Iron ore is any rock that contains a usable quantity of iron. Common iron ore minerals include hematite, magnetite, limonite, and siderite. These are frequently found together. with assorted silicates. Although iron does not occur in its pure form in nature, some kinds of iron ore contain up to 70% iron atoms.
The key economic parameters for magnetite ore being economic are the crystallinity of the magnetite, the grade of the iron within the banded iron formation host rock, and the contaminant elements which exist within the magnetite concentrate.