variety of terrains, but always on Hills.
Iron is one of the first resources to usually be revealed in any given game. Likewise, it is a fairly common, fairly valuable early-game metal that is used to create strong, heavy military units during the Classical and Medieval eras of the game. It is relatively unique in that it grants a Science boost; very few resources save Mercury and Tea are capable of doing this until Aluminum. Early discovery of Iron can therefore can help civilizations with their research efforts as they attempt to gain an early technology lead.
Civilopedia Entry Edit
By mass the most common element on Earth, with an atomic number of 26, iron is fairly malleable under heat … and fairly useful. Iron beads dating to about 3500 BC have been found in the excavations at Gerzah, Egypt. Iron proved useful for all kinds of things needed by early civilizations: cooking pots, hinges, tools, and pointy weapons to stab other people with.
Iron belongs to the elements undoubtedly known to the ancient world. It has been worked, or wrought, for millennia. However, iron objects of great age are much rarer than objects made of gold or silver due to the ease with which iron corrodes.