The use of Iron is PreHistoric.  Genesis mentions Tubal-Cain, 7 generations descendant of Adam, was an "instructor of every artificer in brass and iron."

In AD 400, a tremendous iron pillar was constructed in Dehli, India that still stands today.  The pillar is one solid shaft of wrought iron 7 1/4 meters high and 40 cm in diameter.  Corrosion was minimal though exposed to weather.

Iron is very abundant in the universe, found in the sun and many types of stars in considerable quantity.

Iron is characterized by a stable nuclei.

Iron is the principle component of a class of meteorites known as 'siderites' and a minor constituent of two other classes.

The core of the earth, 2150 m in radius, is believed to be largely composed of iron.

4th most abundant element, by weight, composing the crust of the earth.

Most common iron ore is hematite (Fe₂O₃).  The metal is obtained by means of a reduction reaction with carbon.

Iron is found in widely distributed minerals such as magnetite, a black sand found on beaches and shores.

Common iron is a mixture of four isotopes.  Six isotopes are known to exist.

Iron is a vital component of plant and animal life, appearing, for instance, in hemoglobin.

Pure metal is rarely encountered in commerce; Iron is usually alloyed with carbon or other alloys for use as in structural components amongst a multitude of other applications and uses.  

Iron is very reactive chemically, corroding in the presence of moisture or air.

Pig Iron is composed of Iron and 3% carbon and varying amounts of S, Si, Mn, and P.  Pig Iron is hard, brittle, fairly fusible, and used to produce other alloys such as steel.

Wrought Iron contains a few tenths of a percent of carbon.  Wrought iron is tough, malleable, less fusible, and is characterized by a fibrous structure.

Carbon Steel is an alloy of carbon and iron, containing also small amounts of Mn, S, P, and Si.  Alloy Steels are Carbon Steels with other additives such as nickel, chromium, vanadium, etc.