Iron ore is any rock or mineral from which iron can economically be extracted. It comes in a variety of colors, including dark gray, bright yellow, deep purple, and rusty red. 

The iron comes in the form of iron oxides such as magnetite, hematite, limonite, goethite, or siderite. Economically viable forms of ore contain between 25% and 60% iron. In the old days of mining, some ores, known as "natural ores," had 66% iron and could be fed into iron-making blast furnaces directly.