Metallic Iron. Pure iron is a silver-gray metal with a high melting point and a density of 7.87 g/cm³. It is the second most abundant metal in Earth's crust, after aluminum, and is a major constituent of steel, which is an alloy of iron and carbon. Iron can be found in many forms and compounds and can be extracted from iron ore, which is a rock containing a high concentration of iron minerals such as hematite, magnetite, and limonite.