Occurring as an accessory in feldspathic granites,
Occurring as an accessory in feldspathic granites, it forms a solid solution series with ilmenite over 950ºC, and in other rocks its presence is an indicator of contact metamorphism. Forming from the oxidation of siderite, magnetite, or limonite, it binds the quartz grains together in red sandstones. The mining of its oolitic form is the basis of the economies of Birmingham and Pittsburgh. It is enriched by meteoric waters to a high-grade ore in the Lake Superior District of Minnesota, especially in the Mesabi Range. FTP, name this mineral with formula Fe2O3, the most important ore of iron.
Occurring as an accessory in feldspathic granites, it forms a solid solution series with ilmenite over 950ºC, and in other rocks its presence is an indicator of contact metamorphism.
{hematite}