Making up over a fifth of the earth’s crust, Iron is the 4th most common element that can be found in our planet's crust (the most common being oxygen, followed by silicon and then aluminium). Iron is found and mined from a number of rocks which can vary greatly in their iron content. These rocks are referred to as iron ore, and the iron inside is generally found in the form of Hematite, Magnetite, Goethite, Limonite or Siderite. Each one is comprised of different levels of iron as well as other elements and minerals, for example Hematite has a chemical symbol of Fe2O3, ‘Fe’ symbolising iron, and ‘O’ oxygen. From this we know that the ore is comprised of 2 elements and for every 2 iron atoms there is 3 Oxygen atoms, essentially it is 40% iron.
Having said that, melting iron was never the goal; all that was needed was a way to make it malleable, which can be done once it reaches 800oC. But a kiln offers an inhospitable environment to humans and to heat the iron in the kiln and then remove it to hammer would be an inefficient way to shape it as it would quickly cool down and harden once removed. The need for iron alternatives to bronze was becoming desperate, spurred on by a multitude of factors, such as a tin shortage epidemic that struck between 1500BC and 1300BC.
Fortunately methods of effective iron-working had been developed as early as 1800BC in the Indian Sub-Continent and these methods were being shared and quickly adapted elsewhere. By 1200BC, despite the shortage of bronze materials being resolved, iron implements were known to be stronger, harder, cheaper and lighter; as a result bronze materials never recovered their popularity and former wide-spread use.
The Iron Age symbolises the wide spread use of iron in agricultural, military and domestic settings. The iron used at the time was called Wrought Iron which, in itself, is not a pure iron as, in its purest form, iron is barely harder than its bronze counterparts. Wrought iron was created in a Smith’s forge and it was not made so much as it was shaped by the application of heat and hammer. During the heating process the iron would become soft and absorb some of the carbon which emanated from the forge’s charcoal fire, and though it would only make up 0.05% of the end result, the small amount of carbon would afford wrought iron a great deal more strength than it would otherwise have had.
The Iron Age would last well into the 8th Century, but its end did not mean the end of iron. After the Iron Age came the Medieval Period, also known as the Middle Ages, which was a time remembered for its social reforms, vast urban migrations and its Kings, Queens, Bishops and Popes. Basically it was not symbolised by the prevailing material in use at the time, so despite the end of its age, iron still made up the majority of the tools and weapons used, and continued to do for an additional 1000 years.
Those 1000 years saw great developments and improvements in iron manufacturing, such as the development of the blast furnace in the 12th century and the production of Cast Iron in the 15th century. Cast iron differed from wrought iron as the blast furnace would subject iron ore to the level of heat that would easily melt iron and allow carbon to be absorbed in abundance, to the point that carbon would make up anywhere between 2% and 4.5% of the final product. Cast Iron was an inappropriate material for weapons, as it was brittle and would shatter even under the force of a blacksmith’s hammer; instead it was used for domestic items, decorations and later in the manufacture of steam trains.