Iron ores are rocks and minerals from which metallic iron can be extracted. There are four main types of iron ore deposit: massive hematite, which is the most commonly mined, magnetite, titanomagnetite, and pisolitic ironstone. These ores vary in colour from dark grey, bright yellow, or deep purple to rusty red. Iron is responsible for the red colour in many of our rocks and the deep red sands of the Australian deserts.