The Making of Iron & Steel
2020-8-3 · 2.1 Iron Ore Composition Iron very rarely occurs in the earth''s surface as a metal. It is widely distributed, combined with oxygen as iron oxides. In fact it is believed that iron makes up about 5% by weight of the earth''s crust. Geologists recognise various types of iron ore, classified chiefly according to iron (Fe) content (see Table 1 below).